Population studies of Glossina pallidipes in Ethiopia: emphasis on cuticular hydrocarbons and wing morphometric analysis.

Science.gov (United States)

Getahun, M N; Cecchi, G; Seyoum, E

2014-10-01

Tsetse flies, like many insects, use pheromones for inter- and intra-specific communication. Several of their pheromones are cuticular hydrocarbons (CHCs) that are perceived by contact at close range. We hypothesized that for a successful implementation of the Sterile Insect Technique (SIT), along with proper identification of target area and target species, the target tsetse populations and the sterile flies must chemically communicate with each other. To study the population structuring of Glossina pallidipes in Ethiopia, CHCs were extracted and analyzed from three tsetse belts. As a comparative approach, wing morphometric analysis was performed. The analysis of the relative abundance of CHCs revealed that populations of G. pallidipes from the Rift Valley tsetse belt showed a distinct clustering compared to populations from the other two belts. The spatial pattern of CHC differences was complemented by the wing morphometric analysis. Our data suggest that CHCs of known biological and ecological role, when combined with wing morphometric data, will provide an alternative means for the study of population structuring of Glossina populations. This could aid the planning of area wide control strategies using SIT, which is dependent on sexual competence. Copyright © 2014 International Atomic Energy Agency 2014. Published by Elsevier B.V. All rights reserved.

Genome sequence of the tsetse fly (Glossina morsitans ): Vector of African trypanosomiasis

KAUST Repository

Watanabe, Junichi

2014-04-24

Tsetse flies are the sole vectors of human African trypanosomiasis throughout sub-Saharan Africa. Both sexes of adult tsetse feed exclusively on blood and contribute to disease transmission. Notable differences between tsetse and other disease vectors include obligate microbial symbioses, viviparous reproduction, and lactation. Here, we describe the sequence and annotation of the 366-megabase Glossina morsitans morsitans genome. Analysis of the genome and the 12,308 predicted protein-encoding genes led to multiple discoveries, including chromosomal integrations of bacterial (Wolbachia) genome sequences, a family of lactation-specific proteins, reduced complement of host pathogen recognition proteins, and reduced olfaction/chemosensory associated genes. These genome data provide a foundation for research into trypanosomiasis prevention and yield important insights with broad implications for multiple aspects of tsetse biology.

Genome sequence of the tsetse fly (Glossina morsitans ): Vector of African trypanosomiasis

KAUST Repository

Watanabe, Junichi; Hattori, Masahira; Berriman, Matthew; Lehane, Michael J.; Hall, Neil; Solano, Philippe; Aksoy, Serap; Hide, Winston; Touré , Yé ya Tié moko; Attardo, Geoffrey M.; Darby, Alistair Charles; Toyoda, Atsushi; Hertz-Fowler, Christiane; Larkin, Denis M.; Cotton, James A.; Sanders, Mandy J.; Swain, Martin T.; Quail, Michael A.; Inoue, Noboru; Ravel, Sophie; Taylor, Todd Duane; Srivastava, Tulika P.; Sharma, Vineet Kumar; Warren, Wesley C.; Wilson, Richard K.; Suzuki, Yutaka; Lawson, Daniel; Hughes, Daniel Seth Toney; Megy, Karyn; Masiga, Daniel K.; Mireji, Paul Odhiambo; Hansen, Immo Alex; Van Den Abbeele, Jan; Benoit, Joshua B.; Bourtzis, Kostas; Obiero, George F O; Robertson, Hugh M.; Jones, Jeffery W.; Zhou, Jingjiang; Field, Linda M.; Friedrich, Markus; Nyanjom, Steven R G; Telleria, Erich Loza; Caljon, Guy; Ribeiro, José M. C.; Acosta-Serrano, Alvaro; Ooi, Cherpheng; Rose, Clair; Price, David P.; Haines, Lee Rafuse; Christoffels, Alan G.; Sim, Cheolho; Pham, Daphne Q D; Denlinger, David L.; Geiser, Dawn L.; Omedo, Irene A.; Winzerling, Joy J.; Peyton, Justin T.; Marucha, Kevin K.; Jonas, Mario; Meuti, Megan E.; Rawlings, Neil David; Zhang, Qirui; Macharia, Rosaline Wanjiru; Michalkova, Veronika; Dashti, Zahra Jalali Sefid; Baumann, Aaron A.; Gä de, Gerd; Marco, Heather G.; Caers, Jelle; Schoofs, Liliane; Riehle, Michael A.; Hu, Wanqi; Tu, Zhijian; Tarone, Aaron M.; Malacrida, Anna Rodolfa; Kibet, Caleb K.; Scolari, Francesca; Koekemoer, J. J. O.; Willis, Judith H.; Gomulski, Ludvik M.; Falchetto, Marco; Scott, Maxwell J.; Fu, Shuhua; Sze, Singhoi; Luiz, Thiago; Weiss, Brian L.; Walshe, Deirdre P.; Wang, Jingwen; Wamalwa, Mark; Mwangi, Sarah; Ramphul, Urvashi N.; Snyder, Anna K.; Brelsfoard, Corey L.; Thomas, Gavin H.; Tsiamis, George; Arensburger, Peter; Rio, Rita V M; Macdonald, Sandy J.; Panji, Sumir; Kruger, Adele F.; Benkahla, Alia; Balyeidhusa, Apollo Simon Peter; Msangi, Atway R.; Okoro, Chinyere K.; Stephens, Dawn; Stanley, Eleanor J.; Mpondo, Feziwe; Wamwiri, Florence N.; Mramba, Furaha; Siwo, Geoffrey H.; Githinji, George; Harkins, Gordon William; Murilla, Grace Adira; Lehvä slaiho, Heikki; Malele, Imna I.; Auma, Joanna Eseri; Kinyua, Johnson K.; Ouma, Johnson O.; Okedi, Loyce M A; Manga, Lucien; Aslett, Martin A.; Koffi, Mathurin; Gaunt, Michael W.; Makgamathe, Mmule; Mulder, Nicola Jane; Manangwa, Oliver; Abila, Patrick P.; Wincker, Patrick; Gregory, Richard I.; Bateta, Rosemary; Sakate, Ryuichi; Ommeh, Sheila; Lehane, Stella M.; Imanishi, Tadashi; Osamor, Victor Chukwudi; Kawahara, Yoshihiro

2014-01-01

Tsetse flies are the sole vectors of human African trypanosomiasis throughout sub-Saharan Africa. Both sexes of adult tsetse feed exclusively on blood and contribute to disease transmission. Notable differences between tsetse and other disease vectors include obligate microbial symbioses, viviparous reproduction, and lactation. Here, we describe the sequence and annotation of the 366-megabase Glossina morsitans morsitans genome. Analysis of the genome and the 12,308 predicted protein-encoding genes led to multiple discoveries, including chromosomal integrations of bacterial (Wolbachia) genome sequences, a family of lactation-specific proteins, reduced complement of host pathogen recognition proteins, and reduced olfaction/chemosensory associated genes. These genome data provide a foundation for research into trypanosomiasis prevention and yield important insights with broad implications for multiple aspects of tsetse biology.

The population structure of Glossina fuscipes fuscipes in the Lake Victoria basin in Uganda: implications for vector control

OpenAIRE

Hyseni, Chaz; Kato, Agapitus B; Okedi, Loyce M; Masembe, Charles; Ouma, Johnson O; Aksoy, Serap; Caccone, Adalgisa

2012-01-01

Abstract Background Glossina fuscipes fuscipes is the primary vector of trypanosomiasis in humans and livestock in Uganda. The Lake Victoria basin has been targeted for tsetse eradication using a rolling carpet initiative, from west to east, with four operational blocks (3 in Uganda and 1 in Kenya), under a Pan-African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC). We screened tsetse flies from the three Ugandan PATTEC blocks for genetic diversity at 15 microsatellite loci from con...

Genetically Distinct Glossina fuscipes fuscipes Populations in the Lake Kyoga Region of Uganda and Its Relevance for Human African Trypanosomiasis

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Richard Echodu

2013-01-01

Full Text Available Tsetse flies (Glossina spp. are the sole vectors of Trypanosoma brucei—the agent of human (HAT and animal (AAT trypanosomiasis. Glossina fuscipes fuscipes (Gff is the main vector species in Uganda—the only country where the two forms of HAT disease (rhodesiense and gambiense occur, with gambiense limited to the northwest. Gff populations cluster in three genetically distinct groups in northern, southern, and western Uganda, respectively, with a contact zone present in central Uganda. Understanding the dynamics of this contact zone is epidemiologically important as the merger of the two diseases is a major health concern. We used mitochondrial and microsatellite DNA data from Gff samples in the contact zone to understand its spatial extent and temporal stability. We show that this zone is relatively narrow, extending through central Uganda along major rivers with south to north introgression but displaying no sex-biased dispersal. Lack of obvious vicariant barriers suggests that either environmental conditions or reciprocal competitive exclusion could explain the patterns of genetic differentiation observed. Lack of admixture between northern and southern populations may prevent the sympatry of the two forms of HAT disease, although continued control efforts are needed to prevent the recolonization of tsetse-free regions by neighboring populations.

Macrogeographic population structure of the tsetse fly, Glossina pallidipes (Diptera: Glossinidae)

International Nuclear Information System (INIS)

Ouma, J.O.; Marquez, J.G.; Krafsur, E.S

2005-01-01

Tsetse flies are confined to sub-Saharan Africa where they occupy discontinuous habitats. In anticipation of area-wide control programmes, estimates of gene flow among tsetse populations are necessary. Genetic diversities were partitioned at eight microsatellite loci and five mitochondrial loci in 21 Glossina pallidipes Austin populations. At microsatellite loci, Nei's unbiased gene diversity averaged over loci was 0.659 and the total number of alleles was 214, only four of which were shared among all populations. The mean number of alleles per locus was 26.8. Random mating was observed within but not among populations (fixation index FST=0.18) and 81% of the genetic variance was within populations. Thirty-nine mitochondrial variants were detected. Mitochondrial diversities in populations varied from 0 to 0.85 and averaged 0.42, and FST=0.51. High levels of genetic differentiation were characteristic, extending even to subpopulations separated by tens and hundreds of kilometres, and indicating low rates of gene flow. (author)

Labelling of the tsetse fly Glossina palpalis palpalis by activable elements

International Nuclear Information System (INIS)

Hamann, H.J.; Iwannek, K.H.

1979-01-01

Tsetse flies of the species Glossina palpalis palpalis Rob. Desv. were subjected to various treatments with an aim of achieving labelling with the activable stable elements dysprosium, europium or lanthanum. The substances were injected as chlorides or nitrates, they were added to the food of the flies or applied externally to pupae or adults by dipping, or by spraying with the solutions. Feeding with the labelling substance was in principle the easiest method to handle a large number of flies. Only lanthanum salts have been tested so far and it was found that they were excreted relatively fast. They gave detectable labelling for 4 days after application only. The spraying of adults with lanthanum-containing aerosols was a technique which could be used on a mass-production scale. A fairly homogeneous degree of labelling was achieved, which was so high that during mating a clearly measurable amount of lanthanum was transferred from the labelled male to the female. (Auth.)

Flight Muscle Development in the Males of Glossina Pallidipes Reared for the Sterile Insect Technique

Energy Technology Data Exchange (ETDEWEB)

Ciampor, F Jr; Palosova, Z; Mancosova, L; Takac, P [Institute of Zoology, Slovak Academy of Sciences, Bratislava, SK-845 06 (Slovakia)

2012-07-15

The project's main goal was to study the influence of laboratory conditions on the development of flight muscles and the ability to fly in males of Glossina pallidipes Austen. Flight muscles can serve as an important criterion in the quality control of mass reared tsetse flies. All experiments were performed in the research and training facility in Bratislava which provided the flies. The experiments were generally performed by comparing different age groups and groups with different flight activity. To acquire data, several approaches were employed, i.e. classical measurements (residual dry weight, thoracic surface) as well as other alternatives - flight mill, electron microscopy and immunohistochemistry - to visualize and analyse muscle development. The results clearly identified differences in age groups. Slight changes in the development of flight muscles regarding different chances to fly were also detected, but these were not sufficiently significant to decrease the quality of males produced in mass rearing facilities. No distinct trends (rising or declining of amount of metabolites) in the groups studied were detected. The differences were in the amount of analysed metabolic components and the structure of the flight muscles. Our results suggest that, similar to other Glossina species, in G. pallidipes males the first days after emergence are crucial for successful muscle development. On the other hand, rearing in cages does not negatively influence the quality of males with respect to their ability to fly and actively search for females in the wild after release. We also compared the mating behaviour of irradiated and non-irradiated males. We initiated the development of a functional walk-in field cage in which to rear a small colony of G. pallidipes under semi-natural conditions. Our work suggested that outside climatic conditions and suitable cage components, e.g. food source, limit the successful realization of using such a cage for rearing tsetse flies

Variations in the Peritrophic Matrix Composition of Heparan Sulphate from the Tsetse Fly, Glossina morsitans morsitans

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Evelyn Rogerson

2018-03-01

Full Text Available Tsetse flies are the principal insect vectors of African trypanosomes—sleeping sickness in humans and Nagana in cattle. One of the tsetse fly species, Glossina morsitans morsitans, is host to the parasite, Trypanosoma brucei, a major cause of African trypanosomiasis. Precise details of the life cycle have yet to be established, but the parasite life cycle involves crossing the insect peritrophic matrix (PM. The PM consists of the polysaccharide chitin, several hundred proteins, and both glycosamino- and galactosaminoglycan (GAG polysaccharides. Owing to the technical challenges of detecting small amounts of GAG polysaccharides, their conclusive identification and composition have not been possible until now. Following removal of PMs from the insects and the application of heparinases (bacterial lyase enzymes that are specific for heparan sulphate (HS GAG polysaccharides, dot blots with a HS-specific antibody showed heparan sulphate proteoglycans (HSPGs to be present, consistent with Glossina morsitans morsitans genome analysis, as well as the likely expression of the HSPGs syndecan and perlecan. Exhaustive HS digestion with heparinases, fluorescent labeling of the resulting disaccharides with BODIPY fluorophore, and separation by strong anion exchange chromatography then demonstrated the presence of HS for the first time and provided the disaccharide composition. There were no significant differences in the type of disaccharide species present between genders or between ages (24 vs. 48 h post emergence, although the HS from female flies was more heavily sulphated overall. Significant differences, which may relate to differences in infection between genders or ages, were evident, however, in overall levels of 2-O-sulphation between sexes and, for females, between 24 and 48 h post-emergence, implying a change in expression or activity for the 2-O-sulphotransferase enzyme. The presence of significant quantities of disaccharides containing the

Effects of gamma irradiation on the midgut ultrastructure of Glossina palpalis subspecies

International Nuclear Information System (INIS)

Stiles, J.K.; Molyneux, D.H.; Wallbanks, K.R.; Van der Vloedt, A.M.

1989-01-01

In the sterile insect technique, insects are sterilized prior to release in areas where they are pests. The sterile males compete for and with fertile wild individuals for mates, thus reducing the population's reproductive rate. Tsetse fly (Glossina spp.) populations have been eradicated after release of laboratory-bred flies sterilized by gamma irradiation. However, no studies exist on radiation-induced damage to the midgut morphology and function of the radiation-sterilized insects. After G. palpalis palpalis and G. p. gambiensis were subjected to 130 Gy gamma radiation, their midgut damage and recovery were monitored by electron microscopy. The first sign of damage was atrophy and loss of the microvillous border from epithelial cells. The rate of cell degeneration increased, with young as well as old cells being affected and cellular debris filling the ectoperitrophic space. Muscle cells were destroyed, patches of basal lamina were left bare, intracellular virus- and rickettsia-like organisms became more frequent, and many replacement cells became unusually large. Partial recovery occurred from the 10th day postirradiation. Such changes in midgut ultrastructure and the corresponding inhibition of functions may increase the susceptibility of the fly to trypanosome infection

Multiple Trypanosoma infections are common amongst Glossina species in the new farming areas of Rufiji district, Tanzania

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Malele Imna I

2011-11-01

Full Text Available Abstract Background Tsetse flies and trypanosomiasis are among several factors that constrain livestock development in Tanzania. Over the years Rufiji District was excluded from livestock production owing to tsetse fly infestation, however, a few years ago there was an influx of livestock following evictions aimed at conserving the Usangu wetlands. Methods A study was conducted to determine the efficiency of available traps for catching tsetse flies, Glossina species infesting the area, their infection rates and Trypanosoma species circulating in the area. Trapping was conducted during the semi dry season for a total of 30 days (ten days each month during the onset of the dry season of May - July 2009. Harvested flies after every 24 hours were dissected and examined under a light microscope for trypanosome infections and whole fly DNA was extracted from 82 flies and analyzed for trypanosomes by polymerase chain reaction (PCR using different sets of primers. Results The proportions of total tsetse catches per trap were in the following decreasing order S3 (33%, H-Trap (27%, Pyramidal (19%, sticky panel (11% and biconical trap (10%. Of the 1200 trapped flies, 75.6% were identified as Glossina pallidipes, 11.7% as G. brevipalpis, 9.6% as G. austeni and 3.0% G. morsitans morsitans. Dissections revealed the overall infection rate of 6.6% (13/197. Whole DNA was extracted from 82 tsetse flies and the prevalence of trypanosomes circulating in the area in descending order was 92.7% (76/82 for T. simiae; 70.7% (58/82 for T. brucei types; 48.8% (40/82 for the T. vivax types and 32.9% (27/82 for the T. congolense types as determined by PCR. All trypanosome types were found in all tsetse species analysed except for the T. congolense types, which were absent in G. m. morsitans. None of the T. brucei positive samples contained human infective trypanosomes by SRA - PCR test Conclusion All tsetse species found in Rufiji are biologically important in the

Recent advances in the rearing of Glossina pallidipes Austen

International Nuclear Information System (INIS)

Leegwater-Van der Linden, M.E.

1980-01-01

The rearing technique of Glossina pallidipes Austen in Amsterdam is described. The flies are kept at 25 0 C, 80% relative humidity in very dim light which operates 12 hours a day. Flies are fed on ears of lop-eared rabbits inside the colony room. Nine-day-old females are massmated with an equal number of 12-day-old males for approximately three days. Mated females are kept without males. Under these circumstances the interlarval period is nine years. The first larva is deposited on the 20th day after emergence and the mean longevity hereafter is 60 days average or 101 days with individual attention. Productivity has been observed from 1977 onward. The insemination rate gradually increased from 66 to 97%, and fecundity from about 0.5 to 0.8. Premating deaths remained at a level of 4%. The eclosion rate was 92% and pupal weight 39 mg. In the Amsterdam practice these figures imply that nearly one third of the weekly pupal production is needed to maintain the colony at a set number. The remainder can be used for other purposes. Judging from observations and experience it seems that prevention of chemical contamination and any disturbance, mass-mating at the appropriate time and a very high humidity are relevant points in the various techniques used in rearing G. pallidipes. Attention is now being given to the viability of the colony in Amsterdam for eradicating G. pallidipes in East Africa. Females emerging from pupae sent from a test area near Tanga, Tanzania, were readily inseminated by males from the Amsterdam colony, indicating the possibility of using the sterile male technique for reduction of G. pallidipes in East Africa. (author)

Mating performance of Glossina palpalis gambiensis strains from Burkina Faso, Mali, and Senegal

International Nuclear Information System (INIS)

Mutika, Gratian N.; Kabore, Idrissa; Parker, Andrew G.; Vreysen, Marc J.B.; Seck, Momar T.; Sall, Baba; Bouyer, Jeremy

2012-01-01

The mating performance of Glossina palpalis gambiensis Vanderplank (Diptera: Glossinidae) mass- reared in Burkina Faso (BKF strain) was compared with that of target populations originating from the Bamako peri-urban area of the Niger River Basin, Mali (MLI strain) and the Niayes area, Senegal (SEN strain). The tests were carried out using a field cage either set up outdoors in Burkina Faso or inside the laboratory in Austria. The target population strains(MLI and SEN) were a few generations from the wild whereas the laboratory-reared flies (BKF) were adapted to laboratory rearing over many generations. The laboratory-reared BKF strain significantly out-competed the MLI strain in the mating tests, but showed close to equal competitiveness with the SEN strain. At least one-third of possible matings occurred during each observation period. The females from the two target populations readily mated with males from the BKF strain. The selected mating parameters and behaviour in the cage showed that there was mating compatibility between the strains and this absence of obvious mating barriers indicates the potential of using BKF strain males in programmes that have a sterile insect technique (SIT) component targeting the two G.p.gambiensis populations of Mali and Senegal.

Peptidomics of Neuropeptidergic Tissues of the Tsetse Fly Glossina morsitans morsitans

Science.gov (United States)

Caers, Jelle; Boonen, Kurt; Van Den Abbeele, Jan; Van Rompay, Liesbeth; Schoofs, Liliane; Van Hiel, Matthias B.

2015-12-01

Neuropeptides and peptide hormones are essential signaling molecules that regulate nearly all physiological processes. The recent release of the tsetse fly genome allowed the construction of a detailed in silico neuropeptide database (International Glossina Genome Consortium, Science 344, 380-386 (2014)), as well as an in-depth mass spectrometric analysis of the most important neuropeptidergic tissues of this medically and economically important insect species. Mass spectrometric confirmation of predicted peptides is a vital step in the functional characterization of neuropeptides, as in vivo peptides can be modified, cleaved, or even mispredicted. Using a nanoscale reversed phase liquid chromatography coupled to a Q Exactive Orbitrap mass spectrometer, we detected 51 putative bioactive neuropeptides encoded by 19 precursors: adipokinetic hormone (AKH) I and II, allatostatin A and B, capability/pyrokinin (capa/PK), corazonin, calcitonin-like diuretic hormone (CT/DH), FMRFamide, hugin, leucokinin, myosuppressin, natalisin, neuropeptide-like precursor (NPLP) 1, orcokinin, pigment dispersing factor (PDF), RYamide, SIFamide, short neuropeptide F (sNPF) and tachykinin. In addition, propeptides, truncated and spacer peptides derived from seven additional precursors were found, and include the precursors of allatostatin C, crustacean cardioactive peptide, corticotropin releasing factor-like diuretic hormone (CRF/DH), ecdysis triggering hormone (ETH), ion transport peptide (ITP), neuropeptide F, and proctolin, respectively. The majority of the identified neuropeptides are present in the central nervous system, with only a limited number of peptides in the corpora cardiaca-corpora allata and midgut. Owing to the large number of identified peptides, this study can be used as a reference for comparative studies in other insects.

Population genetics of Glossina palpalis palpalis from central African sleeping sickness foci

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Solano Philippe

2011-07-01

Full Text Available Abstract Background Glossina palpalis palpalis (Diptera: Glossinidae is widespread in west Africa, and is the main vector of sleeping sickness in Cameroon as well as in the Bas Congo Province of the Democratic Republic of Congo. However, little is known on the structure of its populations. We investigated G. p. palpalis population genetic structure in five sleeping sickness foci (four in Cameroon, one in Democratic Republic of Congo using eight microsatellite DNA markers. Results A strong isolation by distance explains most of the population structure observed in our sampling sites of Cameroon and DRC. The populations here are composed of panmictic subpopulations occupying fairly wide zones with a very strong isolation by distance. Effective population sizes are probably between 20 and 300 individuals and if we assume densities between 120 and 2000 individuals per km2, dispersal distance between reproducing adults and their parents extends between 60 and 300 meters. Conclusions This first investigation of population genetic structure of G. p. palpalis in Central Africa has evidenced random mating subpopulations over fairly large areas and is thus at variance with that found in West African populations of G. p. palpalis. This study brings new information on the isolation by distance at a macrogeographic scale which in turn brings useful information on how to organise regional tsetse control. Future investigations should be directed at temporal sampling to have more accurate measures of demographic parameters in order to help vector control decision.

Advancements in bait technology to control Glossina swynnertoni Austen, the species of limited distribution in Kenya and Tanzania border: A review.

Science.gov (United States)

Nagagi, Yakob P; Silayo, Richard S; Kweka, Eliningaya J

2017-01-01

Glossina swynnertoni is a savannah tsetse that is largely confined to the Serengeti-Mara [a very small part of East Africa covering northern Tanzania (Arusha and Manyara regions and parts of Shinyanga and Mara regions) extending Maasai Mara ecosystem in southwestern Kenya]. Nevertheless, it is of great concern to human and animal health and is one of the top target tsetse species for eradication. To achieve this eradication objective, it is important to know about its behaviour so that the appropriate tools/measures especially the right traps can be applied against it. In this paper G. swynnertoni is reviewed in terms of its behaviour, and development of traps for its survey and control. Glossina swynnertoni control is of paramount importance in Tanzania tourism industry and country's income. Since, G. swynnertoni is also distributed in national parks, control is vital as it might reduce tourists excursion/movement, by transmitting the African trypanosomiasis among travelers. Different literature search engines such as Google Scholar and PubMed were deployed for literature search. It was found that the behaviour of G. swynnertoni is relatively similar but unique from other tsetse flies. Its feeding cycle is 2½-3 days as opposed to 3-4 days observed in other tsetse species. The flight activity pattern varied between sex, with male having their peak at 1100-1200 hrs and females 1400-1600 hrs. The activity in both sexes decline rapidly towards the dusk (1700-1800 hrs). It was further that host odours, relatively smaller and vertically oriented devices, as well as host movement are the main attractive factors to this tsetse species, which can be exploited to design efficient artificial devices for control of G. swynnertoni . Therefore, due to its restricted distribution and threat it poses on tourism industry, deliberate efforts need to be made against G. swynnertoni as a next candidate to be eradicated using artificial bait technology.

Role of adult fat body and milk gland in larval nourishment of Glossina morsitans

International Nuclear Information System (INIS)

Langley, P.A.; Bursell, E.

1980-01-01

The Glossina larva is nourished entirely in utero by 'milk' composed of equal parts lipid and protein or protein-derivatives, produced by the adult female accessory gland or milk gland. A series of experiments in which activities of the female fat body and milk gland were studied separately, showed that during early pregnancy fat body synthesized and stored triglyceride and, to a lesser extent, protein, utilizing either 14 C leucine or 14 C palmitate in the process. Late in the pregnancy cycle, synthetic activity of the fat body was reduced whereas that of the milk gland increased, both lipid and protein synthesis being conspicuous at this time. There was apparently a switch in mid-pregnancy at which time the milk gland became the dominant organ for synthesis of nutrient substances. Results support the hypothesis that the adult fat body provides the major store, derived from blood meals ingested during early pregnancy, from which the milk gland obtains the lipid component of the milk. The gland itself synthesizes the bulk of the protein components from digested blood meals ingested during the latter half of pregnancy. Control of the processes identified, and their cyclical nature, suggests a neuroendocrine involvement. Identification of this involvement, and the underlying control mechanisms for hormone synthesis and degradation, may well lead to more specific methods of vector control acting through disruption of larval nutrition. (author)

Laboratory colonisation and genetic bottlenecks in the tsetse fly Glossina pallidipes.

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Marc Ciosi

2014-02-01

Full Text Available The IAEA colony is the only one available for mass rearing of Glossina pallidipes, a vector of human and animal African trypanosomiasis in eastern Africa. This colony is the source for Sterile Insect Technique (SIT programs in East Africa. The source population of this colony is unclear and its genetic diversity has not previously been evaluated and compared to field populations.We examined the genetic variation within and between the IAEA colony and its potential source populations in north Zimbabwe and the Kenya/Uganda border at 9 microsatellites loci to retrace the demographic history of the IAEA colony. We performed classical population genetics analyses and also combined historical and genetic data in a quantitative analysis using Approximate Bayesian Computation (ABC. There is no evidence of introgression from the north Zimbabwean population into the IAEA colony. Moreover, the ABC analyses revealed that the foundation and establishment of the colony was associated with a genetic bottleneck that has resulted in a loss of 35.7% of alleles and 54% of expected heterozygosity compared to its source population. Also, we show that tsetse control carried out in the 1990's is likely reduced the effective population size of the Kenya/Uganda border population.All the analyses indicate that the area of origin of the IAEA colony is the Kenya/Uganda border and that a genetic bottleneck was associated with the foundation and establishment of the colony. Genetic diversity associated with traits that are important for SIT may potentially have been lost during this genetic bottleneck which could lead to a suboptimal competitiveness of the colony males in the field. The genetic diversity of the colony is lower than that of field populations and so, studies using colony flies should be interpreted with caution when drawing general conclusions about G. pallidipes biology.

Odorant and gustatory receptors in the tsetse fly Glossina morsitans morsitans.

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George F O Obiero

2014-04-01

Full Text Available Tsetse flies use olfactory and gustatory responses, through odorant and gustatory receptors (ORs and GRs, to interact with their environment. Glossina morsitans morsitans genome ORs and GRs were annotated using homologs of these genes in Drosophila melanogaster and an ab initio approach based on OR and GR specific motifs in G. m. morsitans gene models coupled to gene ontology (GO. Phylogenetic relationships among the ORs or GRs and the homologs were determined using Maximum Likelihood estimates. Relative expression levels among the G. m. morsitans ORs or GRs were established using RNA-seq data derived from adult female fly. Overall, 46 and 14 putative G. m. morsitans ORs and GRs respectively were recovered. These were reduced by 12 and 59 ORs and GRs respectively compared to D. melanogaster. Six of the ORs were homologous to a single D. melanogaster OR (DmOr67d associated with mating deterrence in females. Sweet taste GRs, present in all the other Diptera, were not recovered in G. m. morsitans. The GRs associated with detection of CO2 were conserved in G. m. morsitans relative to D. melanogaster. RNA-sequence data analysis revealed expression of GmmOR15 locus represented over 90% of expression profiles for the ORs. The G. m. morsitans ORs or GRs were phylogenetically closer to those in D. melanogaster than to other insects assessed. We found the chemoreceptor repertoire in G. m. morsitans smaller than other Diptera, and we postulate that this may be related to the restricted diet of blood-meal for both sexes of tsetse flies. However, the clade of some specific receptors has been expanded, indicative of their potential importance in chemoreception in the tsetse.

Population dynamics of Glossina fuscipes fuscipes on Buvuma Island, Lake Victoria, Uganda

International Nuclear Information System (INIS)

Ogwal, L.M.; Kangwagye, T.N.

1990-01-01

A survey made of Buvuma Island to establish the incidence, distribution and population dynamics of tsetse flies showed that Glossina fuscipes fuscipes Newstead was the most abundant species. This species occurred in the southeastern, western and northern parts of the island. Although the fly is both riverine and peridomestic in its habits, the survey revealed that its population was concentrated mainly within a distance of about 2 km from the lake shores around houses, in banana plantations, at forest edges and roadsides, in fishing villages and ports of call, on grazing grounds and at water collection points. Studies of the population dynamics revealed seasonal variations in the abundance of the species, with a peak during the main dry season, i.e. in the months of January and February. The breeding peak was reached during the minor rainy season. Trap catches were highest in fishing villages and ports of call, followed in decreasing order by catches at forest edge and roadside locations, at water collection points, around houses, in banana plantations and on grazing grounds. It appears that the fishing villages and ports of call were possibly the most suitable breeding grounds. The efficiency of the traps was reflected in the fact that G. f. fuscipes populations were reduced by up to 95% in Tome and 90% in the Bulopa-Walwanda and Lwenyanja villages. Many puparia were also found on the sandy beaches around fishing villages and ports of call. There was evidence of fly movement between the islands and the mainland, indicating that, although geographically isolated, Buvuma Island is not isolated from the mainland in terms of tsetse fly movement. (author). 21 refs, 5 figs, 1 tab

Tsetse flies, biodiversity and the control of sleeping sickness. Structure of a Glossina guild in southwest Côte d'Ivoire

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Gouteux, Jean-Paul; Jarry, Marc

1998-10-01

Tsetse fly guilds usually comprise two or three species. However, the presence of only one species often indicates that anthropic modifications have occurred in the habitat. On the other hand, more than three species are seldom observed in the same zone and the presence of five is extremely rare. Previous detailed studies have always focused on a single species, without taking into account interactions between species. The authors present the results of observations carried out in Côte d'Ivoire on a guild consisting of Glossina palpalis, G. pallicera, G. nigrofusca, G. longipalpis and G. fusca. Glossina have unusual physiological characteristics: both sexes feed exclusively on blood, they have a highly developed larviparity associated with a slow rhythm of reproduction (one larva about every ten days) and a long life expectancy (up to nine months). The authors report on the size of the flies, the hosts, feeding habits, ecodistribution, resting-places, flying heights, circadian activity and seasonal dynamics of tsetse fly populations in order to understand the organization of this guild. Each species feeds indiscriminately on a wide spectrum of hosts without a particular preference. Different species shared habitat (ecodistribution) and time (circadian and annual cycles). Thus, during an annual cycle, there is always a slight time-lag between the density peaks of G. palpalis and G. pallicera, the peak of the dominant species immediately preceding that of the dominated species. In a village area, 77% of the variations in density of G. pallicera were accounted for by the previous variations in density of the dominant species ( G. palpalis). Experiments show that G. pallicera and G. nigrofusca immediately invade anthropic areas from which G. palpalis has been partially removed by trapping. These species thus appear to confront each other in a global dynamic equilibrium. This suggests that there is a 'conflicting coexistence' between the cohabiting species. Whereas the

Glossina palpalis palpalis populations from Equatorial Guinea belong to distinct allopatric clades.

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Cordon-Obras, Carlos; Cano, Jorge; Knapp, Jenny; Nebreda, Paloma; Ndong-Mabale, Nicolas; Ncogo-Ada, Policarpo Ricardo; Ndongo-Asumu, Pedro; Navarro, Miguel; Pinto, Joao; Benito, Agustin; Bart, Jean-Mathieu

2014-01-17

Luba is one of the four historical foci of Human African Trypanosomiasis (HAT) on Bioko Island, in Equatorial Guinea. Although no human cases have been detected since 1995, T. b. gambiense was recently observed in the vector Glossina palpalis palpalis. The existence of cryptic species within this vector taxon has been previously suggested, although no data are available regarding the evolutionary history of tsetse flies populations in Bioko. A phylogenetic analysis of 60 G. p. palpalis from Luba was performed sequencing three mitochondrial (COI, ND2 and 16S) and one nuclear (rDNA-ITS1) DNA markers. Phylogeny reconstruction was performed by Distance Based, Maximum Likelihood and Bayesian Inference methods. The COI and ND2 mitochondrial genes were concatenated and revealed 10 closely related haplotypes with a dominant one found in 61.1% of the flies. The sequence homology of the other 9 haplotypes compared to the former ranged from 99.6 to 99.9%. Phylogenetic analysis clearly clustered all island samples with flies coming from the Western African Clade (WAC), and separated from the flies belonging to the Central Africa Clade (CAC), including samples from Mbini and Kogo, two foci of mainland Equatorial Guinea. Consistent with mitochondrial data, analysis of the microsatellite motif present in the ITS1 sequence exhibited two closely related genotypes, clearly divergent from the genotypes previously identified in Mbini and Kogo. We report herein that tsetse flies populations circulating in Equatorial Guinea are composed of two allopatric subspecies, one insular and the other continental. The presence of these two G. p. palpalis cryptic taxa in Equatorial Guinea should be taken into account to accurately manage vector control strategy, in a country where trypanosomiasis transmission is controlled but not definitively eliminated yet.

Patterns of Genome-Wide Variation in Glossina fuscipes fuscipes Tsetse Flies from Uganda

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Andrea Gloria-Soria

2016-06-01

Full Text Available The tsetse fly Glossina fuscipes fuscipes (Gff is the insect vector of the two forms of Human African Trypanosomiasis (HAT that exist in Uganda. Understanding Gff population dynamics, and the underlying genetics of epidemiologically relevant phenotypes is key to reducing disease transmission. Using ddRAD sequence technology, complemented with whole-genome sequencing, we developed a panel of ∼73,000 single-nucleotide polymorphisms (SNPs distributed across the Gff genome that can be used for population genomics and to perform genome-wide-association studies. We used these markers to estimate genomic patterns of linkage disequilibrium (LD in Gff, and used the information, in combination with outlier-locus detection tests, to identify candidate regions of the genome under selection. LD in individual populations decays to half of its maximum value (r2max/2 between 1359 and 2429 bp. The overall LD estimated for the species reaches r2max/2 at 708 bp, an order of magnitude slower than in Drosophila. Using 53 infected (Trypanosoma spp. and uninfected flies from four genetically distinct Ugandan populations adapted to different environmental conditions, we were able to identify SNPs associated with the infection status of the fly and local environmental adaptation. The extent of LD in Gff likely facilitated the detection of loci under selection, despite the small sample size. Furthermore, it is probable that LD in the regions identified is much higher than the average genomic LD due to strong selection. Our results show that even modest sample sizes can reveal significant genetic associations in this species, which has implications for future studies given the difficulties of collecting field specimens with contrasting phenotypes for association analysis.

The population structure of Glossina palpalis gambiensis from island and continental locations in Coastal Guinea.

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Philippe Solano

Full Text Available We undertook a population genetics analysis of the tsetse fly Glossina palpalis gambiensis, a major vector of sleeping sickness in West Africa, using microsatellite and mitochondrial DNA markers. Our aims were to estimate effective population size and the degree of isolation between coastal sites on the mainland of Guinea and Loos Islands. The sampling locations encompassed Dubréka, the area with the highest Human African Trypanosomosis (HAT prevalence in West Africa, mangrove and savannah sites on the mainland, and two islands, Fotoba and Kassa, within the Loos archipelago. These data are discussed with respect to the feasibility and sustainability of control strategies in those sites currently experiencing, or at risk of, sleeping sickness.We found very low migration rates between sites except between those sampled around the Dubréka area that seems to contain a widely dispersed and panmictic population. In the Kassa island samples, various effective population size estimates all converged on surprisingly small values (10

[Ecology of Glossina palpalis VANDERPLANK, 1949 (Diptera: Glossinidae) in mangrove area of Guinea: influence of tides on tsetse densities].

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Kagbadouno, S M; Salou, E; Rayaisse, J B; Courtin, F; Sanon, A; Solano, P; Camara, M

2016-05-01

The mangrove area on the Guinea littoral constitutes a favourable habitat for transmission of Trypanosoma brucei gambiens, the parasite causing sleeping sickness also called Human African Trypanosmosis (HAT), due the simultaneous presence of the vector (tsetse flies) and the human hosts. In order to assess the influence of the sea tides on the densities of Glossina palpalis gambiensis (Gpg), major vector of HAT in the mangrove, entomological surveys were performed using two transects, according to tides coefficient (great and small) and tide daily fluctuations (high and low). On each transect, 12 biconical traps were deployed through the mangrove to the continent. In total, up to 612 Gpg were caught, giving a density of 2.13 flies/trap/day (f/t/d). Highest captures were recorded during small tides and more tsetse were caught during the dry season than in the wet season. There were significant differences between captures when considering the different biotopes, and highest tsetse densities were recorded at the junction of the river and the channel of the mangrove (6.17±5.24); and in the channels of mangrove (3.50±3.76), during high tides of small coefficients. The results of this study may be used to improve vector control methods.

Impacts of environmental variability on desiccation rate, plastic responses and population dynamics of Glossina pallidipes.

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Kleynhans, E; Clusella-Trullas, S; Terblanche, J S

2014-02-01

Physiological responses to transient conditions may result in costly responses with little fitness benefits, and therefore, a trade-off must exist between the speed of response and the duration of exposure to new conditions. Here, using the puparia of an important insect disease vector, Glossina pallidipes, we examine this potential trade-off using a novel combination of an experimental approach and a population dynamics model. Specifically, we explore and dissect the interactions between plastic physiological responses, treatment-duration and -intensity using an experimental approach. We then integrate these experimental results from organismal water-balance data and their plastic responses into a population dynamics model to examine the potential relative fitness effects of simulated transient weather conditions on population growth rates. The results show evidence for the predicted trade-off for plasticity of water loss rate (WLR) and the duration of new environmental conditions. When altered environmental conditions lasted for longer durations, physiological responses could match the new environmental conditions, and this resulted in a lower WLR and lower rates of population decline. At shorter time-scales however, a mismatch between acclimation duration and physiological responses was reflected by reduced overall population growth rates. This may indicate a potential fitness cost due to insufficient time for physiological adjustments to take place. The outcomes of this work therefore suggest plastic water balance responses have both costs and benefits, and these depend on the time-scale and magnitude of variation in environmental conditions. These results are significant for understanding the evolution of plastic physiological responses and changes in population abundance in the context of environmental variability. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Competitiveness and survival of two strains of Glossina palpalis gambiensis in an urban area of Senegal.

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Bassène, Mireille Djimangali; Seck, Momar Talla; Pagabeleguem, Soumaïla; Fall, Assane Gueye; Sall, Baba; Vreysen, Marc J B; Gimonneau, Geoffrey; Bouyer, Jérémy

2017-12-01

In the Niayes area, located in the west of Senegal, only one tsetse species, Glossina palpalis gambiensis Vanderplank (Diptera: Glossinidae) was present. The Government of Senegal initiated and implemented an elimination programme in this area that included a sterile insect technique (SIT) component. The G. p. gambiensis strain (BKF) mass-reared at the Centre International de Recherche-Développement sur l'Elevage en zone Subhumide (CIRDES) in Burkina Faso was used for the SIT component. Studies conducted in 2011 in four localities in the Niayes area (Pout, Sébikotane, Diacksao Peul and the Parc de Hann) showed that the BKF strain demonstrated inferior survival in the ecosystem of the Parc de Hann, a forested area in the city centre of the capital Dakar. Therefore, G. p. gambiensis flies from the Niayes area (SEN strain) were colonized. Here we compared the competitiveness and survival of the two strains (BKF and SEN) in the Parc de Hann. Released sterile males of the SEN colony showed a daily mortality rate of 0.08 (SD 0.08) as compared with 0.14 (SD 0.08) for the BKF flies but the difference was not significant (p-value = 0.14). However, the competitiveness of the SEN males was lower (0.14 (SD 0.10)) as compared with that of the BKF males (0.76 (SD 0.11)) (p-value competitiveness of the BKF males is deemed more important for the SIT component, as their shorter survival rates can be easily compensated for by more frequent fly releases.

Polytene chromosome maps and RAPD polymorphisms in Glossina austeni

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Gariou-Papalexiou, A.; Yannopoulos, G.; Zacharopoulou, A.; Robinson, A.S.

2000-01-01

A combined methodology of cloned RAPD (random amplification of polymorphic DNA) polymorphic bands and in situ hybridisation to polytene chromosomes is an efficient way to initiate construction of a physical and genetic map of insect disease vectors (Dimopoulos et al. 1996, Mutebi et al. 1997). The studies presented here are the first step in developing this approach in tsetse flies. This technology will be used to support tsetse sterile insect technique (SIT) programmes by providing tools with which population structure and isolation can be assessed and genetic markers that can be used to differentiate released flies from wild flies identified. An added benefit is their possible use in unravelling epidemiological complexity and problems regarding speciation (Besansky et al. 1997). Polytene chromosomes of Diptera have been shown to be excellent material for the study of chromosome structure and function as well as for an understanding of the genetics of natural populations (Lefevre 1976). They provide a means for the accurate mapping of chromosome rearrangements and the precise localisation of genes, using both rearrangement analysis and in situ hybridisation. Previous reports on the cytology of the tsetse flies (Riordan 1968, Maudlin 1970, 1979, Southern et al. 1972, Southern and Pell 1973, Davies and Southern 1976, Southern 1980) have described the basic mitotic karyotype in several Glossina species, and demonstrated the presence of well banded polytene chromosomes in pupal trichogen cells (Southern and Pell 1974, 1981, Pell and Southern 1976). Polytene chromosomes were described for G. austeni Newstead, G. morsitans morsitans Westwood, G. pallidipes Austen and G. fuscipes fuscipes Newstead, but these descriptions are difficult to work with as they are drawings of polytene chromosome elements. In this paper, the photographic chromosome maps of pupal scutellar bristles of G. austeni are presented. They show that these chromosomes can be used with much greater ease

Ecology of Glossina species inhabiting peridomestic agroecosystems in relation to options for tsetse fly control

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Madubunyi, L.C.

1990-01-01

Unbaited blue biconical traps were used to sample populations of Glossina once a week from April 1984 to March 1988 in three peridomestic agroecosystems of the Nsukka area, Nigeria. Serological analysis of 1764 fly midgut contents revealed that G. tachinoides had fed on reptiles, birds and mammals, with the domestic pig accounting for 88.08% of the 730 identifiable bloodmeals. The frequency distribution of flies in various stages of the trophic cycle showed that males and females feed at 2.88 ± 0.42 and 2.43 ± 0.44 day intervals, respectively. Flies were caught in greater numbers in biotopes containing domestic pigs, while the presence of man depressed trap catches. The larger the pig population in an agroecosystem, the larger the G. tachinoides population. However, reduction in the pig population to below five triggered the collapse of one of the G. tachinoides populations, which disappeared following the removal of all the pigs. The fly populations exhibited marked seasonal fluctuations in apparent density, largely caused by routine agronomic practices. These density fluctuations undermine recruitment of new adults into the population, especially during the wet season. It is suggested that tsetse populations in this area, already being kept at low density by routine agricultural procedures, could be further reduced by combining insecticides impregnated traps or targets with insect proofing of the piggeries. Methods aimed at undermining the recruitment of young adults into tsetse populations, capitalizing on naturally occurring sex ratio distortion as well as on maintaining populations of preferred hosts of the tsetse fly at low levels, should form part of integrated tsetse control packages. Selection of sterile male release sites and the number of sterile males to be released in them during sterile insect technique campaigns should take into account the sex ratio dynamics of target tsetse populations. 28 ref, 9 figs, 8 tabs

Original Research Polymerase chain reaction identification of ...

African Journals Online (AJOL)

Molecular identification of T. b. rhodesiense in tsetse flies 11 ... Glossina bravepalpis, and Glossina fuscipes fuscipes5-7) are mainly confined ..... that the feeding habits of these flies are similar to one ... well established that Glossina morsitans morsitans are efficient ... some people.26,27 Notably, the high infection rates that.

Transcriptome analysis of reproductive tissue and intrauterine developmental stages of the tsetse fly (Glossina morsitans morsitans

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Wu Yineng

2010-03-01

Full Text Available Abstract Background Tsetse flies, vectors of African trypanosomes, undergo viviparous reproduction (the deposition of live offspring. This reproductive strategy results in a large maternal investment and the deposition of a small number of progeny during a female's lifespan. The reproductive biology of tsetse has been studied on a physiological level; however the molecular analysis of tsetse reproduction requires deeper investigation. To build a foundation from which to base molecular studies of tsetse reproduction, a cDNA library was generated from female tsetse (Glossina morsitans morsitans reproductive tissues and the intrauterine developmental stages. 3438 expressed sequence tags were sequenced and analyzed. Results Analysis of a nonredundant catalogue of 1391 contigs resulted in 520 predicted proteins. 475 of these proteins were full length. We predict that 412 of these represent cytoplasmic proteins while 57 are secreted. Comparison of these proteins with other tissue specific tsetse cDNA libraries (salivary gland, fat body/milk gland, and midgut identified 51 that are unique to the reproductive/immature cDNA library. 11 unique proteins were homologus to uncharacterized putative proteins within the NR database suggesting the identification of novel genes associated with reproductive functions in other insects (hypothetical conserved. The analysis also yielded seven putative proteins without significant homology to sequences present in the public database (unknown genes. These proteins may represent unique functions associated with tsetse's viviparous reproductive cycle. RT-PCR analysis of hypothetical conserved and unknown contigs was performed to determine basic tissue and stage specificity of the expression of these genes. Conclusion This paper identifies 51 putative proteins specific to a tsetse reproductive/immature EST library. 11 of these proteins correspond to hypothetical conserved genes and 7 proteins are tsetse specific.

Répartition spatiale et préférences trophiques de Glossina palpalis palpalis dans le foyer forestier de Zoukougbeu (Cote d'Ivoire. Implications épidémiologiques

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Sané B.

2000-09-01

Full Text Available Dans le foyer de maladie du sommeil de Zoukougbeu (Côte d'Ivoire, plus d'un quart des glossines capturées s'étaient gorgées sur cochon en zone de plantations, lieux préférentiels de transmission de la trypanosomose humaine. En outre, on y observe une concordance nette entre la localisation des sites où Glossina palpalis palpalis a été capturée gorgée sur ces animaux et la présence de trypanosomés. Ceci laisse penser que, dans le foyer de Zoukougbeu, mais peut-être aussi dans d'autres foyers de trypanosomose humaine africaine du secteur forestier, le cochon joue un rôle plus actif qu'on ne le pense généralement, dans la transmission de l'endémie en permettant une large diffusion du parasite par l'intermédiaire des glossines.

Standardising visual control devices for tsetse flies: Central and West African species Glossina palpalis palpalis.

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Dramane Kaba

Full Text Available BACKGROUND: Glossina palpalis palpalis (G. p. palpalis is one of the principal vectors of sleeping sickness and nagana in Africa with a geographical range stretching from Liberia in West Africa to Angola in Central Africa. It inhabits tropical rain forest but has also adapted to urban settlements. We set out to standardize a long-lasting, practical and cost-effective visually attractive device that would induce the strongest landing response by G. p. palpalis for future use as an insecticide-impregnated tool in area-wide population suppression of this fly across its range. METHODOLOGY/PRINCIPAL FINDINGS: Trials were conducted in wet and dry seasons in the Ivory Coast, Cameroon, the Democratic Republic of Congo and Angola to measure the performance of traps (biconical, monoconical and pyramidal and targets of different sizes and colours, with and without chemical baits, at different population densities and under different environmental conditions. Adhesive film was used as a practical enumerator at these remote locations to compare landing efficiencies of devices. Independent of season and country, both phthalogen blue-black and blue-black-blue 1 m(2 targets covered with adhesive film proved to be as good as traps in phthalogen blue or turquoise blue for capturing G. p. palpalis. Trap efficiency varied (8-51%. There was no difference between the performance of blue-black and blue-black-blue 1 m(2 targets. Baiting with chemicals augmented the overall performance of targets relative to traps. Landings on smaller phthalogen blue-black 0.25 m(2 square targets were not significantly different from either 1 m(2 blue-black-blue or blue-black square targets. Three times more flies were captured per unit area on the smaller device. CONCLUSIONS/SIGNIFICANCE: Blue-black 0.25 m(2 cloth targets show promise as simple cost effective devices for management of G. p. palpalis as they can be used for both control when impregnated with insecticide and for

Population Genetics as a Tool to Select Tsetse Control Strategies: Suppression or Eradication of Glossina palpalis gambiensis in the Niayes of Senegal

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Solano, Philippe; Kaba, Dramane; Ravel, Sophie; Sall, Baba; Mathu Ndung'u, Joseph

2010-01-01

The Government of Senegal has initiated the ''Projet de lutte contre les glossines dans les Niayes'' to remove the trypanosomosis problem from this area in a sustainable way. Due to past failures to sustainably eradicate Glossina palpalis gambiensis from the Niayes area, controversies remain as to the best strategy implement, i.e. ''eradication'' versus ''supression''.To inform this debate, we used population genetics to measure genetic differentiation between G. palpalis gambiensis from the Niayes and those from the southern tsetse belt (Missira).Three different markers (microsatellite DNA, mitochondrial CO1 DNA, and geometric morphometrics of the wings) were used on 153 individuals and revealed that the G. p. gambiensis populations of the Niayes were genetically isolated from the nearest proximate known population of Missira. The genetic differentiation measured between these two areas (h=0.12 using microsatellites) was equivalent to a between-taxa differentiation. We also demonstrated that within the Niayes, the population from Dakar Hann was isolated from the others and had probably experienced a bottleneck.The information presented in this paper leads to the recommendation that an eradication strategy for the Niayes populations is advisable. This kind of study may be repeated in other habitats and for other tsetse species to help decision on appropriate tsetse control strategies and find other possible discontinuities in tsetse distribution.

Effects of Samorin Treatment and Delayed Infection on the Establishment of Trypanosomes in Glossina Pallidipes

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Okoth, S; Mukiria, P; Tinega, G; Murilla, G [Trypanosomiasis Research Centre, Kenya Agricultural Research Institute (TRC-KARI), Box 362, Kikuyu (Kenya)

2012-07-15

The protective role of Samorin (isometamidium chloride) when given with the bloodmeal, and the effect of the age of flies at infective feed, on the establishment of Trypanosoma congolense and Trypanosoma vivax in Glossina pallidipes Austen was evaluated. G. pallidipes was fed on fresh bovine blood containing 0, 6, 8, 10, 12 and 14 {mu}g of Samorin/mL of blood on day 0. A control group was fed in vivo on an infected goat as first feed on the same day (day 0). On day 3 post-Samorin treatment, the flies were infected in vivo by feeding them on a goat infected with either T. congolense or T. vivax. Similar procedures were followed for the experimental groups infected 5, 10 and 20 days post-Samorin treatment. Thereafter flies were maintained on rabbits for 15 and 20 days for the T. vivax and T. congolense groups, respectively. Fly survival was assessed, and the flies were dissected to determine infection rates. Results showed that the age of a fly at infection significantly affected the refractoriness of G. pallidipes to T. congolense ( F{sub 4,20} = 5.241; P=0.0047) and T. vivax ( F{sub 4,20} = 5.410; P=0.0040) infections. However, the effect of Samorin treatment on infection per se was not shown to be significant (F{sub 5,19} = 2.383; P=0733 and F{sub 4,20} = 1.106; P=0.3900) for T. congolense and T. vivax, respectively. The age of flies at infection significantly reduced tsetse survival (F{sub 4,20} = 7.584; P<0.001 and F{sub 4,20} = 10.755; P=0.0001) for T. congolense and T. vivax groups, respectively. However, Samorin treatment did not significantly reduce survival in both Trypanosoma groups (F{sub 5,19} = 0.642; P>0.67 and F{sub 5,19} = 0.485; P=0.783). These results indicated that, for T. congolense and T. vivax, combining Samorin treatment at a concentration of at least 8 {mu}g/mL, and delaying exposure of tsetse to infective feed for at least 3 days post emergence, induces sufficient refractoriness that may counter the increased challenge posed by the mass

Intestinal Bacterial Communities of Trypanosome-Infected and Uninfected Glossina palpalis palpalis from Three Human African Trypanomiasis Foci in Cameroon

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Franck Jacob

2017-08-01

Full Text Available Glossina sp. the tsetse fly that transmits trypanosomes causing the Human or the Animal African Trypanosomiasis (HAT or AAT can harbor symbiotic bacteria that are known to play a crucial role in the fly's vector competence. We hypothesized that other bacteria could be present, and that some of them could also influence the fly's vector competence. In this context the objectives of our work were: (a to characterize the bacteria that compose the G. palpalis palpalis midgut bacteriome, (b to evidence possible bacterial community differences between trypanosome-infected and non-infected fly individuals from a given AAT and HAT focus or from different foci using barcoded Illumina sequencing of the hypervariable V3-V4 region of the 16S rRNA gene. Forty G. p. palpalis flies, either infected by Trypanosoma congolense or uninfected were sampled from three trypanosomiasis foci in Cameroon. A total of 143 OTUs were detected in the midgut samples. Most taxa were identified at the genus level, nearly 50% at the species level; they belonged to 83 genera principally within the phyla Actinobacteria, Bacteroidetes, Firmicutes, and Proteobacteria. Prominent representatives included Wigglesworthia (the fly's obligate symbiont, Serratia, and Enterobacter hormaechei. Wolbachia was identified for the first time in G. p. palpalis. The average number of bacterial species per tsetse sample was not significantly different regarding the fly infection status, and the hierarchical analysis based on the differences in bacterial community structure did not provide a clear clustering between infected and non-infected flies. Finally, the most important result was the evidence of the overall very large diversity of intestinal bacteria which, except for Wigglesworthia, were unevenly distributed over the sampled flies regardless of their geographic origin and their trypanosome infection status.

RNA-seq de novo Assembly Reveals Differential Gene Expression in Glossina palpalis gambiensis Infected with Trypanosoma brucei gambiense vs. Non-Infected and Self-Cured Flies.

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Hamidou Soumana, Illiassou; Klopp, Christophe; Ravel, Sophie; Nabihoudine, Ibouniyamine; Tchicaya, Bernadette; Parrinello, Hugues; Abate, Luc; Rialle, Stéphanie; Geiger, Anne

2015-01-01

Trypanosoma brucei gambiense (Tbg), causing the sleeping sickness chronic form, completes its developmental cycle within the tsetse fly vector Glossina palpalis gambiensis (Gpg) before its transmission to humans. Within the framework of an anti-vector disease control strategy, a global gene expression profiling of trypanosome infected (susceptible), non-infected, and self-cured (refractory) tsetse flies was performed, on their midguts, to determine differential genes expression resulting from in vivo trypanosomes, tsetse flies (and their microbiome) interactions. An RNAseq de novo assembly was achieved. The assembled transcripts were mapped to reference sequences for functional annotation. Twenty-four percent of the 16,936 contigs could not be annotated, possibly representing untranslated mRNA regions, or Gpg- or Tbg-specific ORFs. The remaining contigs were classified into 65 functional groups. Only a few transposable elements were present in the Gpg midgut transcriptome, which may represent active transpositions and play regulatory roles. One thousand three hundred and seventy three genes differentially expressed (DEGs) between stimulated and non-stimulated flies were identified at day-3 post-feeding; 52 and 1025 between infected and self-cured flies at 10 and 20 days post-feeding, respectively. The possible roles of several DEGs regarding fly susceptibility and refractoriness are discussed. The results provide new means to decipher fly infection mechanisms, crucial to develop anti-vector control strategies.

studies on the reproductive status, catch and age compositions of ...

African Journals Online (AJOL)

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reproductive status of samples of Glossina pallidipes, trapped in NGU-2G traps. The objective was to assess ... male flies. Key words/phrases: Abortion, age reproductive status, Glossina pallidipes, NGU-2G traps, pregnancy. INTRODUCTION. From an ... ecology and behaviour of G. pallidipies. The present study was, ...

Long distance transport of irradiated male Glossina palpalis gambiensis pupae and its impact on sterile male yield

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Pagabeleguem, Soumaila; Seck, Momar Talla; Sall, Baba

2015-01-01

The application of the sterile insect technique (SIT) requires mass-production of sterile males of good biological quality. The size of the project area will in most cases determine whether it is more cost effective to produce the sterile flies locally (and invest in a mass-rearing facility) or import the sterile flies from a mass-rearing facility that is located in another country. This study aimed at assessing the effect of long distance transport of sterile male Glossina palpalis gambiensis pupae on adult male fly yield. The male pupae were produced at the Centre International de Recherche-Developpement sur l'Elevage en zone Subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso, and shipped with a commercial courier service in insulated transport boxes at a temperature of ±10° to Senegal (36 h of transport). Upon arrival in the insectary in Dakar, the pupae were transferred to an emergence room and the flies monitored for 3-6 days. The results showed that the used system of isothermal boxes that contained phase change material packs (S8) managed to keep the temperature at around 10° which prevented male fly emergence during transport. The emergence rate was significantly higher for pupae from batch 2 (chilled at 4° for one day in the source insectary before transport) than those from batch 1 (chilled at 4° for two days in the source insectary before transport) i.e. an average (±sd) of 76.1 ± 13.2% and 72.2 ± 14.3%, respectively with a small proportion emerging during transport (0.7 ± 1.7% and 0.9 ± 2.9%, respectively). Among the emerged flies, the percentage with deformed (not fully expanded) wings was significantly higher for flies from batch 1 (12.0 ± 6.3%) than from batch 2 (10.7 ± 7.5%). The amount of sterile males available for release as a proportion of the total pupae shipped was 65.8 ± 13.3% and 61.7 ± 14.7% for batch 1 and 2 pupae, respectively. The results also showed that the temperature inside the parcel must be controlled around 10° with a

Programme for the control of Glossina palpalis gambiensis Vanderplanck by the sterile-male technique in Upper Volta. A study of operational parameters

International Nuclear Information System (INIS)

Cuisance, D.; Politzar, H.; Clair, M.; Sellin, E.; Taze, Y.; Bourdoiseau, G.; Fevrier, J.

1980-01-01

The Institute for Stock-Breeding and Veterinary Medicine in Tropical Countries (Institut d'elevage et de medecine veterinaire des pays tropicaux - IEMVT, France), in association with the German Society for Technical Co-operation (Deutsche Gesellschaft fuer technische Zusammenarbeit - GTZ, Federal Republic of Germany), has been experimenting for four years in Upper Volta on genetic control of G.p. gambiensis, a vector of trypanosomiases in both man and animals, by the release of sterile males. A mass rearing facility has been set up for this glossina, with 45,000 females which produce 250,000 males for irradiation (11,000 rad) annually. This required a parallel facility for rearing 1000 host animals (400 rabbits and 600 guinea pigs). The releases are made twice a week on five experimental sectors isolated by barriers, which represent 32 km of forest galleries inhabited by G.p. gambiensis and G. tachinoides populations of medium density. The whole of this study zone is compared with a control covert 5.5 km in length. In each covert the influence of different parameters was examined: sterile-to-wild male ratio, spacing of release points, combination with insecticide treatment or not, and variation over time of the numbers of males released. First observations indicate that the sterile-male technique is efficient, and analysis of different parameters should make it possible to choose the optimum conditions for applying it. However, if the method is to be used on a larger scale, industrial-type rearing facilities will be required; yet the possibilities are limited by the difficulty of maintaining large numbers of host animals in tropical regions. Artificial feeding on membranes might offer one solution to the problem

Ex-ante benefit-cost analysis of the elimination of a Glossina palpalis gambiensis population in the Niayes of Senegal.

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Fanny Bouyer

2014-08-01

Full Text Available In 2005, the Government of Senegal embarked on a campaign to eliminate a Glossina palpalis gambiensis population from the Niayes area (∼ 1000 km(2 under the umbrella of the Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC. The project was considered an ecologically sound approach to intensify cattle production. The elimination strategy includes a suppression phase using insecticide impregnated targets and cattle, and an elimination phase using the sterile insect technique, necessary to eliminate tsetse in this area.Three main cattle farming systems were identified: a traditional system using trypanotolerant cattle and two "improved" systems using more productive cattle breeds focusing on milk and meat production. In improved farming systems herd size was 45% lower and annual cattle sales were €250 (s.d. 513 per head as compared to €74 (s.d. 38 per head in traditional farming systems (p<10-3. Tsetse distribution significantly impacted the occurrence of these farming systems (p = 0.001, with 34% (s.d. 4% and 6% (s.d. 4% of improved systems in the tsetse-free and tsetse-infested areas, respectively. We calculated the potential increases of cattle sales as a result of tsetse elimination considering two scenarios, i.e. a conservative scenario with a 2% annual replacement rate from traditional to improved systems after elimination, and a more realistic scenario with an increased replacement rate of 10% five years after elimination. The final annual increase of cattle sales was estimated at ∼ €2800/km(2 for a total cost of the elimination campaign reaching ∼ €6400/km(2.Despite its high cost, the benefit-cost analysis indicated that the project was highly cost-effective, with Internal Rates of Return (IRR of 9.8% and 19.1% and payback periods of 18 and 13 years for the two scenarios, respectively. In addition to an increase in farmers' income, the benefits of tsetse elimination include a reduction of grazing pressure on

Standardizing visual control devices for tsetse flies: West African species Glossina tachinoides, G. palpalis gambiensis and G. morsitans submorsitans.

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Jean-Baptiste Rayaisse

Full Text Available Here we describe field trials designed to standardize tools for the control of Glossina tachinoides, G. palpalis gambiensis and G.morsitans submorsitans in West Africa based on existing trap/target/bait technology. Blue and black biconical and monoconical traps and 1 m(2 targets were made in either phthalogen blue cotton, phthalogen blue cotton/polyester or turquoise blue polyester/viscose (all with a peak reflectance between 450-480 nm and a black polyester. Because targets were covered in adhesive film, they proved to be significantly better trapping devices than either of the two trap types for all three species (up to 14 times more for G. tachinoides, 10 times more for G. palpalis gambiensis, and 6.5 times for G. morsitans submorsitans. The relative performance of the devices in the three blue cloths tested was the same when unbaited or baited with a mixture of phenols, 1-octen-3-ol and acetone. Since insecticide-impregnated devices act via contact with flies, we enumerated which device (traps or targets served as the best object for flies to land on by also covering the cloth parts of traps with adhesive film. Despite the fact that the biconical trap proved to be the best landing device for the three species, the difference over the target (20-30% was not significant. This experiment also allowed an estimation of trap efficiency, i.e. the proportion of flies landing on a trap that are caught in its cage. A low overall efficiency of the biconical or monoconical traps of between 11-24% was recorded for all three species. These results show that targets can be used as practical devices for population suppression of the three species studied. Biconical traps can be used for population monitoring, but a correction factor of 5-10 fold needs to be applied to captures to compensate for the poor trapping efficiency of this device for the three species.

Stratified Entomological Sampling in Preparation for an Area-Wide Integrated Pest Management Program: The Example of Glossina palpalis gambiensis (Diptera: Glossinidae) in the Niayes of Senegal

International Nuclear Information System (INIS)

Bouyer, Jeremy; Seck, Momar Talla; Guerrini, Laure; Sall, Baba; Ndiaye, Elhadji Youssou; Vreysen, Marc J.B.

2010-01-01

The riverine tsetse species Glossina palpalis gambiensis Vanderplank 1949 (Diptera: Glossinidae) inhabits riparian forests along river systems in West Africa. The government of Senegal has embarked on a project to eliminate this tsetse species, and African animal trypanosomoses, from the Niayes are using an area-wide integrated pest management approach. A stratified entomological sampling strategy was therefore developed using spatial analytical tools and mathematical modeling. A preliminary phytosociological census identified eight types of suitable habitat, which could be discriminated from LandSat 7ETM satellite images and denominated wet areas. At the end of March 2009, 683 unbaited Vavoua traps had been deployed, and the observed infested area in the Niayes was 525 km2. In the remaining area, a mathematical model was used to assess the risk that flies were present despite a sequence of zero catches. The analysis showed that this risk was above 0.05 in19% of this area that will be considered as infested during the control operations.The remote sensing analysis that identifed the wet areas allowed a restriction of the area to be surveyed to 4% of the total surface area (7,150km2), whereas the mathematical model provided an efficient method to improve the accuracy and the robustness of the sampling protocol. The final size of the control area will be decided based on the entomological collection data.This entomological sampling procedure might be used for other vector or pest control scenarios. (Authors)

Permanent genetic resources added to Molecular Ecology Resources Database 1 December 2010-31 January 2011.

Science.gov (United States)

Agata, Kiyokazu; Alasaad, Samer; Almeida-Val, Vera Maria Fonseca; Alvarez-Dios, J A; Barbisan, F; Beadell, Jon S; Beltrán, J F; Benítez, M; Bino, G; Bleay, Colin; Bloor, P; Bohlmann, Jörg; Booth, Warren; Boscari, E; Caccone, Adalgisa; Campos, Tatiana; Carvalho, B M; Climaco, Gisele Torres; Clobert, Jean; Congiu, L; Cowger, Christina; Dias, G; Doadrio, I; Farias, Izeni Pires; Ferrand, N; Freitas, Patrícia D; Fusco, G; Galetti, Pedro M; Gallardo-Escárate, Cristian; Gaunt, Michael W; Ocampo, Zaneli Gomez; Gonçalves, H; Gonzalez, E G; Haye, Pilar; Honnay, O; Hyseni, Chaz; Jacquemyn, H; Jowers, Michael J; Kakezawa, Akihiro; Kawaguchi, Eri; Keeling, Christopher I; Kwan, Ye-Seul; La Spina, Michelangelo; Lee, Wan-Ok; Leśniewska, M; Li, Yang; Liu, Haixia; Liu, Xiaolin; Lopes, S; Martínez, P; Meeus, S; Murray, Brent W; Nunes, Aline G; Okedi, Loyce M; Ouma, Johnson O; Pardo, B G; Parks, Ryan; Paula-Silva, Maria Nazaré; Pedraza-Lara, C; Perera, Omaththage P; Pino-Querido, A; Richard, Murielle; Rossini, Bruno C; Samarasekera, N Gayathri; Sánchez, Antonio; Sanchez, Juan A; Santos, Carlos Henrique Dos Anjos; Shinohara, Wataru; Soriguer, Ramón C; Sousa, Adna Cristina Barbosa; Sousa, Carolina Fernandes Da Silva; Stevens, Virginie M; Tejedo, M; Valenzuela-Bustamante, Myriam; Van de Vliet, M S; Vandepitte, K; Vera, M; Wandeler, Peter; Wang, Weimin; Won, Yong-Jin; Yamashiro, A; Yamashiro, T; Zhu, Changcheng

2011-05-01

This article documents the addition of 238 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Alytes dickhilleni, Arapaima gigas, Austropotamobius italicus, Blumeria graminis f. sp. tritici, Cobitis lutheri, Dendroctonus ponderosae, Glossina morsitans morsitans, Haplophilus subterraneus, Kirengeshoma palmata, Lysimachia japonica, Macrolophus pygmaeus, Microtus cabrerae, Mytilus galloprovincialis, Pallisentis (Neosentis) celatus, Pulmonaria officinalis, Salminus franciscanus, Thais chocolata and Zootoca vivipara. These loci were cross-tested on the following species: Acanthina monodon, Alytes cisternasii, Alytes maurus, Alytes muletensis, Alytes obstetricans almogavarii, Alytes obstetricans boscai, Alytes obstetricans obstetricans, Alytes obstetricans pertinax, Cambarellus montezumae, Cambarellus zempoalensis, Chorus giganteus, Cobitis tetralineata, Glossina fuscipes fuscipes, Glossina pallidipes, Lysimachia japonica var. japonica, Lysimachia japonica var. minutissima, Orconectes virilis, Pacifastacus leniusculus, Procambarus clarkii, Salminus brasiliensis and Salminus hilarii. © 2011 Blackwell Publishing Ltd.

Use of a trypanosomal antigen ELISA to monitor tsetse and trypanosomosis control programmes in Kenya

Energy Technology Data Exchange (ETDEWEB)

Olaho-Mukani, W; Munga, L K; Nyanga` O, J N.M.; Ouma, J O; Masika, P; Okech, G; Ndungu, J M [Kenya Trypanosomiasis Research Inst., Kikuyu (Kenya)

1997-02-01

The capture Antigen-ELISA was used to monitor serum samples originating from three study areas in Kenya. At the Galana ranch the test was used to assess re-invasion of an area previously cleared of Glossina pallidipes. In Busia district the Ag-ELISA is being used to monitor the progress of a tsetse and trypanosomosis control programme. At Taita and Tara ranches the capture Antigen ELISA and the buffy coat technique (BCT) were used to evaluate the efficacy of a commercial Cypermethrin dip for the control of Glossina pallidipes. (author). 3 refs, 4 figs, 2 tabs.

Research Results from the Tsetse Fly Mass Rearing Laboratory at Cirdes and their Application during 2003-2008

Energy Technology Data Exchange (ETDEWEB)

Bance, A Z; Kabore, I; Sidibe, I; Rayaisse, J B; Bengaly, Z [Centre International de Recherche-Developpement sur l' Elevage en Zone Subhumide, No559, rue 5-31 angle avenue du Gouverneur Louveau 01, B.P. 454, Bobo Dioulasso 01 (Burkina Faso)

2012-07-15

Some reduction in feeding frequency was possible. Glossina morsitans submorsitans Newstead easily tolerated a reduction from six to three days per week (Monday, Wednesday, Friday) without reducing female productivity. However, Glossina palpalis gambiensis Vanderplank and Glossina tachinoides Westwood tolerated a reduction from six to only four days per week. Even without ATP, blood that had been frozen enabled tsetse flies to achieve a high level of productivity. Using ATP unnecessarily increased the cost of producing Glossina by about 0.027 Euros per fly. Regarding handling tsetse flies, the procedure of day-zero-mating, which aims to minimize fly manipulation with one's hands, was applied to both G. m. submorsitans and G. p. gambiensis. The results showed that using emerging males (zero days old) for mating has no negative effect on female productivity. The optimal fly density in each new TPU-3 cage was 64 females and 16 males, i.e. 80 flies per box for all three species. Regarding applying the sterile insect technique (SIT), experiments with irradiated males of G. p. gambiensis showed that the percentage sterility induced to inseminated females was 89.8, 94.3 and 95.2% at doses of 102, 112 and 122 Gy, respectively. Biological parameters linked to sexual activity, e.g. insemination rate, spermathecal filling rate and survival rate, were not changed by the different irradiation doses. Finally, validation of the TPU-3 holding/feeding system showed that it reduced the feeding time considerably (by 80%) when compared with the old manual system. Productivity parameters of G. p. gambiensis using the TPU-3 system were: pupal weight 28.1{+-}0.6 mg and adult emergence 89.0{+-}1.7%. (author)

An update of the tsetse fly (Diptera: Glossinidae distribution and African animal trypanosomosis prevalence in north-eastern KwaZulu-Natal, South Africa

Directory of Open Access Journals (Sweden)

Chantel J. de Beer

2016-06-01

Full Text Available An unpredicted outbreak of African animal trypanosomosis or nagana in 1990 in north-eastern KwaZulu-Natal necessitated an emergency control programme, utilising the extensive cattledipping system in the area, as well as a reassessment of the tsetse and trypanosomosis problem in the province. Since 1990, sporadic blood sampling of cattle at the dip tanks in the naganainfested areas were undertaken to identify trypanosome species involved and to determine the infection prevalence in cattle. The distribution and species composition of the tsetse populations in the area were also investigated. From November 2005 to November 2007 selected dip tanks were surveyed for trypanosome infection prevalence. During April 2005 to August 2009 the distribution and abundance of tsetse populations were assessed with odour-baited H traps. The tsetse and trypanosome distribution maps were updated and potential correlations between tsetse apparent densities (ADs and the prevalence of trypanosomosis were assessed. Glossina brevipalpis Newstead and Glossina austeni Newstead were recorded in locations where they have not previously been collected. No significant correlation between tsetse relative abundance and nagana prevalence was found, which indicated complex interactions between tsetse fly presence and disease prevalence. This was epitomised by data that indicated that despite large differences in the ADs of G. austeni and G. brevipalpis, trypanosome infection prevalence was similar in all three districts in the area. This study clearly indicated that both tsetse species play significant roles in trypanosome transmission and that it will be essential that any control strategy, which aims at sustainable management of the disease, should target both species. Keywords: Tsetse distribution; Glossina brevipalpis; Glossina austeni; trypanosome infection prevalence

Detection of Trypanosoma brucei gambiense and T. b. rhodesiense ...

African Journals Online (AJOL)

Detection of Trypanosoma brucei gambiense and T. b. rhodesiense in Glossina fuscipes fuscipes ( Diptera: Glossinidae ) and Stomoxys flies using the polymerase chain reaction (PCR) technique in southern Sudan.

Role of cytokines in Trypanosoma brucei-induced anaemia: A ...

African Journals Online (AJOL)

species Trypanosoma brucei that are transmitted by a tsetse fly (Glossina spp.) ... of autologous immunoglobulin antibodies on the red cell surfaces and also to ... development for the detection and management of anaemia in trypanosomiasis.

Etude de la rémanence du triflumuron, inhibiteur de la synthèse de la chitine, selon la nature du tissu à l'égard de la mouche tsé-tsé Glossina palpalis gambiensis, dans une perspective de lutte autocide

Directory of Open Access Journals (Sweden)

Dabiré, R.

2006-01-01

Full Text Available Study of Remanence of Triflumuron, Synthesis Inhibitor, According to the Nature of Cloth with Regard to Tsetse Fly Glossina palpalis gambiensis in View of Self-killed Fight. The objective of this study is to assess the persistence of triflumuron impregated at a dosis of 9,7 g.m-2 on blue cotton, polyester and polypropylene material in comparison with the reference material made of 67% polyester and 33% cotton used in the control of tsetse fly. Impregnated materials were exposed to field conditions during six months. One sample of each material was monthly taken and tsetse flies were exposed to it to assess the effects on the reproduction parameters of contaminated flies. Two types of contamination were evaluated: 20 days old females were contaminated by exposure to impregnated tissues while teneral females (3 days old were contaminated through the mating with males contaminated like the old females. Measured parameters were: the abortions, the pupa production, the non viable pupa and the hatching. The results from the old females showed that impregnated polypropylene material significantly reduced the average of hatching rate during six months (1 1.4% in comparison with impregnated reference material (15.14 21%, cotton material (14 25% and polyester one (21.5 34.3%. For young females the same tendencies were observed. During the six months period of investigation, triflumuron persistence was better on the polypropylene material than on the reference material for the control of tsetse flies by self sterilisation.

Patterns of development of trypanosomes and related parasites in insect hosts

International Nuclear Information System (INIS)

Molyneux, D.H.

1980-01-01

The trypanosome parasites of man and his domestic animals and the closely related Leishmania parasites pathogenic to man have widely different patterns of development in their various vector species. However, certain common features of the development of these parasites are exhibited when they develop in insects. These features include temporary storage in the crop; transformation from mammalian forms to primary multiplicative forms; avoidance of digestion by host enzymes; association with the peritrophic membrane; establishment of infection and, associated with this, attachment and colonization of surfaces; migration to different areas of gut to sites of development; formation of a reservoir of forms to ensure sufficient organisms are available for transformation to forms infective to the vertebrate host; subsequent transmission by bite or by contamination of host surfaces. The different features of development outlined above are discussed in relation to trypanosomes and related parasites. The utilization of different model systems for use in this type of study are discussed in view of difficulties in obtaining adequate numbers of infected flies (e.g. Glossina, or sandflies), and the costs and frequent problems of maintaining such colonies. Recent studies (1) on Glossina-transmitted Salivarian trypanosomes are described which indicate possible behavioural differences between infected and uninfected flies that have a bearing on epidemiology and epizootiology; (2) on the fluid mechanics of the Glossina labrum infected and uninfected with trypanosomes; and (3) on attachment of trypanosomes and Leishmania to insect gut wall surfaces. (author)

Interactions comportementales et rythmes d’activité de Glossina palpalis gambiensis et G. tachinoides (Diptera : Glossinidae en galerie forestière au Burkina Faso

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Salou E.

2012-08-01

Full Text Available Glossina palpalis gambiensis et G. tachinoides sont des vecteurs majeurs des trypanosomoses humaines et animales en Afrique de l’Ouest. Sur une partie de leur aire de répartition, elles sont présentes en sympatrie, mais très peu d’informations sont disponibles sur leurs interactions. Nous avons capturé ces deux espèces en utilisant un système attractif composé d’écrans de tissu noir/bleu/ noir muni de film adhésif, afin de retenir toutes les glossines posées et de pouvoir mesurer la hauteur à laquelle elles se sont posées, ainsi que leur rythme d’activité en fonction de l’heure de la journée. L’étude a eu lieu dans deux zones du sud du Burkina Faso : Kartasso en amont du fleuve Mouhoun, où seule G. p. gambiensis est présente, et Folonzo sur le fleuve Comoé, où les deux espèces cohabitent. Les résultats, sur 3 800 glossines capturées, montrent une forte prédominance des captures de G. tachinoides par rapport à G. p. gambiensis à Folonzo (84 % contre 16 % des captures respectivement. À Kartasso, où elle est seule, G. p. gambiensis est capturée en moyenne à 46 cm du sol. À Folonzo, G. p. gambiensis est en moyenne attrapée à une hauteur de 65 cm, et G. tachinoides à 55 cm, ces différences de hauteurs étant significatives. Les femelles sont capturées en général plus haut que les mâles. Les deux espèces montrent un rythme d’activité similaire en fonction de l’heure de capture, mais seule G. p. gambiensis réduit sa hauteur de vol aux heures les plus chaudes. Plusieurs hypothèses, non exclusives, sont évoquées pour expliquer ces hauteurs de capture différentes : la nature de la galerie forestière, un comportement d’approche qui différerait entre espèces, mais aussi la possibilité de phénomènes de compétition interspécifique en relation avec l’utilisation de ressources énergétiques limitées (métabolisme lié à la proline. Sont également discutées les conséquences possibles

Evaluation of the effect of horse blood supplemented with human ...

African Journals Online (AJOL)

Tsetse flies are large biting insects that belong to the genus Glossina. Both .... and binary data (e.g mortality, pupae classes, etc) and b) one way analysis of variance for ..... Automation of tsetse mass rearing for use in sterile insect technique.

The behaviour of tsetse flies in an odour plume

NARCIS (Netherlands)

Groenendijk, C.A.

1996-01-01

The tsetse flies Glossina pallidipes Austen and G. m. morsitans Westw. (Diptera: Glossinidae) are obligatory blood feeding insects that do not live in close association with their hosts (mainly mammals). Tsetse flies are relatively long lived

Insemination, pregnancy and abortion rates in a population of ...

African Journals Online (AJOL)

Insemination, pregnancy and abortion rates in a population of Glossina palpalis palpalis (robineau-desvoidy) at a relict forest in the Southern Guinea Savanna, Nigeria. ... The results indicate that nutritional and physical stress were the likely constraints to optimum productivity. Keywords: insemination, pregnancy ...

Arsenophonus and Sodalis Symbionts in Louse Flies: an Analogy to the Wigglesworthia and Sodalis System in Tsetse Flies

Czech Academy of Sciences Publication Activity Database

Nováková, Eva; Husník, Filip; Sochová, E.; Hypša, Václav

2015-01-01

Roč. 81, č. 18 (2015), s. 6189-6199 ISSN 0099-2240 Grant - others:GA ČR(CZ) GA13-01878S Institutional support: RVO:60077344 Keywords : bat flies * phylogenetic analysis * Glossina morsitans Subject RIV: EH - Ecology, Behaviour Impact factor: 3.823, year: 2015

Tryptophan metabolism in tsetse flies and the consequences of its derangement

Directory of Open Access Journals (Sweden)

R. H. Gooding

1987-01-01

Full Text Available Literature comparing salmon and wild type Glossina morsitans morsitans and that comparing tan and wild type Glossina palpalis palpalis is reviewed. New information is presented on behaviour and biochemistry of salmon and wild type G. m. morsitans. The eye color mutants result from two lesions in the tryptophan to xanthommatin pathway: lack of tryptophan oxygenase in G. m morsitans and failure to produce or retain xanthommatin in eyes (but not in testes of G. p. palpalis. The salmon allele in G. m. morsitans is pleiotropic and profoundly affects many aspects of fly biology including longevity, reproductive capacity, vision, vectorial capacity and duration of flight, but not circadian rhythms. The tan allele in G. p. palpalis has little effect upon the biology of flies under laboratory conditions, except that tan flies appear less active than normal. Adult tsetse flies metabolize tryptophan to kynurenine which is excreted; fluctuations in activities of the enzymes producing kynurenine suggest this pathway is under metabolic control.

Research in Biological and Medical Sciences Including Biochemistry, Communicable Disease and Immunology, Internal Medicine, Nuclear Medicine, Physiology, Psychiatry, Surgery, and Veterinary Medicine, Volume 2

Science.gov (United States)

1976-07-01

in some cases, the chromatln had divided two or more times. 3. Cultivation of Trypanosoma brucel In a cell line of Glossina morsltans Studies on T... brucel and other African pathogenic trypanosomes have been hampered by the Inability of the infectious forms to grow in vitro. Once placed in

Molecular identification of tsetse fly ( Diptera: Glossinidae ) species ...

African Journals Online (AJOL)

Inspite of the few mixed clusters, the pattern produced in the phylogenetic trees can provide a good guide to support any other method of Glossina identification. It was recommended that evaluations be made to validate other genetic markers that can produce better resolutions to identify tsetse fly species using phylogenetic ...

Is there a suburban sleeping sickness in Libreville?

African Journals Online (AJOL)

EB

moisturized sites for its development. The structure, compaction, temperature and moisture of the ground of all that survey area is suitable for Glossina larvae development, but, in swamp mangrove where are built landing stages, there is a frequent variation of tide that impede the maturation of larvae. Nevertheless, it was in ...

Browse Title Index

African Journals Online (AJOL)

Items 1 - 50 of 391 ... Vol 13, No 2 (2011), A review of the evolution of trappiing strategies for the control of trypanosomiasis and tsetse flies (Glossina spp) in africa (1908 -2004), Abstract ... Vol 9, No 2 (2007):, A survey of indigenous knowledge of stingless bees (Apidae: meliponini) in the central region of Ghana, Abstract.

Research article

African Journals Online (AJOL)

Raul

2009-08-28

Aug 28, 2009 ... tsetse used to be reinvaded many years later, we have carried out an entomological survey in the area with the aim to verify what has happened more than twenty years later; given that suitable environmental conditions for Glossina are still available. Methods: Sixteen pyramidal traps were set out at the ...

THEORETICAL ASPECTS OF THE CONTROL OF GLOSSINA ...

African Journals Online (AJOL)

at the end of successive hunger cycles is not known, but since starvation appears to be a common cause of death under natural conditions (Bursell 1961), it is clear that a substantial proportion of tsetse flies exhaust their food reserves before they succeed in their search for a suitable host. In view of this it may be legitimate ...

Identification of Glossina morsitans morsitans odorant binding ...

African Journals Online (AJOL)

Tsetse flies are vectors of trypanosome parasites, causative agents of Trypanosomiasis in humans and animals. Odorant Binding Proteins (OBPs) are critical in insect olfaction as they bind volatile odours from the environment and transport them to receptors within olfactory receptor neurons for processing providing critical ...

Detection of Trypanozoon trypanosomes infections on Glossina ...

African Journals Online (AJOL)

TOSHIBA

district, Blue Nile state, Sudan using a PCR technique. ... in the southern region of the Blue Nile State. This area is located .... control DNA used was extracted from FTA cards. Thus, .... conducted in East and West Africa (McNamara et al.,. 1995 ...

Horizontally Transferred Genetic Elements in the Tsetse Fly Genome: An Alignment-Free Clustering Approach Using Batch Learning Self-Organising Map (BLSOM).

Science.gov (United States)

Nakao, Ryo; Abe, Takashi; Funayama, Shunsuke; Sugimoto, Chihiro

2016-01-01

Tsetse flies ( Glossina spp.) are the primary vectors of trypanosomes, which can cause human and animal African trypanosomiasis in Sub-Saharan African countries. The objective of this study was to explore the genome of Glossina morsitans morsitans for evidence of horizontal gene transfer (HGT) from microorganisms. We employed an alignment-free clustering method, that is, batch learning self-organising map (BLSOM), in which sequence fragments are clustered based on the similarity of oligonucleotide frequencies independently of sequence homology. After an initial scan of HGT events using BLSOM, we identified 3.8% of the tsetse fly genome as HGT candidates. The predicted donors of these HGT candidates included known symbionts, such as Wolbachia , as well as bacteria that have not previously been associated with the tsetse fly. We detected HGT candidates from diverse bacteria such as Bacillus and Flavobacteria, suggesting a past association between these taxa. Functional annotation revealed that the HGT candidates encoded loci in various functional pathways, such as metabolic and antibiotic biosynthesis pathways. These findings provide a basis for understanding the coevolutionary history of the tsetse fly and its microbes and establish the effectiveness of BLSOM for the detection of HGT events.

A pilot study to delimit tsetse target populations in Zimbabwe.

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Gerald Chikowore

2017-05-01

Full Text Available Tsetse (Glossina sensu stricto are cyclical vectors of human and animal trypanosomoses, that are presently targeted by the Pan African Tsetse and Trypanosomiasis Eradication Campaign (PATTEC coordinated by the African Union. In order to achieve effective control of tsetse, there is need to produce elaborate plans to guide intervention programmes. A model intended to aid in the planning of intervention programmes and assist a fuller understanding of tsetse distribution was applied, in a pilot study in the Masoka area, Mid-Zambezi valley in Zimbabwe, and targeting two savannah species, Glossina morsitans morsitans and Glossina pallidipes.The field study was conducted between March and December 2015 in 105 sites following a standardized grid sampling frame. Presence data were used to study habitat suitability of both species based on climatic and environmental data derived from MODIS and SPOT 5 satellite images. Factors influencing distribution were studied using an Ecological Niche Factor Analysis (ENFA whilst habitat suitability was predicted using a Maximum Entropy (MaxEnt model at a spatial resolution of 250 m. Area Under the Curve (AUC, an indicator of model performance, was 0.89 for G. m. morsitans and 0.96 for G. pallidipes. We then used the predicted suitable areas to calculate the probability that flies were really absent from the grid cells where they were not captured during the study based on a probability model using a risk threshold of 0.05. Apart from grid cells where G. m. morsitans and G. pallidipes were captured, there was a high probability of presence in an additional 128 km2 and 144 km2 respectively.The modelling process promised to be useful in optimizing the outputs of presence/absence surveys, allowing the definition of tsetse infested areas with improved accuracy. The methodology proposed here can be extended to all the tsetse infested parts of Zimbabwe and may also be useful for other PATTEC national initiatives in other

Activities of the Entomology Unit. Report No.1, 1988

International Nuclear Information System (INIS)

1988-11-01

This semiannual report describes the activities carried out by the staff of the Entomology Unit at the Agency's Laboratories, Seibersdorf, between 1 January and 31 July 1988. The colonization of Glossina spp. was continued to provide insects for ongoing and anticipated control programmes and supporting research activities. Hybridization of the two subspecies palpalis palpalis (GPP) and palpalis gambiensis (GPG) was studied. Rearing of medfly was studied. Figs and tabs

Eradicating tsetse from the Southern Rift Valley of Ethiopia

International Nuclear Information System (INIS)

2003-01-01

Farming activities in Ethiopia, as in much of sub-Saharan Africa, are restricted by the presence of tsetse flies (Glossina spp.). These carry the livestock and human disease, trypanosomosis, which severely affects agricultural production and human well-being. In collaboration with the Ethiopian authorities, the International Atomic Energy Agency is sponsoring a Sterile Insect Technique (SIT) programme to eradicate tsetse from the Southern Rift Valley of Ethiopia. (IAEA)

Tsetse eradication: Zanzibar

International Nuclear Information System (INIS)

2003-01-01

Tsetse flies (Glossina sp.) continue to make livestock production difficult or impossible throughout a very large part of Africa. One of the most promising techniques for eradicating tsetse from certain locations is the environmentally safe Sterile Insect Technique (SIT). In collaboration with the Tanzanian authorities, the Department of Technical Co-operation is sponsoring a programme, with technical support from the Joint FAO/IAEA Division, to eradicate tsetse from Zanzibar using the SIT. (IAEA)

Bovine trypanosomosis prevalence at the edge of Hluhluwe-iMfolozi Park, KwaZulu-Natal, South Africa

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Lundi Ntantiso

2014-09-01

Full Text Available The northern KwaZulu-Natal (NKZN region of South Africa is the southern limit of the African tsetse belt. Entomological information on Glossina brevipalpis and Glossina austeni was generated following the outbreak of trypanosomosis in cattle in 1990. However, these data have not been supported by parallel studies on epidemiology of the disease and therefore there has been no control policy in place. This study presented the first intensive investigations to address the epidemiology of trypanosomosis in NKZN. Tsetse abundance, trypanosome herd average prevalence (HAP, herd average anaemia (HAA and herd average packed cell volume (HA-PCV were investigated at three communal diptanks located at the edge of Hluhluwe-iMfolozi Park by monthly sampling from June 2006 – November 2007. Seasonal trypanosome surveys were conducted at seven other communal diptanks. Glossina brevipalpis prevalence was high at two of the diptanks, Mvutshini and Ekuphindisweni, but low at Ocilwane, whilst G. austeni was only collected from Mvutshini. This high and low tsetse challenge presented different disease scenarios. Cattle at Mvutshini and Ekuphindisweni had the highest HAP of 12.3% and 8.9% respectively, both significantly different (p = 0.001 from the HAP obtained from cattle at Ocilwane (2.9%. These two cattle herds also had the highest HAA, 27.7% and 33.4% respectively, whilst cattle at Ocilwane had the lowest, 11.1% (p = 0.001. Conversely, cattle at Ocilwane had the highest HA-PCV, ranging between 29.0% and 32.0%, whilst cattle at Mvutshini and Ekuphindisweni had the lowest HA-PCV (24.0% – 29.0%. By combining the data from the three diptanks (1318 observations, 62.0% of the infected cattle were found anaemic, compared to 20.0% in the uninfected group. Trypanosome seasonal surveys showed that cattle at all the seven diptanks were infected with trypanosomes; mean HAP, HAA and HA-PCV of 10.2%, 46.6% and 23.7%, respectively. This study generated information on the

Developing Quality Control Procedures to Sustain a Supply of High Quality Blood for Mass Rearing Tsetse Flies

Energy Technology Data Exchange (ETDEWEB)

De Beer, C J; Venter, G J; Potgieter, F T [ARC-Onderstepoort Veterinary Institute, Old Soutpans Road, Private Bag X05, 0110 Onderstepoort (South Africa)

2012-07-15

Mass rearing tsetse flies Glossina spp. is dependent on the sustained availability of a high quality blood diet. In any mass rearing facility, the logistics for obtaining sterile, high quality fresh blood is challenging. An added complication is the influence of potential chemical, physical and microbiological elements present in the blood of donors, as well as contamination during collection, handling and storage. Research at the Agricultural Research Council - Onderstepoort Veterinary institute (ARC-OVI) is directed towards the development of quality control procedures for the supply of the in vitro diet used to maintain productive colonies of Glossina brevipalpis Newstead and Glossina austeni Newstead. Factors that may influence the blood diet, e.g. defibrination, feeding times, collection of blood in anticoagulants, treatment of blood with taste stimuli, repeated freezing and thawing of blood, effect of bovine growth hormones, and also a preference for bovine or porcine blood were tested. A 25 day bioassay was used to determine the effects of these factors on tsetse survival and reproduction. Defibrination of the blood for 10 to 15 minutes gave the best results for both species. It was found that G. brevipalpis should be fed three times per week for 5 minutes each time, and G. austeni three times per week for 10 minutes. Heparin, acid citrate dextrose (ACD), citric acid, citrate phosphate dextrose adenine (CPDA) and a combination of sodium citrate and citric acid were effective anticoagulants in the blood diets of G. brevipalpis and G. austeni. Blood treated with inosine triphosphate (ITP) gave the highest quality factor (QFC) values for both G. austeni and G. brevipalpis. Repeated freezing and thawing of blood definitely affects pupal production negatively; G. brevipalpis especially produced significantly smaller pupae. A premixed diet of equal amounts of bovine and porcine blood was found to be best suited for G. brevipalpis, and for G. austeni a mixture of

The Characterization of the Phlebotomus papatasi Transcriptome

Science.gov (United States)

2013-04-01

Le. infantum (Li: CAM68214.1), Le. major (Lm: XP_001683430.1), Homo sapiens (Hs: AAD17527.1) and Bo. mori (Bm: NP_001108470.1). The WAG substitution...blood meals in Ph. langeroni (Dillon, El Kordy 1997). Here we have identified 23 unique Ph. papatasi sequences with high identity (BLASTP, əe-50) to...Perkin SAH, Caler E, Bonaldo MF, Soares MB, El -Sayeed N, Aksoy S. Analysis of fat body transcriptome from the adult tsetse fly, Glossina morsitans

Insect acetyl-CoA carboxylase: activity during the larval, pupal and adult stages of insect development.

Science.gov (United States)

Goldring, J P; Read, J S

1993-12-01

1. The activity of the lipogenic enzyme, acetyl-CoA carboxylase, was investigated in four insect species; Bombyx mori (Lepidoptera), Tenebrio molitor (Coleoptera), Glossina morsitans and Sarcophaga nodosa (Diptera). 2. Acetyl-CoA carboxylase activity in larval, pupal and adult forms was compared with the saponifiable lipid mass at each stage of the life-cycle, and found to follow similar patterns except for Tenebrio molitor. 3. The results are examined in relation to known metabolic requirements for each insect.

Structure-activity relationship study of sesquiterpene lactones and their semi-synthetic amino derivatives as potential antitrypanosomal products

CSIR Research Space (South Africa)

Zimmermann, S

2014-03-01

Full Text Available Stefanie Zimmermann 1,2, Gerda Fouché 3, Maria De Mieri 1, Yukiko Yoshimoto 4, Toyonobu Usuki 4, Rudzani Nthambeleni 3, Christopher J. Parkinson 5, Christiaan van der Westhuyzen 3, Marcel Kaiser 2,6, Matthias Hamburger 1 and Michael Adams 1,* 1... 1. Introduction Sleeping sickness, or human African trypanosomiasis (HAT), is a deadly protozoal disease caused by Trypanosoma brucei species spread by tsetse flies (Glossina spp.). The two human pathogenic subspecies, T. b. rhodesiense (95...

The behaviour of tsetse flies in an odour plume

OpenAIRE

Groenendijk, C.A.

1996-01-01

The tsetse flies Glossina pallidipes Austen and G. m. morsitans Westw. (Diptera: Glossinidae) are obligatory blood feeding insects that do not live in close association with their hosts (mainly mammals). Tsetse flies are relatively long lived insects and have to take a blood meal regularly. Tsetse flies use smell and vision to find their hosts. In the last decade, many aspects of tsetse foraging and host-location behaviour have been elucida...

Example of decision support for trypanosomiasis control using a geographical information system in eastern Zambia.

CSIR Research Space (South Africa)

Robinson, TP

2002-06-01

Full Text Available , in whether the benebullet5 ts are private (e.g. trypanoci- dal drugs) or public (e.g. bait technology) and also in whether the onus is on the individual, the community or some external body to conduct and bullet5 nance them. The ecological, epidemiological..., G.A., Lovemore, D. F., Flint, S., and Cockbill, G. F., 1988, Odor-baited targets to control tsetse bullet6 ies, Glossina spp. (Diptera: Glossinidae), in Zimbabwe. Bulletin of Entomologica l Research, 78, 31–50. Vine, M. F., Degnan, D...

Factors affecting the efficiency of the sterile insect release method for tsetse

International Nuclear Information System (INIS)

Curtis, C.F.

1980-01-01

Data are reviewed on the levels of sterility, survival and competitiveness of Glossina males after irradiation with various gamma-ray doses delivered in air or nitrogen. A simple population model helps in the choice of the optimum dose. Field studies of mating competitiveness require a measure of the ratio of sterile to fertile males and of sterile to fertile matings, and both ratio estimates will be subject to sampling error. Data on multiple mating of female Glossina are reviewed. There is some degree of precedence for sperm from the first mating but sterile sperm are fully competitive for fertilization and, following the early death of an embryo, the timing of the next ovulation is only advanced to a slight extent. Thus in an isolated population the occurrence or non-occurrence of female polygamy would be of almost no consequence. Where mated females were immigrating into the release area female polygamy would be advantageous. The low recovery potential of tsetse populations is the main reason for thinking them suitable for control by the introduction of sterility. In trying to measure this recovery potential it is important to distinguish it from natural seasonal increase. If natural population fluctuations are studied to detect density dependent effects it is important not to confuse cause with effect. Non-isolation of the 'target' population is almost certainly the most serious obstacle to practical application of the sterile insect release method, and a steady 'rolling forward' of the release area may be a possible solution. (author)

Contrasting Population Structures of Two Vectors of African Trypanosomoses in Burkina Faso: Consequences for Control

Science.gov (United States)

Ravel, Sophie; Vreysen, Marc J. B.; Domagni, Kouadjo T.; Causse, Sandrine; Solano, Philippe; de Meeûs, Thierry

2011-01-01

Background African animal trypanosomosis is a major obstacle to the development of more efficient and sustainable livestock production systems in West Africa. Riverine tsetse species such as Glossina palpalis gambiensis Vanderplank and Glossina tachinoides Westwood are the major vectors. A wide variety of control tactics is available to manage these vectors, but their removal will in most cases only be sustainable if the control effort is targeting an entire tsetse population within a circumscribed area. Methodology/Principal Findings In the present study, genetic variation at microsatellite DNA loci was used to examine the population structure of G. p. gambiensis and G. tachinoides inhabiting four adjacent river basins in Burkina Faso, i.e. the Mouhoun, the Comoé, the Niger and the Sissili River Basins. Isolation by distance was significant for both species across river basins, and dispersal of G. tachinoides was ∼3 times higher than that of G. p. gambiensis. Thus, the data presented indicate that no strong barriers to gene flow exists between riverine tsetse populations in adjacent river basins, especially so for G. tachinoides. Conclusions/Significance Therefore, potential re-invasion of flies from adjacent river basins will have to be prevented by establishing buffer zones between the Mouhoun and the other river basin(s), in the framework of the PATTEC (Pan African Tsetse and Trypanosomosis Eradication Campaign) eradication project that is presently targeting the northern part of the Mouhoun River Basin. We argue that these genetic analyses should always be part of the baseline data collection before any tsetse control project is initiated. PMID:21738812

Observation d'une flambée de trypanosomose équine due à Trypanosoma vivax en zone urbaine au Sénégal

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Dehoux, JP.

1996-01-01

Full Text Available Observation of an Outbreak of Equine Trypanosomiasis due to Trypanosoma vivax in Urban Environment in Senegal. An outbreak of trypanosomiasis in imported and local horses and ponies occurred in September 1994 in a private horseriding farm near Dakar. Trypanosoma vivax was isolated. 5 mortalities (which a local pony were registered on 20 ill animals. The clinical signs were fever, depression, emaciation, anemia ad oedema. Curative treatment with intramuscular diminazene (3.5 mg/kg and prophylactic intravenous isometamidium (0.5 mg/kg were injected in October 1994 and July 1995. Glossina palpalis gambiensis was isolated near the farm.

Activities Report 2007 PATTEC-Mali

International Nuclear Information System (INIS)

2007-01-01

This annual report is a summary of main activities undertaken in 2007 under the Pan African Tsetse and Trypanosomiasis project. It results from the initiative of African governments in 2000 to eradicate tsetse flies and trypanosomiasis from infested areas in the African continent in order to mitigate poverty and improve food security in six countries (Ethiopia, Uganda, Kenya, Mali, Burkina, Ghana). . areas An integrated approach of combating tsetse is used, from simples techniques such as trapping nets impregnate with insecticides and skin treatment of animals for suppression, and sterile insect technique for eradicating of the residual population of glossina.Methods and basic socio-epidemiological conducted in the field are presented

Genetics of tsetse fly. Part of a coordinated programme on sterile insect techniques for tsetse fly control or eradication

International Nuclear Information System (INIS)

Helle, W.

1977-08-01

Genetic variation in the tsetse fly, Glossina m. morsitans was studied using isoenzyme patterns. As the investigators intended to show that the method could be used for field collected material, several factors which may affect isoenzyme analysis such as fly age, reproductive status, nutrition, storage at low temperatures etc. were studied. Fifteen enzyme systems were included. Seven of these showed genetic polymorphism and some differences were related to geographic distribution. Because of interference from various factors, it is recommended that pupae be collected and that flies be analyzed at least 24 hours after the last blood meal. Methods of holding material for analysis are suggested

Tsetse flies and their control.

Science.gov (United States)

Rogers, D J; Hendrickx, G; Slingenbergh, J H

1994-12-01

The authors use a quantitative modelling framework to describe and explore the features of the biology of tsetse flies (Glossina spp.) which are important in determining the rate of transmission of the African trypanosomiases between hosts. Examples are presented of the contribution of previous research on tsetse to quantified epidemiological and epizootiological understanding, and areas of current ignorance are identified for future study. Spatial and temporal variations in risk are important (but rarely-studied) determinants of the impact of trypanosomiasis on humans, domestic animals and agricultural activities. Recent grid-based sampling surveys to Togo provide valuable data sets on tsetse, cattle and trypanosomiasis throughout the country. A combination of ground-based meterological and remotely-sensed satellite data, within linear discriminant analytical models, enables description of the observed distributions of the five species of tsetse occurring in Togo, with accuracies of between 72% (Glossina palpalis and G. tachinoides) and 98% (G. fusca). Abundance classes of the two most widespread species, G. palpalis and G. tachinoides, are described with accuracies of between 47% and 83%. This is especially remarkable given the relatively small differences between the average values of the predictor variables in areas of differing fly abundance. Similar analyses could be used to predict the occurrence and abundance of flies in other areas, which have not been surveyed to date, in order to plan tsetse control campaigns or explore development options. Finally, some recent tsetse control campaigns are briefly reviewed. The shift of emphasis from fly eradication to fly control is associated with a devolution of responsibility for control activities from central government to local areas, communities or even individuals. The future role of central governments will remain crucial, however, in determining the areas in which different control options are practised, in

Arsenophonus and Sodalis Symbionts in Louse Flies: an Analogy to the Wigglesworthia and Sodalis System in Tsetse Flies.

Science.gov (United States)

Nováková, Eva; Husník, Filip; Šochová, Eva; Hypša, Václav

2015-09-01

Symbiosis between insects and bacteria result in a variety of arrangements, genomic modifications, and metabolic interconnections. Here, we present genomic, phylogenetic, and morphological characteristics of a symbiotic system associated with Melophagus ovinus, a member of the blood-feeding family Hippoboscidae. The system comprises four unrelated bacteria representing different stages in symbiosis evolution, from typical obligate mutualists inhabiting bacteriomes to freely associated commensals and parasites. Interestingly, the whole system provides a remarkable analogy to the association between Glossina and its symbiotic bacteria. In both, the symbiotic systems are composed of an obligate symbiont and two facultative intracellular associates, Sodalis and Wolbachia. In addition, extracellular Bartonella resides in the gut of Melophagus. However, the phylogenetic origins of the two obligate mutualist symbionts differ. In Glossina, the mutualistic Wigglesworthia appears to be a relatively isolated symbiotic lineage, whereas in Melophagus, the obligate symbiont originated within the widely distributed Arsenophonus cluster. Although phylogenetically distant, the two obligate symbionts display several remarkably similar traits (e.g., transmission via the host's "milk glands" or similar pattern of genome reduction). To obtain better insight into the biology and possible role of the M. ovinus obligate symbiont, "Candidatus Arsenophonus melophagi," we performed several comparisons of its gene content based on assignments of the Cluster of Orthologous Genes (COG). Using this criterion, we show that within a set of 44 primary and secondary symbionts, "Ca. Arsenophonus melophagi" is most similar to Wigglesworthia. On the other hand, these two bacteria also display interesting differences, such as absence of flagellar genes in Arsenophonus and their presence in Wigglesworthia. This finding implies that a flagellum is not essential for bacterial transmission via milk glands

Structuration génétique de trois populations de Glossina palpalis ...

African Journals Online (AJOL)

L'objectif général de cette étude était de détecter un éventuel isolement des populations de G. p. palpalis de ces 3 sites et d'évaluer l'effet de la peinture insecticide de micro encapsulation bio-polymérique Inesfly™ 5 A IGR NG sur la densité des glossines du parc zoologique. Sept marqueurs microsatellites ont été utilisés ...

Towards an Early Warning System for Rhodesian Sleeping Sickness in Savannah Areas: Man-Like Traps for Tsetse Flies

Science.gov (United States)

Vale, Glyn A.; Hall, David R.; Chamisa, Andrew; Torr, Stephen J.

2012-01-01

Background In the savannahs of East and Southern Africa, tsetse flies (Glossina spp.) transmit Trypanosoma brucei rhodesiense which causes Rhodesian sleeping sickness, the zoonotic form of human African trypanosomiasis. The flies feed mainly on wild and domestic animals and are usually repelled by humans. However, this innate aversion to humans can be undermined by environmental stresses on tsetse populations, so increasing disease risk. To monitor changes in risk, we need traps designed specifically to quantify the responsiveness of savannah tsetse to humans, but the traps currently available are designed to simulate other hosts. Methodology/Principal Findings In Zimbabwe, two approaches were made towards developing a man-like trap for savannah tsetse: either modifying an ox-like trap or creating new designs. Tsetse catches from a standard ox-like trap used with and without artificial ox odor were reduced by two men standing nearby, by an average of 34% for Glossina morsitans morsitans and 56% for G. pallidipes, thus giving catches more like those made by hand-nets from men. Sampling by electrocuting devices suggested that the men stopped flies arriving near the trap and discouraged trap-entering responses. Most of human repellence was olfactory, as evidenced by the reduction in catches when the trap was used with the odor of hidden men. Geranyl acetone, known to occur in human odor, and dispensed at 0.2 mg/h, was about as repellent as human odor but not as powerfully repellent as wood smoke. New traps looking and smelling like men gave catches like those from men. Conclusion/Significance Catches from the completely new man-like traps seem too small to give reliable indices of human repellence. Better indications would be provided by comparing the catches of an ox-like trap either with or without artificial human odor. The chemistry and practical applications of the repellence of human odor and smoke deserve further study. PMID:23301107

Towards an early warning system for Rhodesian sleeping sickness in savannah areas: man-like traps for tsetse flies.

Directory of Open Access Journals (Sweden)

Glyn A Vale

Full Text Available BACKGROUND: In the savannahs of East and Southern Africa, tsetse flies (Glossina spp. transmit Trypanosoma brucei rhodesiense which causes Rhodesian sleeping sickness, the zoonotic form of human African trypanosomiasis. The flies feed mainly on wild and domestic animals and are usually repelled by humans. However, this innate aversion to humans can be undermined by environmental stresses on tsetse populations, so increasing disease risk. To monitor changes in risk, we need traps designed specifically to quantify the responsiveness of savannah tsetse to humans, but the traps currently available are designed to simulate other hosts. METHODOLOGY/PRINCIPAL FINDINGS: In Zimbabwe, two approaches were made towards developing a man-like trap for savannah tsetse: either modifying an ox-like trap or creating new designs. Tsetse catches from a standard ox-like trap used with and without artificial ox odor were reduced by two men standing nearby, by an average of 34% for Glossina morsitans morsitans and 56% for G. pallidipes, thus giving catches more like those made by hand-nets from men. Sampling by electrocuting devices suggested that the men stopped flies arriving near the trap and discouraged trap-entering responses. Most of human repellence was olfactory, as evidenced by the reduction in catches when the trap was used with the odor of hidden men. Geranyl acetone, known to occur in human odor, and dispensed at 0.2 mg/h, was about as repellent as human odor but not as powerfully repellent as wood smoke. New traps looking and smelling like men gave catches like those from men. CONCLUSION/SIGNIFICANCE: Catches from the completely new man-like traps seem too small to give reliable indices of human repellence. Better indications would be provided by comparing the catches of an ox-like trap either with or without artificial human odor. The chemistry and practical applications of the repellence of human odor and smoke deserve further study.

Dynamics of tsetse natural infection rates in the Mouhoun river, Burkina Faso, in relation with environmental factors

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Jérémy eBouyer

2013-08-01

Full Text Available In Burkina Faso, the cyclical vectors of African animal trypanosomoses (AAT are riverine tsetse species, namely Glossina palpalis gambiensis Vanderplank (G.p.g. and Glossina tachinoides Westwood (G. t. (Diptera: Glossinidae. Experimental work demonstrated that environmental stress can increase the sensitivity of tsetse to trypanosome infection.Seasonal variations of the tsetse infection rates were monitored monthly over 17 months (May 2006-Sept 2007 in two sites (Douroula and Kadomba. In total, 1,423 flies were dissected and the infection of the proboscis, middle intestine and salivary glands was noted. All the positive organs were analyzed using monospecific polymerase chain reaction (PCR primers. To investigate the role of different environmental factors, fly infection rates were analyzed using generalized linear mixed binomial models using the species, sex, and monthly averages of the maximal, minimal and mean daily temperatures, rainfalls, Land Surface Temperature day (LSTd and night (LSTn as fixed effects and the trap position as a random effect.The overall infection rate was 10% from which the predominant species was T. congolense (7.6% of the flies, followed by T. vivax (2.2% of the flies. The best model (lowest AICc for the global infection rates was the one with the maximal daily temperature only as fixed effect (p<0.001. For T. congolense, the best model was the one with the tsetse species, sex, maximal daily temperature and rainfalls as fixed effect, where the maximal daily temperature was the main effect (p<0.001. The number of T. vivax infections was too low to allow the models to converge. The maturation rate of T. congolense was very high (94%, and G. t. harbored a higher maturation rate (p=0.03.The results are discussed in view of former laboratory studies showing that temperature stress can increase the susceptibility of tsetse to trypanosomes, as well as the possibility to improve AAT risk mapping using satellite images.

History of the sterile insect technique

International Nuclear Information System (INIS)

Klassen, W.; Curtis, C.F.

2005-01-01

During the 1930s and 1940s the idea of releasing insects of pest species to introduce sterility (sterile insect technique or SIT) into wild populations, and thus control them, was independently conceived in three extremely diverse intellectual environments. The key researchers were A. S. Serebrovskii at Moscow State University, F. L. Vanderplank at a tsetse field research station in rural Tanganyika (now Tanzania), and E. F. Knipling of the United States Department of Agriculture. Serebrovskii's work on chromosomal translocations for pest population suppression could not succeed in the catastrophic conditions in the USSR during World War II, after which he died. Vanderplank used hybrid sterility to suppress a tsetse population in a large field experiment, but lacked the resources to develop this method further. Knipling and his team exploited H. J. Muller's discovery that ionizing radiation can induce dominant lethal mutations, and after World War II this approach was applied on an area-wide basis to eradicate the New World screwworm Cochliomyia hominivorax (Coquerel) in the USA, Mexico, and Central America. Since then very effective programmes integrating the SIT have been mounted against tropical fruit flies, some species of tsetse flies Glossina spp., the pink bollworm Pectinophora gossypiella (Saunders), and the codling moth Cydia pomonella (L.). In non-isolated onion fields in the Netherlands, the onion maggot Delia antiqua (Meigen) has since 1981 been suppressed by the SIT. In the 1970s there was much research conducted on mosquito SIT, which then went into 'eclipse', but now appears to be reviving. Development of the SIT for use against the boll weevil Anthonomus grandis grandis Boheman and the gypsy moth Lymantria dispar (L.) has ended, but it is in progress for two sweetpotato weevil species, Cylas formicarius (F.) and Euscepes postfasciatus (Fairmaire), the false codling moth Cryptophlebia leucotreta (Meyrick), the carob moth Ectomyelois ceratoniae

Theoretical and Practical Studies on a Possible Genetic Method for Tsetse Fly Control

Energy Technology Data Exchange (ETDEWEB)

Curtis, C. F. [Tsetse Research Laboratory, School of Veterinary Science, University Of Bristol, Langford, Bristol (United Kingdom); Hill, W. G. [Institute of Animal Genetics, Edinburgh (United Kingdom)

1968-06-15

Chromosome translocations may be useful in pest control because they are a common type of mutation in a variety of organisms and, frequently, the heterozygote is semi-sterile and the homo- zygote folly fertile. It might be possible to induce such a translocation in a pest species, to breed from a selected ancestral pair of translocation homozygotes a large number of the homozygotes and to release these into a wild population. This would cause the production of heterozygotes in the wild population and hence would reduce the fertility of the population. This reduction would persist for a number of generations. Calculations, based on simplified assumptions, showed that this method of fertility reduction might be more economical than the use of sterilized males. In the present paper a theoretical comparison is made of the translocation and sterilized-male methods for the control of tsetse flies (Glossina sp.). A computer model has been set up which simulates, as far as possible, the known facts about birth, mating and death in a wild tsetse population. The predicted effects of releases of sterilized males and of translocation homozygotes are described and the modifications which would be caused by density-dependent mortality, migration and reduced viability of the translocation genotypes and sterilized males are indicated. It is concluded that to eradicate a well isolated wild population the numbers of translocation homozygotes required might well be considerably less than the number of sterilized males required for the same task. However, immigration into the population would greatly reduce the efficiency of the translocation method. The progress so far in attempting to produce a suitable translocation in Glossina austeni is described. Males have been treated with 5-7 krad of gamma radiation and a number of semi-sterile individuals have been selected from among their progeny. The semi-sterility is inherited and, by analogy with the results in other organisms, is

Use of gamma-irradiated blood for feeding tsetse flies

International Nuclear Information System (INIS)

Bauer, B.; Iwannek, K.H.; Hamann, H.J.; Adamsky, G.

1980-01-01

Freshly collected pig blood was sterilized by 60 Co gamma irradiation. A dose of 100 krad proved to be effective against Pseudomonas aeruginosa at concentrations of at least 4.7x10 5 /ml. Glossina morsitans morsitans (Westw.) were maintained on this blood by feeding them five days per week on silicone membrane for nine months. Their performance was compared with a control fed untreated blood. In spite of the slightly faster haemolysis of the irradiated blood, the results from the experimental group compared favourably with the control. This was especially true for the percentage of daily mortality. The irradiation seems to offer a promising approach for the establishment of mass rearing plants in Africa based on in vitro feeding provided the blood from donor animals is suitable for tsetse flies. (author)

Wolbachia symbiont infections induce strong cytoplasmic incompatibility in the tsetse fly Glossina morsitans.

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Uzma Alam

2011-12-01

Full Text Available Tsetse flies are vectors of the protozoan parasite African trypanosomes, which cause sleeping sickness disease in humans and nagana in livestock. Although there are no effective vaccines and efficacious drugs against this parasite, vector reduction methods have been successful in curbing the disease, especially for nagana. Potential vector control methods that do not involve use of chemicals is a genetic modification approach where flies engineered to be parasite resistant are allowed to replace their susceptible natural counterparts, and Sterile Insect technique (SIT where males sterilized by chemical means are released to suppress female fecundity. The success of genetic modification approaches requires identification of strong drive systems to spread the desirable traits and the efficacy of SIT can be enhanced by identification of natural mating incompatibility. One such drive mechanism results from the cytoplasmic incompatibility (CI phenomenon induced by the symbiont Wolbachia. CI can also be used to induce natural mating incompatibility between release males and natural populations. Although Wolbachia infections have been reported in tsetse, it has been a challenge to understand their functional biology as attempts to cure tsetse of Wolbachia infections by antibiotic treatment damages the obligate mutualistic symbiont (Wigglesworthia, without which the flies are sterile. Here, we developed aposymbiotic (symbiont-free and fertile tsetse lines by dietary provisioning of tetracycline supplemented blood meals with yeast extract, which rescues Wigglesworthia-induced sterility. Our results reveal that Wolbachia infections confer strong CI during embryogenesis in Wolbachia-free (Gmm(Apo females when mated with Wolbachia-infected (Gmm(Wt males. These results are the first demonstration of the biological significance of Wolbachia infections in tsetse. Furthermore, when incorporated into a mathematical model, our results confirm that Wolbachia can be used successfully as a gene driver. This lays the foundation for new disease control methods including a population replacement approach with parasite resistant flies. Alternatively, the availability of males that are reproductively incompatible with natural populations can enhance the efficacy of the ongoing sterile insect technique (SIT applications by eliminating the need for chemical irradiation.

Midgut absorption of proteins by tsetse flies, Glossina morsitans morsitans Westwood (Diptera: Glossinidae)

International Nuclear Information System (INIS)

Nogge, G.; Giannetti, M.

1980-01-01

Experiments have been conducted to determine how far tsetse flies are able to absorb undigested proteins from the midgut and to transport into the haemolymph. Comparison of the protein pattern of blood serum and haemolymph as revealed by electrophoresis shows no congruency except for the albumin fraction, which is about 10% of the total protein contents. The peritrophic membrane of tsetse flies allows the passage of FITC-conjugated dextrans up to but not greater than a molecular weight of approximately 45,000. It can be concluded therefore that complete serum globulins cannot pass through the peritrophic membrane, but fragments of globulins and albumin might do so. The presence of serum proteins in the haemolymph of tsetse flies after oral administration was investigated by immunological techniques. With the help of immunoelectrophoresis as well as Ouchter-Lony tests, albumin, Fab-, and Fc-fragments were found to be present in the haemolymph. Tsetse flies usually fed on bovine blood replace bovine albumin present in their haemolymph by human albumin when fed on human blood. Quantitative determinations with the aid of rocket immunoelectrophoresis after Laurell revealed the occurrence of human albumin in relation to the size and number of blood meals. When fed continuously on human blood, the amount of human albumin rises following eight to ten blood meals after which the achieved level is maintained. Human albumin disappears from the haemolymph and is replaced by bovine albumin when the flies are fed again with bovine blood. On the basis of these results the amount of albumin absorbed from a single blood meal lies in the range of 0.01 to 0.035% of its albumin contents. (author)

Transcriptome Profiling of Trypanosoma brucei Development in the Tsetse Fly Vector Glossina morsitans.

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Amy F Savage

Full Text Available African trypanosomes, the causative agents of sleeping sickness in humans and nagana in animals, have a complex digenetic life cycle between a mammalian host and an insect vector, the blood-feeding tsetse fly. Although the importance of the insect vector to transmit the disease was first realized over a century ago, many aspects of trypanosome development in tsetse have not progressed beyond a morphological analysis, mainly due to considerable challenges to obtain sufficient material for molecular studies. Here, we used high-throughput RNA-Sequencing (RNA-Seq to profile Trypanosoma brucei transcript levels in three distinct tissues of the tsetse fly, namely the midgut, proventriculus and salivary glands. Consistent with current knowledge and providing a proof of principle, transcripts coding for procyclin isoforms and several components of the cytochrome oxidase complex were highly up-regulated in the midgut transcriptome, whereas transcripts encoding metacyclic VSGs (mVSGs and the surface coat protein brucei alanine rich protein or BARP were extremely up-regulated in the salivary gland transcriptome. Gene ontology analysis also supported the up-regulation of biological processes such as DNA metabolism and DNA replication in the proventriculus transcriptome and major changes in signal transduction and cyclic nucleotide metabolism in the salivary gland transcriptome. Our data highlight a small repertoire of expressed mVSGs and potential signaling pathways involving receptor-type adenylate cyclases and members of a surface carboxylate transporter family, called PADs (Proteins Associated with Differentiation, to cope with the changing environment, as well as RNA-binding proteins as a possible global regulators of gene expression.

Acoustic Method for Testing the Quality of Sterilized Male Tsetse Flies Glossina Pallidipes

Energy Technology Data Exchange (ETDEWEB)

Kratochvil, H [Department of Evolutionary Biology, University of Vienna, Halsriegelstr. 34, Vienna A-1090 (Austria); Noll, A [Institut fuer Schallforschung, Oe Ak d Wiss, Wohllebengasse 12-14, Vienna A-1040 (Austria); Bolldorf, J [Umweltbundesamt, Spittelauer Laende 5, Vienna A-1090 (Austria); Parker, A G [Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, FAO/IAEA Agriculture and Biotechnology Laboratory, Seibersdorf A-2444 (Austria)

2012-07-15

Tsetse flies are able to emit different acoustic signals. An acoustic method to test the quality of sterilized male tsetse flies was developed. Differences in the sound characteristics between males and females, between sterilized and unsterilized males, and between males sterilized in air and nitrogen, were determined. Also, the acoustic parameters (frequency, time, sound pressure level) of the sounds that are useful as criteria for quality control were determined. It was demonstrated that only the so-called 'feeding sounds' can be used as a quality criterion. Both sexes emitted feeding sounds while feeding on a host. These sounds were also used to find sexual partners, and had an effect on male copulation success. An acoustic sound analysis programme was developed; it automatically measured sound activity (only feeding sounds) under standard conditions (random sample, relative humidity, temperature, light intensity). (author)

Parturition in Tsetse Flies: Endocrine Control

Energy Technology Data Exchange (ETDEWEB)

Zd' arek, J; Cvacka, J; Sanda, M [Institute of Organic Chemistry and Biochemistry, AV CR, Prague (Czech Republic); Takac, P; Keszeliova, D; Simo, L; Roller, L [Institute of Zoology, SAV, Bratislava (Slovakia)

2012-07-15

A problem in tsetse mass rearing facilities is the increased incidence of abortions of underdeveloped larvae or pupariation of larvae within the mother's uterus. We analysed the problem by investigating neural, hormonal and environmental factors controlling parturition. Input from the mother's brain is essential for normal parturition, since a female whose brain is disconnected by ligation fails to deposit her larva. The expulsion of a larva is stimulated by a putative parturition hormone present within the female's uterus. The hormone also elicits abortion when injected into neck ligated females at earlier stages of pregnancy. This report describes attempts to reveal the chemical nature of this hormone by purification of extracts of uteri of Glossina females and identification of behaviourally active fractions using a MALDI-MS instrument. Genomic (BLAST) analysis of the identified sequences did not reveal a significant match with any protein with bioactive properties in other species. However, similarity with various enzymes or structural proteins (and hypothetical proteins) was detected occasionally. In the Glossina genomic and cDNA databases no nucleotide sequence corresponding to the deduced AA sequences was found. Perhaps the deduced sequences are too short to obtain more significant hits both in protein and nucleotide databases. We also made investigations to elucidate environmental influences and physiological mechanisms associated with tsetse parturition. We found that the circadian rhythm of parturition of flies kept in Bratislava (G. m. morsitans, G. f. fuscipes and G. pallidipes) is less pronounced than under natural conditions. The loss of synchrony in the laboratory may have three possible causes: (i) genetic - absence of selective pressure, (ii) environmental - low intensity or absence of an entraining light or temperature stimulus, and (iii) physiological - impaired sensitivity to olfactory stimulation by a hypothetical 'oviposition' pheromone that

Detection and characterisation of trypanosome strains supposedly resistant to trypanocidal drugs in Senegal

International Nuclear Information System (INIS)

Diaite, A.; Seye, M.; Mane, A.; Ndiaye, T.; Seye, M.M.

1997-01-01

In the region of Sokone cattle are constantly exposed to infections with trypanosomes transmitted by Glossina morsitans submorsitans and G. palpalis gambiensis. Trypanocidal drugs are widely used by the farmers on the 50,000 cattle present in the region. Consequently, drug resistance has become a major problem. During the present study goats were inoculated with trypanosome strains isolated from infected cattle. Following the appearance of parasitaemia, the animals were treated with either Berenil, Samorin or Ethidium. The results indicated the parasites were susceptible to Samorin, but one of the Trypanosoma vivax strains showed resistance to Berenil and Ethidium. In addition, the performance of the antigen detection ELISA was compared with that of the Buffy Coat Technique using more than 1000 serum samples from the Sokone region and 100 samples from Northern Senegal infested with tsetse flies. The results showed a very high specificity of 98%. However, additional tests will be necessary to assess the sensitivity properly. (author). 3 refs, 7 tabs

Detection and characterisation of trypanosome strains supposedly resistant to trypanocidal drugs in Senegal; Detection au buffy coat technique et en ELISA de souches de trypanosomes supposees chimioresistantes au Senegal et caracterisation therapeutique

Energy Technology Data Exchange (ETDEWEB)

Diaite, A; Seye, M; Mane, A; Ndiaye, T; Seye, M M [Institut Senegalais de Recherches Agricoles (ISRA), Dakar (Senegal). Lab. de Parasitologie

1997-02-01

In the region of Sokone cattle are constantly exposed to infections with trypanosomes transmitted by Glossina morsitans submorsitans and G. palpalis gambiensis. Trypanocidal drugs are widely used by the farmers on the 50,000 cattle present in the region. Consequently, drug resistance has become a major problem. During the present study goats were inoculated with trypanosome strains isolated from infected cattle. Following the appearance of parasitaemia, the animals were treated with either Berenil, Samorin or Ethidium. The results indicated the parasites were susceptible to Samorin, but one of the Trypanosoma vivax strains showed resistance to Berenil and Ethidium. In addition, the performance of the antigen detection ELISA was compared with that of the Buffy Coat Technique using more than 1000 serum samples from the Sokone region and 100 samples from Northern Senegal infested with tsetse flies. The results showed a very high specificity of 98%. However, additional tests will be necessary to assess the sensitivity properly. (author). 3 refs, 7 tabs.

Excreted/Secreted Proteins from Trypanosome Procyclic Strains

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Celestine Michelle Atyame Nten

2010-01-01

Full Text Available Trypanosoma secretome was shown to be involved in parasite virulence and is suspected of interfering in parasite life-cycle steps such as establishment in the Glossina midgut, metacyclogenesis. Therefore, we attempted to identify the proteins secreted by procyclic strains of T. brucei gambiense and T. brucei brucei, responsible for human and animal trypanosomiasis, respectively. Using mass spectrometry, 427 and 483 nonredundant proteins were characterized in T. brucei brucei and T. brucei gambiense secretomes, respectively; 35% and 42% of the corresponding secretome proteins were specifically secreted by T. brucei brucei and T. brucei gambiense, respectively, while 279 proteins were common to both subspecies. The proteins were assigned to 12 functional classes. Special attention was paid to the most abundant proteases (14 families because of their potential implication in the infection process and nutrient supply. The presence of proteins usually secreted via an exosome pathway suggests that this type of process is involved in trypanosome ESP secretion. The overall results provide leads for further research to develop novel tools for blocking trypanosome transmission.

Blood Collection from Local Abattoirs for Mass Production of Tsetse Flies to be used in the Sterile Insect Technique

Energy Technology Data Exchange (ETDEWEB)

Byamungu, M B; Kiimbisa, B; Matembo, S; Mashenga, G [Tsetse and Trypanosomiasis Research Institute, P.O. Box 1026, Tanga (Tanzania, United Republic of)

2012-07-15

The mass production of tsetse flies (Glossina spp.) for the sterile insect technique (SIT) requires a supply of quality blood. For some years already cattle blood has been used as food for laboratory reared flies. The blood is collected from an abattoir using standard procedures. The collection procedures, handling and storage require aseptic conditions to avoid contamination of the blood, which could be fatal to the flies. Fly mortality caused by low quality blood endangers the success of mass rearing. To rear healthy flies with good survival and production the blood should be of good quality - free of contamination and with a packed cell volume (PCV) above 25%. The present work involved the seasonal collection of blood from abattoirs in the United Republic of Tanzania (Tanga, Arusha, Dodoma, Dar-es-salaam). Dodoma was identified as having the best conditions for blood collection. To assess the quality of the blood as a diet for tsetse, blood was screened for the presence of bacteria, and the pathogens were identified. Protocols were developed for blood quality assurance. (author)

Genetic engineering technology for the improvement of the sterile insect technique. Proceedings of a final research co-ordination meeting

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-01-01

Since the beginning of the joint FAO/IAEA programme on the research and development of insect pest control methodology, emphasis has been placed on the basic and applied aspects of implementing the sterile insect technique (SIT). Special emphasis has always been directed at the assembly of technological progress into workable systems that can be implemented in developing countries. The general intention is to solve problems associated with insect pests that have an adverse impact on production of food and fibre. For several insect species SIT has proven to be a powerful method for control. This includes the New World screwworm fly (Cochliomyia hominivorox), the Mediterranean fruit fly (Ceratitis capitata), the melon fly (Bactrocera cucurbitae), the Queensland fruit fly (Bactrocera tryoni) and one tsetse fly species (Glossina austeni). Improvements of the SIT are possible, especially through the use of molecular techniques. The final report of the Co-ordinated Research Programme on ``Genetic Engineering Technology for the Improvement of the Sterile Insect Technique`` highlights the progress made towards the development of transformation systems for non-drosophilid insects and the research aimed at the identification and engineering of potential target genes or traits. Refs, figs, tabs.

Challenging the Wigglesworthia, Sodalis, Wolbachia symbiosis dogma in tsetse flies: Spiroplasma is present in both laboratory and natural populations.

Science.gov (United States)

Doudoumis, V; Blow, F; Saridaki, A; Augustinos, A; Dyer, N A; Goodhead, I; Solano, P; Rayaisse, J-B; Takac, P; Mekonnen, S; Parker, A G; Abd-Alla, A M M; Darby, A; Bourtzis, K; Tsiamis, G

2017-07-05

Profiling of wild and laboratory tsetse populations using 16S rRNA gene amplicon sequencing allowed us to examine whether the "Wigglesworthia-Sodalis-Wolbachia dogma" operates across species and populations. The most abundant taxa, in wild and laboratory populations, were Wigglesworthia (the primary endosymbiont), Sodalis and Wolbachia as previously characterized. The species richness of the microbiota was greater in wild than laboratory populations. Spiroplasma was identified as a new symbiont exclusively in Glossina fuscipes fuscipes and G. tachinoides, members of the palpalis sub-group, and the infection prevalence in several laboratory and natural populations was surveyed. Multi locus sequencing typing (MLST) analysis identified two strains of tsetse-associated Spiroplasma, present in G. f. fuscipes and G. tachinoides. Spiroplasma density in G. f. fuscipes larva guts was significantly higher than in guts from teneral and 15-day old male and female adults. In gonads of teneral and 15-day old insects, Spiroplasma density was higher in testes than ovaries, and was significantly higher density in live versus prematurely deceased females indicating a potentially mutualistic association. Higher Spiroplasma density in testes than in ovaries was also detected by fluorescent in situ hybridization in G. f. fuscipes.

Mass rearing and radiation sterilization of tsetse flies. Part of a coordinated programme on control and eradication of tsetse flies by the sterile insect technique

International Nuclear Information System (INIS)

Offori, E.

1980-12-01

Studies were conducted with the tsetse flies Glossina palpalis palpalis, G.p. gambiensis and G. tachinoides to evaluate the practicality in Ghana of various laboratory and field procedures used to conduct a sterile insect release programme. Investigations revealed that in colony rearing rabbits, guinea pigs and goats could be used as host animals and that alternation of hosts had little effect on colony performance. Over 90% sterility in 10-day-old males irradiated at 12 kR was obtained with little or no effect on survival. At 15 kR, 98% sterility was obtained but with some loss in viability observed. In mating experiments, G. p. palpalis and G. p. gambiensis mated readily with each other and indicated that sterile males of one sub-species could be released with advantage into an area predominantly occupied by the other sub-species. In field tests, the moving vehicle traps proved most efficient of the various sampling techniques evaluated. It was noted that in spite of the rapid expansion of the city of Accra, tsetse flies were still present within a distance of 4 km of the city

Genetic engineering technology for the improvement of the sterile insect technique. Proceedings of a final research co-ordination meeting

International Nuclear Information System (INIS)

1998-01-01

Since the beginning of the joint FAO/IAEA programme on the research and development of insect pest control methodology, emphasis has been placed on the basic and applied aspects of implementing the sterile insect technique (SIT). Special emphasis has always been directed at the assembly of technological progress into workable systems that can be implemented in developing countries. The general intention is to solve problems associated with insect pests that have an adverse impact on production of food and fibre. For several insect species SIT has proven to be a powerful method for control. This includes the New World screwworm fly (Cochliomyia hominivorox), the Mediterranean fruit fly (Ceratitis capitata), the melon fly (Bactrocera cucurbitae), the Queensland fruit fly (Bactrocera tryoni) and one tsetse fly species (Glossina austeni). Improvements of the SIT are possible, especially through the use of molecular techniques. The final report of the Co-ordinated Research Programme on ''Genetic Engineering Technology for the Improvement of the Sterile Insect Technique'' highlights the progress made towards the development of transformation systems for non-drosophilid insects and the research aimed at the identification and engineering of potential target genes or traits

Annual Report 2015: Project Glossines

International Nuclear Information System (INIS)

2016-04-01

On the basis of the results of the feasibility study which (i) confirmed the presence of Glossina palpalis gambiensis on the Dakar-Thies-Kayar triangle and the disease it transmits (trypanosomiasis) and (ii) Isolated from the area in relation to other tsetse infested areas, the control phase started in 2010. The following results were obtained: block I (Kayar) has been rehabilitated since 2012; populations of tsetse flies are reduced to more than 99% in Block II (Sebikotane, Diacsaw Peulh, Pout) where the release of sterile males of tsetse fly sterile insect technique since 2013 for the complete liberation of the area, are terminally ill; the reduction of tsetse populations has started since June 2015 in blocks 3a (Dakar, Rufisque) and 3b (Thies) with a success rate of more than 95%. Starting of sterile male releases is planned for June 2016; the prevalence of trypanosomiasis, a disease transmitted by tsetse flies, increased from 10% to less than 1%; the total elimination of tsetse flies in the Niayes area is expected by the end of 2017. Activities in 2015 consisted of entomological monitoring throughout the Project area (blocks 1, 2 and 3), suppression in the block 3, elimination in block 2, parasitological monitoring, environmental monitoring and socio-economic study at the selected sites. (Author)

Monitoring of a tsetse and trypanosomosis control programme in plateau and Bauchi State, Nigeria, using antigen ELISA and parasitological techniques

International Nuclear Information System (INIS)

Ajayi, S.A.; Ogedengbe, J.D.; Dogo, G.I.; Frame, I.A.

1997-01-01

Between July 1994 and January 1995 a total of 1153 samples were collected from cattle in Plateau and Bauchi State, Nigeria, and analyzed for the presence of trypanosome infections using parasitological (Buffy Coat Technique [BCT] and blood film smears) and serological techniques (Ag-ELISA). A simple random sampling technique was employed. Tsetse flies and other insects were trapped during the same period using NITSE and biconical traps. Twenty two tsetse flies (6 Glossina p. palpalis, 3 G. longipalpis and 13 G. tachinoides) were caught, identified and dissected to check for trypanosomal infections. The results obtained using parasitological techniques showed an average prevalence rate in the two states surveyed of 3.4%. The antigen-capture ELISA technique (Ag-ELISA) was used to analyze 280 serum samples which were negative for trypanosomes when checked by BCT. Of these samples none were positive for T. congolense and 4 (1.4%) were detected positive for T. brucei. A subset of 120 samples was analyzed for the presence of T. vivax and 3 (2.5%) were found to be positive. The relative specificity of the Ag-ELISA for T. brucei, T. congolense and T. vivax was 98.5% 100% and 97.5%, respectively. (author). 8 refs, 1 fig., 3 tabs

Tsetse elimination: its interest and feasibility in the historical sleeping sickness focus of Loos islands, Guinea

Directory of Open Access Journals (Sweden)

Kagbadouno M.

2009-03-01

Full Text Available Guinea is the West African country which is currently the most prevalent for sleeping sickness. The littoral area is the region where most of the recent sleeping sickness cases have been described, especially the mangrove sleeping sickness foci of Dubreka and Boffa where Glossina palpalis gambiensis is the vector. Loos islands constitute a small archipelago 5 km apart from the capital, Conakry. Medical, animal, and entomological surveys were implemented in these islands in Oct-Nov 2006. No pathogenic trypanosomes were found in these surveys. The locally very high tsetse densities (up to more than 100 tsetse/trap/day linked to pig rearing, constitute a high potential risk for humans (taking into account populations movements with neighboring active sleeping sickness foci of the Guinea littoral, and the history of sleeping sickness on these islands, and for the economically important pig rearing, as well as a danger for tourism. This situation, associated to the possibility of elimination of these tsetse populations due to low possibility of reinvasion, led the National Control Program to launch a tsetse elimination project following an “area wide” strategy for the first time in West Africa, which participates in the global objective of the PATTEC (Pan African Tsetse and Trypanosomosis Eradication Campaign.

Monitoring of a tsetse and trypanosomosis control programme in plateau and Bauchi State, Nigeria, using antigen ELISA and parasitological techniques

Energy Technology Data Exchange (ETDEWEB)

Ajayi, S A; Ogedengbe, J D; Dogo, G I [National Veterinary Research Inst., Vom, Plateau State (Nigeria). Parasitology Div.; Frame, I A [London School of Hygiene and Tropical Medicine, London (United Kingdom). Dept. of Med. Parasitol

1997-02-01

Between July 1994 and January 1995 a total of 1153 samples were collected from cattle in Plateau and Bauchi State, Nigeria, and analyzed for the presence of trypanosome infections using parasitological (Buffy Coat Technique [BCT] and blood film smears) and serological techniques (Ag-ELISA). A simple random sampling technique was employed. Tsetse flies and other insects were trapped during the same period using NITSE and biconical traps. Twenty two tsetse flies (6 Glossina p. palpalis, 3 G. longipalpis and 13 G. tachinoides) were caught, identified and dissected to check for trypanosomal infections. The results obtained using parasitological techniques showed an average prevalence rate in the two states surveyed of 3.4%. The antigen-capture ELISA technique (Ag-ELISA) was used to analyze 280 serum samples which were negative for trypanosomes when checked by BCT. Of these samples none were positive for T. congolense and 4 (1.4%) were detected positive for T. brucei. A subset of 120 samples was analyzed for the presence of T. vivax and 3 (2.5%) were found to be positive. The relative specificity of the Ag-ELISA for T. brucei, T. congolense and T. vivax was 98.5% 100% and 97.5%, respectively. (author). 8 refs, 1 fig., 3 tabs.

Characterization of recombinant Trypanosoma brucei gambiense Translationally Controlled Tumor Protein (rTbgTCTP) and its interaction with Glossina midgut bacteria.

Science.gov (United States)

Bossard, Géraldine; Bartoli, Manon; Fardeau, Marie-Laure; Holzmuller, Philippe; Ollivier, Bernard; Geiger, Anne

2017-09-03

In humans, sleeping sickness (i.e. Human African Trypanosomiasis) is caused by the protozoan parasites Trypanosoma brucei gambiense (Tbg) in West and Central Africa, and T. b. rhodesiense in East Africa. We previously showed in vitro that Tbg is able to excrete/secrete a large number of proteins, including Translationally Controlled Tumor Protein (TCTP). Moreover, the tctp gene was described previously to be expressed in Tbg-infected flies. Aside from its involvement in diverse cellular processes, we have investigated a possible alternative role within the interactions occurring between the trypanosome parasite, its tsetse fly vector, and the associated midgut bacteria. In this context, the Tbg tctp gene was synthesized and cloned into the baculovirus vector pAcGHLT-A, and the corresponding protein was produced using the baculovirus Spodoptera frugicola (strain 9) / insect cell system. The purified recombinant protein rTbgTCTP was incubated together with bacteria isolated from the gut of tsetse flies, and was shown to bind to 24 out of the 39 tested bacteria strains belonging to several genera. Furthermore, it was shown to affect the growth of the majority of these bacteria, especially when cultivated under microaerobiosis and anaerobiosis. Finally, we discuss the potential for TCTP to modulate the fly microbiome composition toward favoring trypanosome survival.

Patterns of genetic diversity and differentiation in the tsetse fly Glossina morsitans morsitans Westwood populations in East and southern Africa

International Nuclear Information System (INIS)

Ouma, J.O.; Marquez, J.G.; Krafsur, E.S

2007-01-01

Genetic diversity and differentiation within and among nine G. morsitans morsitans populations from East and southern Africa was assessed by examining variation at seven microsatellite loci and a mitochondrial locus, cytochrome oxidase (COI). Mean COI diversity within populations was 0.63 ± 0.33 and 0.81 taken over all populations. Diversities averaged over microsatellite loci were high (mean number of alleles/locus ≥7.4; mean HE ≥ 65%) in all populations. Diversities averaged across populations were greater in East Africa (mean number of alleles = 22 ± 2.6; mean he = 0.773 ± 0.033) than in southern Africa (mean number of alleles = 18.7 ± 4.0; mean he = 0.713 ± 0.072). Differentiation among all populations was highly significant (RST = 0.25, FST = 0.132). Nei’s Gij statistics were 0.09 and 0.19 within regions for microsatellites and mitochondria, respectively; between regions, Gij was 0.14 for microsatellites and 0.23 for mitochondria. GST among populations was 0.23 for microsatellite loci and 0.40 for mitochondria. The F, G and R statistics indicate highly restricted gene flow among G. m. morsitans populations separated over geographic scales of 12–917 km. (author)

Near Infrared Imaging As a Method of Studying Tsetse Fly (Diptera: Glossinidae) Pupal Development.

Science.gov (United States)

Moran, Zelda R; Parker, Andrew G

2016-01-01

Near infrared (NIR) photography and video was investigated as a method for observing and recording intrapuparial development in the tsetse fly Glossina palpalis gambiensis and other Muscomorpha (Cyclorrhapha) Diptera. We showed that NIR light passes through the puparium, permitting images of the true pupae and pharate adult to be captured. Various wavelengths of NIR light from 880 to 1060 nm were compared to study the development of tsetse fly pupae from larviposition to emergence, using time-lapse videos and photographs. This study was carried out to advance our understanding of tsetse pupal development, specifically with the goal of improving a sorting technique which could separate male from female tsetse flies several days before emergence. Separation of the sexes at this stage is highly desirable for operational tsetse sterile insect technique control programmes, as it would permit the easy retention of females for the colony while allowing the males to be handled, irradiated and shipped in the pupal stage when they are less sensitive to vibration. In addition, it presents a new methodology for studying the pupal stage of many coarctate insects for many applications. NIR imaging permits observation of living pupae, allowing the entire development process to be observed without disruption. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America.

Mycetomes and symbionts of tsetse flies maintained on a membrane feeding system and the agents interfering with natural reproduction

International Nuclear Information System (INIS)

Soldan, T.; Matha, V.; Weyda, F.

1990-01-01

Mycetomes from male and female adults and puparia of Glossina palpalis palpalis were dissected from specimens obtained from the IAEA Laboratory at Seibersdorf, Austria. The structure and ultrastructure of the mycetocytes and endosymbionts and their quantitative changes are described and compared with other species of tsetse fly. Pronounced degenerative morphological changes can be caused by, among other factors, starvation. Irradiation by gamma rays produced only slight structural changes and non-significant changes in the endosymbiont number. In organ culture (Leibowitz medium), mycetomes of unfed females release spherical clusters of mycetocytes and lose their dense cover of microvilli. The ultrastructural changes of individual endosymbionts under these conditions are described in detail. The results of basic bioassays showing intensive DNA synthesis and in vitro production of several de novo synthesized proteins of molecular weights of 52-159 kilodalton are given. The possible role of endosymbionts in reproduction and their transmission to the offspring are discussed. While the necessity of a functional mycetome in females can, at least partially, be explained by the production of proteins necessary for reproduction, the role of the mycetome in males remains unclear. The function of the tsetse fly mycetome is shown to be much more complex than earlier supposed and further detailed data on its reproductive function are needed. (author). 26 refs, 3 figs

Prospects for area-wide integrated control of tsetse flies (Diptera:Glossinidae and trypanosomosis in sub-Saharan Africa Perspectivas para el control integrado abarcativo del área de moscas tse-tsé (Diptera: Glossinidae y la tripanosomiasis en el África sub-Sahariana

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Marc J.B. Vreysen

2006-07-01

Full Text Available Countries in sub-Saharan Africa are among the least developed in the world and hunger and poverty remains widespread in most of the rural communities. Reducing hunger and chronic under nourishment through the introduction of productive livestock as a source of traction and manure for crop production, transport, milk and meat is deemed to be a fundamental first step towards better rural development. The presence of the tsetse fly in one third of the African continent and the disease trypanosomosis it transmits is considered the major barrier to the development of productive livestock. Despite the yearly administration of 35 million doses of trypanocidal drugs (at US$ 1 per dose, African farmers lose 3 million cattle every year to the disease and annual direct economic losses are estimated at US$ 600 to 1200 million. Tsetse flies mainly affect the rural poor and are rightfully considered 'a root cause of poverty ' in Africa . The most desirable way of containing the disease trypanosomosis is undoubtedly the elimination of entire populations of the vector from delimited geographical areas using an integration of various control tactics, i.e. an areawide integrated pest management (AW-IPM approach. Efficient methods to suppress or even eliminate tsetse populations have been available for the last 50 years and are mostly based on the use of insecticides or entail devices that attract and kill. Nevertheless, despite gigantic efforts in the past century, there are only a few examples where the elimination of tsetse flies has proven to be sustainable, e.g. the elimination of Glossina pallidipes Austen from South Africa in the 1950 's using mainly aerial spraying of residual insecticides or the creation of a zone free of Glossina austeni Newstead on Unguja Island of Zanzibar (1994-1997 through the integration of various control tactics including the release of sterile insects. The decentralisation of the tsetse control offices resulting in a shift from

Effect of gamma radiation on the tsetse fly, Glossina palpalis palpalis (Rob.-Desv.)(Diptera, Glossinidae) with observations on the reproductive biology

International Nuclear Information System (INIS)

Vloedt, A.M.V. van der; Taher, M.; Tenabe, S.O.

1978-01-01

The sterility of male G. p, palpalis irradiated in the pupal stage and as adults with gamma doses of 4-12 krad given in air was investigated. The treatments did not reduce viability, mating effectiveness and longevity. Fertility showed a dose-dependent reduction with increasing dose. The doses required to reduce fertility to 5% or less in males treated as -10 or +5 day-old flies were about 6 and 12 krad respectively. Indirect effect on their mates was demonstrated by the extrusion of dead embryonated eggs at irregular intervals following ovulation and the occurrence of aberrations in the reproductive system as a direct consequence of incompleted pregnancy cycles. (author)

2013 Annual Report: Project to combat the Tsetse Fly and Trypanosomiasis in the Niayes Area

International Nuclear Information System (INIS)

2014-05-01

The period 2009-2010 was a transition phase, used to analyze the basic data collected, in particular those relating to entomology and parasitology, in order to define a control strategy. An entomological and parasitological follow-up aimed at understanding the spatio-temporal dynamics of the system before the struggle has thus been put in place. Similarly, socio-economic studies have continued with the finalization of the survey and test reports produced by certain breeders. On the basis of the results of the feasibility study which confirmed the presence of Glossina palpalis gambiensis on the Dakar-Thies-Kayar triangle and the disease it transmits (trypanosomiasis) and Isolated from the area in relation to other tsetse infested areas, the fighting phase started in 2010 in block I (Kayar) and then in 2012 in block II (Sebikotane, Diacsaw Peulh, Pout) with the deployment of impregnated traps Deltamethrin and livestock ''on'' treatment. Entomological controls (monthly measurements of apparent densities) showed a significant decrease in tsetse populations in the target areas.The phase of elimination of tsetse flies began in 2011 in the Kayar area with weekly releases of sterile males to the soil. Operational air releases began in 2013 with cardboard boxes. They will continue in 2014 with an automatic machine specially designed by a Mexican company specializing in the release of fruit flies.On the parasitological level, sick animals are detected and treated, in order to reduce the prevalence of the disease. (Author)

Annual report 1998

International Nuclear Information System (INIS)

1998-01-01

In two key areas, genetic sexing in the medfly, Ceratitis capitata, and mass rearing of the tsetse, Glossina pallidipes, 1998 has been a year of consolidation. For medfly, programme managers now view the use of genetic sexing strains - (GSS) as an integral part of the Sterile Insect Technique (SIT) for control and/or eradication of this pest. Since its introduction only 4 years ago, this technology is having an increasing impact on the implementation of medfly SIT. For tsetse, a rearing system has been designed and tested which will form the basic rearing module for the mass rearing facility to be built in Addis Ababa, Ethiopia. The system is cheap, easy to maintain and can be locally constructed. The facility in Addis Ababa will produce sterile G. pallidipes males for the SIT component of a large tsetse eradication programme in the Southern Rift valley. The Unit will continue to play a unique role in the further development of these technology transfer programmes. The Unit continues to maintain many strains of tsetse and medfly which are used to supply numerous institutions and individuals with biological material for research work. In addition, medfly GSS are provided to operational SIT programmes as required. This support provided to Member States, especially in the area of tsetse research, appears to be of increasing importance as the number of requests rise each year. All of this material is provided free of charge

Mapping Landscape Friction to Locate Isolated Tsetse Populations that are Candidates for Elimination

International Nuclear Information System (INIS)

Bouyer, Jérémy; Dicko, Ahmadou H.; Cecchi, Giuliano; Ravel, Sophie; Solano, Philippe; Guerrini, Laure; Vreysen, Marc J. B.; De Meeûs, Thierry; Lancelot, Renaud

2016-01-01

Tsetse flies are the cyclical vectors of deadly human and animal trypanosomes in sub-Saharan Africa. Tsetse control is a key component for the integrated management of both plagues, but local eradication successes have been limited to less than 2% of the infested area. This is attributed to either resurgence of residual populations that were omitted from the eradication campaign or reinvasion from neighboring infested areas. Here we focused on Glossina palpalis gambiensis, a riverine tsetse species representing the main vector of trypanosomoses in West Africa. We mapped landscape resistance to tsetse genetic flow, hereafter referred to as friction, to identify natural barriers that isolate tsetse populations. For this purpose, we fitted a statistical model of the genetic distance between 37 tsetse populations sampled in the region, using a set of remotely sensed environmental data as predictors. The least-cost path between these populations was then estimated using the predicted friction map. The method enabled us to avoid the subjectivity inherent in the expert-based weighting of environmental parameters. Finally, we identified potentially isolated clusters of G. p. gambiensis habitat based on a species distribution model and ranked them according to their predicted genetic distance to the main tsetse population. The methodology presented here will inform the choice on the most appropriate intervention strategies to be implemented against tsetse flies in different parts of Africa. It can also be used to control other pests and to support conservation of endangered species. (author)

Prevalence of mixed Trypanosoma congolense infections in livestock and tsetse in KwaZulu-Natal, South Africa

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K. Gillingwater

2010-05-01

Full Text Available Trypanosoma congolense causes the most economically important animal trypanosomosis in Africa. In South Africa, a rinderpest pandemic of the 1890s removed many host animals, resulting in the near-eradication of most tsetse species. Further suppression was achieved through spraying with dichlorodiphenyltrichloroethane (DDT; however, residual populations of Glossina austeni and G. brevipalpis remained in isolated pockets. A total of 506 of these tsetse flies were captured in the Hluhluwe-iMfolozi Park, the St Lucia Wetland Park and Boomerang commercial farm. The polymerase chain reaction (PCR was used to determine the infection rate and frequency of mixed infections of these flies. Additionally, 473 blood samples were collected from cattle at communal diptanks and a commercial farm in the area and each one examined by the haematocrit centrifugation technique (HCT. Furthermore, buffy coats from these blood samples were spotted onto FTA Elute cards and the DNA extracted from each one tested using 3 separate PCRs. The HCT revealed the presence of trypanosomes in only 6.6 % of the blood samples; by contrast, species-specific PCR detected trypanosome DNA in 50 % of the samples. The species-specific PCR detected trypanosome DNA in 17 % of the tsetse flies, compared with the nested PCR targeting rDNA which detected trypanosome DNA in only 14 % of the samples. Over time, the transmission of Savannah-type T. congolense and Kilifi-type T. congolense as mixed infections could have an impact on disease manifestation in different hosts in the area.

Les ailes de glossines, une carte d'identité de l'insecte ?

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De La Rocque S.

2002-09-01

Full Text Available Dans les études de dynamique de population des glossines, vecteurs des trypanosomoses en Afrique, la taille de l'insecte peut être mise en relation avec leur longévité et leur capacité vectorielle. La taille des individus est généralement appréciée par la mesure de nervures remarquables de l'aile. Un logiciel semi-automatique a été développé par le Cirad et l'IRD pour réaliser une série de mesures à partir de photos numérisées des ailes. Il a été utilisé sur des populations sauvages de Glossina tachinoides Westwood et G. palpalis gambiensis Vanderplank (Diptera : Glossinidae capturées autour de Bobo Dioulasso, au Burkina Faso. A partir d'une photo de l'aile, réalisée sous une loupe binoculaire et numérisée, le logiciel calcule la longueur des segments alaires, le rapport entre ces segments, la surface de la cellule "en hache" caractéristique des glossines et le niveau de gris de la membrane. Ces variables ont révélé leur intérêt taxonomique pour la diagnose entre ces espèces, mais également apportent des informations sur les caractéristiques physiologiques de la population étudiée.

Challenges in the diagnosis and management of sleeping sickness in Tanzania: a case report.

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Sindato, C; Kibona, S N; Nkya, G M; Mbilu, T J N K; Manga, C; Kaboya, J S; Rawille, F

2008-07-01

In Tanzania sleeping sickness presents a serious threat to human health with a country-wide average of 400 cases reported annually. Both wild and domestic animals have been found to play a significant role in the epidemiology of sleeping sickness. Serengeti National Park in northern Tanzania, has experienced a number of sleeping sickness epidemics since 1922. The epidemics were associated with abundant game animals in the areas and Glossina swynnertoni was incriminated as the main vector. However since 2001 there has been no case of sleeping sickness reported from the park. This case report highlights on the possibility of resurgence and challenges in the diagnosis and management of sleeping sickness in Serengeti. A 38 years old Tanzanian man working in the Serengeti National Park who had experienced various tsetse bites was presented with a febrile condition and history of unsuccessful case management at different health facilities. Blood and cerebrospinal fluid (CSF) samples were examined for the presence oftrypanosomes using wet film, Field's stain and concentration techniques. Typanosoma brucei rhodesiense were detected in both the blood and CSF samples. The patient was treated successfully with melarsoprol. The results of this case study highlight the possibility of resurgence of sleeping sickness in the park hence calls for the need to create more awareness among the community and clinicians. There is need for early reporting to health facility and strengthening the diagnostic capacity of healthcare facilities in and around national parks endemic for sleeping sickness.

Costs Of Using “Tiny Targets” to Control Glossina fuscipes fuscipes, a Vector of Gambiense Sleeping Sickness in Arua District of Uganda

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Shaw, Alexandra P. M.; Tirados, Inaki; Mangwiro, Clement T. N.; Esterhuizen, Johan; Lehane, Michael J.; Torr, Stephen J.; Kovacic, Vanja

2015-01-01

Introduction To evaluate the relative effectiveness of tsetse control methods, their costs need to be analysed alongside their impact on tsetse populations. Very little has been published on the costs of methods specifically targeting human African trypanosomiasis Methodology/Principal Findings In northern Uganda, a 250 km2 field trial was undertaken using small (0.5 X 0.25 m) insecticide-treated targets (“tiny targets”). Detailed cost recording accompanied every phase of the work. Costs were calculated for this operation as if managed by the Ugandan vector control services: removing purely research components of the work and applying local salaries. This calculation assumed that all resources are fully used, with no spare capacity. The full cost of the operation was assessed at USD 85.4 per km2, of which USD 55.7 or 65.2% were field costs, made up of three component activities (target deployment: 34.5%, trap monitoring: 10.6% and target maintenance: 20.1%). The remaining USD 29.7 or 34.8% of the costs were for preliminary studies and administration (tsetse surveys: 6.0%, sensitisation of local populations: 18.6% and office support: 10.2%). Targets accounted for only 12.9% of the total cost, other important cost components were labour (24.1%) and transport (34.6%). Discussion Comparison with the updated cost of historical HAT vector control projects and recent estimates indicates that this work represents a major reduction in cost levels. This is attributed not just to the low unit cost of tiny targets but also to the organisation of delivery, using local labour with bicycles or motorcycles. Sensitivity analyses were undertaken, investigating key prices and assumptions. It is believed that these costs are generalizable to other HAT foci, although in more remote areas, with denser vegetation and fewer people, costs would increase, as would be the case for other tsetse control techniques. PMID:25811956

Freeze dried blood and development of an artificial diet for blood feeding arthropods

International Nuclear Information System (INIS)

DeLoach, J.R.; Spates, G.E.; Kapatsa, G.M.; Sheffield, C.L.; Kabayo, J.P.

1990-01-01

The goals of the research were to determine the biochemical differences between freeze dried bovine and porcine blood relative to their nutritional value to Glossina palpalis palpalis and Stomoxys calcitrans and to develop an artificial diet for mass rearing these flies. Freeze dried bovine and porcine blood were found to differ in their amino acid content; total dietary lipids did not significantly differ, but some notable exceptions were found in fatty acid content. Both sonication and addition of foetal bovine serum to freeze dried bovine blood improved its nutritional value for G. p. palpalis. A two component, semi-defined artificial diet was developed for G. p. palpalis and S. calcitrans. The College Station diet consisted of lipid contaminated bovine haemoglobin (BHb) and bovine serum albumin (BSA). To conduct dietary deletion tests, a process was developed for preparing large quantities of ultrapure lipid free bovine haemoglobin. S. calcitrans fed on lipid free BHb plus BSA had zero fecundity. Lipids were re-added to the protein diet in three forms: (1) lipid contaminated BHb, (2) pure erythrocyte ghosts, and (3) pure lipids. It was found that membrane lipid from the erythrocyte is required by S. calcitrans. A defined artificial diet consisting of lipid free BHb, BSA, sphingomyelin, phosphatidyl ethanolamine, phosphatidyl serine and cholesterol gave normal adult survival, as well as near normal fecundity and percentage egg hatch for S. calcitrans. Knowing the identity of the lipids, it is now possible to prepare dietary formulations to alleviate dependency on the blood proteins BHb and BSA. (author). 34 refs, 1 fig., 15 tabs

Multiple evolutionary origins of Trypanosoma evansi in Kenya.

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Christine M Kamidi

2017-09-01

Full Text Available Trypanosoma evansi is the parasite causing surra, a form of trypanosomiasis in camels and other livestock, and a serious economic burden in Kenya and many other parts of the world. Trypanosoma evansi transmission can be sustained mechanically by tabanid and Stomoxys biting flies, whereas the closely related African trypanosomes T. brucei brucei and T. b. rhodesiense require cyclical development in tsetse flies (genus Glossina for transmission. In this study, we investigated the evolutionary origins of T. evansi. We used 15 polymorphic microsatellites to quantify levels and patterns of genetic diversity among 41 T. evansi isolates and 66 isolates of T. b. brucei (n = 51 and T. b. rhodesiense (n = 15, including many from Kenya, a region where T. evansi may have evolved from T. brucei. We found that T. evansi strains belong to at least two distinct T. brucei genetic units and contain genetic diversity that is similar to that in T. brucei strains. Results indicated that the 41 T. evansi isolates originated from multiple T. brucei strains from different genetic backgrounds, implying independent origins of T. evansi from T. brucei strains. This surprising finding further suggested that the acquisition of the ability of T. evansi to be transmitted mechanically, and thus the ability to escape the obligate link with the African tsetse fly vector, has occurred repeatedly. These findings, if confirmed, have epidemiological implications, as T. brucei strains from different genetic backgrounds can become either causative agents of a dangerous, cosmopolitan livestock disease or of a lethal human disease, like for T. b. rhodesiense.

The prevalence of African animal trypanosomoses and tsetse presence in Western Senegal

International Nuclear Information System (INIS)

Seck, M.T.; Bouyer, J.; Sall, B.; Bengaly, Z.; Vreysen, M.J.B.

2010-01-01

In 2005, the Government of Senegal initiated a tsetse eradication campaign in the Niayes and La Petite Côte aiming at the removal of African Animal Trypanosomosis (AAT), which is one of the main constraints to the development of more effective cattle production systems. The target area has particular meteorological and ecological characteristics that provide great potential for animal production, but it is unfortunately still infested by the riverine tsetse species Glossina palpalis gambiensis Vanderplank (Diptera: Glossinidae). The tsetse project in Senegal has adopted an area- wide integrated pest management (AW-IPM) approach that targets the entire tsetse population within a delimited area. During the first phase of the programme, a feasibility study was conducted that included the collection of entomological, veterinary, population genetics, environmental and socio-economic baseline data. This paper presents the parasitological and serological prevalence data of AAT in cattle residing inside and outside the tsetse-infested areas of the target zone prior to the control effort. At the herd level, a mean parasitological prevalence of 2.4 % was observed, whereas a serological prevalence of 28.7 %, 4.4 %, and 0.3 % was obtained for Trypanosoma vivax, T. congolense and T. brucei brucei, respectively. The observed infection risk was 3 times higher for T. congolense and T. vivax in the tsetse-infested than in the assumed tsetse-free areas. Moreover, AAT prevalence decreased significantly with distance from the nearest tsetse captured which indicated that cyclical transmission of the parasites by tsetse was predominant over mechanical transmission by numerous other biting flies present. The importance of these results for the development of a control strategy for the planned AW-IPM campaign is discussed. (Authors) [fr

The eBioKit, a stand-alone educational platform for bioinformatics.

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Hernández-de-Diego, Rafael; de Villiers, Etienne P; Klingström, Tomas; Gourlé, Hadrien; Conesa, Ana; Bongcam-Rudloff, Erik

2017-09-01

Bioinformatics skills have become essential for many research areas; however, the availability of qualified researchers is usually lower than the demand and training to increase the number of able bioinformaticians is an important task for the bioinformatics community. When conducting training or hands-on tutorials, the lack of control over the analysis tools and repositories often results in undesirable situations during training, as unavailable online tools or version conflicts may delay, complicate, or even prevent the successful completion of a training event. The eBioKit is a stand-alone educational platform that hosts numerous tools and databases for bioinformatics research and allows training to take place in a controlled environment. A key advantage of the eBioKit over other existing teaching solutions is that all the required software and databases are locally installed on the system, significantly reducing the dependence on the internet. Furthermore, the architecture of the eBioKit has demonstrated itself to be an excellent balance between portability and performance, not only making the eBioKit an exceptional educational tool but also providing small research groups with a platform to incorporate bioinformatics analysis in their research. As a result, the eBioKit has formed an integral part of training and research performed by a wide variety of universities and organizations such as the Pan African Bioinformatics Network (H3ABioNet) as part of the initiative Human Heredity and Health in Africa (H3Africa), the Southern Africa Network for Biosciences (SAnBio) initiative, the Biosciences eastern and central Africa (BecA) hub, and the International Glossina Genome Initiative.

Occurrence, clinical manifestation and the epidemiological implications of naturally occurring canine trypanosomosis in western Kenya

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G.O. Matete

2003-11-01

Full Text Available Domestic dogs were screened for Trypanosoma brucei infection using the haematocrit centrifugation technique as part of routine active surveillance exercises in the Busia and Teso districts of Kenya. The purpose was to assess the role of dogs as sentinels for the occurrence of human sleeping sickness. Out of 200 dogs screened, five were found to be infected at the various test sites. These five succumbed to the disease within four weeks, and exhibited a distinct and pronounced corneal opacity before death. Blood from two naturally infected dogs were tested for the presence of the serum resistance associated (SRA gene and one tested positive, confirming it as human infective (T. brucei rhodesiense prevalence (0.5 %. It is considered that the occurrence of this clinical sign could be used as an early warning prediction of future outbreaks. This type of prediction could form an integral part of an indigenous technical knowledge set in areas lying at the edges of the tsetse (Glossina belts where T. brucei is the main trypanosome species that affects dogs. The occurrence of corneal opacity in dogs could indicate a rise in the levels of T. brucei a proportion of which could be human infective T. b. rhodesiense circulating in the population early enough before disease outbreak occurs. It is thought that during sleeping sickness epidemics the domestic dog will be the first casualty rapidly succumbing to disease long before it is noticed in man. Prompt prediction of disease outbreaks would thus enable early interventions that would reduce the morbidity, mortality and the general economic losses associated with sleeping sickness to be instituted.

Genetic basis of the sterile insect technique

International Nuclear Information System (INIS)

Robinson, A.S.

2005-01-01

The use of the sterile insect technique (SIT) for insect control relies on the introduction of sterility in the females of the wild population. This sterility is produced following the mating of these females with released males carrying, in their sperm, dominant lethal mutations that have been induced by ionizing radiation. The reasons why the SIT can only be effective when the induced sterility in the released males is in the form of dominant lethal mutations, and not some form of sperm inactivation, are discussed, together with the relationship of dominant lethal mutations to dose, sex, developmental stage and the particular species. The combination of genetic sterility with that induced by radiation is also discussed in relation to the use of genetic sexing strains of the Mediterranean fruit fly Ceratitis capitata (Wiedemann) in area-wide integrated pest management (AW-IPM) programmes that integrate the SIT. A case is made to lower the radiation dose used in such programmes so as to produce a more competitive sterile insect. Increased competitiveness can also be achieved by using different radiation environments. As well as radiation-induced sterility, natural mechanisms can be recruited, especially the use of hybrid sterility exemplified by a successful field trial with tsetse flies Glossina spp. in the 1940s. Genetic transformation will make some impact on the SIT, especially regarding the introduction of markers for released flies, and the construction of genetic sexing strains. It is concluded that using a physical process, such as radiation, will always have significant advantages over genetic and other methods of sterilization for the large-scale application of the SIT. (author)

2010 Annual Report: Project to combat the Tsetse Fly and Trypanosomiasis in the Niayes

International Nuclear Information System (INIS)

2011-03-01

Several control campaigns were carried out in the 70-80 years in the Niayes area to rid it of the only tsetse species that lives there, Glossina palpalis gambiensis.The tsetse or tsetse fly is responsible for trypanosomiasis in animals and sleeping sickness in humans. Untreated, disease leads to death. After a 15 - year respite following the aforementioned control campaigns, the presence of the vector and the disease it transmits has again been detected in the area thanks to studies carried out in 1999 with FAO support.To solve the problem in a sustainable way, the Ministry of Livestock set up a new program in 2006, with the support of the International Atomic Energy Agency (IAEA), based on the use of the Sterile Insect.This program is coordinated by the Department of Veterinary Services (DSV) in partnership with the Senegalese Institute of Agricultural Research (ISRA) for the research component and the Ecological Monitoring Center (CSE) for the Geographic Information System (GIS). The Center for International Cooperation in Agronomic Research for Development (CIRAD) provides scientific support to the project. The environmental study started in 2010 with the implementation of the protocol on the environmental impact assessment and the preparation of the dossier of the Strategic Environmental Assessment (SEA). During the phase of control preparation, currently underway, a suppression device was tested on a small area in Kayar, and experimental releases of sterile males were set up at two sites to assess their survival and competitiveness, after having set up a transport system running the irradiated pupae of the CIRDES insectarium (Bobo Dioulasso, Burkina Faso) to that of Senegalese Institute for Agricultural Research (ISRA). (Author)

Tsetse GmmSRPN10 has anti-complement activity and is important for successful establishment of trypanosome infections in the fly midgut.

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Cher-Pheng Ooi

2015-01-01

Full Text Available The complement cascade in mammalian blood can damage the alimentary tract of haematophagous arthropods. As such, these animals have evolved their own repertoire of complement-inactivating factors, which are inadvertently exploited by blood-borne pathogens to escape complement lysis. Unlike the bloodstream stages, the procyclic (insect stage of Trypanosoma brucei is highly susceptible to complement killing, which is puzzling considering that a tsetse takes a bloodmeal every 2-4 days. In this study, we identified four tsetse (Glossina morsitans morsitans serine protease inhibitors (serpins from a midgut expressed sequence tag (EST library (GmmSRPN3, GmmSRPN5, GmmSRPN9 and GmmSRPN10 and investigated their role in modulating the establishment of a T. brucei infection in the midgut. Although not having evolved in a common blood-feeding ancestor, all four serpins have an active site sharing remarkable homology with the human complement C1-inhibitor serpin, SerpinG1. RNAi knockdown of individual GmmSRPN9 and GmmSRPN10 genes resulted in a significant decreased rate of infection by procyclic form T. brucei. Furthermore, recombinant GmmSRPN10 was both able to inhibit the activity of human complement-cascade serine proteases, C1s and Factor D, and to protect the in vitro killing of procyclic trypanosomes when incubated with complement-activated human serum. Thus, the secretion of serpins, which may be part of a bloodmeal complement inactivation system in tsetse, is used by procyclic trypanosomes to evade an influx of fresh trypanolytic complement with each bloodmeal. This highlights another facet of the complicated relationship between T. brucei and its tsetse vector, where the parasite takes advantage of tsetse physiology to further its chances of propagation and transmission.

Tsetse GmmSRPN10 has anti-complement activity and is important for successful establishment of trypanosome infections in the fly midgut.

Science.gov (United States)

Ooi, Cher-Pheng; Haines, Lee R; Southern, Daniel M; Lehane, Michael J; Acosta-Serrano, Alvaro

2015-01-01

The complement cascade in mammalian blood can damage the alimentary tract of haematophagous arthropods. As such, these animals have evolved their own repertoire of complement-inactivating factors, which are inadvertently exploited by blood-borne pathogens to escape complement lysis. Unlike the bloodstream stages, the procyclic (insect) stage of Trypanosoma brucei is highly susceptible to complement killing, which is puzzling considering that a tsetse takes a bloodmeal every 2-4 days. In this study, we identified four tsetse (Glossina morsitans morsitans) serine protease inhibitors (serpins) from a midgut expressed sequence tag (EST) library (GmmSRPN3, GmmSRPN5, GmmSRPN9 and GmmSRPN10) and investigated their role in modulating the establishment of a T. brucei infection in the midgut. Although not having evolved in a common blood-feeding ancestor, all four serpins have an active site sharing remarkable homology with the human complement C1-inhibitor serpin, SerpinG1. RNAi knockdown of individual GmmSRPN9 and GmmSRPN10 genes resulted in a significant decreased rate of infection by procyclic form T. brucei. Furthermore, recombinant GmmSRPN10 was both able to inhibit the activity of human complement-cascade serine proteases, C1s and Factor D, and to protect the in vitro killing of procyclic trypanosomes when incubated with complement-activated human serum. Thus, the secretion of serpins, which may be part of a bloodmeal complement inactivation system in tsetse, is used by procyclic trypanosomes to evade an influx of fresh trypanolytic complement with each bloodmeal. This highlights another facet of the complicated relationship between T. brucei and its tsetse vector, where the parasite takes advantage of tsetse physiology to further its chances of propagation and transmission.

Description of a nanobody-based competitive immunoassay to detect tsetse fly exposure.

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Guy Caljon

2015-02-01

Full Text Available Tsetse flies are the main vectors of human and animal African trypanosomes. The Tsal proteins in tsetse fly saliva were previously identified as suitable biomarkers of bite exposure. A new competitive assay was conceived based on nanobody (Nb technology to ameliorate the detection of anti-Tsal antibodies in mammalian hosts.A camelid-derived Nb library was generated against the Glossina morsitans morsitans sialome and exploited to select Tsal specific Nbs. One of the three identified Nb families (family III, TsalNb-05 and TsalNb-11 was found suitable for anti-Tsal antibody detection in a competitive ELISA format. The competitive ELISA was able to detect exposure to a broad range of tsetse species (G. morsitans morsitans, G. pallidipes, G. palpalis gambiensis and G. fuscipes and did not cross-react with the other hematophagous insects (Stomoxys calcitrans and Tabanus yao. Using a collection of plasmas from tsetse-exposed pigs, the new test characteristics were compared with those of the previously described G. m. moristans and rTsal1 indirect ELISAs, revealing equally good specificities (> 95% and positive predictive values (> 98% but higher negative predictive values and hence increased sensitivity (> 95% and accuracy (> 95%.We have developed a highly accurate Nb-based competitive immunoassay to detect specific anti-Tsal antibodies induced by various tsetse fly species in a range of hosts. We propose that this competitive assay provides a simple serological indicator of tsetse fly presence without the requirement of test adaptation to the vertebrate host species. In addition, the use of monoclonal Nbs for antibody detection is innovative and could be applied to other tsetse fly salivary biomarkers in order to achieve a multi-target immunoprofiling of hosts. In addition, this approach could be broadened to other pathogenic organisms for which accurate serological diagnosis remains a bottleneck.

Sterility induction in tsetse

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Curtis, C F [London School of Hygiene and Tropical Medicine (UK); Langley, P A [Bristol Univ. (UK)

1982-01-01

The first laboratory and field experiments on genetic control were with tsetse flies, and they made use of the sterility in crosses and hybrids between closely related species of the Glossina morsitans complex. Backcrosses indicate that there are two separate sterility mechanisms involved: (a) genetic incompatibility between a mother and the products of alien genes in the embryo or larva in the uterus; (b) inability of hybrid males to inseminate due to incompatibility of their X-chromosomes with an alien Y or autosomes. The two largest sterile male release programmes have been in Tanzania and Upper Volta, and have used irradiation at the pupal or adult stage, respectively, for the production of sterility. Male tsetse are remarkably resistant to radiosterilization and, with the doses required to induce dominant lethals in more than 95% of sperms, premature senescence and lethargic behaviour of the males tends to result. With G. morsitans irradiated at the puparial stage these effects can be alleviated by the use of a nitrogen atmosphere during irradiation. If the puparia are then transferred to air at 11/sup 0/C for transport to the release site, immediate emergence occurs on re-warming after arrival. This advantageous procedure was used for the releases in Tanzania. In addition to dominant lethals, irradiation also produces chromosome translocations which cause inherited partial sterility. A homozygous translocation line was selected but this example did not have sufficient fitness to be used in a mass rearing programme. Chemosterilants can be applied by pupal dipping, adult contact with deposits or in aerosols. Studies are now in progress on their use in association with odour-baited traps or pheromone-baited decoys as a means of sterilizing the wild population and thus avoiding the costly and difficult process of mass rearing tsetse.

Trapping tsetse flies on water

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Laveissière C.

2011-05-01

Full Text Available Riverine tsetse flies such as Glossina palpalis gambiensis and G. tachinoides are the vectors of human and animal trypanosomoses in West Africa. Despite intimate links between tsetse and water, to our knowledge there has never been any attempt to design trapping devices that would catch tsetse on water. In mangrove (Guinea one challenging issue is the tide, because height above the ground for a trap is a key factor affecting tsetse catches. The trap was mounted on the remains of an old wooden dugout, and attached with rope to nearby branches, thereby allowing it to rise and fall with the tide. Catches showed a very high density of 93.9 flies/”water-trap”/day, which was significantly higher (p < 0.05 than all the catches from other habitats where the classical trap had been used. In savannah, on the Comoe river of South Burkina Faso, the biconical trap was mounted on a small wooden raft anchored to a stone, and catches were compared with the classical biconical trap put on the shores. G. p. gambiensis and G. tachinoides densities were not significantly different from those from the classical biconical one. The adaptations described here have allowed to efficiently catch tsetse on the water, which to our knowledge is reported here for the first time. This represents a great progress and opens new opportunities to undertake studies on the vectors of trypanosomoses in mangrove areas of Guinea, which are currently the areas showing the highest prevalences of sleeping sickness in West Africa. It also has huge potential for tsetse control using insecticide impregnated traps in savannah areas where traps become less efficient in rainy season. The Guinean National control programme has already expressed its willingness to use such modified traps in its control campaigns in Guinea, as has the national PATTEC programme in Burkina Faso during rainy season.

Studies on the infection rates and transmission characteristics of pathogenic trypanosomes in laboratory reared tsetse flies as part of the SIT programme

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Moloo, S.K.

1981-04-01

Investigations were conducted on the infection rates and transmission characteristics of sterile male Glossina morsitans morsitans for T. vivax, T. congolense and T. brucei. Pupae were irradiated after the first flush of female emergences to 7, 10 or 13 krad in a Caesium 137 radiation source under normal room conditions. The male emergences were fed on the T. vivax infected goat at peak parasitaemia. They were mated when 8 days old with 3 days old normal virgin females. A batch of sexually fertile males which had been infected as tenerals on the goat at the same time were similarly mated to serve as control. All the tsetse were maintained on rabbits' ears; the survival and reproductive performance were monitored for 7 age group periods of 9 days each. The sterility rates of the males were 73%, 91% and 98% for the 7, 10 and 13 krad radiation; the percentage infection rates were 78.3, 82.3 and 74.4, respectively. For the control males, the fecundity of the mated females was 90%; the infection rate 75.7%. In all other experiments, 10 krad dose was selected since both the survival and the sterility of the irradiated males were good. The T. vivax challenged cows and goats died with anaemic condition at death. There was no difference in the transmission characteristics between sterile and fertile vectors. Also, there was no significant difference in the infection rates and the transmission frequency of T. congolense and T. brucei to cattle, goats and mice between the sterile and normal males. The results are discussed from viewpoint of the use of Sterile Insect Release method alone or integrated with insecticidal spraying for tsetse eradication operations in terms of the impact on the environment including the trypanosomiasis epidemiology

Synthetic analogues of natural semiochemicals as promising insect control agents

International Nuclear Information System (INIS)

Ujvary, Istvan; Toth, Miklos; Guerin, Patrick

2000-01-01

Zeller; analogues of (Z)-11-hexadecenyl acetate, a principal component of several important lepidopteran species and analogues of 1-octen-3-ol and 3-n-propylphenol, two kairomonal cattle odour components attractive to tsetse flies (Glossina spp.)

Epidemiology of Sleeping Sickness in Boffa (Guinea): Where Are the Trypanosomes?

Science.gov (United States)

Kagbadouno, Moise Saa; Camara, Mamadou; Rouamba, Jeremi; Rayaisse, Jean-Baptiste; Traoré, Ibrahima Sory; Camara, Oumou; Onikoyamou, Mory Fassou; Courtin, Fabrice; Ravel, Sophie; de Meeûs, Thierry; Bucheton, Bruno; Jamonneau, Vincent; Solano, Philippe

2012-01-01

Human African Trypanosomiasis (HAT) in West Africa is a lethal, neglected disease caused by Trypanosoma brucei gambiense transmitted by the tsetse Glossina palpalis gambiensis. Although the littoral part of Guinea with its typical mangrove habitat is the most prevalent area in West Africa, very few data are available on the epidemiology of the disease in such biotopes. As part of a HAT elimination project in Guinea, we carried a cross-sectional study of the distribution and abundance of people, livestock, tsetse and trypanosomes in the focus of Boffa. An exhaustive census of the human population was done, together with spatial mapping of the area. Entomological data were collected, a human medical survey was organized together with a survey in domestic animals. In total, 45 HAT cases were detected out of 14445 people who attended the survey, these latter representing 50.9% of the total population. Potential additional carriers of T. b. gambiense were also identified by the trypanolysis test (14 human subjects and two domestic animals). No trypanosome pathogenic to animals were found, neither in the 874 tsetse dissected nor in the 300 domestic animals sampled. High densities of tsetse were found in places frequented by humans, such as pirogue jetties, narrow mangrove channels and watering points. The prevalence of T. b. gambiense in humans, combined to low attendance of the population at risk to medical surveys, and to an additional proportion of human and animal carriers of T. b. gambiense who are not treated, highlights the limits of strategies targeting HAT patients only. In order to stop T. b. gambiense transmission, vector control should be added to the current strategy of case detection and treatment. Such an integrated strategy will combine medical surveillance to find and treat cases, and vector control activities to protect people from the infective bites of tsetse. PMID:23272259

The influence of sex and fly species on the development of trypanosomes in tsetse flies.

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Lori Peacock

Full Text Available Unlike other dipteran disease vectors, tsetse flies of both sexes feed on blood and transmit pathogenic African trypanosomes. During transmission, Trypanosoma brucei undergoes a complex cycle of proliferation and development inside the tsetse vector, culminating in production of infective forms in the saliva. The insect manifests robust immune defences throughout the alimentary tract, which eliminate many trypanosome infections. Previous work has shown that fly sex influences susceptibility to trypanosome infection as males show higher rates of salivary gland (SG infection with T. brucei than females. To investigate sex-linked differences in the progression of infection, we compared midgut (MG, proventriculus, foregut and SG infections in male and female Glossina morsitans morsitans. Initially, infections developed in the same way in both sexes: no difference was observed in numbers of MG or proventriculus infections, or in the number and type of developmental forms produced. Female flies tended to produce foregut migratory forms later than males, but this had no detectable impact on the number of SG infections. The sex difference was not apparent until the final stage of SG invasion and colonisation, showing that the SG environment differs between male and female flies. Comparison of G. m. morsitans with G. pallidipes showed a similar, though less pronounced, sex difference in susceptibility, but additionally revealed very different levels of trypanosome resistance in the MG and SG. While G. pallidipes was more refractory to MG infection, a very high proportion of MG infections led to SG infection in both sexes. It appears that the two fly species use different strategies to block trypanosome infection: G. pallidipes heavily defends against initial establishment in the MG, while G. m. morsitans has additional measures to prevent trypanosomes colonising the SG, particularly in female flies. We conclude that the tsetse-trypanosome interface works

Trypanosome infection establishment in the tsetse fly gut is influenced by microbiome-regulated host immune barriers.

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Brian L Weiss

Full Text Available Tsetse flies (Glossina spp. vector pathogenic African trypanosomes, which cause sleeping sickness in humans and nagana in domesticated animals. Additionally, tsetse harbors 3 maternally transmitted endosymbiotic bacteria that modulate their host's physiology. Tsetse is highly resistant to infection with trypanosomes, and this phenotype depends on multiple physiological factors at the time of challenge. These factors include host age, density of maternally-derived trypanolytic effector molecules present in the gut, and symbiont status during development. In this study, we investigated the molecular mechanisms that result in tsetse's resistance to trypanosomes. We found that following parasite challenge, young susceptible tsetse present a highly attenuated immune response. In contrast, mature refractory flies express higher levels of genes associated with humoral (attacin and pgrp-lb and epithelial (inducible nitric oxide synthase and dual oxidase immunity. Additionally, we discovered that tsetse must harbor its endogenous microbiome during intrauterine larval development in order to present a parasite refractory phenotype during adulthood. Interestingly, mature aposymbiotic flies (Gmm(Apo present a strong immune response earlier in the infection process than do WT flies that harbor symbiotic bacteria throughout their entire lifecycle. However, this early response fails to confer significant resistance to trypanosomes. Gmm(Apo adults present a structurally compromised peritrophic matrix (PM, which lines the fly midgut and serves as a physical barrier that separates luminal contents from immune responsive epithelial cells. We propose that the early immune response we observe in Gmm(Apo flies following parasite challenge results from the premature exposure of gut epithelia to parasite-derived immunogens in the absence of a robust PM. Thus, tsetse's PM appears to regulate the timing of host immune induction following parasite challenge. Our results

Recording and Analysis of Tsetse Flight Responses in Three Dimensions

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Guerin, P M; Gurba, A; Harraca, V; Perret, J -L [Institute of Biology, University of Neuchatel, Rue Emile-Argand 11, Case Postale 158, 2009 Neuchatel (Switzerland); Casera, S; Donnet, S [Institute of Informatics, University of Neuchatel, Rue Emile-Argand 11, Case Postale 158, 2009 Neuchatel (Switzerland)

2012-07-15

Recording and analysing three dimensional (3D) motions of tsetse flies in flight are technically challenging due to their speed of flight. However, video recording of tsetse fly flight responses has already been made in both wind tunnels and the field. The aim of our research was to study the way tsetse flies exploit host odours and visual targets during host searching. Such knowledge can help in the development of better trapping devices. We built a wind tunnel where it is possible to control environmental parameters, e.g. temperature, relative humidity and light. The flight of the flies was filmed from above with two high speed Linux-embedded cameras equipped with fish-eye objectives viewing at 60o from one another. The synchronized stereo images were used to reconstruct the trajectory of flies in 3D and in real time. Software permitted adjustment for parameters such as luminosity and size of the tsetse species being tracked. Interpolation permitted us to calculate flight coordinates and to measure modifications of flight parameters such as acceleration, velocity, rectitude, angular velocity and curvature according to the experimental conditions. Using this system we filmed the responses of Glossina brevipalpis Newstead obtained from a colony at the IAEA Entomology Unit, Seibersdorf, Austria to human breath presented with and without a visual target. Flights lasting up to 150 s duration and covering up to 153 m were recorded. G. brevipalpis flights to human breath were characterized by wide undulations along the course. When a visual target was placed in the plume of breath, flights of G. brevipalpis were more tightly controlled, i.e. slower and more directed. This showed that after multiple generations in a laboratory colony G. brevipalpis was still capable of complex behaviours during bloodmeal searching. (author)

Enquête entomologique dans le foyer historique de trypanosomose humaine africaine de Bendjé (Gabon

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Kohagne Tongué L.

2011-11-01

Full Text Available La situation de la maladie du sommeil est très peu connue au Gabon. De nombreux foyers historiques n’ont pas été prospectés depuis plus de 15 ans. Le foyer historique de Bendjé fournit régulièrement quelques cas, dépistés passivement, qui concernent le plus souvent des pêcheurs dont il est a priori difficile de déterminer le lieu probable de contamination du fait de leur grande mobilité au cours de leurs activités. La présence des hommes infectés dans ce foyer historique pourrait favoriser son réveil s’il existe un contact étroit entre les différents éléments potentiellement présents du cycle épidémiologique (homme, vecteur, trypanosome. Afin de vérifier l’existence éventuelle d’un risque trypanosomien dans ce foyer, nous y avons mené une enquête entomologique. Des pièges ont été posés dans des biotopes fréquentés par l’homme et laissés en place pendant quatre jours. Trois espèces de glossines (Glossina palpalis palpalis, G. pallicera newsteadi et G. caliginea ont été capturées et deux espèces de trypanosomes (Trypanosoma vivax et T. brucei s.l. identifiées par PCR. Ces résultats suggèrent l’existence d’un cycle de transmission animal. Le contact entre les hommes et les glossines est particulièrement étroit dans tous les types de site prospectés, à l’exception de la mangrove.

Tsetse immune system maturation requires the presence of obligate symbionts in larvae.

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Brian L Weiss

2011-05-01

Full Text Available Beneficial microbial symbionts serve important functions within their hosts, including dietary supplementation and maintenance of immune system homeostasis. Little is known about the mechanisms that enable these bacteria to induce specific host phenotypes during development and into adulthood. Here we used the tsetse fly, Glossina morsitans, and its obligate mutualist, Wigglesworthia glossinidia, to investigate the co-evolutionary adaptations that influence the development of host physiological processes. Wigglesworthia is maternally transmitted to tsetse's intrauterine larvae through milk gland secretions. We can produce flies that lack Wigglesworthia (Gmm(Wgm- yet retain their other symbiotic microbes. Such offspring give rise to adults that exhibit a largely normal phenotype, with the exception being that they are reproductively sterile. Our results indicate that when reared under normal environmental conditions Gmm(Wgm- adults are also immuno-compromised and highly susceptible to hemocoelic E. coli infections while age-matched wild-type individuals are refractory. Adults that lack Wigglesworthia during larval development exhibit exceptionally compromised cellular and humoral immune responses following microbial challenge, including reduced expression of genes that encode antimicrobial peptides (cecropin and attacin, hemocyte-mediated processes (thioester-containing proteins 2 and 4 and prophenoloxidase, and signal-mediating molecules (inducible nitric oxide synthase. Furthermore, Gmm(Wgm- adults harbor a reduced population of sessile and circulating hemocytes, a phenomenon that likely results from a significant decrease in larval expression of serpent and lozenge, both of which are associated with the process of early hemocyte differentiation. Our results demonstrate that Wigglesworthia must be present during the development of immature progeny in order for the immune system to function properly in adult tsetse. This phenomenon provides

Effects of flow rate and temperature on cyclic gas exchange in tsetse flies (Diptera, Glossinidae).

Science.gov (United States)

Terblanche, John S; Chown, Steven L

2010-05-01

Air flow rates may confound the investigation and classification of insect gas exchange patterns. Here we report the effects of flow rates (50, 100, 200, 400 ml min(-1)) on gas exchange patterns in wild-caught Glossina morsitans morsitans from Zambia. At rest, G. m. morsitans generally showed continuous or cyclic gas exchange (CGE) but no evidence of discontinuous gas exchange (DGE). Flow rates had little influence on the ability to detect CGE in tsetse, at least in the present experimental setup and under these laboratory conditions. Importantly, faster flow rates resulted in similar gas exchange patterns to those identified at lower flower rates suggesting that G. m. morsitans did not show DGE which had been incorrectly identified as CGE at lower flow rates. While CGE cycle frequency was significantly different among the four flow rates (prate treatment variation. Using a laboratory colony of closely related, similar-sized G. morsitans centralis we subsequently investigated the effects of temperature, gender and feeding status on CGE pattern variation since these factors can influence insect metabolic rates. At 100 ml min(-1) CGE was typical of G. m. centralis at rest, although it was significantly more common in females than in males (57% vs. 43% of 14 individuals tested per gender). In either sex, temperature (20, 24, 28 and 32 degrees C) had little influence on the number of individuals showing CGE. However, increases in metabolic rate with temperature were modulated largely by increases in burst volume and cycle frequency. This is unusual among insects showing CGE or DGE patterns because increases in metabolic rate are usually modulated by increases in frequency, but either no change or a decline in burst volume. Copyright 2009 Elsevier Ltd. All rights reserved.

Tsetse Fly Genome Breakthrough: The FAO and IAEA Crack the Code

International Nuclear Information System (INIS)

Dixit, Aabha

2014-01-01

With the breakthrough in sequencing the genome of the tsetse fly species Glossina morsitans in April 2014, another milestone has been achieved in helping to solve a problem that has had horrendous ramifications for Africa. Finding a solution to the havoc created by tsetse flies to livestock has been a major challenge for the combined scientific efforts of the IAEA and the Food and Agriculture Organization of the United Nations (FAO), as well as for the World Health Organization (WHO), which has focused on combating human sleeping sickness. Joint research over the past decades to block the spread of severe infection from tsetse flies resulted in the introduction by the FAO and IAEA of the environmentally friendly sterile insect technique (SIT), a biologically-based method for the management of key insect pests of agricultural, medical and veterinary importance. A form of insect birth control, the SIT involves releasing mass-bred male flies that have been sterilized by low doses of radiation into infested areas, where they mate with wild females. These do not produce offspring and, as a result, the technique can suppress and, if applied systematically on an area-wide basis, eventually eradicate populations of wild flies. The newly acquired knowledge of the tsetse fly genome provides a wealth of information for the improvement of the entire SIT package and can help unravel interactions between tsetse flies, symbionts and trypanosomes. The decoding of the genome was detailed in a press release issued by the IAEA on 24 April 2014 entitled Tsetse Fly Genome Breakthrough Brings Hope for African Farmers. Tsetse flies were successfully eradicated in 1997 from the Tanzanian island of Zanzibar using the SIT. Ethiopia and Senegal are making significant progress in infested areas with the same method. The FAO and IAEA are helping 14 countries control tsetse populations through applying area-wide integrated pest management approaches

Protecting cows in small holder farms in East Africa from tsetse flies by mimicking the odor profile of a non-host bovid.

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Rajinder K Saini

2017-10-01

Full Text Available For the first time, differential attraction of pathogen vectors to vertebrate animals is investigated for novel repellents which when applied to preferred host animals turn them into non-hosts thereby providing a new paradigm for innovative vector control. For effectively controlling tsetse flies (Glossina spp., vectors of African trypanosomosis, causing nagana, repellents more powerful than plant derived, from a non-host animal the waterbuck, Kobus ellipsiprymnus defassa, have recently been identified. Here we investigate these repellents in the field to protect cattle from nagana by making cattle as unattractive as the buck.To dispense the waterbuck repellents comprising guaiacol, geranylacetone, pentanoic acid and δ-octalactone, (patent application we developed an innovative collar-mounted release system for individual cattle. We tested protecting cattle, under natural tsetse challenge, from tsetse transmitted nagana in a large field trial comprising 1,100 cattle with repellent collars in Kenya for 24 months. The collars provided substantial protection to livestock from trypanosome infection by reducing disease levels >80%. Protected cattle were healthier, showed significantly reduced disease levels, higher packed cell volume and significantly increased weight. Collars >60% reduced trypanocide use, 72.7% increase in ownership of oxen per household and enhanced traction power (protected animals ploughed 66% more land than unprotected. Land under cultivation increased by 73.4%. Increase in traction power of protected animals reduced by 69.1% acres tilled by hand per household per ploughing season. Improved food security and household income from very high acceptance of collars (99% motivated the farmers to form a registered community based organization promoting collars for integrated tsetse control and their commercialization.Clear demonstration that repellents from un-preferred hosts prevent contact between host and vector, thereby

Integration of the sterile insect technique (SIT) and autosterilisation lethality in the eradication of Glossina fuscipes fuscipes Newst. (Diptera, Glossinidae) in Buvuma Islands in Lake Victoria, Uganda

International Nuclear Information System (INIS)

Oloo, F.P.; Langley, P.A.; Luyimbazi, F.; Ogwal, L.M.

2000-01-01

The years of 1970s to 1990s saw the development of bait technology for the control of tsetse flies from their infancy to their optimum levels. The technology relies on attracting the flies to trapping and killing devices, relying on olfactory and visual cues to artificial and natural objects which the flies probably perceive as their hosts. Despite the present level of improvement, the catching or trapping efficiency is low, averaging 20-35%, and some tsetse species hardly respond to these techniques. This makes sustaining control programmes to a level where economic development can proceed effectively elusive, leading to the re-invasion and collapse of many tsetse control projects. Efforts are therefore being made to incorporate different killing methods into the trapping systems. Lethal insect techniques (LIT) with pathogens, insect growth regulators and other chemosterilants are incorporated into bait technology to amplify their effectiveness as the flies can transfer them to other members of the species which cannot get access to the attractive devices. They are compatible with the sterile insect technique. Prospects for autosterilisation of the tsetse flies have been reviewed by Langley and Coates (1982) who also assessed the incorporation of sex pheromones and bisazir in the field. Encouraging field results were obtained with Pyroprxyfen (Sumitomo Chemical Co.) which is a juvenile hormone mimic that allows the larvae of G. morsitans morsitans to be produced normally but on pupation, further development was arrested after twenty days of the thirty day intrapupal period, 'effectively' making the females sterile (Hargrove and Langley 1990). However, when triflumuron is applied at doses of 0.5 micrograms per tsetse fly the following reproductive cycle was arrested with no recovery over four reproductive cycles (forty five days). Birth products of the sterilised flies ranged from abortion of eggs to fully grown larvae which formed non-viable puparia. The aim of this trial was to assess the effectiveness of triflumuron on G. f. fuscipes

Effect of rearing diet on the infection rate in flies released for the control of tsetse populations by sterile males

International Nuclear Information System (INIS)

Maudlin, I.

1990-01-01

In areas where sleeping sickness is endemic, it is the practice of sterile insect technique (SIT) programmes to give sterilized males a bloodmeal before release into the wild in order to reduce the risk of these released flies acting as disease vectors. This strategy has been adopted because of experimental evidence which showed that it was essential to infect flies at their first feed to establish a Tripanosoma brucei gambiense or T. b rhodesiense infection in tsetse flies. The aim of the work was to test artificial tsetse diets produced in the IAEA Laboratory at Seibersdorf in order to determine whether they were as effective as whole blood in inhibiting T. brucei sensu lato (sl) infections in flies. Seven artificial diets were tested with T.b. rhodesiense; Glossina morsitans morsitans males were fed one meal of the diet and then starved for 3 days before the infective feed. None of these diets significantly altered the infection rate of the treated flies and the seven groups produced statistically homogeneous results, with a mean midgut rate of 16% (control flies fed pig blood: 17%). Flies infected as tenerals with the same trypanosome stock produced midgut rates of 61%. Three of the diets were also tested with a T. congolense stock. There were no significant differences between flies fed artificial (mean midgut infection rate: 15%) and whole blood diets (19%). G. m. morsitans infected as tenerals with this trypanosome stock produced midgut rates of 66%. As with T. brucei sl infections, teneral flies were far more likely to develop a T. congolense infection than fed flies; this result suggests that all the tsetse flies used in SIT programmes should be fed before release in order to reduce the risk both to man and his livestock. Artificial diets are as effective as whole blood in inhibiting trypanosome infections. The effect of bloodmeal on the fly infection rates is discussed in relation to lectin production in fed flies. (author). 13 refs, 2 tabs

Where, when and why do tsetse contact humans? Answers from studies in a national park of Zimbabwe.

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Stephen J Torr

Full Text Available BACKGROUND: Sleeping sickness, also called human African trypanosomiasis, is transmitted by the tsetse, a blood-sucking fly confined to sub-Saharan Africa. The form of the disease in West and Central Africa is carried mainly by species of tsetse that inhabit riverine woodland and feed avidly on humans. In contrast, the vectors for the East and Southern African form of the disease are usually savannah species that feed mostly on wild and domestic animals and bite humans infrequently, mainly because the odours produced by humans can be repellent. Hence, it takes a long time to catch many savannah tsetse from people, which in turn means that studies of the nature of contact between savannah tsetse and humans, and the ways of minimizing it, have been largely neglected. METHODOLOGY/PRINCIPAL FINDINGS: The savannah tsetse, Glossina morsitans morsitans and G. pallidipes, were caught from men in the Mana Pools National park of Zimbabwe. Mostly the catch consisted of young G. m. morsitans, with little food reserve. Catches were increased by 4-8 times if the men were walking, not stationary, and increased about ten times more if they rode on a truck at 10 km/h. Catches were unaffected if the men used deodorant or were baited with artificial ox odour, but declined by about 95% if the men were with an ox. Surprisingly, men pursuing their normal daily activities were bitten about as much when in or near buildings as when in woodland. Catches from oxen and a standard ox-like trap were poor indices of the number and physiological state of tsetse attacking men. CONCLUSION/SIGNIFICANCE: The search for new strategies to minimize the contact between humans and savannah tsetse should focus on that occurring in buildings and vehicles. There is a need to design a man-like trap to help to provide an index of sleeping sickness risk.

Efficacy of Electrocuting Devices to Catch Tsetse Flies (Glossinidae and Other Diptera.

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Glyn A Vale

2015-10-01

Full Text Available The behaviour of insect vectors has an important bearing on the epidemiology of the diseases they transmit, and on the opportunities for vector control. Two sorts of electrocuting device have been particularly useful for studying the behaviour of tsetse flies (Glossina spp, the vectors of the trypanosomes that cause sleeping sickness in humans and nagana in livestock. Such devices consist of grids on netting (E-net to catch tsetse in flight, or on cloth (E-cloth to catch alighting flies. Catches are most meaningful when the devices catch as many as possible of the flies potentially available to them, and when the proportion caught is known. There have been conflicting indications for the catching efficiency, depending on whether the assessments were made by the naked eye or assisted by video recordings.Using grids of 0.5m2 in Zimbabwe, we developed catch methods of studying the efficiency of E-nets and E-cloth for tsetse, using improved transformers to supply the grids with electrical pulses of ~40kV. At energies per pulse of 35-215mJ, the efficiency was enhanced by reducing the pulse interval from 3200 to 1ms. Efficiency was low at 35mJ per pulse, but there seemed no benefit of increasing the energy beyond 70mJ. Catches at E-nets declined when the fine netting normally used became either coarser or much finer, and increased when the grid frame was moved from 2.5cm to 27.5cm from the grid. Data for muscoids and tabanids were roughly comparable to those for tsetse.The catch method of studying efficiency is useful for supplementing and extending video methods. Specifications are suggested for E-nets and E-cloth that are ~95% efficient and suitable for estimating the absolute numbers of available flies. Grids that are less efficient, but more economical, are recommended for studies of relative numbers available to various baits.

Stoichiometric estimates of the biochemical conversion efficiencies in tsetse metabolism

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Custer Adrian V

2005-08-01

Full Text Available Abstract Background The time varying flows of biomass and energy in tsetse (Glossina can be examined through the construction of a dynamic mass-energy budget specific to these flies but such a budget depends on efficiencies of metabolic conversion which are unknown. These efficiencies of conversion determine the overall yields when food or storage tissue is converted into body tissue or into metabolic energy. A biochemical approach to the estimation of these efficiencies uses stoichiometry and a simplified description of tsetse metabolism to derive estimates of the yields, for a given amount of each substrate, of conversion product, by-products, and exchanged gases. This biochemical approach improves on estimates obtained through calorimetry because the stoichiometric calculations explicitly include the inefficiencies and costs of the reactions of conversion. However, the biochemical approach still overestimates the actual conversion efficiency because the approach ignores all the biological inefficiencies and costs such as the inefficiencies of leaky membranes and the costs of molecular transport, enzyme production, and cell growth. Results This paper presents estimates of the net amounts of ATP, fat, or protein obtained by tsetse from a starting milligram of blood, and provides estimates of the net amounts of ATP formed from the catabolism of a milligram of fat along two separate pathways, one used for resting metabolism and one for flight. These estimates are derived from stoichiometric calculations constructed based on a detailed quantification of the composition of food and body tissue and on a description of the major metabolic pathways in tsetse simplified to single reaction sequences between substrates and products. The estimates include the expected amounts of uric acid formed, oxygen required, and carbon dioxide released during each conversion. The calculated estimates of uric acid egestion and of oxygen use compare favorably to

Quality Control for Expanded Tsetse Production, Sterilization and Field Application

International Nuclear Information System (INIS)

2012-07-01

The use of the sterile insect technique (SIT) for the control of pest insects as part of an integrated, area-wide approach is widely accepted. Its application for the eradication of different tsetse flies, the vectors of human sleeping sickness and African animal trypanosomosis, is attracting increasing interest. Following several initial demonstrations of the application of the SIT for tsetse control the technique was applied on the island of Unguja, Zanzibar, in the mid-1990s and, as the final component of an integrated control programme, led to the eradication of the only tsetse species on the island, Glossina austeni. This successful programme encouraged a number of countries to embark on projects with an SIT component for tsetse control, most Ethiopia. In 2001 the Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC) was launched by the Organization of African Unity (now African Union, AU) and, subsequently, six countries obtained funding from the African Development Bank (AfDB) in 2005 to support control programmes with an SIT component. A further six countries have subsequently requested AfDB funding for their programmes. The FAO/IAEA coordinated research project (CRP) on Automation for Tsetse Mass Rearing For Use in Sterile Insect Technique Programmes, which was completed in 2001, led to the development of a semi-automated system for tsetse production. Using this new system, a large rearing facility was established in Addis Ababa, Ethiopia, to supply sterile males for an elimination programme in the southern Rift Valley. The development of large-scale rearing highlighted the need for improved quality control procedures and, with this in mind, the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture established a CRP in 2003 entitled Improved and Harmonized Quality Control for Expanded Tsetse Production, Sterilization and Field Application with the Objective of Improving and Expanding the Quality Control Sections of the FAO

Spatial distribution and trypanosome infection of tsetse flies in the sleeping sickness focus of Zimbabwe in Hurungwe District

Directory of Open Access Journals (Sweden)

William Shereni

2016-11-01

Full Text Available Abstract Background In Zimbabwe, cases of human African trypanosomiasis (HAT are caused by the unicellular protozoan Trypanosoma brucei, sub-species T. b. rhodesiense. They are reported from the tsetse-infested area in the northern part of the country, broadly corresponding to the valley of the Zambezi River. Tsetse-transmitted trypanosomes, in particular T. congolense and T. vivax, also cause morbidity and mortality in livestock, thus generating poverty and food insecurity. Two species of tsetse fly, Glossina morsistans morsitans and G. pallidipes, are known to be present in the Zambezi Valley, although their distributional patterns and densities have not been investigated in detail. The present study tries to address this gap by providing some insight into the dynamics of trypanosomiasis in humans and livestock. Methods Tsetse distribution and trypanosome infections were studied using traps and fixed fly rounds located at 10 km intervals along a 110 km long transect straddling the southern escarpment of the Zambezi Valley. Three km long fly rounds were conducted on 12 sites, and were repeated 11 times over a 7-month period. Additional traps were deployed and monitored in selected sites. Microscopic examination of 2092 flies for trypanosome infections was conducted. Results Surveys confirmed the presence of G. morsitans morsitans and G. pallidipes in the Zambezi Valley floor. Moving south, the apparent density of tsetse flies appears to peak in the vicinity of the escarpment, then drops on the highlands. Only one fly was caught south of the old game fence separating protected and settled areas. A trypanosome infection rate of 6.31% was recorded in tsetse flies dissected. Only one infection of the T. brucei-type was detected. Conclusions Tsetse fly distribution in the study area appears to be driven by ecological factors such as variation in land use and altitude-mediated climatic patterns. Although targeted control of tsetse flies have played

Characterisation of the wildlife reservoir community for human and animal trypanosomiasis in the Luangwa Valley, Zambia.

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Neil E Anderson

2011-06-01

Full Text Available Animal and human trypanosomiasis are constraints to both animal and human health in Sub-Saharan Africa, but there is little recent evidence as to how these parasites circulate in wild hosts in natural ecosystems. The Luangwa Valley in Zambia supports high densities of tsetse flies (Glossina species and is recognised as an historical sleeping sickness focus. The objective of this study was to characterise the nature of the reservoir community for trypanosomiasis in the absence of influence from domesticated hosts.A cross-sectional survey of trypanosome prevalence in wildlife hosts was conducted in the Luangwa Valley from 2005 to 2007. Samples were collected from 418 animals and were examined for the presence of Trypanosoma brucei s.l., T. b. rhodesiense, Trypanosoma congolense and Trypanosoma vivax using molecular diagnostic techniques. The overall prevalence of infection in all species was 13.9% (95% confidence interval [CI]: 10.71-17.57%. Infection was significantly more likely to be detected in waterbuck (Kobus ellipsiprymnus (Odds ratio [OR]=10.5, 95% CI: 2.36-46.71, lion (Panthera leo (OR=5.3, 95% CI: 1.40-19.69, greater kudu (Tragelaphus strepsiceros (OR=4.7, 95% CI: 1.41-15.41 and bushbuck (Tragelaphus scriptus (OR=4.5, 95% CI: 1.51-13.56. Bushbucks are important hosts for T. brucei s.l. while the Bovidae appear the most important for T. congolense. The epidemiology of T. vivax was less clear, but parasites were detected most frequently in waterbuck. Human infective T. b. rhodesiense were identified for the first time in African buffalo (Syncerus caffer and T. brucei s.l. in leopard (Panthera pardus. Variation in infection rates was demonstrated at species level rather than at family or sub-family level. A number of significant risk factors interact to influence infection rates in wildlife including taxonomy, habitat and blood meal preference.Trypanosoma parasites circulate within a wide and diverse host community in this bio

The detection and treatment of human African trypanosomiasis

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Bouteille B

2012-06-01

Full Text Available Bernard Bouteille,1 Alain Buguet21Laboratory of Parasitology, Dupuytren University Hospital of Limoges, France; 2Polyclinic Marie-Louise Poto-Djembo, Pointe-Noire, CongoAbstract: Human African trypanosomiasis (HAT is caused by the injection of Trypanosoma brucei (T. b. gambiense or T. b. rhodesiense by Glossina, the tsetse fly. Three historical eras followed the exclusive clinical approach of the 19th century. At the turn of the century, the “initial research” era was initiated because of the dramatic spread of HAT throughout intertropical Africa, and scientists discovered the agent and its vector. Two entities, recurrent fever and sleeping sickness, were then considered a continuum between hemolymphatic stage 1 and meningoencephalitic stage 2. Treatments were developed. Soon after World War I, specific services and mobile teams were created, initiating the “epidemiological” era, during which populations were visited, screened, and treated. As a result, by 1960, annual new cases were rare. New mass screening and staging tools were then developed in a third, “modern” era, especially to counter a new epidemic wave. Currently, diagnosis still relies on microscopic detection of trypanosomes without (wet and thick blood films or with concentration techniques (capillary tube centrifugation, miniature anion-exchange centrifugation technique. Staging is a vital step.Stage 1 patients are treated on site with pentamidine or suramin. However, stage 2 patients are treated in specialized facilities, using drugs that are highly toxic and/or that require complex administration procedures (melarsoprol, eflornithine, or nifurtimox-eflornithine combination therapy. Suramin and melarsoprol are the only medications active against Rhodesian HAT. Staging still relies on cerebrospinal fluid examination for trypanosome detection and white blood cell counts: stage 1, absence of trypanosomes, white blood cell counts ≤ 5/µL; stage 2, presence of

Entomology Unit annual report 2003

International Nuclear Information System (INIS)

2003-01-01

As described in the 2002 Annual Report an improved medfly genetic sexing strain (GSS) was developed, VIENNA 8. This strain shows improved production characteristics and will have a major impact on the production efficiency in SIT rearing facilities. During 2003 this strain was transferred to four rearing facilities in Guatemala, Peru, South Africa and Tunisia based on acceptable QC data developed for the strain in the Unit. For the first time the strain was transferred to the different facilities under an agreement that prevents further distribution to third parties without consent of the Unit. In the past, strains originating from the Unit have been freely exchanged within the medfly SIT community, sometimes with not always the best results. During 2003 there has been a substantial increase in the resources devoted to activities in fruit flies other than medfly e.g. Bactrocera oleae and Anastrepha fraterculus. Rearing of the olive fly, B. oleae has traditionally not been straightforward due to the very specific, and expensive, larval diet that is required by this monophagous pest. With the disappearance of an essential larval diet component from the commercial market an urgent search is underway for an alternative. In 2004, experiments will be carried out to identify improved larval diets. For A. fraterculus, a large-scale evaluation of mating compatibility between different geographical races has been carried out by a consultant. Progress has been made in the containerised rearing of tsetse fly colonies. The container required considerable work before the temperature and humidity controls were suitable for tsetse rearing and a closed colony of Glossina fuscipes is now being reared. Discussions are now underway to install a version of TPU 3.2 (an automated tsetse feeding and production unit) in the container. A protocol for the handling, irradiation and eventual release of large numbers of sterile male tsetse has been formulated and it will involve at least two

Quality Control for Expanded Tsetse Production, Sterilization and Field Application

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-07-15

The use of the sterile insect technique (SIT) for the control of pest insects as part of an integrated, area-wide approach is widely accepted. Its application for the eradication of different tsetse flies, the vectors of human sleeping sickness and African animal trypanosomosis, is attracting increasing interest. Following several initial demonstrations of the application of the SIT for tsetse control the technique was applied on the island of Unguja, Zanzibar, in the mid-1990s and, as the final component of an integrated control programme, led to the eradication of the only tsetse species on the island, Glossina austeni. This successful programme encouraged a number of countries to embark on projects with an SIT component for tsetse control, most Ethiopia. In 2001 the Pan African Tsetse and Trypanosomosis Eradication Campaign (PATTEC) was launched by the Organization of African Unity (now African Union, AU) and, subsequently, six countries obtained funding from the African Development Bank (AfDB) in 2005 to support control programmes with an SIT component. A further six countries have subsequently requested AfDB funding for their programmes. The FAO/IAEA coordinated research project (CRP) on Automation for Tsetse Mass Rearing For Use in Sterile Insect Technique Programmes, which was completed in 2001, led to the development of a semi-automated system for tsetse production. Using this new system, a large rearing facility was established in Addis Ababa, Ethiopia, to supply sterile males for an elimination programme in the southern Rift Valley. The development of large-scale rearing highlighted the need for improved quality control procedures and, with this in mind, the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture established a CRP in 2003 entitled Improved and Harmonized Quality Control for Expanded Tsetse Production, Sterilization and Field Application with the Objective of Improving and Expanding the Quality Control Sections of the FAO

An exploratory GIS-based method to identify and characterise landscapes with an elevated epidemiological risk of Rhodesian human African trypanosomiasis

Directory of Open Access Journals (Sweden)

Wardrop Nicola A

2012-11-01

Full Text Available Abstract Background Specific land cover types and activities have been correlated with Trypanosoma brucei rhodesiense distributions, indicating the importance of landscape for epidemiological risk. However, methods proposed to identify specific areas with elevated epidemiological risk (i.e. where transmission is more likely to occur tend to be costly and time consuming. This paper proposes an exploratory spatial analysis using geo-referenced human African trypanosomiasis (HAT cases and matched controls from Serere hospital, Uganda (December 1998 to November 2002 to identify areas with an elevated epidemiological risk of HAT. Methods Buffers 3 km from each case and control were used to represent areas in which village inhabitants would carry out their daily activities. It was hypothesised that the selection of areas where several case village buffers overlapped would enable the identification of locations with increased risk of HAT transmission, as these areas were more likely to be frequented by HAT cases in several surrounding villages. The landscape within these overlap areas should more closely relate to the environment in which transmission occurs as opposed to using the full buffer areas. The analysis was carried out for each of four annual periods, for both cases and controls, using a series of threshold values (number of overlapping buffers, including a threshold of one, which represented the benchmark (e.g. use of the full buffer area as opposed to the overlap areas. Results A greater proportion of the overlap areas for cases consisted of seasonally flooding grassland and lake fringe swamp, than the control overlap areas, correlating well with the preferred habitat of the predominant tsetse species within the study area (Glossina fuscipes fuscipes. The use of overlap areas also resulted in a greater difference between case and control landscapes, when compared with the benchmark (using the full buffer area. Conclusions These results

Success in Zanzibar: Eradication of tsetse

International Nuclear Information System (INIS)

Msangi, A.R.; Kiwia, N.; Malele, I.I.; Mramba, F.; Saleh, K.M.; Mussa, W.A.; Juma, K.G.; Dyck, V.A.; Vreysen, M.J.B.; Parker, A.G.; Feldmann, U.; Zhu, Z.R.; Pan, H.

2000-01-01

There are about 22 species of tsetse flies found nowhere else in the world except in 36 countries of sub-Saharan Africa. Tsetse flies transmit a debilitating and often fatal disease, trypanosomosis, which causes tremendous losses of livestock, and severely limits agricultural production (it reduces output of milk and meat, causes mortality, infertility and abortion in livestock, deprives the rural population of draught power and manure to improve and increase crop production). Tsetse flies also transmit human trypanosomosis, commonly known as 'sleeping sickness'. It is estimated that over 55 million people living in rural sub-Saharan Africa are at risk from this fatal disease. Tanzania's Zanzibar Island is situated 35 km off the eastern coast and comprises two main islands, Unguja and Pemba. Previous surveys revealed that out of the seven tsetse species found on mainland Tanzania, only Glossina austeni Newstead infested Unguja Island. No tsetse fly was found on the island of Pemba. The fly is responsible for the cyclical transmission of trypanosomosis in livestock, the causative agents being mainly Trypanosoma congolense and, to a lesser extent, T. vivax. It is estimated that in Zanzibar, the disease causes annual losses of US$2 million. Since fly suppression by conventional techniques has often resulted in short-term success, Tanzania has always appreciated that the long-term solution to the trypanosomosis problem is the eradication of tsetse flies in the country. In 1994, the International Atomic Energy Agency (IAEA) and the United Republic of Tanzania embarked on a project with the objective of eradicating tsetse flies from Zanzibar Island by applying the sterile insect technique (SIT) (Dyck et al. 1995, in press). Previous tsetse eradication efforts in Tanzania using SIT, enabled the establishment of a modest capacity on tsetse mass rearing in Tanga (Williamson et al. 1983). The Zanzibar tsetse project was successfully completed in 1997. The estimated cost was

Geographic range of vector-borne infections and their vectors: the role of African wildlife.

Science.gov (United States)

van Vuuren, M; Penzhorn, B L

2015-04-01

equi, and buffalo, which are reservoirs of Theileria parva. The latter causes Corridor disease when transmitted from buffaloto cattle, butthis appearsto be a self-limiting condition, at least in southern Africa. Wild animals are important reservoirs of tsetse-transmitted Trypanosoma spp. infection. The distribution and abundance of some tsetse species, e.g. Glossina morsitans and G. pallidipes, are closely related to the occurrence of their preferred wildlife hosts.

Effect of Feeding Blood Treated with Isometamidium Chloride to Glossina Morsitans Morsitans on the Flies' Subsequent Vectorial Capacity, and Evaluation of an In Vitro Feeding System for the Maintenance of Infected Tsetse Flies

Energy Technology Data Exchange (ETDEWEB)

Van den Bossche, P; Van Den Abbeele, J; De Deken, R [Veterinary and Parasitology Departments, Prince Leopold Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp (Belgium)

2012-07-15

A repercussion of the release of large numbers of sterile male tsetse flies is the sudden increase in the number of disease vectors. To avoid the potential creation of a trypanosomosis epidemic, studies were conducted aimed at reducing the vectorial capacity of male tsetse flies by offering them a single bloodmeal containing the prophylactic trypanocidal drug isometamidium chloride. Experiments using the pair G. m. morsitans and T. congolense or T. b. brucei showed that a single treatment with isometamidium chloride protected flies from infection with susceptible and resistant trypanosomes for up to 5 days post-treatment. Starvation of isometamidium-treated flies increased their susceptibility to infection with T. congolense. Studies evaluating in vitro feeding of infected flies on citrated bovine blood showed that this feeding regime adversely affected the capacity of trypanosomes to develop in the fly. (author)

Identification of different trypanosome species in the mid-guts of tsetse flies of the Malanga (Kimpese sleeping sickness focus of the Democratic Republic of Congo

Directory of Open Access Journals (Sweden)

Simo Gustave

2012-09-01

Full Text Available Abstract Background The Malanga sleeping sickness focus of the Democratic Republic of Congo has shown an epidemic evolution of disease during the last century. However, following case detection and treatment, the prevalence of the disease decreased considerably. No active survey has been undertaken in this focus for a couple of years. To understand the current epidemiological status of sleeping sickness as well as the animal African trypanosomiasis in the Malanga focus, we undertook the identification of tsetse blood meals as well as different trypanosome species in flies trapped in this focus. Methods Pyramidal traps were use to trap tsetse flies. All flies caught were identified and live flies were dissected and their mid-guts collected. Fly mid-gut was used for the molecular identification of the blood meal source, as well as for the presence of different trypanosome species. Results About 949 Glossina palpalis palpalis were trapped; 296 (31.2% of which were dissected, 60 (20.3% blood meals collected and 57 (19.3% trypanosome infections identified. The infection rates were 13.4%, 5.1%, 3.5% and 0.4% for Trypanosoma congolense savannah type, Trypanosoma brucei s.l., Trypanosoma congolense forest type and Trypanosoma vivax, respectively. Three mixed infections including Trypanosoma brucei s.l. and Trypanosoma congolense savannah type, and one mixed infection of Trypanosoma vivax and Trypanosoma congolense savannah type were identified. Eleven Trypanosoma brucei gambiense infections were identified; indicating an active circulation of this trypanosome subspecies. Of all the identified blood meals, about 58.3% were identified as being taken on pigs, while 33.3% and 8.3% were from man and other mammals, respectively. Conclusion The presence of Trypanosoma brucei in tsetse mid-guts associated with human blood meals is indicative of an active transmission of this parasite between tsetse and man. The considerable number of pig blood meals combined

Major vectors and vector-borne diseases in small ruminants in Ethiopia: A systematic review.

Science.gov (United States)

Asmare, Kassahun; Abayneh, Takele; Sibhat, Berhanu; Shiferaw, Dessie; Szonyi, Barbara; Krontveit, Randi I; Skjerve, Eystein; Wieland, Barbara

2017-06-01

five genera, four species of Glossina and 4 genera of biting flies were reported. Despite the evidence on presence of various vectors including ticks, flies, mosquitoes and midges, studies on vector-borne diseases in Ethiopia are surprisingly rare, especially considering risks related to climate change, which is likely to affect distribution of vectors. Thus better evidence on the current situation is urgently needed in order to prevent spread and to model future distribution scenarios. Copyright © 2017 Elsevier B.V. All rights reserved.

Improved attractants for enhancing tsetse fly suppression

International Nuclear Information System (INIS)

2003-09-01

that previously were difficult to monitor. - The combination of some plant volatiles with new and standard host odours constitute attractant odour blends for several tsetse species for which previously no odour attractants were known. - The novel hydrocarbons identified and characterized from several tsetse species specifically influence (stimulate or inhibit) the sexual behaviour of tsetse males and offer useful tools in rearing/control operations. An incorporation of specific operational research with identified host and habitat odour blends for Glossina fuscipes fuscipes, G. palpalis gambiensis and G. swynnertoni should be considered as part of ongoing tsetse intervention projects that are supported by IAEA-TC and other partners. Thus the findings under this CRP can be refined for large scale field application and eventually benefit integrated tsetse intervention campaigns through availability of improved standard tools for fly population monitoring, for tsetse suppression operations and for the establishment of (temporary) barrier systems

Influence de l’anthropisation sur la végétation locale et l’abondance des tsé-tsé au sud du Burkina Faso*

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Rayaissé J.B.

2009-03-01

Full Text Available Des enquêtes entomologiques couplées à une analyse phytosociologique ont été menées dans la zone de Folonzo au sud du Burkina Faso sur la rivière Comoé. L’étude avait pour objectif de comparer l’abondance et la diversité des espèces de glossines dans une zone protégée et une zone non protégée, grâce à des transects perpendiculaires au cours d’eau. Des pièges ont été posés le long de ces transects depuis la rivière Comoé jusqu’à la savane en passant par la galerie forestière. Une analyse diachronique de la zone entre 1980 et 2008 a également été menée par comparaison d’images satellites Landsat et à partir de l’évolution des densités de tsé-tsé. Sur chacun des transects, une description de la flore a été faite, incluant toutes les espèces situées dans un rayon de 10 m autour de chaque piège. Il existe une très grande homogénéité floristique entre les transects, particulièrement pour la forêt-galerie, en revanche la savane montre une relative hétérogénéité. L’enquête entomologique révèle la présence de quatre espèces de glossines qui sont Glossina tachinoides (74 %, G. morsitans submorsitans (20 %, G. palpalis gambiensis (4 % et G. medicorum (2 %. Une différence nette s’observe entre la zone non protégée et la zone protégée, avec une densité moyenne de tsé-tsé quatre fois inférieure dans la première. Cette différence est particulièrement importante pour G. m. submorsitans, dont les densités sont divisées par neuf dans la zone non protégée. Cette régression s’explique par la diminution de la faune sauvage hors de la zone protégée, et ceci est extrapolable à l’ensemble du pays où cette espèce de glossine est en net recul. L’évolution du terroir de Folonzo montre une augmentation impressionnante des densités humaines et des surfaces cultivées, qui n’a pas (encore d’impact visible sur la composition floristique des lieux d’analyse, mais qui

FAO/IAEA Consultants Group Meeting on The Potential for Tsetse Flies to Develop Resistance to Insecticides

International Nuclear Information System (INIS)

1993-01-01

Chemical insecticides are playing an increasingly important role in control of tsetse flies (Glossina spp), vectors of human and animal trypanosomiasis in large regions of Africa. Although insecticide resistance has not yet been reported in tsetse, there is no cause for complacency regarding its occurrence in the future. As new reports of insecticide resistance in other disease vectors and agronomic pests continue to accumulate at a rapid rate, it is increasingly clear that no comprehensive approach to tsetse control can afford to ignore the potential resistance problem, as the loss of insecticides from the limited set of options for control would be disastrous. it is likely that one or more of the pyrethroid resistance mechanisms already known from several other species of Diptera will manifest itself in tsetse, in response to the increased selection engendered by the wider adoption of deltamethrin-treated targets in tsetse control at the local level and in eradication efforts. Also, selection for behavioural avoidance of traps and targets could result in decreased control efficiency, although the mechanisms that might cause such behavioural resistance are poorly understood at present. There is thus an increasingly urgent need for information on the potential for resistance development in tsetse, on accurate and feasible methods for detection, monitoring, and characterization of resistance, on properties of resistant strains, and on appropriate tactics for resistance prevention and management. Because of the extraordinary difficulties in rearing posed by tsetse life history, it is essential that these research efforts get underway immediately. The Consultants Group on the Possibility of Development of Insecticide Resistance in Tsetse has accordingly prepared this report with a consideration of the present state of knowledge, a discussion of the essential elements of a resistance research program, and specific recommendations. A summary of the recommendations in

FAO/IAEA Consultants Group Meeting on The Potential for Tsetse Flies to Develop Resistance to Insecticides

Energy Technology Data Exchange (ETDEWEB)

NONE

1993-07-01

Chemical insecticides are playing an increasingly important role in control of tsetse flies (Glossina spp), vectors of human and animal trypanosomiasis in large regions of Africa. Although insecticide resistance has not yet been reported in tsetse, there is no cause for complacency regarding its occurrence in the future. As new reports of insecticide resistance in other disease vectors and agronomic pests continue to accumulate at a rapid rate, it is increasingly clear that no comprehensive approach to tsetse control can afford to ignore the potential resistance problem, as the loss of insecticides from the limited set of options for control would be disastrous. it is likely that one or more of the pyrethroid resistance mechanisms already known from several other species of Diptera will manifest itself in tsetse, in response to the increased selection engendered by the wider adoption of deltamethrin-treated targets in tsetse control at the local level and in eradication efforts. Also, selection for behavioural avoidance of traps and targets could result in decreased control efficiency, although the mechanisms that might cause such behavioural resistance are poorly understood at present. There is thus an increasingly urgent need for information on the potential for resistance development in tsetse, on accurate and feasible methods for detection, monitoring, and characterization of resistance, on properties of resistant strains, and on appropriate tactics for resistance prevention and management. Because of the extraordinary difficulties in rearing posed by tsetse life history, it is essential that these research efforts get underway immediately. The Consultants Group on the Possibility of Development of Insecticide Resistance in Tsetse has accordingly prepared this report with a consideration of the present state of knowledge, a discussion of the essential elements of a resistance research program, and specific recommendations. A summary of the recommendations in

Potential for area-wide control or eradication of tsetse flies in Africa

International Nuclear Information System (INIS)

Kabayo, J.P.; Feldmann, U.

2000-01-01

Tsetse flies (Glossina) are found in Africa over an area, estimated by various authors, of 7-11 million sq. km. The northern limit of this area corresponds closely to the southern edges of the Sahara and Somali Deserts, running along 14 deg. N and extending across the continent from Senegal in the west to Somalia in the east. The southern limit of tsetse distribution corresponds closely to the northern edges of the Kalahari and Namibian Deserts in the west and runs generally at 20-30 deg. S to the east of the continent (Ford and Katondo 1977). This tsetse fly belt covers the following 38 countries (listed below) in which the tsetse flies spread African trypanosomosis, a severe disease that affects man and his domestic livestock, and is among the factors responsible for limiting the pace and extent of development in those countries. The disease is of a major economic importance. Throughout the affected countries within the fly belt, areas that are heavily infested by the tsetse fly are virtually devoid of cattle and other species of domestic livestock. Distribution of livestock in all countries on the African continent where densely infested foci exist is almost exactly the reverse of the distribution of the fly (Finelle 1974, Brunhes et al. 1994). Attempts to control African trypanosomosis date back to the beginning of this century. Several different methods of control, some aimed at the disease-causing organism and other aimed at the vector, were employed (Nagel 1995, Jordan 1986). Until after the Second World War, when insecticides became available for use in tsetse control campaigns, the most widely used control measure against tsetse flies was habitat destruction (involving felling trees and bush-clearing), the elimination of host animals (involving killing of wild game) and, to a certain extent, the use of various trapping devices to catch the flies. The tsetse control campaigns mounted in the 40s, 50s and 60s were invariably extensive 'roll up the country

Studies on the infection rates and transmission characteristics of pathogenic trypanosomes in laboratory reared Glossina species as part of the SIT programme. Part of a coordinated programme on use of radiation and isotopes to develop diets for mass rearing hematophagous insects for sterile insect releases and to study disease transmission by these vectors

International Nuclear Information System (INIS)

Moloo, S.K.

1985-02-01

The releases of sterile male tsetse in tsetse control programmes will potentially increase the trypanosomiasis risk in the affected area. Hence appropriate measures should be integrated in any SIR method of tsetse control campaign in order to provide adequate protection to man and his livestock

Consultants Group Meeting on Production System Analysis and Economics for Tsetse Fly Mass-Rearing and the Use of the Sterile Insect Technique in Eradication Programmes in Africa

Energy Technology Data Exchange (ETDEWEB)

NONE

1991-07-01

R and D philosophy to one of large-scale production. 2. At the current status of the programme, the main cost of production is staff cost, accounting for over 50%. Operational costs are approximately US$ 0.40 per usuable pupa and US$ 0.60 per sterile male pupa. These costs are in line with other studies on production and are quite good for an R and D operation. 3. Estimations of field operation costs, including sterile male release for eradication and sterile female release for detection, indicate the feasibility of SIT programmes in a West African situation, but also show the value of a lower cost of mass-produced flies as an important consideration in making decisions regarding eradication programmes. The group concluded that: 1. The Tsetse Unit at Seibersdorf should focus its structure and activities to R and D with respect to mass-rearing techniques for the SIT in Africa. 2. A number of experiments should be conducted which might help to overcome problems and limiting factors of the present rearing methods. An emphasis on improvements in mass-rearing is justified given the economic indicators shown as a result of the present study. 3. Written documentation should be generated immediately so that the current production process is defined, controllable, transferable and easily discussed. 4. In order to assess more rigorously the actual overhead costs to the production colony (i.e. the Glossina tachinoides model) and the scope for targeting cost reductions, it is necessar to identify, quantify and accurately cot the actual overheads of the production unit. Similarly, disaggregation of the consumable usage is necessary in order to carry out constructive cost analysis. In addressing criteria for the development of a successful mass-rearing facility for the SIT in Africa, the group commented on the relative merits of tsetse production contracted to private industry or performed by an agency, regional or national facility, and made a comparison of the advantages of a

New systems for the large-scale production of male tsetse flies (Diptera: Glossinidae)

International Nuclear Information System (INIS)

Opiyo, E.; Luger, D.; Robinson, A.S.

2000-01-01

Tsetse flies, vectors of trypanosomiasis, infest 36 African countries and their distribution covers approximately 10 million km 2 . Trypanosomiasis is a debilitating and often fatal disease of domestic livestock and humans and is considered the most important limiting factor for the development of the livestock sector in Africa. Approximately 50 million cattle and scores of millions of small ruminants are at risk of contracting trypanosomiasis. Direct losses in meat production, milk yield and traction power and the cost of control programmes are estimated to amount to more than US$500 million each year (FAO 1994). In addition, 100 million people are at risk of contracting the disease. According to the World Health Organization, about 300,000 new cases of human trypanosomiasis occur annually (WHO 1997). If the lost potential in livestock production is combined with that of crop production through loss of traction power, trypanosomiasis is estimated to cost Africa US$4 billion or more each year (FAO 1994). The available and environmentally accepted intervention methods for the management of tsetse and trypanosomiasis include parasite control using drugs, the promotion of trypanotolerant livestock and vector control. Parasite control is plagued by the development of resistance to the available drugs and programmes for the development of new drugs are limited. Vector control and eradication involve application of insecticide treated attractive devices on animals including cattle, and the sterile insect technique (SIT). In spite of the efforts spent on the control of the disease and the vector, tsetse flies remain a threat to agricultural development of the region. Experience indicates that only a combination of several of these intervention methods can effectively support sustainable agricultural systems. The feasibility of rearing tsetse flies in Africa for use in SIT was first demonstrated in Tanzania (Williamson et al. 1983) where a colony of 60,000 Glossina