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Sample records for simulium chirostilbia pertinax

  1. [Susceptibility of populations of Simulium (Chirostilbia) pertinax Kollar, 1832 (Culicomorpha, Simuliidae) to eemephos and to Bacillus thuringiensis var. israelensis-based formulation].

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    de Andrade, C F; Castello Branco Júnior, A

    1991-10-01

    The use of wooden troughs on stream beds, artificially colonized by blackfly larvae, is proposed for larvicide evaluations. Mortality was recorded 3 or 4 hours after treatment. Larval susceptibility was also evaluated utilizing the LT50 criterion. In there field assays Simulium (C.) pertinax populations from the litoral of S. Paulo and Rio de Janeiro States were shown to be resistant to temephos, even when subjected to high concentrations. Vectobac 12 AS, a Bacillus thuringiensis var. israelensis product, was shown to be more potent against late instar larvae and efficient in concentrations higher than 7,200 ITU/l (10 min). The LT50 to 3,744 ITU/l (10 min) was calculated as 70.9 min.

  2. The phylogeny of Simulium (Chirostilbia (Diptera: Simuliidae and perspectives on the systematics of the genus in the Neotropical Region

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    Leonardo Henrique Gil-Azevedo

    2012-03-01

    Full Text Available Recently, knowledge of Neotropical Simuliidae has been accumulating quickly. However, information about supra-specific relationships is scarce and diagnoses of Simulium subgenera are unsatisfactory. To investigate the relationships among Simulium (Chirostilbia species and test the subgenus monophyly, we performed a cladistic analysis. The ingroup included all species of this subgenus and the outgroup included representatives of the 17 species groups of Neotropical Simulium and three Holarctic species. The study was based on a data matrix with 31 terminal taxa and 45 morphological characteristics of adult, pupa and larva. The phylogenetic analysis under equal weights resulted in eight most-parsimonious trees (length = 178, consistency index = 34, retention index = 67. The monophyly of the S. (Chirostilbia was not supported in our analysis. The Simulium subpallidum species group was closer to Simulium (Psilopelmia and Simulium (Ectemnaspis than to the Simulium pertinax species group. Additionally, we describe the three-dimensional shape of the terminalia of male and female of Simulium (Chirostilbia for the first time and provide comments about the taxonomic problems involving some species of the subgenus: Simulium acarayense, Simulium papaveroi, S. pertinax, Simulium serranum, Simulium striginotum and S. subpallidum.

  3. Susceptibilidade de populações de Simulium (Chirostilbia pertinax Kollar, 1832 (Culicomorpha, Simuliidae ao temephos e a um formulado à base de Bacillus thuringiensis var. israelensis Susceptibility of population of Simulium (Chirostilbia pertinax Kollar, 1832 (Culicomorpha, Simuliidae to temephos and Bacillus thuringiensis var. israelensis formulation

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    Carlos Fernando S. de Andrade

    1991-10-01

    Full Text Available O uso de pequenas calhas de madeira no leito de riachos, manualmente colonizadas com borrachudos, é proposto para avaliações da eficiência de larvicidas 3 ou 4 horas após as aplicações. A susceptibilidade larval também foi avaliada pelo critério de TL50. Em três ensaios no litoral do Estado de São Paulo e Rio de Janeiro, populações de Simulium (C. pertinax Kollar, 1832 mostraram-se resistentes ao temephos, mesmo em altas concentrações. Vectobac 12 AS, à base de Bacillus thuringiensis var. israelensis mostrou-se mais potente contra larvas dos últimos estádios e eficiente para controle em concentrações a partir de 7.200 UIP/1 (10 min.. O TL50para 3.744 UIP/1 (10 min. foi de 70,9 minutos.The use of wooden troughs on stream beds, artificially colonized by blackfly larvae, is proposed for larvicide evaluations. Mortality was recorded 3 or 4 hours after treatment. Larval susceptibility was also evaluated utilizing the LT50 criterion. In there field assays Simulium (C. pertinax populations from the litoral of S. Paulo and Rio de Janeiro States were shown to be resistant to temephos, even when subjected to high concentrations. Vectobac 12 AS, a Bacillus thuringiensis var. israelensis product, was shown to be more potent against late instar larvae and efficient in concentrations higher than 7,200 ITU/1 (10 min. The LT50 to 3,744 ITU/1 (10 min was calculated as 70.9 min.

  4. Evaluation of the impact of Bacillus thuringiensis serovar israelensis and Temephos, used for the control of Simulium (Chirostilbia pertinax Kollar, 1832 (Diptera, Simuliidae on the associated entomofauna, Paraty, state of Rio de Janeiro, Brazil

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    Araújo-Coutinho Carlos José Pereira da Cunha de

    2003-01-01

    Full Text Available The study was set up to evaluate the impact of two commercial larvicide formulations, Bacillus thuringiensis serovar israelensis base (Bti at 15 ppm/1 min and temephos at 0.03 ppm of active ingredient, used to control Simulium pertinax populations, on associated non-target entomofauna occupying the same breeding sites. The experiments were carried out on the Pedra Branca and Muricana rivers, on the slopes of Serra do Mar massif, municipality of Paraty, state of Rio de Janeiro, Brazil. Bti was applied to the river Pedra Branca and temephosto theriver Muricana. On both rivers, treatment and control sections were labeled as such, each one with two observation posts: slow moving water and fast water regions respectively. Artificial substrata was used to evaluate the abundance of associated entomofauna. Attached immature stages of arthropods were removed from both of its surfaces fortnightly. Were collected, from the two rivers, 28 477 specimens of the entomofauna associated with S. pertinax. The families Hydropsychidae, Chironomidae, Bactidae, Simuliidae, Blephariceridae and Megapodagrionidae were represented. These was an impact of temephos on the entomofauna associated with S. pertinax only in Simuliidae and Chironomidae, and to Bti only in Simuliidae. However, the reduction in their numbers was not statistically significant.

  5. Evaluation of the impact of Bacillus thuringiensis serovar israelensis and Temephos, used for the control of Simulium (Chirostilbia) pertinax Kollar, 1832 (Diptera, Simuliidae) on the associated entomofauna, Paraty, state of Rio de Janeiro, Brazil.

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    de Araújo-Coutinho, Carlos José Pereira da Cunha; Cunha, Andrea de Barros Pinto Viviani; Serra-Freire, Nicolau Maués; de Mello, Rubens Pinto

    2003-07-01

    The study was set up to evaluate the impact of two commercial larvicide formulations, Bacillus thuringiensis serovar israelensis base (Bti) at 15 ppm/1 min and temephos at 0.03 ppm of active ingredient, used to control Simulium pertinax populations, on associated non-target entomofauna occupying the same breeding sites. The experiments were carried out on the Pedra Branca and Muricana rivers, on the slopes of Serra do Mar massif, municipality of Paraty, state of Rio de Janeiro, Brazil. Bti was applied to the river Pedra Branca and temephosto theriver Muricana. On both rivers, treatment and control sections were labeled as such, each one with two observation posts: slow moving water and fast water regions respectively. Artificial substrata was used to evaluate the abundance of associated entomofauna. Attached immature stages of arthropods were removed from both of its surfaces fortnightly. Were collected, from the two rivers, 28 477 specimens of the entomofauna associated with S. pertinax. The families Hydropsychidae, Chironomidae, Bactidae, Simuliidae, Blephariceridae and Megapodagrionidae were represented. These was an impact of temephos on the entomofauna associated with S. pertinax only in Simuliidae and Chironomidae, and to Bti only in Simuliidae. However, the reduction in their numbers was not statistically significant.

  6. Histopathological and ultrastructural effects of delta-endotoxins of Bacillus thuringiensis serovar israelensis in the midgut of Simulium pertinax larvae (Diptera, Simuliidae

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    CFG Cavados

    2004-08-01

    Full Text Available The bacterium Bacillus thuringiensis (Bt produces parasporal crystals containing delta-endotoxins responsible for selective insecticidal activity on larvae. Upon ingestion, these crystals are solubilized in the midgut lumen and converted into active toxins that bind to receptors present on the microvilli causing serious damage to the epithelial columnar cells. We investigated the effect of these endotoxins on larvae of the Simulium pertinax, a common black fly in Brazil, using several concentrations during 4 h of the serovar israelensis strain IPS-82 (LFB-FIOCRUZ 584, serotype H-14 type strain of the Institute Pasteur, Paris. Light and electron microscope observations revealed, by time and endotoxin concentration, increasing damages of the larvae midgut epithelium. The most characteristic effects were midgut columnar cell vacuolization, microvilli damages, epithelium cell contents passing into the midgut lumen and finally the cell death. This article is the first report of the histopathological effects of the Bti endotoxins in the midgut of S. pertinax larvae and the data obtained may contribute to a better understanding of the mode of action of this bacterial strain used as bioinsecticide against black fly larvae.

  7. Two new Species of Simulium (Simulium) (Diptera: Simuliidae) From Mount Murud, Sarawak, Malaysia.

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    Takaoka, Hiroyuki; Ya'cob, Zubaidah; Sofian-Azirun, Mohd

    2015-01-01

    Two new species of black flies, Simulium (Simulium) murudense and Simulium (Simulium) cheedhangi, are described on the basis of females, males, pupae, and larvae collected in Mount Murud, Sarawak, Malaysia. Both species belong to the Simulium melanopus Edwards species group. S. (S.) murudense sp. nov. is distinguished from most known species by a combination of the haired basal portion of the radial vein and the darkened fore coxae, and S. (S.) cheedhangi sp. nov. is characterized in the female by having a medium-sized claw tooth and in the pupa by six somewhat inflated gill filaments. Notes are given on the S. melanopus species-group in Sarawak and Sabah. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Controle integrado de espécies de Simulium (Diptera, Simuliidae por Bacillus thuringiensis e manejos mecânicos no riacho e nos vertedouros de tanques de piscicultura, Almirante Tamandaré, Paraná, Brasil Integrated pest control of Simulium (Diptera, Simuliidae with Bacillus thuringiensis and mechanical handling in creek and pisciculture spillway, Almirante Tamandaré, Paraná, Brazil

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    Fabiane Petry

    2004-03-01

    Full Text Available No Riacho dos Padres na Chácara Evíssima, numa microempresa de agronegócio com criação de peixes e animais domésticos, área de lazer e salão de eventos, localizada na Região Metropolitana de Curitiba, os simulídeos em grande proliferação causaram sério impacto com as picadas a tal ponto que dificultaram o convívio habitual. De janeiro a agosto de 2002, coletou-se 24.021 pupas por meio das quais foram identificadas as espécies: Simulium inaequale, Simulium perflavum, Simulium pertinax com 85,98% e Simulium orbitale, Simulium subnigrum, Simulium distinctum e Simulium incrustatum com somente 14,02% de freqüência. O combate a estas populações iniciado em 28 de fevereiro terminou em 08 de agosto de 2002. O controle integrado consistiu na aplicação de biopesticida Bacillus thuringiensis var. israelensis (Bti e em manejos mecânicos não só removendo os imaturos (ovos, larvas e pupas por meio de escovação de vertedouros, mas também pela retirada de substratos naturais e antrópicos do leito. A densidade larvária média inicial, antes da aplicação de Bti no leito do riacho (75 m e no último vertedouro, verificada em substratos antrópicos fitilhos (área 13.500 cm², foi de 6,7 e 11,5 larvas/cm², respectivamente. Nestes habitats, o controle integrado com Bti de 1,77 a 2,09 mg/litro do ingrediente ativo, suplementado com manejos mecânicos, monitorado em substratos fitilhos (área 20.250 cm², resultou em redução larvar de 72,61% a 99,97% e de 74,91% a 99,45%, respectivamente, nas vazões de 0,39 a 0,45 e de 0,38 a 0,43 m³/min. No primeiro vertedouro (área 5.110 cm², porém, só com manejos mecânicos, atingiu-se a redução larvária de 53,81% a 99,59%. O controle efetuado reduziu as picadas hematófagas ao nível esperado, surtindo o efeito positivo almejado.At Riacho dos Padres, Chácara Evíssima, a small agribusiness venture featuring fish, poultry and cattle farming; a recreation outdoor facility and Event Hall

  9. Morphology and Ecological Notes on the Larvae and Pupae of Simulium (Simulium from Korea

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    Sam-Kyu Kim

    2015-10-01

    Full Text Available Morphological features of larvae and pupae of twelve species of Simulium (Simulium from Korea are investigated and redescribed. Detailed descriptions of immature stages of each species are provided with photographs. For the Korean members of subgenus Simulium, combinations of the following characteristics can be used to separate them from other Korean subgenera: larval abdomen without a pair of conical-shaped ventral tubercles; postgenal cleft variously shaped, viz., miter shaped, spearhead, bullet shaped or triangular; rectal papillae 3 simple lobe or compound lobes; pupal gill of 6-16 filaments; cocoon shoe, boot or slipper shaped; and head trichomes 3 pairs (1 facial+2 frontal. Habitat information and other ecological aspects of each species are provided. Updated keys to larvae and pupae of the Korean species of the subgenus Simulium are also provided to facilitate species identification. Taxonomic treatment based on external morphologies of larvae and pupae of Korean species of the subgenus Simulium are focused and included in this study. To understand their interspecific relationships, phylogenetic analyses using multiple data from molecule, morphology, and ecology are warranted in future research. Also continued exploration for new character systems is needed to establish more stable boundaries for subgenus and species delimitations.

  10. Karyotypic studies of four species of the blackfly, Simulium (Diptera ...

    African Journals Online (AJOL)

    mallory

    2012-01-12

    Jan 12, 2012 ... Drosophila melanogaster: Practical uses in cell and molecular biology in: Goldstein LSB (Eds). Methods in cell biology. Academic Press Inc. p. 555. Henry W, Dey SK, Varma R (2009). The salivary gland chromosomes of the Himalayan Black fly Simulium (Simulium) dentatum (Diptera: Simuliidae). Zool. Sci.

  11. Insight into Energy Conservation via Alternative Carbon Monoxide Metabolism in Carboxydothermus pertinax Revealed by Comparative Genome Analysis.

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    Fukuyama, Yuto; Omae, Kimiho; Yoneda, Yasuko; Yoshida, Takashi; Sako, Yoshihiko

    2018-05-04

    Carboxydothermus species are some of the most studied thermophilic carboxydotrophs. Their varied carboxydotrophic growth properties suggest distinct strategies for energy conservation via CO metabolism. In this study, we used comparative genome analysis of the genus Carboxydothermus to show variations in the CO dehydrogenase/energy-converting hydrogenase gene cluster, which is responsible for CO metabolism with H 2 production (hydrogenogenic CO metabolism). Indeed, ability or inability to produce H 2 with CO oxidation is explained by the presence or absence of this gene cluster in C. hydrogenoformans , C. islandicus , and C. ferrireducens Interestingly, despite its hydrogenogenic CO metabolism, C. pertinax lacks the Ni-CO dehydrogenase catalytic subunit (CooS-I) and its transcriptional regulator encoding genes in this gene cluster probably due to inversion. Transcriptional analysis in C. pertinax showed that the Ni-CO dehydrogenase gene ( cooS-II ) and distantly encoded energy-converting hydrogenase related genes were remarkably upregulated under 100% CO. In addition, when thiosulfate was available as a terminal electron acceptor under 100% CO, C. pertinax maximum cell density and maximum specific growth rate were 3.1-fold and 1.5-fold higher, respectively, than when thiosulfate was absent. The amount of H 2 produced was only 63% of the consumed CO, less than expected according to hydrogenogenic CO oxidation: CO + H 2 O → CO 2 + H 2 Accordingly, C. pertinax would couple CO oxidation by Ni-CO dehydrogenase-II with simultaneous reduction of not only H 2 O but thiosulfate when grown under 100% CO. IMPORTANCE Anaerobic hydrogenogenic carboxydotrophs are thought to fill a vital niche with scavenging potentially toxic CO and producing H 2 as available energy source for thermophilic microbes. This hydrogenogenic carboxydotrophy relies on a Ni-CO dehydrogenase/energy-converting hydrogenase gene cluster. This feature is thought to be as common to these organisms. However

  12. Tests of conspecificity for allopatric vectors: Simulium nodosum and Simulium shirakii (Diptera: Simuliidae) in Asia.

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    Low, Van Lun; Adler, Peter H; Sofian-Azirun, Mohd; Srisuka, Wichai; Saeung, Atiporn; Huang, Yao-Te; Hadi, Upik Kesumawati; Da Pham, Xuan; Takaoka, Hiroyuki

    2015-05-29

    Allopatric populations present challenges for biologists working with vectors. We suggest that conspecificity can be concluded in these cases when data from four character sets-chromosomal, ecological, molecular, and morphological-express variation no greater between the allopatric populations than between corresponding sympatric populations. We use this approach to test the conspecificity of Simulium nodosum Puri on the mainland of Southeast Asia and Simulium shirakii Kono & Takahasi in Taiwan. The validity of these two putative species has long been disputed given that they are morphologically indistinguishable. The mitochondria-encoded cytochrome c oxidase subunit I (COI), 12S rRNA, and 16S rRNA genes and the nuclear-encoded 28S rRNA gene support the conspecific status of S. nodosum from Myanmar, Thailand, and Vietnam and S. shirakii from Taiwan; 0 to 0.19 % genetic differences between the two taxa suggest intraspecific polymorphism. The banding patterns of the polytene chromosomes of the insular Taiwanese population of S. shirakii and mainland populations of S. nodosum are congruent. The overlapping ranges of habitat characteristics and hosts of S. nodosum and S. shirakii corroborate the chromosomal, molecular, and morphological data. Four independent sources of evidence (chromosomes, DNA, ecology, and morphology) support the conspecificity of S. nodosum and S. shirakii. We, therefore, synonymize S. shirakii with S. nodosum. This study provides a guide for applying the procedure of testing conspecificity to other sets of allopatric vectors.

  13. Simulium (Gomphostilbia) merapiense sp. nov. (Diptera: Simuliidae) from Java, Indonesia.

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    Takaoka, Hiroyuki; Sofian-Azirun, Mohd; Ya'cob, Zubaidah; Chen, Chee Dhang; Low, Van Lun; Zaid, Adnan

    2016-01-01

    Simulium (Gomphostilbia) merapiense sp. nov. is described based on females, males, pupae, and mature larvae from Yagyakarta, Java, Indonesia. This new species is placed in the Simulium epistum species-group, and is characterized by the pupal gill with eight short filaments all arising at the same level from a short stalk, somewhat enlarged basal fenestra, entirely bare pupal head and thoracic integument, and small and short larval postgenal cleft. These characters rarely are found in the subgenus. Taxonomic notes are given to separate this new species from related species of the S. epistum species-group. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Simulium hiroyukii, a new species of the subgenus Gomphostilbia (Diptera: Simuliidae) from Mount Murud, Sarawak, Malaysia.

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    Ya'cob, Zubaidah; Takaoka, Hiroyuki; Sofian-Azirun, Mohd

    2015-01-20

    Simulium (Gomphostilbia) hiroyukii is described based on females, males, pupae and larvae collected in Mount Murud, Sarawak, Malaysia. This new species is assigned to the Simulium darjeelingense species-group of the subgenus Gomphostilbia, and is characterized by the darkened fore coxae and the pupal gill with eight long filaments, of which middle and dorsal triplets have elongated primary and secondary stalks, respectively. 

  15. Larvas de simulídeos (Diptera, Simuliidae do centro oeste, sudeste e sul do Brasil, parasitadas por microsporídeos (Protozoa e mermitídeos (Nematoda Simulids larvae (Diptera, Simuliidae from middle western, southeastern and southern Brazil, with microsporids (Protozoa and mermithids (Nematoda parasites

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    Carmen Ambrós Ginarte

    2003-09-01

    Full Text Available A survey of simulid larval parasites was carried out in different localities of the states of Mato Grosso, Minas Gerais, São Paulo, Paraná, Santa Catarina and Rio Grande do Sul, Brazil, from February 1996 to May 1998. Prevalences for the microsporidian Polydispyrenia simulii Lutz & Splendore, 1908 were found in Morungaba and Leme, São Paulo, ranging from around 0.7 to 66.7%, depending mainly on the host simulid species. Microsporidiosis was registered in localities of São Paulo, Paraná, Santa Catarina and Rio Grande do Sul. Parasitism by Isomermis sp. (Nematoda, Mermithidae was found in Simulium larvae from Serra do Japi, ranging from 0.8 to 45.8%, depending on the simulid species and the larval microhabitat in the stream, whether a cemented ramp in a lake outlet or the natural stream bed. Parasitism by mermithids was also found in ten localities. Mycoses caused by Coelomycidium sp. were for the first time recorded for larvae of Simulium (Chirostilbia pertinax Kollar, 1832.

  16. Identification of semiochemicals attractive to Simulium vittatum (IS-7).

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    Verocai, G G; McGAHA, T W; Iburg, J P; Katholi, C R; Cupp, E W; Noblet, R; Unnasch, T R

    2017-06-01

    Many blackfly species (Diptera: Simuliidae) are economically important insect pests, both as nuisance biters and as vectors of pathogens of medical and veterinary relevance. Among the important blackfly pest species in North America is Simulium vittatum Zetterstedt sensu lato. The objective of this study was to identify compounds excreted by mammalian hosts that are attractive to host-seeking S. vittatum females. The attractiveness of putative compounds to colonized S. vittatum was tested through electrophysiological (electroantennography; n = 58 compounds) and behavioural (Y-tube assays; n = 7 compounds in three concentrations) bioassays. Five compounds were significantly attractive to host-seeking S. vittatum females: 1-octen-3-ol; 2-heptanone; acetophenone; 1-octanol, and naphthalene. These candidate compounds might be useful as attractants in traps that could be developed for use in alternative or complementary management tactics in programmes to suppress nuisance blackfly populations, or for the collection of samples in which to study the transmission ecology of pathogens transmitted by blackflies of the S. vittatum complex. © 2016 The Royal Entomological Society.

  17. Septímio Severo e a Consecratio de Pertinax: rituais de morte e poder Septimius Severus and the Pertinaces' Consecratio: death and power rithuals

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    Ana Teresa Marques Gonçalves

    2007-01-01

    Full Text Available Nosso objetivo neste artigo é analisar a cerimônia de deificação do Imperador Pertinax, que ocorreu após a sua morte, como definia a tradição romana, e foi promovida pelo seu sucessor, o Imperador Lúcio Septímio Severo. Esta cerimônia encontra-se descrita com riqueza de detalhes na obra de Dion Cássio, intitulada História Romana.Our aim is analyze the Emperor Pertinaces' deification cerimony, which occurred after his death, as defined by the Roman tradition, promoted by his successor, the Emperor Lucius Septimius Severus. That ceremony is described in detail in Dio Cassius' work, Roman History.

  18. Distribution of larval and pupal stages of Simulium (Diptera: Simuliidae) flies in the Nilgiris hills of Tamil Nadu.

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    Soundararajan, C; Nagarajan, K; Arul Prakash, M

    2017-09-01

    Endemicity of onchocerciasis (river blindness) in humans is linked to the location of Simulium spp. (black fly). The distribution of immature stages of Simulium in Sholur, Pykara, Gudalur, Coonoor and Kotagiri streams of the Nilgiris hills of Tamil Nadu was investigated during the months of May and July 2012. Out of these five streams, only Sholur was infested with larval and pupal stages of Simulium spp. Out of six plants collected from various water bodies, larval and pupal stages were found on the leaves and stems of an aquatic plant Nasturtium officinale and on the roots and leaves of Pennisetum glandulosum. The stages of Simulium were observed only during the summer month of May.

  19. Isozyme variation in four species of the Simulium perflavum species group (Diptera: Simuliidae from the Brazilian Amazon

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    Vera Margarete Scarpassa

    2003-01-01

    Full Text Available Electrophoretic studies of isozymes were done with four closely related species of the Simulium perflavum species group (Diptera: Simuliidade in the Brazilian Amazon, using last-instar larvae collected in the field. Ten enzymes were studied, which yielded 11 loci. Diagnostic loci were not found between Simulium maroniense cytotype D and Simulium rorotaense. Simulium maroniense and S. rorotaense differed from Simulium trombetense by two diagnostic loci (Me and Xdh, and Simulium perflavum differed from the other three species by four diagnostic loci (Me, Xdh, Mdh, and Got. The mean number of alleles per locus ranged from 1.30 to 2.30, the percentage of polymorphic loci ranged from 18.2 to 63.6% and the mean heterozygosity values observed ranged from 0.062 to 0.108. Genetic distances among the species ranged from 0.010 to 0.581. The lowest value was obtained between S. maroniense and S. rorotaense, and the highest between S. perflavum and S. trombetense. The genetic relationships among the four S. perflavum group species indicate that they are closely related. The high similarity at the isozyme level, allied to previous studies of morphology and polytene chromosomes, may suggest that the divergence time since the separation of S. maroniense and S. rorotaense is still too recent for diagnostic loci to have evolved.

  20. Identification of entomopathogenic Bacillus isolated from Simulium (Diptera, Simuliidae larvae and adults

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    Cavados CFG

    2001-01-01

    Full Text Available Entomopathogenic bacteria isolated from Simulium larvae and adults from breeding sites in the states of São Paulo and Rio de Janeiro, Brazil, were identified as 18 strains of Bacillus thuringiensis and one of B. sphaericus. Most of these strains were serotyped according to their flagellar antigens. However, nine of the B. thuringiensis samples, could not be serotyped and were designated as "autoagglutinating"; they were also shown to be toxic in preliminary tests against Aedes aegypti larvae. Additionally, B. sphaericus was also shown to be toxic towards Culex quinquefasciatus larvae.

  1. Simukunin from the Salivary Glands of the Black Fly Simulium vittatum Inhibits Enzymes That Regulate Clotting and Inflammatory Responses

    Czech Academy of Sciences Publication Activity Database

    Tsujimoto, H.; Kotsyfakis, Michalis; Francischetti, I.M.B.; Eum, J. H.; Strand, M. R.; Champagne, D. E.

    2012-01-01

    Roč. 7, č. 2 (2012), e29964 E-ISSN 1932-6203 Institutional research plan: CEZ:AV0Z60220518 Keywords : Simulium vittatum * Kunitz-family protein * elastase * cathepsin G * Factor Xa * coagulation * inflammation * serine proteases * BPTI-like inhibitor * Simukunin Subject RIV: EC - Immunology Impact factor: 3.730, year: 2012

  2. Individual exposure to Simulium bites and intensity of Onchocerca volvulus infection

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    Enyong P

    2010-06-01

    Full Text Available Abstract Background Onchocerca volvulus, the causative agent of river blindness, is transmitted through the black fly Simulium damnosum s.l., which breeds in turbulent river waters. To date, the number of flies attacking humans has only been determined by standard fly collectors near the river or the village. In our study, we counted the actual number of attacking and successfully feeding S. damnosum s.l. flies landing on individual villagers during their routine day-time activities in two villages of the Sudan-savannah and rainforest of Cameroon. We compared these numbers to the number of flies caught by a standard vector-collector, one positioned near the particular villager during his/her daily activity and the other sitting at the nearest Simulium breeding site. Results Using these data obtained by the two vector-collectors, we were able to calculate the Actual Index of Exposure (AIE. While the AIE in the savannah was on average 6,3%, it was 34% in the rainforest. The Effective Annual Transmission Potential (EATP for individual villagers was about 20 fold higher in the rainforest compared to the savannah. Conclusions Here we show for the first time that it is possible to determine the EATP. Further studies with more subjects are needed in the future. These data are important for the development of future treatment strategies.

  3. Cardiocladius oliffi (Diptera: Chironomidae as a potential biological control agent against Simulium squamosum (Diptera: Simuliidae

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    Wilson Michael D

    2009-04-01

    Full Text Available Abstract Background The control of onchocerciasis in the African region is currently based mainly on the mass drug administration of ivermectin. Whilst this has been found to limit morbidity, it does not stop transmission. In the absence of a macrofilaricide, there is a need for an integrated approach for disease management, which includes vector control. Vector control using chemical insecticides is expensive to apply, and therefore the use of other measures such as biological control agents is needed. Immature stages of Simulium squamosum, reared in the laboratory from egg masses collected from the field at Boti Falls and Huhunya (River Pawnpawn in Ghana, were observed to be attacked and fed upon by larvae of the chironomid Cardiocladius oliffi Freeman, 1956 (Diptera: Chironomidae. Methods Cardiocladius oliffi was successfully reared in the rearing system developed for S. damnosum s.l. and evaluated for its importance as a biological control agent in the laboratory. Results Even at a ratio of one C. oliffi to five S. squamosum, they caused a significant decrease in the number of adult S. squamosum emerging from the systems (treatments. Predation was confirmed by the amplification of Simulium DNA from C. oliffi observed to have fed on S. squamosum pupae. The study also established that the chironomid flies could successfully complete their development on a fish food diet only. Conclusion Cardiocladius oliffi has been demonstrated as potential biological control agent against S. squamosum.

  4. Cues used by the black fly, Simulium annulus, for attraction to the common loon (Gavia immer).

    Science.gov (United States)

    Weinandt, Meggin L; Meyer, Michael; Strand, Mac; Lindsay, Alec R

    2012-12-01

    The parasitic relationship between a black fly, Simulium annulus, and the common loon (Gavia immer) has been considered one of the most exclusive relationships between any host species and a black fly species. To test the host specificity of this blood-feeding insect, we made a series of bird decoy presentations to black flies on loon-inhabited lakes in northern Wisconsin, U.S.A. To examine the importance of chemical and visual cues for black fly detection of and attraction to hosts, we made decoy presentations with and without chemical cues. Flies attracted to the decoys were collected, identified to species, and quantified. Results showed that S. annulus had a strong preference for common loon visual and chemical cues, although visual cues from Canada geese (Branta canadensis) and mallards (Anas platyrynchos) did attract some flies in significantly smaller numbers. © 2012 The Society for Vector Ecology.

  5. Diurnal biting periodicity of parous Simulium (Diptera: Simuliidae) vectors in the onchocerciasis Amazonian focus.

    Science.gov (United States)

    Grillet, M-E; Villamizar, N J; Cortez, J; Frontado, H L; Escalona, M; Vivas-Martínez, S; Basáñez, M-G

    2005-05-01

    We describe the hourly patterns of parous biting activity of the three main simuliid vectors of human onchocerciasis in the Amazonian focus straddling between Venezuela and Brazil, namely, Simulium guianense s.l. Wise; S. incrustatum Lutz, and S. oyapockense s.l. Floch and Abonnenc. Time series of the hourly numbers of host-seeking parous flies caught in five Yanomami villages during dry, rainy, and their transition periods from 1995 to 2001 were investigated using harmonic analysis (assuming an underlying circadian rhythm) and periodic correlation (based on Spearman's r). Parous S guianense s.l. showed a bimodal activity pattern, with a minor peak in mid-morning and a major peak at 16:00 h. S. incrustatum exhibited mainly unimodal activity during either early morning or midday according to locality. S. oyapockense s.l. bit humans throughout the day mainly between 10:00 and 16:00 h but also showed bimodal periodicity in some localities. Superimposed on the endogenous, species-specific daily cycles, parous activity showed variation according to locality, season, air temperature and relative humidity, with biting being promoted by warmer and drier hours during wet seasons/periods and reduced during hotter times in dry seasons or transitions. The results are discussed in terms of their implications for blackfly biology and ecology as well as onchocerciasis epidemiology and control.

  6. Phylogeography and population diversity of Simulium hirtipupa Lutz (Diptera: Simuliidae based on mitochondrial COI sequences.

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    Vanderly Andrade-Souza

    Full Text Available High morphological homogeneity and cryptic speciation may cause the diversity within Simuliidae to be underestimated. Recent molecular studies on population genetics and phylogeography have contributed to reveal which factors influenced the diversity within this group. This study aimed at examining the genetic diversity of Simulium hirtipupa Lutz, 1910 in populations from the biomes Caatinga, Cerrado, and Atlantic Forest. In this study, we carried out phylogeographic and population genetic analyses using a fragment of the mitochondrial gene COI. The 19 populations studied were clustered into seven groups, most of which are associated with geography indicating certain genetic structure. The northern region of the state of Minas Gerais is most likely the center of origin of this species. The average intergroup genetic distance was 3.7%, indicating the presence of cryptic species. The species tree as well as the haplotype network recovered all groups forming two major groups: the first comprises groups Gr-Bahia (in which the São Francisco river has not acted as geographical barrier, Gr-Pernambuco, and Gr-Mato Grosso do Sul. The second included groups comprising populations of the states of Goiás, Tocantins, Minas Gerais, Bahia, São Paulo, and Espírito Santo. The mismatch distribution for groups was consistent with the model of demographic expansion, except for the Gr-Central-East_1 group. The diversification in this group occurred about 1.19 Mya during the Pleistocene, influenced by paleoclimatic oscillations during the Quaternary glacial cycles.

  7. Evidence of phenotypic plasticity of larvae of Simulium subpallidum Lutz in different streams from the Brazilian Cerrado

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    Ronaldo Figueiró

    2015-03-01

    Full Text Available In this paper, the overall morphological differences between populations of Simulium subpallidum Lutz, 1909 are studied. Several studies found in the literature point to a relationship between the labral fans and body size and the habitat where blackfly larvae occur. However, other characteristics potentially related to the microhabitat, such as abdominal hook circlet morphology, which is used for larvae to fix themselves in the substratum, and thoracic prolegs morphology, which help larvae move in the substratum, were analyzed in three different populations of S. subpallidum, one of which occupied a faster flow. The results suggest phenotypic plasticity in S. subpallidum and a tendency toward larger structures in faster flows.

  8. On the ecology of the fauna of stones in the current in a South African river supporting a very large simulium (Diptera) population

    CSIR Research Space (South Africa)

    Chutter, FM

    1968-12-01

    Full Text Available the studies described here were made. The first aim of this work was to record the density of the Simulium larvae and also of the other invertebrate animals in the river at different times of the year from Warrenton down to Barkly West....

  9. Mercury concentration in black flies Simulium spp. (Diptera, Simuliidae) from soft-water streams in Ontario, Canada

    International Nuclear Information System (INIS)

    Harding, K.M.; Gowland, J.A.; Dillon, P.J.

    2006-01-01

    Total Hg in Simulium spp. (Diptera, Simuliidae) was measured in 17 soft-water streams in the District of Muskoka and Haliburton County (Ontario, Canada) during 2003 and 2004. Black flies contained 0.07-0.64 μg/g total Hg (dry weight). The methylmercury concentration was measured in 6 samples of the 17, and ranged from 58% to 93% of total Hg. The concentration of total Hg is much higher than has been found in other filter feeding insects, and represents a significant potential source of Hg to fish. Mercury concentrations in Simulium spp. at different sites were strongly positively correlated with dissolved organic carbon, and the proportion of land within each catchment that was wetland. There was also a strong negative correlation with pH. By examining Hg concentration in filter feeding insects we have found a significant entry point for Hg and MeHg into the food web. - Accumulation of total mercury by black fly larvae is affected by stream pH, DOC and wetland area in the stream catchment

  10. Development of a Novel Trap for the Collection of Black Flies of the Simulium ochraceum Complex

    Science.gov (United States)

    Rodríguez-Pérez, Mario A.; Adeleke, Monsuru A.; Burkett-Cadena, Nathan D.; Garza-Hernández, Javier A.; Reyes-Villanueva, Filiberto; Cupp, Eddie W.; Toé, Laurent; Salinas-Carmona, Mario C.; Rodríguez-Ramírez, Américo D.; Katholi, Charles R.; Unnasch, Thomas R.

    2013-01-01

    Background Human landing collections are currently the standard method for collecting onchocerciasis vectors in Africa and Latin America. As part of the efforts to develop a trap to replace human landing collections for the monitoring and surveillance of onchocerciasis transmission, comprehensive evaluations of several trap types were conducted to assess their ability to collect Simulium ochraceum sensu lato, one of the principal vectors of Onchocerca volvulus in Latin America. Methodology/Principal Findings Diverse trap designs with numerous modifications and bait variations were evaluated for their abilities to collect S. Ochraceum s.l. females. These traps targeted mostly host seeking flies. A novel trap dubbed the “Esperanza window trap” showed particular promise over other designs. When baited with CO2 and BG-lure (a synthetic blend of human odor components) a pair of Esperanza window traps collected numbers of S. Ochraceum s.l. females similar to those collected by a team of vector collectors. Conclusions/Significance The Esperanza window trap, when baited with chemical lures and CO2 can be used to collect epidemiologically significant numbers of Simulium ochraceum s.l., potentially serving as a replacement for human landing collections for evaluation of the transmission of O. volvulus. PMID:24116169

  11. Mercury concentration in black flies Simulium spp. (Diptera, Simuliidae) from soft-water streams in Ontario, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Harding, K.M. [Trent University, 1600 West Bank Drive, Peterborough, ON K9J 7B8 (Canada); Gowland, J.A. [Trent University, 1600 West Bank Drive, Peterborough, ON K9J 7B8 (Canada); Dillon, P.J. [Trent University, 1600 West Bank Drive, Peterborough, ON K9J 7B8 (Canada)]. E-mail: pdillon@trentu.ca

    2006-10-15

    Total Hg in Simulium spp. (Diptera, Simuliidae) was measured in 17 soft-water streams in the District of Muskoka and Haliburton County (Ontario, Canada) during 2003 and 2004. Black flies contained 0.07-0.64 {mu}g/g total Hg (dry weight). The methylmercury concentration was measured in 6 samples of the 17, and ranged from 58% to 93% of total Hg. The concentration of total Hg is much higher than has been found in other filter feeding insects, and represents a significant potential source of Hg to fish. Mercury concentrations in Simulium spp. at different sites were strongly positively correlated with dissolved organic carbon, and the proportion of land within each catchment that was wetland. There was also a strong negative correlation with pH. By examining Hg concentration in filter feeding insects we have found a significant entry point for Hg and MeHg into the food web. - Accumulation of total mercury by black fly larvae is affected by stream pH, DOC and wetland area in the stream catchment.

  12. Infective larvae of five Onchocerca species from experimentally infected Simulium species in an area of zoonotic onchocerciasis in Japan

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    Fukuda M.

    2008-06-01

    Full Text Available Microfilariae of five Onchocerca species, O. dewittei japonica (the causative agent of zoonotic onchocerciasis in Oita, Kyushu, Japan from wild boar (Sus scrofa, O. skrjabini and O. eberhardi from sika deer (Cervus nippon, O. lienalis from cattle, and an as yet unnamed Onchocerca sp. from wild boar, were injected intrathoracically into newly-emerged black flies of several species from Oita to search the potential vector(s of these parasites and identify their infective larvae. Development of O. dewittei japonica microfilariae to the infective larvae occurred in Simulium aokii, S. arakawae, S. bidentatum, S. japonicum, S. quinquestriatum, and S. rufibasis while development of infective larvae of O. skrjabini, O. eberhardi, and the unnamed Onchocerca sp. was observed in S. aokii, S. arakawae, and S. bidentatum. Development of O. lienalis microfilaria to infective larvae occurred in S. arakawae. Based on the morphology of infective larvae obtained, we proposed a key of identification of Onchocerca infective larvae found in Oita. We also reconsider the identification of three types of infective larvae previously recovered from Simulium species captured at cattle sheds: the large type I larvae that may be an undescribed species; the small type III identified as O. lienalis may include O. skrjabini too; the intermediary type II that may be O. gutturosa, or O. dewittei japonica, or the unnamed Onchocerca sp. of wild boar.

  13. The Genomic Architecture of Novel Simulium damnosum Wolbachia Prophage Sequence Elements and Implications for Onchocerciasis Epidemiology

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    James L. Crainey

    2017-05-01

    Full Text Available Research interest in Wolbachia is growing as new discoveries and technical advancements reveal the public health importance of both naturally occurring and artificial infections. Improved understanding of the Wolbachia bacteriophages (WOs WOcauB2 and WOcauB3 [belonging to a sub-group of four WOs encoding serine recombinases group 1 (sr1WOs], has enhanced the prospect of novel tools for the genetic manipulation of Wolbachia. The basic biology of sr1WOs, including host range and mode of genomic integration is, however, still poorly understood. Very few sr1WOs have been described, with two such elements putatively resulting from integrations at the same Wolbachia genome loci, about 2 kb downstream from the FtsZ cell-division gene. Here, we characterize the DNA sequence flanking the FtsZ gene of wDam, a genetically distinct line of Wolbachia isolated from the West African onchocerciasis vector Simulium squamosum E. Using Roche 454 shot-gun and Sanger sequencing, we have resolved >32 kb of WO prophage sequence into three contigs representing three distinct prophage elements. Spanning ≥36 distinct WO open reading frame gene sequences, these prophage elements correspond roughly to three different WO modules: a serine recombinase and replication module (sr1RRM, a head and base-plate module and a tail module. The sr1RRM module contains replication genes and a Holliday junction recombinase and is unique to the sr1 group WOs. In the extreme terminal of the tail module there is a SpvB protein homolog—believed to have insecticidal properties and proposed to have a role in how Wolbachia parasitize their insect hosts. We propose that these wDam prophage modules all derive from a single WO genome, which we have named here sr1WOdamA1. The best-match database sequence for all of our sr1WOdamA1-predicted gene sequences was annotated as of Wolbachia or Wolbachia phage sourced from an arthropod. Clear evidence of exchange between sr1WOdamA1 and other Wolbachia

  14. Simulium (Psaroniocompsa tergospinosum new species (Diptera: Simuliidae in siolii group from the southern part of the State of Amazonas, Brazil

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    Neusa Hamada

    2000-12-01

    Full Text Available The larva, pupa, male and female of Simulium tergospinosum n. sp. are described and illustrated. The adults of this new species share many characters with species in the subgenus Psaroniocompsa, where it is placed. The larva of this species bears dorsal and lateral triangular tubercles on the abdomen and multiply branched scale-like setae on the body, suggesting that it belongs to the S. siolii species group. S. tergospinosum n.sp. was collected along the Juma River, Apuí county, in the southern part of the State of Amazonas, Brazil. The Juma, a black-water river, is a tributary of the Aripuanã River in the Madeira River hydrographic basin, on the southern part of Amazonas. Females were collected biting humans along the water courses during the sampling period (in the dry season.

  15. Simulium (Psilopelmia virescens, a new black-fly species (Diptera: Simuliidae from the southwestern region of the state of Bahia, Brazil

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    Neusa Hamada

    2012-02-01

    Full Text Available The last-instar larva, pupa, male and female of Simulium virescens sp. nov. are described and illustrated. This species has a peculiar larva, which has an elongated head capsule and light-green colour. The first thoracic segment has tubercle on its dorsal region and the third thoracic segment has one pair of tubercles; the first to the fourth abdominal segments have one pair of tubercles on each segment. Until now this new species had only been collected at the type locality, which is on the middle stretch of the Correntina River in the southwestern portion of the state of Bahia, Brazil. Females were voraciously biting humans during the field work. This new species represents the second species of Simulium(Psilopelmia in Brazil and the first registered outside of the Brazilian Amazon Region.

  16. New molecular identifiers for Simulium limbatum and Simulium incrustatum s.l. and the detection of genetic substructure with potential implications for onchocerciasis epidemiology in the Amazonia focus of Brazil.

    Science.gov (United States)

    Conceição, Priscila A; Crainey, James L; Almeida, Tatiana P; Shelley, Anthony J; Luz, Sergio L B

    2013-08-01

    The Amazonia onchocerciasis focus of southern Venezuela and northern Brazil is the larger of the two remaining Latin American onchocerciasis foci where disease transmission still occurs and is often regarded as the most challenging of all the Latin American foci to eliminate onchocerciasis. The site is home to a population of over 20,000 semi-nomadic, hunter-gatherer Yanomami people and is made-up of a mosaic of rainforest and savannah ecologies, which are influenced by the area's undulating terrain and rich geological diversity. At least six blackfly vectors have been implicated in onchocerciasis transmission in this focus; however, because of the difficulty in their routine identification the relative importance of each has been obscured. Simulium limbatum and Simulium incrustatum s.l. have both been recorded as vectors in the Amazonia focus, but they are difficult to discriminate morphologically and thus the ecological range of these species, and indeed the presence of S. limbatum in the Amazonia focus at all, have remained controversial. In the work described here, we report 15 S. incrustatum s.l. CO1 sequences and 27 S. limbatum sequences obtained from field-caught adult female blackflies collected from forest and savannah localities, inside and just outside the Amazonia focus. Phylogenetic analysis with the sequences generated in this study, showed that both the S. limbatum and the S. incrustatum s.l. CO1 sequences obtained (even from specimens living in sympatry) all fell into discrete species-specific bootstrap-supported monophyletic groups and thus confirmed the utility of the CO1 gene for identifying both these species inside the Amazonia focus. As the S. limbatum-exclusive cluster included CO1 sequences obtained from forest-caught and morphologically identified specimens these results provide the clearest evidence yet of the presence of S. limbatum inside the Amazonia focus. The question, however, of whether S. limbatum is actually a vector in the focus

  17. Aspectos ecológicos de Simulium goeldii (Diptera: Simuliidae: relação entre substrato e densidade de larvas Ecological aspects of Simulium goeldii (Diptera: Simuliidae: relation between substrate and larval density

    Directory of Open Access Journals (Sweden)

    Neusa Hamada

    1989-01-01

    Full Text Available The distribution of larvae of Simulium goeldii was studies in four streams in upland tropical forest near Manaus, Amazonas, Brazil. In each month 32 points were sampled, each with an area of 30 x 50 cm. The areas of all substrates available were measured at each point. The larvae of S. goeldii were collected and later counted for all substrate types where larvae of this species were found. The available substrates were classified into eight types: dry leaves, green leaves, branches, fruits, detritus, rocks and sand; anly the first four types had larvae present. The Kruskal-Wallis test and analysis of variance indicated that the larvae occupy these substrates differently; the Newman-Keuls identified the following differences in intensity of occupation of the susbstrates: branchs differ from roots, dry leaves and green leaves, and green leaves differ from roots and dry leaves. The highest density of larvae was observed on green leaves. However, because the most abundant substrates in the study area were roots and dry leaves, I suggest that the latter two substrates are the most important ones for the esteblishment of this population of S. goeldii.

  18. A new simple technique for rearing F1 progeny from females of the Simulium damnosum Theobald complex.

    Science.gov (United States)

    Raybould, J N; Barro, T; Sawadogo, R; Mordzifa, F

    1982-06-01

    Laboratory rearing of Simulium damnosum complex species enables female adults to be indirectly identified from their larval progeny. A simple, readily transportable rearing apparatus was developed for investigations by the Onchocerciasis Control programme by using unbreakable, easily packed and reassembled parts and by feeding the larvae at least partly with living green algae (Chlorophyceae) cultured in the laboratory. Although the larvae are sensitive to excess nitrogen compounds, the use of algae and a large volume of water obviated the need for a separate purification system in which water was circulated by an A/C electrical centrifugal pump between a container and an inclined trough in which most of the larvae developed. The rate of development was rapid giving rise to full size larvae (suitable for cytotaxonomic determination), pupae and adults. The adults were attracted into a collecting device by light. Developments to protect the larvae during electrical power failures included a slow-drying wooden rearing trough and an automatic switch to an alternative D/C power supply and pump. This technique has been in general use in O.C.P. laboratories in Benin, Ghana, Ivory Coast and Upper Volta and many thousands of larvae have been reared.

  19. Determining the Number of Instars in Simulium quinquestriatum (Diptera: Simuliidae) Using k-Means Clustering via the Canberra Distance.

    Science.gov (United States)

    Yang, Yao Ming; Jia, Ruo; Xun, Hui; Yang, Jie; Chen, Qiang; Zeng, Xiang Guang; Yang, Ming

    2018-02-21

    Simulium quinquestriatum Shiraki (Diptera: Simuliidae), a human-biting fly that is distributed widely across Asia, is a vector for multiple pathogens. However, the larval development of this species is poorly understood. In this study, we determined the number of instars in this pest using three batches of field-collected larvae from Guiyang, Guizhou, China. The postgenal length, head capsule width, mandibular phragma length, and body length of 773 individuals were measured, and k-means clustering was used for instar grouping. Four distance measures-Manhattan, Euclidean, Chebyshev, and Canberra-were determined. The reported instar numbers, ranging from 4 to 11, were set as initial cluster centers for k-means clustering. The Canberra distance yielded reliable instar grouping, which was consistent with the first instar, as characterized by egg bursters and prepupae with dark histoblasts. Females and males of the last cluster of larvae were identified using Feulgen-stained gonads. Morphometric differences between the two sexes were not significant. Validation was performed using the Brooks-Dyar and Crosby rules, revealing that the larval stage of S. quinquestriatum is composed of eight instars.

  20. Cytological and isoenzyme analysis of the Bucay and Quevedo cytotypes of the onchocerciasis vector Simulium exiguum (Diptera: Simuliidae in Ecuador

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    M. Charalambous

    1993-03-01

    Full Text Available Four cytotypes of Simulium exiguum occur in Ecuador, where this morphospecies is the primary vector of onchocerciasis. In this paper, we give the first full description of the banding pattern of the larval polytene chromosomes of the Quevedo cytotypes differ from the chromosomal standard sequence (of the Cayapa cytotype by the fixed inversions IIL-5 and IIL-6. The Quevedo cytotype additionally differs from the standard and Bucay cytotypes by processing a differentiated X chromosome, wich is indicated by the inversion IIS-A. As the degree of reproductive isolation between the Bucay and Quevedo cytotypes has not yet been estabilished, they must be regarded as intraspecific variants of the same species. In fact, isoenzyme characterizations showed that the Bucay and Quevedo cytotypes are differentiated only to the extent expected of incipient species or geographical populations. Moreover, the sibiling species status previously given to the Bucay cytotype needs be reassessed, there being inadequate analysis from areas in Ecuador where Bucay occurs in sympatry with the standard Cayapa cytotype. No isoenzyme electromorphs were discovered that identified all or mostadult females of any one (cytotype-pure collection.

  1. Occurrence of filamentous fungi in Simulium goeldii Cerqueira & Nunes de Mello (diptera: simuliidae larvae in central Amazonia, Brazil Ocorrência de fungos filamentosos associados a larvas de Simulium goeldii Cerqueira & Nunes de Mello da Amazônia Central, Brasil

    Directory of Open Access Journals (Sweden)

    Quézia Ribeiro Fonseca

    2008-06-01

    Full Text Available The family Simuliidae is the host of simbiontes fungi that inhabit the digestive tracts of arthropods. This paper reports the presence of fungi in Simulium goeldii Cerqueira & Nunes de Mello larvae in Amazonia. We observed that the larvae are a good component of aquatic systems to isolate filamentous fungi.A família Simuliidae é hospedeira de fungos simbiontes que habitam o trato digestivo de artrópodos. Este estudo reporta a presença de fungos em larvas de Simulium goeldii Cerqueira & Nunes de Mello da Amazônia. Foi observado que as larvas são bons componentes do sistema aquático para isolar fungos filamentosos.

  2. Cryptic Biodiversity and the Origins of Pest Status Revealed in the Macrogenome of Simulium colombaschense (Diptera: Simuliidae, History's Most Destructive Black Fly.

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    Peter H Adler

    Full Text Available The European black fly Simulium (Simulium colombaschense (Scopoli, once responsible for as many as 22,000 livestock deaths per year, is chromosomally mapped, permitting its evolutionary relationships and pest drivers to be inferred. The species is 12 fixed inversions removed from the standard sequence of the subgenus Simulium. Three of these fixed inversions, 38 autosomal polymorphisms, and a complex set of 12 X and 6 Y chromosomes in 29 zygotic combinations uniquely characterize S. colombaschense and reveal 5 cytoforms: 'A' in the Danube watershed, 'B' in Italy's Adige River, 'C' in the Aliakmonas River of Greece, 'D' in the Aoös drainage in Greece, and 'E' in the Belá River of Slovakia. 'C' and 'D' are reproductively isolated from one another, and 'B' is considered a cytotype of 'A,' the probable name bearer of colombaschense. The species status of 'E' cannot be determined without additional collections. Three derived polytene sequences, based on outgroup comparisons, place S. colombaschense in a clade of species composed of the S. jenningsi, S. malyschevi, and S. reptans species groups. Only cytoforms 'A' and 'B' are pests. Within the Simuliidae, pest status is reached through one of two principal pathways, both of which promote the production of large populations of blood-seeking flies: (1 colonization of the world's largest rivers (habitat specialization or (2 colonization of multiple habitat types (habitat generalization. Evolutionary acquisition of the ability to colonize large rivers by an ancestor of the S. jenningsi-malyschevi-reptans clade set the scene for the pest status of S. colombaschense and other big-river members of the clade. In an ironic twist, the macrogenome of S. colombaschense reveals that the name associated with history's worst simuliid pest represents a complex of species, two or more of which are nonpests potentially vulnerable to loss of their limited habitat.

  3. Molecular identification of infective larvae of three species of Onchocerca found in wild-caught females of Simulium bidentatum in Japan

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    Fukuda M.

    2010-03-01

    Full Text Available Wild female black flies attracted to a man or an idling automobile were collected at Oita, Japan where five cases of zoonotic onchocerciasis had occurred. Among the five Simulium species captured, 2% of Simulium bidentatum, the predominant species, were infected with filarial larvae. There were at least two types of infective larvae, types A and B, based on morphometric observation. Moreover, molecular analysis of the mitochondrial cytochrome c oxidase subunit 1 (CO1 gene revealed that types A and B were represented by a single unknown species of Onchocerca and two species, i.e., Onchocerca dewittei japonica from wild boar, the causative agent of zoonotic onchocerciasis in Japan, and an undescribed Onchocerca sp. from wild boar, respectively. Phylogenetic analysis based on the sequences of the mitochondrial 12S ribosomal RNA (12S rRNA gene also showed that type A is likely to be an unknown species of Onchocerca. Natural infection of black flies with infective larvae of O. dewittei japonica and O. sp. was demonstrated for the first time. The present study strongly suggests that S. bidentatum plays a role as a vector in the transmission of zoonotic onchocerciasis due to O. dewittei japonica in Japan.

  4. Seasonal and diurnal biting activities and zoonotic filarial infections of two Simulium species (Diptera: Simuliidae in northern Thailand

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    Ishii Y.

    2008-06-01

    Full Text Available Seasonal and daily biting activity patterns, and natural filarial infections of adult black flies attracted to human bait were investigated at Ban Pang Faen, a rural area in Chiang Mai Province in northern Thailand. Collections were carried out twice a month from 06-00 to 18-00 hours from January 2005 to February 2006. Among ten Simulium species collected, S. nodosum and S. asakoae were predominant occupying 57.3% and 37.2% of the total 16, 553 females, respectively. These two predominant species showed different patterns in seasonal abundance: majority of S. nodosum (86.7% were collected in hot season (from mid February to mid May, while most of S. asakoae (74.5% were collected in rainy season (from mid May to mid October. For the daily biting activity, S. nodosum had two patterns: the main one was unimodal with a peak from 17-00 to 18-00, and the other was bimodal and had the major peak from 16-00 to 18-00 and the minor one from 07-00 to 09-00. The pattern of S. asakoae was mostly unimodal with a peak from 06-00 to 10-00. The filarial larvae found in S. nodosum and S. asakoae were morphologically different from each other. The short and thick infective larvae found in S. asakoae differed from all known filarial larvae; it is suggested that they might be a bird parasite, Splendidofilariinae or Lemdaninae. The infection of the mammophilic S. nodosum with large Onchocerca type infective larvae was confirmed in this area. Natural filarial infections were found in each month (except December in either S. nodosum or S. asakoae or in both. Monthly infection rates with all stages of larvae were 0.6-5.0% for S. nodosum, and 1.0-4.0% for S. asakoae. It is suggested that people in this village are exposed to the risk of infection with zoonotic filariae throughout the year.

  5. Comments on the association of immatures of Hemerodromia (Diptera, Empididae) and Simulium (Diptera, Simuliidae), and first record of this association in the Atlantic Forest (Brazil).

    Science.gov (United States)

    Sánchez Molina, Óscar; Gil-Azevedo, Leonardo Henrique

    2016-11-01

    Larvae of Empididae (Diptera) prey on black fly immatures and its pupae can be collected from pupal cases of Simuliidae (Diptera). The aim of our work was to report the second record of association between immatures of Empididae and Simuliidae in the Neotropical Region and the first for the Atlantic Forest (Rio de Janeiro, Brazil). We collected 4982 pupae and exuviae of Simulium Latreille, (Diptera, Simuliidae) and found three with a pupa of Hemerodromia Meigen (Diptera, Empididae) inside. This shows that the use of black flies cocoons by dance flies occurs at extremely low frequencies, which might explain why this association is so rarely recorded. Our results are relevant for a better comprehension of the predator-prey relationship between these families. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Larval biometry of Simulium rubrithorax (Diptera: Simuliidae and size comparison between populations in the states of Minas Gerais and Roraima, Brazil

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    Alvan-Aguilar Miriam Adriana

    2003-01-01

    Full Text Available The number of larval instars of Simulium (Hemicnetha rubrithorax Lutz (Diptera: Nematocera was determined using the lateral length of the head capsule. In this study 1,035 larvae, of different sizes, were measured (639 from the state of Roraima and 396 from the state of Minas Gerais. A frequency distribution analysis was carried out on the measurements of the lateral length of the head capsule to determine the number of larval instars. The limits of each instar were defined by the lower frequency of the measurements falling in a range of values, by the presence of the "egg burster" that characterizes the first larval instar, and by the developmental stage of the gill histoblast. The determination of the instar number was tested using a Student's t-test (p 0.05 were observed between them.

  7. Seasonal Variation in Biting Rates of Simulium damnosum sensu lato, Vector of Onchocerca volvulus, in Two Sudanese Foci.

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    Isam M A Zarroug

    Full Text Available The abundance of onchocerciasis vectors affects the epidemiology of disease in Sudan, therefore, studies of vector dynamics are crucial for onchocerciasis control/elimination programs. This study aims to compare the relative abundance, monthly biting-rates (MBR and hourly-based distribution of onchocerciasis vectors in Abu-Hamed and Galabat foci. These seasonally-based factors can be used to structure vector control efforts to reduce fly-biting rates as a component of onchocerciasis elimination programs.A cross-sectional study was conducted in four endemic villages in Abu-Hamed and Galabat foci during two non-consecutive years (2007-2008 and 2009-2010. Both adults and aquatic stages of the potential onchocerciasis vector Simulium damnosum sensu lato were collected following standard procedures during wet and dry seasons. Adult flies were collected using human landing capture for 5 days/month. The data was recorded on handheld data collection sheets to calculate the relative abundance, MBR, and hourly-based distribution associated with climatic factors. The data analysis was carried out using ANOVA and Spearman rank correlation tests.Data on vector surveillance revealed higher relative abundance of S. damnosum s.l. in Abu- Hamed (39,934 flies than Galabat (8,202 flies. In Abu-Hamed, vector populations increased in January-April then declined in June-July until they disappeared in August-October. Highest black fly density and MBR were found in March 2007 (N = 9,444, MBR = 58,552.8 bites/person/month, and March 2010 (N = 2,603, MBR = 16,138.6 bites/person/month while none of flies were collected in August-October (MBR = 0 bites/person/month. In Galabat, vectors increased in September-December, then decreased in February-June. The highest vector density and MBR were recorded in September 2007 (N = 1,138, MBR = 6,828 bites/person/month and September 2010 (N = 1,163, MBR = 6,978 bites/person/month, whereas, none appeared in collection from April to

  8. The Potential for Dispersal of Onchocerciasis in Ecuador in Relation to the Distribution of the Vector Simulium exiguum (Diptera:Simuliidae

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    Charalambous M

    1997-01-01

    Full Text Available The future dispersal of onchocerciasis in Ecuador is dependent on the distribution of cytotypes of the vector species complex Simulium exiguum. Over the last 14 years, collections of larvae have been made from over 25 rivers, between 80-1600 m altitude, from various sites on both sides of the Andes. Analysis of larval polytene chromosomes was used to determine the distributions of each cytotype. On the western side of the Andes, the Cayapa cytotype (the only cytotype directly incriminated as a vector has a distribution from Santo Domingo de los Colorados northwards. The Quevedo and Bucay cytotypes occur from Santo Domingo de los Colorados southwards. On the eastern side of the Andes, the Aguarico cytotype occurs in the Rio Aguarico and a new cytotype is present in the tributaries of the Rio Napo. Whether the disease will spread south of Santo Domingo and on the eastern side of the Andes depends on vector capacity of the cytotypes and the dispersal patterns of individuals infected with onchocerciasis. At present the Aguarico, Bucay and Quevedo cytotypes are known to be efficient hosts, but their biting preferences and biting densities have not yet been evaluated

  9. Mitochondrial DNA markers reveal high genetic diversity but low genetic differentiation in the black fly Simulium tani Takaoka & Davies along an elevational gradient in Malaysia.

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    Van Lun Low

    Full Text Available The population genetic structure of Simulium tani was inferred from mitochondria-encoded sequences of cytochrome c oxidase subunits I (COI and II (COII along an elevational gradient in Cameron Highlands, Malaysia. A statistical parsimony network of 71 individuals revealed 71 haplotypes in the COI gene and 43 haplotypes in the COII gene; the concatenated sequences of the COI and COII genes revealed 71 haplotypes. High levels of genetic diversity but low levels of genetic differentiation were observed among populations of S. tani at five elevations. The degree of genetic diversity, however, was not in accordance with an altitudinal gradient, and a Mantel test indicated that elevation did not have a limiting effect on gene flow. No ancestral haplotype of S. tani was found among the populations. Pupae with unique structural characters at the highest elevation showed a tendency to form their own haplotype cluster, as revealed by the COII gene. Tajima's D, Fu's Fs, and mismatch distribution tests revealed population expansion of S. tani in Cameron Highlands. A strong correlation was found between nucleotide diversity and the levels of dissolved oxygen in the streams where S. tani was collected.

  10. Stability and change in the distribution of cytospecies of the Simulium damnosum complex (Diptera: Simuliidae) in southern Ghana from 1971 to 2011.

    Science.gov (United States)

    Post, Rory J; Cheke, Robert A; Boakye, Daniel A; Wilson, Michael D; Osei-Atweneboana, Mike Y; Tetteh-Kumah, Anthony; Lamberton, Poppy Hl; Crainey, J Lee; Yaméogo, Laurent; Basáñez, María-Gloria

    2013-07-13

    Simulium damnosum s.l., the most important vector of onchocerciasis in Africa, is a complex of sibling species that have been described on the basis of differences in their larval polytene chromosomes. These (cyto) species differ in their geographical distributions, ecologies and epidemiological roles. In Ghana, distributional changes have been recorded as a consequence of vector control and environmental change (e.g. deforestation), with potential disease consequences. We review the distribution of cytospecies in southern Ghana and report changes observed with reference to historical data collated from 1971 to 2005 and new identifications made between 2006 and 2011. Larvae were collected from riverine breeding sites, fixed in Carnoy's solution and chromosome preparations made. Cytotaxonomic identifications from 1,232 samples (including 49 new samples) were analysed. We report long-term stability in cytospecies distribution in the rivers Afram, Akrum, Pawnpawn and Pru. For the rivers Oda, Ofin and Tano we describe (for the first time) patterns of distribution. We could not detect cytospecies composition changes in the upper Pra, and the lower Pra seems to have been stable. The elimination of the Djodji form of S. sanctipauli in the Volta Region seems to have had no long-term effects on the distribution of the other cytospecies, despite an initial surge by S. yahense. There has been a recent increase in the occurrence of savannah cytospecies in the river Asukawkaw, and this might be related to continuing deforestation. Cytospecies' distributions have not been stable from 1971 to 2011. Although there are no obvious causes for the temporary appearance and subsequent disappearance of cytospecies in a particular location, a major influence has been vector control and migration patterns, probably explaining observed changes on the Black Volta and lower Volta rivers. Deforestation was previously implicated in an increase of savannah cytospecies in southern Ghana (1975

  11. Morphometric comparison of Simulium perflavum larvae (Diptera: Simuliidae in relation to season and gender in Central Amazônia, Brazil

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    Yamile B Alencar

    2001-08-01

    Full Text Available Number of larval instars, age structure and environmental effects on these parameters represent basic information in the study of insect population biology. When species have economic importance, this information is essential in order to choose the best period to apply different control methods and to determine the stages of the life cycle of the insect that are most susceptible to each treatment. The family Simuliidae has many species of medical/veterinary importance in the world, and some studies in the temperate region have suggested that the number of larval instars and the larval size can vary according to the season, gender and some environmental factors, such as temperature and diet. This study, with the zoophilic species Simulium perflavum Roubaud, is the first in the Neotropics observing some of these factors and will serve as a template for other species of medical importance in the region. S. perflavum larvae were collected in five streams in Central Amazônia (Manaus and Presidente Figueiredo counties, State of Amazonas, in Sept./Oct. 1996 (dry season and Feb./Mar. 1997 (rainy season. These larvae were measured (lateral length of head capsule and width of cephalic apodema to determine the number of larval instars (n=3985, to compare the larval size between seasons and genders (last and penultimate larval instars, n=200. Seven larval instars were determined for this species using frequency distributions, t-tests and Crosby´s growth rule. Significant differences were not detected (t-test, p>0.05 in larval size between seasons and genders. Our results differ from some found in temperate regions suggesting that in the Neotropical region the larval size in different seasons and different genders remains constant, although some environmental parameters, such as diet, change depending on the season.

  12. Caractéristiques du développement larvaire de Simulium buissoni Roubaud, 1906 et de S. sechani Craig et Fossati, 1995 (Diptera : Simuliidae dans l'archipel des Marquises (Polynésie Française

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    Séchan Y.

    2001-03-01

    Full Text Available Deux espèces de Simulies anthropophiles sévissent dans l'archipel des Marquises en Polynésie Française : Simulium buissoni Roubaud, 1906 et S . sechani Craig & Fossati, 1995. la nécessité de leur contrôle implique une meilleure connaissance de leur développement larvaire, les larves constituent en effet actuellement la seule phase du cycle susceptible d'être détruite. Une étude biométrique réalisée à partir de mesures des capsules céphaliques des larves des deux espèces montre qu'elles présentent toutes deux sept stades de développement. Les variations de taille suivant les espèces et les lieux de récoltes sont examinées, ainsi que les variations suivant le sexe pour les larves les plus âgées. Une expérience de recolonisation après traitement d'une section de rivière permet de déterminer que la durée de développement larvaire de S . buissoni est d'environ 12 jours. Ces données permettent de déterminer la fréquence optimale de traitement.

  13. Distribuição, abundância e diversidade de Simuliidae (Diptera em uma bacia hidrográfica impactada no sul do Brasil Distribution, abundance and diversity of Simuliidae (Diptera in an impacted watershed in southern Brazil

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    Milton Norberto Strieder

    2006-03-01

    Full Text Available Este estudo foi realizado na bacia do rio Caí, no Rio Grande do Sul, em duas áreas com diferentes estados de conservação ambiental: uma fortemente alterada pela intensa avicultura e suinocultura e outra mais conservada. Para padronizar as coletas das larvas e pupas de simulídeos foram utilizados substratos artificiais, instalados nos arroios por períodos de 14 dias. Em todos os pontos de amostragens foram feitas coletas simultâneas de água para análise físico-química e microbiológica. Na área mais conservada foram coletadas onze espécies com as seguintes freqüências: Psaroniocompsa incrustata (42,95%, P. auripellita (17,66%, Chirostilbia pertinax (16,86%, Inaequalium subclavibranchium (8,43%, I. nogueirai (5,80%, P. anamariae (3,69%, I. clavibranchium (1,58%, C. riograndense (0,92%, Lutzsimulium hirticosta (0,92%, I. botulibranchium (0,79%, Thyrsopelma itaunense (0,40%. Na área de maior impacto foram coletadas apenas seis espécies: C. pertinax (84,31%, C. riograndense (7,52%, T. itaunense (4,68%, P. incrustata (2,94%, I. subclavibranchium (0,33%, Ectemnaspis dinellii (0,22%. As concentrações de Nitrato e Nitrito na água foram os fatores que melhor permitem distinguir os pontos amostrados. A concentração de nitrato esteve significativamente relacionada com C. pertinax (r²= 0,54; P This study was carried out in two areas with different degrees of environmental degradation in the Caí river basin, in Rio Grande do Sul. One sampling area is less altered and the other is strongly impaired by organic pollutants from avian and swine production. The larvae and pupae of simulids were collected using artificial substrates that remain submersed in streams for 14 days. In all sampling sites water was collected simultaneously for physical-chemical and microbiological analysis. In the less disturbed area eleven species were collected with the following frequencies: Psaroniocompsa incrustata (42.95%, P. auripellita (17.66%, Chirostilbia

  14. Efectos de la dispersión sobre la reconstrucción por árboles reconciliados y el patrón de distribución de los subgéneros neotropicales de Simulium (Diptera:Simuliidae

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    Miranda-Esquivel Daniel Rafael

    2001-07-01

    Full Text Available The analysis ofthe distribution pattern ofNeotropical Simulium (Diptera:Simuliidae subgenera suggests that dispersal between Mesoamerica and the Pacifíc region, and SE of Brazil and Cerrado could interfere with the evaluation of the general pattern. To agree with the premise ofno dispersion when reconciliated trees is used and to tackle the dispersal problem, the most frequent events of dispersal to each subgenus were eliminated. The dispersal evaluation was carried out using the dispersal-vicariance approach. Reconciliated trees approach, optimizing losses, yields six cladograms and the strict consensus is congruent with previous works using terrestrial organisms where there are two domains: Neotropics and antarctic.El análisis de los patrones biogeográficos de los subgéneros neotropicales de Simulium (Diptera:Simuliidae, sugiere que los eventos de dispersión desde Mesoamerica a la región Pacífica y del SE de Brasil al Cerrado pueden oscurecer la reconstrucción del patrón de las áreas. Para ser concordantes con este fenómeno y  con las limitantes del método de árboles reconciliados, que supone no dispersión, se evaluó los eventos de dispersión para cada subgénero usando el enfoque de dispersión-vicarianza y los eventos de dispersión más frecuentes fueron eliminados de la reconstrucción al usar árboles reconciliados. Al optimizar el número de perdidas se obtienen seis cladogramas de áreas; el consenso estricto sugiere relaciones entre áreas que son congruentes con estudios biogeográficos preliminares usando organismos terrestres donde se presentan claramente los dominios antártico y neotropical. 

  15. Variabilité selon le captureur de l'efficacité de répulsifs à base d'huiles végétales dans la protection individuelle contre les piqûres de Simulium damnosum s. l.

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    Sylla M.

    2002-12-01

    Full Text Available Dans le présent article, nous faisons état de la variabilité selon le captureur de l'efficacité de répulsifs à base d'huiles végétales appliquées sur la peau contre les piqûres de Simulium damnosum s. l. Les expérimentations ont été effectuées en zones de savane (Chaussée-Niaka et de forêt (Soubré de Côte d'Ivoire. Les formulations (lotions, crèmes] testées lors de ces travaux ont été obtenues à partir d'huiles d'amande de palme (Elaeis guineensis, de coco (Cocos nucifera et de gobi (Carapa procera. La technique classique de capture sur homme à l'aide de tubes à hémolyse en matière plastique a été utilisée. Pour chaque journée d'expérimentation, un captureur non traité (jambes non enduites de répulsif servait de témoin. Les résultats indiquent qu'en savane, quels que soient le répulsif et le captureur, la densité simulidienne se situait de 1 à 4, 1 à 6 et de 2 à 10 simulies par homme et par jour lorsque le captureur était respectivement protégé avec le coco, le palmiste et le gobi. Avec les mêmes répulsifs, en zone de forêt, l'agressivité simulidienne variait de 9 à 16, de 2 à 30 et de 8 à 49 piqûres par jour. En comparaison, le témoin recevait de 67 à 90 et de 310 à 533 piqûres par jour, respectivement en zones de savane et de forêt. Malgré les variations importantes dans le nombre de simulies capturées en fonction du captureur choisi, nos résultats montrent que quels que soient le répulsif et l'espèce simulidienne, une protection similaire est conférée à tous les captureurs. Ils indiquent également que le recours à des substances naturelles locales, utilisées comme répulsifs en application dermique, est l'une des meilleures méthodes de protection personnelle contre les simulies.

  16. Biting-density and microfilariae infection of Simulium damnosum ...

    African Journals Online (AJOL)

    Investigations on the biting-density and microfilariae infection rate of S. damnosumsl population caught around the Mada River was conducted between May 2013 to April 2014. Captured flies were morphologically identified and dissected for parity and infectivity rate. A total of 308 adult female S. damnosum sl were caught, ...

  17. distribution of simulium species and its infection with onchocerca

    African Journals Online (AJOL)

    DR. AMINU

    . Detection of the parasites in the vector was attained by dissection of flies under dissecting microscope. The result revealed that the prevalence of microfilariae among insects collected in the months July and August was 23.08% and 21.47%.

  18. Water pollution and distribution of the black fly (Diptera: Simuliidae) in the Atlantic Forest, Brazil.

    Science.gov (United States)

    Docile, Tatiana N; Figueiró, Ronaldo; Gil-Azevedo, Leonardo H; Nessimian, Jorge L

    2015-09-01

    Black flies have medical importance because some species are vectors of the unenocerciasis and Mansonelosis, nevertheless, their ecology and potential use as bioindicators is still poorly studied in the Neotropical Region. In Brazil, bioindicators use is strongly focused in a multimetrical ecological index approach; this way, we investigated the black fly spatial distribution, in relation to abiotic factors correlated to water quality, to provide baseline information for their utilization as standalone indicators of lotic systems integrity. We have tested the hypothesis that environmental changes related to urbanization, lead to decreased abundance and loss in the number of species of the black fly fauna. The sampling was conducted in 10 urban and 10 preserved streams during the dry season (August-September) of 2012, in the mountainous region of Teres6polis, State of Rio de Janeiro, Brazil. The streams were characterized for their environmental integrity conditions and physico-chemical properties of water. In each stream, five different rapid points were sampled in a section of 50 meters, 10 meters apart from each other. The black flies were sampled with a kick-net sampler on rocky substrates. The material was separated and the larvae were sorted in morphotypes, and later, the final instar specimens were dissected and identified with the help of taxonomical literature at species level. A total abundance of 488 larvae from nine species were collected, 5 (1.02 %) in extremely impacted streams, 470 (96.31 %) in intermediate streams and 13 (2.66 %) in preserved streams. The visual evaluation (HII) differed in relation to the water physico-chemical evaluation, in which more variation in the characterization of the sampling sites was observed. In Canonical Correspondence Analysis Simulium subpallidum, S. inscrustatum and S. pertinax were significantly associated with intermediate values of most of the variables, and then to intermediate impacted sites. On the other hand

  19. Water pollution and distribution of the black fly (Diptera: Simuliidae in the Atlantic Forest, Brazil

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    Tatiana N Docile

    2015-09-01

    Full Text Available Abstract:Black flies have medical importance because some species are vectors of the Onchocerciasis and Mansonelosis, nevertheless, their ecology and potential use as bioindicators is still poorly studied in the Neotropical Region. In Brazil, bioindicators use is strongly focused in a multimetrical ecological index approach; this way, we investigated the black fly spatial distribution, in relation to abiotic factors correlated to water quality, to provide baseline information for their utilization as standalone indicators of lotic systems integrity. We have tested the hypothesis that environmental changes related to urbanization, lead to decreased abundance and loss in the number of species of the black fly fauna. The sampling was conducted in 10 urban and 10 preserved streams during the dry season (August-September of 2012, in the mountainous region of Teresópolis, State of Rio de Janeiro, Brazil. The streams were characterized for their environmental integrity conditions and physico-chemical properties of water. In each stream, five different rapid points were sampled in a section of 50 meters, 10 meters apart from each other. The black flies were sampled with a kick-net sampler on rocky substrates. The material was separated and the larvae were sorted in morphotypes, and later, the final instar specimens were dissected and identified with the help of taxonomical literature at species level. A total abundance of 488 larvae from nine species were collected, 5 (1.02 % in extremely impacted streams, 470 (96.31 % in intermediate streams and 13 (2.66 % in preserved streams. The visual evaluation (HII differed in rela&tion to the water physico-chemical evaluation, in which more variation in the characterization of the sampling sites was observed. In Canonical Correspondence Analysis Simulium subpallidum, S. inscrustatumand S. pertinaxwere significantly associated with intermediate values of most of the variables, and then to intermediate impacted

  20. Fauna of Simuliidae (Diptera from the state of Espírito Santo, Brazil: distribution, new records and list of species

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    Karina Bertazo

    2013-03-01

    Full Text Available Fauna of Simuliidae (Diptera from the state of Espírito Santo, Brazil: Distribution, new records and list of species. The fauna of Simuliidae in Brazil is composed of 87 species, 17 of which are recorded from the state of Espírito Santo. Entomological collections were carried out in 2010-2011 with the objective of increasing the knowledge of the species richness of this family in the state. Ninety three rivers and streams were sampled, each collection being carried out in a 50m transect. During the study period 30 species were collected, 13 of which represent new records for the state, 12 of the genus Simulium and one of the genus Lutzsimulium. Among these new state records one, Simulium lobatoi, also represents a new record from southeastern Brazil. The other newly recorded species are: Lutzsimulium hirticosta, Simulium distinctum, Simulium exiguum, Simulium oyapockense, Simulium botulibranchium, Simulium petropoliense, Simulium clavibranchium, Simulium rappae, Simulium minusculum, Simulium dinellii, Simulium ochraceum and Simulium scutistriatum.

  1. Checklist of the family Simuliidae (Diptera of Finland

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    Jari Ilmonen

    2014-09-01

    Full Text Available A checklist of the family Simuliidae (Diptera is provided for Finland and recognizes 56 species. One new record has been added (Simulium latipes and one name sunken in synonymy (Simulium carpathicum. Furthermore, Simulium tsheburovae is treated as a doubtful record.

  2. Blackflies (Diptera: Simuliidae) in Croatia: species richness, distribution and relationship to surrounding countries.

    Science.gov (United States)

    Ivković, Marija; Kúdela, Matuš; Kúdelová, Tatiana

    2016-05-05

    All records of blackflies (Simuliidae) from the territory of Croatia are summarized, including previously unpublished data. The blackfly fauna of Croatia consists of 28 species. Simulium (Nevermannia) angustitarse (Lundström), Simulium (Nevermannia) cryophilum (Rubtsov) complex, Simulium (Nevermannia) lundstromi (Enderlein), Simulium (Nevermannia) vernum Macquart complex, Simulium (Simulium) argyreatum Meigen, Simulium (Simulium) bezzii (Corti) complex, Simulium paraequinum Puri and Simulium pseudequinum Séguy are reported for the first time from Croatia. Information related to the ecoregions, in which species were found and specific species traits are given. Genus Prosimulium Roubaud is represented by one species only. Genus Simulium Latreille is represented by 27 species in six subgenera, with subgenus Simulium Latreille s. str. being most species rich (13 species) and subgenera Boophthora Enderlein and  Trichodagmia Enderlein represented each by only one species. Compared to the neighboring countries, the Croatian species assemblage is most similar to the fauna of Slovenia and least similar to that of Italy. The relatively low number of species, presence of several species complexes and unclear identity of other species show that further research of blackflies in Croatia is needed.

  3. NCBI nr-aa BLAST: CBRC-TBEL-01-1221 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-TBEL-01-1221 ref|YP_635917.1| cell division protein [Helicosporidium sp. ex Simulium jones...ii] sp|Q2EEX7|FTSH_HELSJ Cell division protease ftsH homolog gb|ABD33966.1| ftsH protease [Helicosporidium sp. ex Simulium jonesii] YP_635917.1 3.4 24% ...

  4. African Journal of Science and Technology (AJST ...

    African Journals Online (AJOL)

    Administrator

    the disease bring about the need to control onchocerciasis by understanding the mechanism of the host's ... The insect vector of Onchocerca is the black fly, Simulium. The larvae ...... D. immitis infection in dogs (WHO, 1987). Introduction of.

  5. Stability Analysis of a Mathematical Model for Onchocerciaisis ...

    African Journals Online (AJOL)

    ADOWIE PERE

    ABSTRACT: In this work, we propose a Deterministic Mathematical Model that ... blackflies Center for Disease Control and World ... villages located along fast flowing rivers where the ..... distribution of Blackflies (Simulium Species) in.

  6. Prevalence of Concomitant Onchocerciasis-Malaria Infection in ...

    African Journals Online (AJOL)

    2012 to April 2014 to ascertain the prevalence of onchocerciasis-malaria co-infec on. Four hundred and ... features with ophthalmic signs often presen ng several years .... breeding of both Simulium damnosum and Anopheles mosquitoes ...

  7. African Journal of Aquatic Science - Vol 31, No 2 (2006)

    African Journals Online (AJOL)

    Estimation of preferred water flow parameters for four species of Simulium ... The distribution and abundance of the endangered Knysna seahorse ... The food and feeding habits of five freshwater and brackish-water fish species in Nigeria ...

  8. Onchocerciasis (River Blindness) FAQs

    Science.gov (United States)

    ... an infection caused by the parasitic worm Onchocerca volvulus , spread by the bite of an infected Simulium ... indicate that you are still infected with O. volvulus . What is the treatment for onchocerciasis? There are ...

  9. Seasonal biodiversity of black flies (Diptera: Simuliidae) and evaluation of ecological factors influencing species distribution at Doi Pha Hom Pok National Park, Thailand.

    Science.gov (United States)

    Srisuka, Wichai; Takaoka, Hiroyuki; Otsuka, Yasushi; Fukuda, Masako; Thongsahuan, Sorawat; Taai, Kritsana; Choochote, Wej; Saeung, Atiporn

    2015-09-01

    This is the first study on the seasonal biodiversity of black flies and evaluation of ecological factors influencing their distribution at Doi Pha Hom Pok National Park, northern Thailand. Larvae were collected from six fixed-stream sites in relation to altitude gradients from May 2011 to April 2013. The water temperature, water pH, conductivity, total dissolved solids (TDS), salt, water velocity, stream width and depth, streambed particle sizes, riparian vegetation, and canopy cover were recorded from each site. Monthly collections from the six sites yielded 5475 last-instar larvae, belonging to 29 black fly species. The most frequently found species from all sites were Simulium asakoae (100%) followed by Simulium yuphae (83.3%), and Simulium chiangdaoense, Simulium gombakense, Simulium phahompokense, Simulium fruticosum, Simulium maeaiense and Simulium fenestratum (66.6%). Of the 5475 last-instar larvae, S. maeaiense (19.3%), S. chiangdaoense (15.8%) and S. asakoae (14.8%), were the three most abundant species. The Shannon diversity index (H) at the six sites with different altitudes of 2100m, 2000m, 1500m, 1400m, 700m, and 500m above mean sea level, were 2.042, 1.832, 2.158, 2.123, 1.821 and 1.822, respectively. The Shannon index and number of taxa in the cold season were higher than those in the rainy and hot seasons. Principal component analysis (PCA) indicated that at least three principal components have eigen values >1.0 and accounted for 93.5% of the total variability of ecological factors among sampling sites. The Canonical correspondence analyses (CCA) showed that most species had a trend towards altitude, canopy cover, riparian vegetation and water velocity. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  10. Natural range expansion and local extirpation of an exotic psittacine--an unsuccessful colonization attempt

    Science.gov (United States)

    Wiley, J.W.

    1993-01-01

    The Brown-throated Parakeet Aratinga pertinax is native to Panama, northern South America, and the islands off the northern coast of Venezuela. It is widely believed that the parakeet was introduced to St. Thomas, Virgin Islands, from Curacao before the mid-19th century, although no records exist as to when and how this may have occurred. The parakeet was not recorded from Vieques or Culebra islands or mainland Puerto Rico before 1975. However, in that year A. pertinax underwent an apparent natural range expansion from St. Thomas into each of these sites. The 5 birds in the eastern Puerto Rico population made 5 breeding attempts and fledged 11 young since their discovery in April1975. That population grew to a maximum size of 10 birds in June 1979. However there was only 1 bird left by July 1980, and the population no longer existed at the beginning of what would have been the 1982 breeding season. The populations on Culebra and Vieques islands were apparently extirpated by 1976. Losses in the eastern Puerto Rico population were low during the first four years of colonization, when reproduction was adequate and the mortality was low. However, between 1978 and the time of population disappearance in 1982, the expected extirpation was 0.999. Habitat use, general behavior, breeding biology, competitors and predators of the colonizing population in eastern Puerto Rico are described. Biogeographic, evolutionary, and conservation implications of these observations are discussed.

  11. ONCHOCERCIASIS – A PUBLIC HEALTH PERSPECTIVE ...

    African Journals Online (AJOL)

    Onchocerciasis is a chronic parasitic disease with a wide range of cutaneous and ocular manifestations. It is caused by the tissue nematode, Onchocerca volvulus, and it is transmitted by the bite of a female black fly, Simulium damnosum. Onchocerciasis is a serious public health and socio-economic problem with 95% of all ...

  12. Impact of winter flow regulation on pest-level populations of blackfly ...

    African Journals Online (AJOL)

    The mid-reaches of the Great Fish River in the Eastern Cape Province of South Africa experience regular outbreaks of the pest blackfly Simulium chutteri as a direct consequence of increased flows caused by an inter-basin transfer scheme. There are opportunities to control these outbreaks through flow manipulation by ...

  13. Author Details

    African Journals Online (AJOL)

    Ejezie, GC. Vol 5, No 2 (2005) - Articles Factors affecting the transmission of human onchocerciasis by Simulium damnosum s l. in a fringe savanna village in Cross River State, Nigeria Abstract · Vol 1 (2000) - Articles Nutritional Status of Pre-School Children in Rural Nigeria: Relationships with Intestinal Helminthiasis

  14. Author Details

    African Journals Online (AJOL)

    Factors affecting the transmission of human onchocerciasis by Simulium damnosum s l. in a fringe savanna village in Cross River State, Nigeria Abstract · Vol 9, No 1 (2009) - Articles Histochemical Characterization of Rain-Forest Strain of Onchocerca Volvulus Microfilariae Isolated in Akamkpa, Cross River State, Nigeria.

  15. Author Details

    African Journals Online (AJOL)

    Opoku, AA. Vol 13, No 1 (2008) - Articles The Effect of C02, Sweat, Chemical Vapours and Air on Simulium ornatum: Implications for Control Abstract PDF · Vol 9, No 1 (2006) - Articles The ecology and biting activity of blackflies (Simuliidae) and the prevalence of onchocerciasis in an agricultural community in Ghana

  16. 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.

  17. Chromosomal Translocations in Black Flies (Diptera: Simuliidae-Facilitators of Adaptive Radiation?

    Directory of Open Access Journals (Sweden)

    Peter H Adler

    Full Text Available A macrogenomic investigation of a Holarctic clade of black flies-the Simulium cholodkovskii lineage-provided a platform to explore the implications of a unique, synapomorphic whole-arm interchange in the evolution of black flies. Nearly 60 structural rearrangements were discovered in the polytene complement of the lineage, including 15 common to all 138 analyzed individuals, relative to the central sequence for the entire subgenus Simulium. Three species were represented, of which two Palearctic entities (Simulium cholodkovskii and S. decimatum were sympatric; an absence of hybrids confirmed their reproductive isolation. A third (Nearctic entity had nonhomologous sex chromosomes, relative to the other species, and is considered a separate species, for which the name Simulium nigricoxum is revalidated. A cytophylogeny is inferred and indicates that the two Palearctic taxa are sister species and these, in turn, are the sister group of the Nearctic species. The rise of the S. cholodkovskii lineage encompassed complex chromosomal and genomic restructuring phenomena associated with speciation in black flies, viz. expression of one and the same rearrangement as polymorphic, fixed, or sex linked in different species; taxon-specific differentiation of sex chromosomes; and reciprocal translocation of chromosome arms. The translocation is hypothesized to have occurred early in male spermatogonia, with the translocated chromosomal complement being transmitted to the X- and Y-bearing sperm during spermatogenesis, resulting in alternate disjunction of viable F1 translocation heterozygotes and the eventual formation of more viable and selectable F2 translocation homozygous progeny. Of 11 or 12 independently derived whole-arm interchanges known in the family Simuliidae, at least six are associated with subsequent speciation events, suggesting a facilitating role of translocations in adaptive radiations. The findings are discussed in the context of potential

  18. Variation in density of cattle-visiting muscid flies between Danish inland pastures

    DEFF Research Database (Denmark)

    Jensen, Karl-Martin Vagn; Jespersen, Jørgen B.; Nielsen, B. Overgaard

    1993-01-01

    The density of cattle-visiting flies (Muscidae) and the load of black-flies (Simulium spp.) were estimated in twelve and eighteen inland pastures in Denmark in 1984 and 1985 respectively. No differences in the geographical distribution pattern of the predominant cattle-visiting Muscidae were reco......-exposed pastures. A comparable relationship was found for Haematobia irritans. With Haematobosca stimulans (Mg.) and Morellia spp. no relation between grassland environment and fly density was detected....

  19. Leucocytozoonosis in Canada Geese at the Seney National Wildlife Refuge

    Science.gov (United States)

    Herman, C.M.; Barrow, J.H.; Tarshis, I.B.

    1975-01-01

    A history is given of the Seney National Wildlife Refuge and the losses of goslings of Canada geese (Branta canadensis) recorded since inception of the refuge in 1935. Since 1960, when more reliable data became available, losses have been extensive every 4 years. Gosling deaths are attributed to the infection with Leucocytozoon simondi. The blackfly (Simulium innocens) is considered to be the prime vector in the transmission of this blood parasite to goslings.

  20. Vietnam, a Hotspot for Chromosomal Diversity and Cryptic Species in Black Flies (Diptera: Simuliidae)

    Science.gov (United States)

    Takaoka, Hiroyuki; Sofian-Azirun, Mohd; Low, Van Lun; Ya’cob, Zubaidah; Chen, Chee Dhang; Lau, Koon Weng; Pham, Xuan Da

    2016-01-01

    The increasing attention on Vietnam as a biodiversity hotspot prompted an investigation of the potential for cryptic diversity in black flies, a group well known elsewhere for its high frequency of isomorphic species. We analyzed the banding structure of the larval polytene chromosomes in the Simulium tuberosum species group to probe for diversity beyond the morphological level. Among 272 larvae, 88 different chromosomal rearrangements, primarily paracentric inversions, were discovered in addition to 25 already known in the basic sequences of the group in Asia. Chromosomal diversity in Vietnam far exceeds that known for the group in Thailand, with only about 5% of the rearrangements shared between the two countries. Fifteen cytoforms and nine morphoforms were revealed among six nominal species in Vietnam. Chromosomal evidence, combined with available molecular and morphological evidence, conservatively suggests that at least five of the cytoforms are valid species, two of which require formal names. The total chromosomal rearrangements and species (15) now known from the group in Vietnam far exceed those of any other area of comparable size in the world, supporting the country’s status as a biodiversity hotspot. Phylogenetic inference based on uniquely shared, derived chromosomal rearrangements supports the clustering of cytoforms into two primary lineages, the Simulium tani complex and the Southeast Asian Simulium tuberosum subgroup. Some of these taxa could be threatened by habitat destruction, given their restricted geographical distributions and the expanding human population of Vietnam. PMID:27695048

  1. "Jejenes" (Diptera: Simuliidae of Nahuel Huapi National Park, Patagonia, Argentina: Preliminary results "Jejenes" (Diptera: Simuliidae del Parque Nacional Nahuel Huapi, Patagonia, Argentina: Resultados preliminares

    Directory of Open Access Journals (Sweden)

    Luis M. Hernández

    2009-06-01

    Full Text Available The Simuliidae is a family of Diptera with approximately 2072 described species worldwide. The females of the majority of the species feed from vertebrates' blood, which makes them a significant plague that affects both men as well as cattle, birds, and other vertebrates. The objective of this paper is to create an inventory of Simuliidae and to reveal certain aspects of the biology and distribution of this family of aquatic insects in the Nahuel Huapi National Park. Moreover, information on the zoogeography of Simuliidae in Patagonia is provided. Five genera, 3 subgenera and 32 species Simuliidae are recorded from Patagonia: Cnesia (three spp., Cnesiamima (one sp., Gigantodax (14 spp., Paraustrosimulium (one sp., Simulium (Ectemnaspis (one sp., S. (Psaroniocompsa (one sp. and S. ( Pternaspatha (11 spp., At present, we have collected all five genera, one subgenus of Simulium (Pternaspatha, and 19 species of Simuliidae in the park, which amounts to 57% of the Simuliidae fauna in this area. Puerto Blest, a characteristic area of the High-Andean phytogeographical province (humid forest, showed the highest diversity of Simuliidae.Los simúlidos pertenecen a una familia de Diptera (Simuliidae con alrededor de 2.072 especies descritas a nivel mundial. Las hembras de la mayoría de las especies se alimentan con sangre de vertebrados, lo cual las convierte en importantes plagas que afectan tanto al hombre como al ganado, aves y otros vertebrados. Los objetivos de este trabajo son llevar a cabo un inventario de Simuliidae y dar a conocer algunos aspectos de la biología y la distribución de esta familia de insectos acuáticos en el Parque Nacional Nahuel Huapi, Argentina. Además, se proporciona información sobre la biogeografía de Simuliidae en la Patagonia. Cinco géneros, un subgénero y 32 especies de simúlidos han sido registrados para Patagonia: Cnesia (3 spp., Cnesiamima (1 sp., Gigantodax (14 spp., Paraustrosimulium (1 sp., Simulium

  2. Parasites of larval black flies (Diptera: Simuliidae in Thailand

    Directory of Open Access Journals (Sweden)

    Sanae Jitklang

    2012-12-01

    Full Text Available Parasites of larval black flies are reported for the first time from Thailand, including mermithid nematodes(Mermithidae, microsporidian fungi (Zygomycota, and the fungus Coelomycidium simulii Debaisieux (Blastocladiomycetes.The following nine species of black flies were infected with one or more parasites: Simulium asakoae, S. chamlongi,S. chiangmaiense, S. fenestratum, S. feuerborni, S. nakhonense, S. nodosum, S. quinquestriatum, and S. tani. The prevalenceof patent infections per host species per season was 0.1–7.1% for mermithids, 0.1–6.0% for microsporidia, and 0.1–3.0% forC. simulii.

  3. Breve nota acerca de simúlidos colombianos

    Directory of Open Access Journals (Sweden)

    Leopoldo Briceño Iragorry

    1946-08-01

    Full Text Available Durante corta permanencia en la ciudad de Cali, Colombia (1.000 mts. Alt. 4 de junio de 1946, tuvimos oportunidad de colectar a orillas del rio Cauca a su paso par la prospera capital del Departamento del Valle, ejemplares de Simúlidos al estado de pupa en las inmediaciones del parque donde la admiración conciudadana ha erigido un busto al escritor Jorge Isaacs Iragorri. Pudimos, no obstante las pocas facilidades de que disponíamos, obtener par cría adultos que facilitaron el estudio completo de los ejemplares en referencia, que permitió clasificarlos como Simulium (E lutzianus.

  4. Interruption of Onchocerca volvulus transmission in Northern Venezuela.

    Science.gov (United States)

    Convit, Jacinto; Schuler, Harland; Borges, Rafael; Olivero, Vimerca; Domínguez-Vázquez, Alfredo; Frontado, Hortencia; Grillet, María E

    2013-10-07

    Onchocerciasis is caused by Onchocerca volvulus and transmitted by Simulium species (black flies). In the Americas, the infection has been previously described in 13 discrete regional foci distributed among six countries (Brazil, Colombia, Ecuador, Guatemala, Mexico and Venezuela) where more than 370,000 people are currently considered at risk. Since 2001, disease control in Venezuela has relied on the mass drug administration to the at-risk communities. This report provides empirical evidence of interruption of Onchocerca volvulus transmission by Simulium metallicum in 510 endemic communities from two Northern foci of Venezuela, after 10-12 years of 6-monthly Mectizan (ivermectin) treatment to all the eligible residents. In-depth entomologic and epidemiologic surveys were serially conducted from 2001-2012 in selected (sentinel and extra-sentinel) communities from the North-central (NC) and North-east (NE) onchocerciasis foci of Venezuela in order to monitor the impact of ivermectin treatment. From 2007-2009, entomological indicators in both foci confirmed that 0 out of 112,637 S. metallicum females examined by PCR contained L3 infection in insect heads. The upper bound of the 95% confidence intervals of the infective rate of the vector reached values below 1% by 2009 (NC) and 2012 (NE). Additionally, after 14 (NC) and 22 (NE) rounds of treatment, the seasonal transmission potential (±UL CIs) of S. metallicum was under the critical threshold of 20 L3 per person per season. Serological analysis in school children Venezuela.

  5. Simuliidae diversity (Diptera: Nematocera of three water courses in Klabin’s ecological park – Telêmaco Borba, State of Paraná Diversidade de Simuliidae (Diptera: Nematocera de três cursos d’ água no parque ecológico da Klabin S.A. – Telêmaco Borba, Estado do Paraná

    Directory of Open Access Journals (Sweden)

    José Lopes

    2010-10-01

    Full Text Available Simuliidae have been considered object of concern due to their hemophagia, anthropophilic habits and high proliferation, causing discomfort to the population, damages to agricultural activities and rural tourism, besides being pathogens vectors. With the purpose of understanding the community structure and specific diversity of these insects, a survey of the species was conducted in three streams in an ecological park in Telêmaco Borba – Paraná, Brazil. Immature specimens were collected in mineral and vegetable substrates on the riverbanks. Chemical and physical analyses of the water were carried out. The Simuliidae collection included 14,397 individuals, being 14,150 larvae and 247 pupae. The following species were identified: Simullium subnigrum, S. subpallidum, S. rubrithorax, S. incrustatum, S. pertinax, S. inaequale, S. anamariae, S. rubiginosum, S. travassosi, S. riograndense and S. dinelli. This is the first registry of S. rubiginosum and S. dinelli in the State of Paraná. The lesser-impacted areas presented greater diversity. However, the impacted areas presented an abundance of borrachudos, represented by a single species, S. rubrithorax. It was concluded that preservation areas with lotic waters and riparian forest are considered a refuge area for Simuliidae species. Impact of anthropical activities upon the environment interferes in the dynamics of species, favoring one or more of them, which proliferate and predominate. Os simulídeos têm sido objeto de preocupação devido ao seu hábito hematófago, forte antropofilia e alta proliferação, causando desconforto à população, prejuízos em atividades agropecuárias e de turismo rural, além de serem vetores de patógenos. Objetivando conhecer a estrutura de comunidade e diversidade específica desses insetos, foi realizado o levantamento de espécies em três riachos de um parque ecológico em Telêmaco Borba – Paraná. Coletaram-se imaturos em substratos minerais e

  6. Mansonella ozzardi and its vectors in the New World: an update with emphasis on the current situation in Haiti.

    Science.gov (United States)

    Raccurt, C P

    2017-10-25

    Mansonella ozzardi (Nematoda: Onchocercidae) is a little studied filarial nematode. This human parasite, transmitted by two families of dipteran vectors, biting midges (most of them members of the genus Culicoides) and blackflies (genus Simulium), is endemic to the Neotropical regions of the New World. With a patchy geographical distribution from southern Mexico to north-western Argentina, human infection with M. ozzardi is highly prevalent in some of the Caribbean islands, along riverine communities in the Amazon Basin, and on both sides of the border between Bolivia and Argentina. Studies conducted in Haiti between 1974 and 1984 allowed the first complete description of the adult worm and permitted clarification of the taxonomic position of this filarial species. This paper reports the known geographical distribution of M. ozzardi in Neotropical regions of the Americas, and focuses on the current situation in Haiti where this filariasis remains a completely neglected public health problem.

  7. Variation in density of cattle-visiting muscid flies between Danish inland pastures

    DEFF Research Database (Denmark)

    Jensen, Karl-Martin Vagn; Jespersen, Jørgen B.; Nielsen, B. Overgaard

    1993-01-01

    recorded, whilst the relative abundance and density of the species and the total fly-load varied considerably between pastures. In most cases the mean loads of Haematobia irritans (L.) and Hydrotaea irritans (Fall.) on heifers varied significantly in relation to site topography and shelter. These crude......The density of cattle-visiting flies (Muscidae) and the load of black-flies (Simulium spp.) were estimated in twelve and eighteen inland pastures in Denmark in 1984 and 1985 respectively. No differences in the geographical distribution pattern of the predominant cattle-visiting Muscidae were...... site variables explained 65-98% of the variation in densities of horn flies and sheep head flies observed between pastures. Highest densities of Hydrotaea irritans were primarily associated with permanent, low-lying, fairly sheltered grassland sites, whereas the density was low in temporary, dry, wind...

  8. Chemical Control of Black Flies in Large Rivers as an Impact in Agrochemical Residue-Biota Interactions in Water Ecosystems

    International Nuclear Information System (INIS)

    Haufe, W.O.

    1981-01-01

    Livestock losses have been an obstacle to economic development of the farming and livestock industry in more northerly areas of Canada until two species of black fly, Simulium arcticum and S. luggeri, outbreaks are controlled effectively. The problem is complicated by its association with an abundance of large rivers and streams. Since effective control of black flies is presently limited to reduction of their breeding sources in flowing water, the managers of Canadian inland waters have been concerned about any major practice of using pesticides as black fly larvicides. Consequently, Canadian inland waters have been subject to continuous monitoring of major drainage systems with special attention to the chlorinated hydrocarbon insecticides. The latest status of residues was published from a Canadian Survey of 333 sampling locations between 1972 and 1975

  9. Revisión epidemiológica de la Oncocercosis en América Latina

    OpenAIRE

    Rodríguez C, Guadalupe C; Lizarazo O, Cristian

    2010-01-01

    La oncocercosis es una enfermedad exclusiva del ser humano, caracterizada por prurito intenso, lesiones dérmicas y daño ocular que puede llegar a la ceguera. Las regiones endémicas están limitadas a zonas con latitud, relieve, temperatura y humedad relativa óptimas para el desarrollo del parásito y el insecto vector. Estas zonas se encuentran en el oeste de África, Yemen y algunos países de América latina. El parásito es transmitido a través de la mordedura de una mosca del género Simulium, q...

  10. PENGGUNAAN MAKROZOOBENTOS SEBAGAI INDIKATOR STATUS PERAIRAN HULU SUNGAI CISADANE, BOGOR

    Directory of Open Access Journals (Sweden)

    Dyah Muji Rahayu

    2015-04-01

    Full Text Available Anthropogenic pollution (organic matter and Hg around Cisadane River upstream can affect the abundances of macrozoobenthos. The aim of this research was to identify the abundances of macrozoobenthos and feeding groups, and also to identify the status of waters based on macrozoobenthos community. The research was conducted on January to March in four locations in the upstream of Cisadane River, covering Cikuluwung (ST 1, Cisarua (ST 2, Curug Bitung (ST 3, and Lukut (ST 4. Samples were collected with kick net and Eckman Grab. The dominance macrozoobenthos are Bungona (171 ind/m2, Simulium (101 ind/m2, Cheumatopsyche (50 ind/m2, and Polypedilum (28 ind/m2. Based on feeding groups, the dominance are filtering collector and gatherer collector. Based on the Pollution Index and Heavy Metal Pollution Index (Hg on sediment, the upstream of Cisadane River is low polluted whereas EPT Index and Signal showed that upstream of Cisadane River is moderate polluted.

  11. X-ray diffraction analysis of particles ingested by filter-feeding animals

    International Nuclear Information System (INIS)

    Merritt, R.W.; Gersabeck, E.F.; Ross, D.H.; Mortland, M.M.

    1978-01-01

    The size and relative abundance of mineral particles ingested by two filter-feeding aquatic insects, Simulium vittatum Zett. (Diptera: Simuliidae) and Aedes triseriatus (Say) (Diptera: Culicidae) were determined by X-ray diffraction methods. Different minerals representing different particle size categories were supplied larval black flies and mosquitoes. Since minerals possess characteristic diffraction properties, their presence and relative abundance can be determined. Early instars of the black fly ingested and retained particles of three different size ranges: however, more coarse particles relative to fine particles were retained by smaller instars as compared with the larger instars. With mosquito larvae, there was a proportional increase in coarser material ingested with increasing age and size of larvae. Other applications of this method are discussed. (Auth.)

  12. A revision of male ants of the Malagasy Amblyoponinae (Hymenoptera: Formicidae with resurrections of the genera Stigmatomma and Xymmer.

    Directory of Open Access Journals (Sweden)

    Masashi Yoshimura

    Full Text Available In a male-based revision of ants of the subfamily Amblyoponinae from the Southwest Indian Ocean islands (SWIO: Comoros, Madagascar, Mauritius, Mayotte, Reunion, and Seychelles, we explore and reconsider male morphological characters that distinguish genera within the group. Our investigation redefines Amblyopone Erichson sensu Brown (1960, here referred to as Amblyopone sensu lato, into three genera: Xymmer Santschi stat. rev.,Amblyopone sensu stricto, Stigmatomma Roger stat. rev. All species names under Amblyopone s. l. reassign into Xymmer and Amblyopone s. s., which are small, well-defined genera, and Stigmatomma, a large group with a generic delimitation that still needs further refinement. Based on a study of male mandible characters and our scenario for mandibular evolution of the worker caste within Amblyopone s. l, we conclude that Amblyopone s. s. nests outside of XMAS (Xymmer+Mystrium+Adetomyrma+Stigmatomma clade. The following names are transferred from Amblyopone s. l. to Xymmer as comb. rev.: muticus. The following names are transferred from Amblyopone s. l. to Stigmatomma as comb. rev.: amblyops, armigerum, bellii, bierigi, bruni, celata, chilense, denticulatum, elongatum, emeryi, feae, impressifrons, luzonicum, minuta, normandi, oregonense, pallipes, quadratum, reclinatum, rothneyi, santschii, saundersi, silvestrii, zwaluwenburgi; as comb. nov.: agostii, annae, besucheti, boltoni, caliginosum, cleae, crenatum, degeneratum, egregium, electrinum, eminia, exiguum, falcatum, ferrugineum, fulvidum, gaetulicum, gingivalis, glauerti, gnoma, gracile, groehni, heraldoi, lucidum, lurilabes, monrosi, mystriops, noonadan, octodentatum, ophthalmicum, orizabanum, papuanum, pertinax, pluto, punctulatum, rubiginoum, sakaii, smithi, trigonignathum, trilobum, wilsoni, zaojun, and testaceum. A male-based key to the genera of Malagasy amblyoponine ants, their diagnoses, and a discussion of the evolution of the morphological character of males in the

  13. Насекомые, вредящие деревянным постройкам на территории музея-заповедника «Кижи»

    OpenAIRE

    Полевой, А.; Козлов, В.; Кистерная, М.

    2008-01-01

    Описан видовой состав насекомых, повреждающих памятники деревянного зодчества. Показано, что основными вредителями являются домовый (Hadrobregmus pertinax L.) и северный (Н. confusus Kraaz) точильщики. Приведены данные о периоде лёта точильщиков в условиях музея-заповедника «Кижи». Обсуждаются пути проникновения этих вредителей и способы защиты деревянных конструкций и коллекций....

  14. Identification of Human Semiochemicals Attractive to the Major Vectors of Onchocerciasis

    Science.gov (United States)

    Young, Ryan M.; Burkett-Cadena, Nathan D.; McGaha, Tommy W.; Rodriguez-Perez, Mario A.; Toé, Laurent D.; Adeleke, Monsuru A.; Sanfo, Moussa; Soungalo, Traore; Katholi, Charles R.; Noblet, Raymond; Fadamiro, Henry; Torres-Estrada, Jose L.; Salinas-Carmona, Mario C.; Baker, Bill; Unnasch, Thomas R.; Cupp, Eddie W.

    2015-01-01

    Background Entomological indicators are considered key metrics to document the interruption of transmission of Onchocerca volvulus, the etiological agent of human onchocerciasis. Human landing collection is the standard employed for collection of the vectors for this parasite. Recent studies reported the development of traps that have the potential for replacing humans for surveillance of O. volvulus in the vector population. However, the key chemical components of human odor that are attractive to vector black flies have not been identified. Methodology/Principal Findings Human sweat compounds were analyzed using GC-MS analysis and compounds common to three individuals identified. These common compounds, with others previously identified as attractive to other hematophagous arthropods were evaluated for their ability to stimulate and attract the major onchocerciasis vectors in Africa (Simulium damnosum sensu lato) and Latin America (Simulium ochraceum s. l.) using electroantennography and a Y tube binary choice assay. Medium chain length carboxylic acids and aldehydes were neurostimulatory for S. damnosum s.l. while S. ochraceum s.l. was stimulated by short chain aliphatic alcohols and aldehydes. Both species were attracted to ammonium bicarbonate and acetophenone. The compounds were shown to be attractive to the relevant vector species in field studies, when incorporated into a formulation that permitted a continuous release of the compound over time and used in concert with previously developed trap platforms. Conclusions/Significance The identification of compounds attractive to the major vectors of O. volvulus will permit the development of optimized traps. Such traps may replace the use of human vector collectors for monitoring the effectiveness of onchocerciasis elimination programs and could find use as a contributing component in an integrated vector control/drug program aimed at eliminating river blindness in Africa. PMID:25569240

  15. Identification of human semiochemicals attractive to the major vectors of onchocerciasis.

    Science.gov (United States)

    Young, Ryan M; Burkett-Cadena, Nathan D; McGaha, Tommy W; Rodriguez-Perez, Mario A; Toé, Laurent D; Adeleke, Monsuru A; Sanfo, Moussa; Soungalo, Traore; Katholi, Charles R; Noblet, Raymond; Fadamiro, Henry; Torres-Estrada, Jose L; Salinas-Carmona, Mario C; Baker, Bill; Unnasch, Thomas R; Cupp, Eddie W

    2015-01-01

    Entomological indicators are considered key metrics to document the interruption of transmission of Onchocerca volvulus, the etiological agent of human onchocerciasis. Human landing collection is the standard employed for collection of the vectors for this parasite. Recent studies reported the development of traps that have the potential for replacing humans for surveillance of O. volvulus in the vector population. However, the key chemical components of human odor that are attractive to vector black flies have not been identified. Human sweat compounds were analyzed using GC-MS analysis and compounds common to three individuals identified. These common compounds, with others previously identified as attractive to other hematophagous arthropods were evaluated for their ability to stimulate and attract the major onchocerciasis vectors in Africa (Simulium damnosum sensu lato) and Latin America (Simulium ochraceum s. l.) using electroantennography and a Y tube binary choice assay. Medium chain length carboxylic acids and aldehydes were neurostimulatory for S. damnosum s.l. while S. ochraceum s.l. was stimulated by short chain aliphatic alcohols and aldehydes. Both species were attracted to ammonium bicarbonate and acetophenone. The compounds were shown to be attractive to the relevant vector species in field studies, when incorporated into a formulation that permitted a continuous release of the compound over time and used in concert with previously developed trap platforms. The identification of compounds attractive to the major vectors of O. volvulus will permit the development of optimized traps. Such traps may replace the use of human vector collectors for monitoring the effectiveness of onchocerciasis elimination programs and could find use as a contributing component in an integrated vector control/drug program aimed at eliminating river blindness in Africa.

  16. The vectoral role of several blackfly species (Diptera: Simuliidae) in relation to human onchocerciasis in the Sierra Parima and Upper Orinoco regions of Venezuela.

    Science.gov (United States)

    Basáñez, M G; Yarzábal, L; Takaoka, H; Suzuki, H; Noda, S; Tada, I

    1988-12-01

    Experimental and natural infections with Onchocerca volvulus were studied in several anthropophilic blackfly species present in the endemic area of the Upper Orinoco region of Venezuela. When fed on four different Yanomami volunteers in the Sierra Parima, the total infection rate was 31.4% for Simulium guianense in comparison with 7.5% for S. limbatum. The proportion of ingested microfilariae that entered the thorax during the first 24 hours and completed development to the infective stage was also much lower in the latter than in the former species. There was no larval development of O. volvulus in S. antillarum, but one female harboured in its head six infective larvae of a zoonotic filaria. When S. oyapokense s.l. was fed on an infected volunteer in the Upper Orinoco most flies ingested few microfilariae, and further development reached only the L1 stage. Natural infection and infectivity rates for S. guianense in two localities of the Sierra Parima were 0.2-4.0% and 1.3-10.2%, respectively, more than 50% of the L3 larvae being in the head. The corresponding data for S. oyapockense s.l. in the Upper Orinoco were 0.1-0.5%, although the only L3 larva found did not correspond to O. volvulus. It is suggested that S. guianense is the main vector of onchocerciasis in the Sierra Parima and that S. limbatum could play a secondary role. Simulium oyapockense s.l. replaces them in the Upper Orinoco and may maintain a degree of transmission, but its epidemiological importance remains to be assessed.

  17. The Cracow’s pious laymen or Beghard heretics? From the study on the 14th century Tractatus contra beghardos by Henryk Harrer

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    Tomasz Gałuszka

    2012-12-01

    Full Text Available Tractatus contra beghardos written by a Chech Dominican Henryk Harrer is a masterpiece of exceptional value for both historians of the medieval heterodox movements as well as for scholars interested in the history of theology and law in the 14th century. The treaty was commissioned by Cracow Dominicans in the years 1328 to 1334. Commissioning the treaty to Henryk Harrer, a stranger expert from the Prague monastery of St. Clemens was dictated by a series of controversies among Cracow clergy around the judgement of conduct of a certain group of people whose religious practices and a way of life stood out from the rest of the congregation. Undertaking the task of writing the treaty Henryk Harrer based his work around three charges pressed against the suspected of heresy: breaking off the Church and establishing an illegal organization (singularitas vite; corrupted attitude towards recognized religious practices (contemptibilitas sacramenti eucharistiae; numerous flaws and perverse disposition (pertinax voluntas. Not only did Harrer decide to comment on all aspects of life of central figures of Contra beghardos but he also honestly mentioned all arguments he was not able to undermine. Despite these objective difficulties, the Czech Dominican was certain that the expertise he came up with was sufficient to link the lay movement with the sect of Beghard Heretics. The author of this study proved that, contrary to Harrer’s keen intention, his Tractatus contra beghardos does not unambiguously show heresy in the Cracow diocese. What is more, the reader, instead of indictment against the conduct of a group of laymen paradoxically received a confirmation of their innocence and orthodoxy. In the light of analysis of the text Contra beghardos, the claim that Beghard Heretics from Harrer’s work turn out to be pious layman, living in communion with the Church, seems to be fully substantiated. Of course their way of life and the practice of asceticism made

  18. Interruption of Onchocerca volvulus transmission in Northern Venezuela

    Science.gov (United States)

    2013-01-01

    Background Onchocerciasis is caused by Onchocerca volvulus and transmitted by Simulium species (black flies). In the Americas, the infection has been previously described in 13 discrete regional foci distributed among six countries (Brazil, Colombia, Ecuador, Guatemala, Mexico and Venezuela) where more than 370,000 people are currently considered at risk. Since 2001, disease control in Venezuela has relied on the mass drug administration to the at-risk communities. This report provides empirical evidence of interruption of Onchocerca volvulus transmission by Simulium metallicum in 510 endemic communities from two Northern foci of Venezuela, after 10–12 years of 6-monthly Mectizan® (ivermectin) treatment to all the eligible residents. Methods In-depth entomologic and epidemiologic surveys were serially conducted from 2001–2012 in selected (sentinel and extra-sentinel) communities from the North-central (NC) and North-east (NE) onchocerciasis foci of Venezuela in order to monitor the impact of ivermectin treatment. Results From 2007–2009, entomological indicators in both foci confirmed that 0 out of 112,637 S. metallicum females examined by PCR contained L3 infection in insect heads. The upper bound of the 95% confidence intervals of the infective rate of the vector reached values below 1% by 2009 (NC) and 2012 (NE). Additionally, after 14 (NC) and 22 (NE) rounds of treatment, the seasonal transmission potential (±UL CIs) of S. metallicum was under the critical threshold of 20 L3 per person per season. Serological analysis in school children < 15 years-old demonstrated that 0 out of 6,590 individuals were harboring antibodies to Ov-16. Finally, epidemiological surveys made during 2010 (NC) and 2012 (NE) showed no evidence of microfilariae in the skin and eyes of the population. Conclusions These results meet the WHO criteria for absence of parasite transmission and disease morbidity in these endemic areas which represent 91% of the population previously at

  19. The elimination of the onchocerciasis vector from the island of Bioko as a result of larviciding by the WHO African Programme for Onchocerciasis Control.

    Science.gov (United States)

    Traoré, S; Wilson, M D; Sima, A; Barro, T; Diallo, A; Aké, A; Coulibaly, S; Cheke, R A; Meyer, R R F; Mas, J; McCall, P J; Post, R J; Zouré, H; Noma, M; Yaméogo, L; Sékétéli, A V; Amazigo, U V

    2009-09-01

    The island of Bioko is part of the Republic of Equatorial Guinea and is the only island in the World to have endemic onchocerciasis. The disease is hyperendemic and shows a forest-type epidemiology with low levels of blindness and high levels of skin disease, and the whole population of 68,000 is estimated to be at risk. Control of onchocerciasis began in 1990 using ivermectin and this yielded significant clinical benefits but transmission was not interrupted. Feasibility and preparatory studies carried out between 1995 and 2002 confirmed the probable isolation of the vector on the island, the high vectorial efficiency of the Bioko form of Simulium yahense, the seasonality of river flow, blackfly breeding and biting densities, and the distribution of the vector breeding sites. It was proposed that larviciding should be carried out from January to April, when most of the island's rivers were dry or too low to support Simulium damnosum s.l., and that most rivers would not need to be treated above 500 m altitude because they were too small to support the breeding of S. damnosum s.l. Larviciding (with temephos) would need to be carried out by helicopter (because of problems of access by land), supplemented by ground-based delivery. Insecticide susceptibility trials showed that the Bioko form was highly susceptible to temephos, and insecticide carry was tested in the rivers by assessing the length of river in which S. damnosum s.l. larvae were killed below a temephos dosing point. Regular fly catching points were established in 1999 to provide pre-control biting densities, and to act as monitoring points for control efforts. An environmental impact assessment concluded that the proposed control programme could be expected to do little damage, and a large-scale larviciding trial using ground-based applications of temephos (Abate 20EC) throughout the northern (accessible) part of the island was carried out for five weeks from 12 February 2001. Following this, a first

  20. Novel in vitro diagnosis of equine allergies using a protein array and mathematical modelling approach: a proof of concept using insect bite hypersensitivity.

    Science.gov (United States)

    Marti, E; Wang, X; Jambari, N N; Rhyner, C; Olzhausen, J; Pérez-Barea, J J; Figueredo, G P; Alcocer, M J C

    2015-10-15

    Insect bite hypersensitivity (IBH) is a seasonal recurrent skin allergy of horses caused by IgE-mediated reactions to allergens present in the saliva of biting insects of the genus Culicoides, and possibly also Simulium and Stomoxys species. In this work we show that protein microarrays containing complex extracts and pure proteins, including recombinant Culicoides allergens, can be used as a powerful technique for the diagnosis of IBH. Besides the obvious advantages such as general profiling and use of few microliters of samples, this microarray technique permits automation and allows the generation of mathematical models with the calculation of individual risk profiles that can support the clinical diagnosis of allergic diseases. After selection of variables on influence on the projection (VIP), the observed values of sensitivity and specificity were 1.0 and 0.967, respectively. This confirms the highly discriminatory power of this approach for IBH and made it possible to attain a robust predictive mathematical model for this disease. It also further demonstrates the specificity of the protein array method on identifying a particular IgE-mediated disease when the sensitising allergen group is known. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Black flies (Diptera : Simuliidae attracted to humans and water buffalos and natural infections with filarial larvae, probably Onchocerca sp., in northern Thailand

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    Takaoka H.

    2003-03-01

    Full Text Available Several Simulium species were investigated as to their biting habits and natural infections with filarial larvae at Ban Pan Fan, Chiang Mai Province, in northern Thailand. Female adults flies landing on or flighting around a human and a water buffalo were collected during the daytime from 06.00 to 19.00 hours on 22 June 2001. As a result, 217 S. nodosum, 86 S. asakoae and two S. nigrogilvum were obtained from a human attractant, and 416 S. nodosum, 25 S. nakhonense, 16 S. asakoae, four 5. fenestratum and two S. nigrogilvum, from a water buffalo. The blood-feeding was confirmed only for S. nodosum and S. nigrogilvum on humans, and for S. nodosum and S. nakhonense on water buffalos. Dissections of these simuliids showed that S. nodosum was naturally infected with developing filarial larvae. Two types of microfilariae were distinguished but only one type of infective larvae. These larvae resembled Onchocerca suzukii, a parasite from a wild Japanese bovid, suggesting that an unknown Onchocerca species from ruminants was transmitted in Thailand. Infection rates with all stages of larvae and third-stage larvae were 2.3 % (14/608 and 1 .0 % (6/608, respectively. This is the first report of natural infections of black flies with Onchocerca larvae in Southeast Asia, and the involved black fly species is shown to be not only anthropophilic but also zoophilic in this region.

  2. Lack of Active Onchocerca volvulus Transmission in the Northern Chiapas Focus of Mexico

    Science.gov (United States)

    Rodríguez-Pérez, Mario A.; Unnasch, Thomas R.; Domínguez-Vázquez, Alfredo; Morales-Castro, Alba L.; Richards, Frank; Peña-Flores, Graciela P.; Orozco-Algarra, María Eugenia; Prado-Velasco, Gibert

    2010-01-01

    The northern Chiapas onchocerciasis focus has undergone 11 years of ivermectin mass treatment. No evidence of microfilariae in the cornea and/or anterior chamber of the eye or in skin snips was seen in residents examined in 2006 in two sentinel communities (upper limit of the 95% confidence interval [UL 95% CI] = 0.5% and 0.3%, respectively). In children 10 and under, 0 of 305 were found to harbor antibodies to Ov16, a marker of parasite exposure; 0 of 4,400 Simulium ochraceum s.l. collected in 2005 contained parasite DNA, giving an UL 95% CI for the infective rate of 0.9/2,000, and an UL 95% CI of the seasonal transmission potential of 1.2 L3/person. These data, assumed to be representative of the focus as a whole, suggest that there is no ongoing transmission of Onchocerca volvulus in the northern Chiapas focus. Community-wide treatments with ivermectin were halted in 2008, and a post-treatment surveillance phase was initiated. PMID:20595471

  3. Evaluation of larvicides in developing management guidelines for long-term control of pest blackflies (Diptera: Simuliidae) along the Orange River, South Africa.

    Science.gov (United States)

    Palmer, R W; Rivers-Moore, N A

    2008-12-01

    In 2000 and 2001 Orange River levels were higher than normal: associated serious outbreaks of blackfly had a substantial detrimental impact on the local economy. The poor control was attributed to the suspected development of larval resistance to temephos. A long-term solution to blackfly control, through the identification of a suitable replacement to temephos for use during high flow conditions, was proposed. This study, however, failed to identify or register a suitable larvicide for use during high flow conditions. Although permethrin was highly effective against blackfly larvae, it was rejected because of its detrimental impacts on non-target fauna. Various formulations of locally produced dry Bacillus thuringiensis var. israelensis (B.t.i.) were tested, but these were ineffective against blackflies. The study also confirmed that resistance to temephos has developed among Simulium chutteri in the middle and lower Orange River. The feasibility of "reversing" the resistance to temephos through the use of the synergist piperonyl butoxide (PBO) was investigated, but the results were not favourable. Furthermore, PBO was highly toxic to blackflies and non-target organisms, and was not recommended for further testing. This means that B.t.i. currently remains the only symptomatic measure of treatment currently applied. Although resistance to B.t.i. has not been reported for blackflies elsewhere in South Africa, there is a need to remain vigilant and to implement an operational strategy that minimizes the risks of resistance developing.

  4. Distribution of black flies (Diptera: Simuliidae) along an elevational gradient in the Andes Mountains of Colombia during the El Niño Southern Oscillation.

    Science.gov (United States)

    Mantilla, Juan S; Moncada, Ligia I; Matta, Nubia E; Adler, Peter H

    2018-07-01

    Vector ecology is a key factor in understanding the transmission of disease agents, with each species having an optimal range of environmental requirements. Scarce data, however, are available for how interactions of local and broad-scale climate phenomena, such as seasonality and the El Niño Southern Oscillation (ENSO), affect simuliids. We, therefore, conducted an exploratory study to examine distribution patterns of species of Simuliidae along an elevational gradient of the Otún River in the Colombian Andes, encompassing four ecoregions. Larval and pupal simuliids were sampled at 52 sites ranging from 1800 to 4750 m above sea level in dry and wet seasons and during the La Niña phase (2011-2012) and the El Niño phase (2015-2016) of the ENSO; physicochemical measurements were taken during the El Niño phase. Twenty-seven species in two genera (Gigantodax and Simulium) were collected. Species richness and occurrence in each ecoregion were influenced by elevation, seasonality, and primarily the warm El Niño and cool La Niña phases of the ENSO. The degree of change differed among ecoregions and was related to physicochemical factors, mainly with stream discharge. Some putative simuliid vectors of Leucocytozoon, such as G. misitu and S. muiscorum, markedly changed in distribution and occurrence, potentially influencing parasite transmission. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Some factors effecting algal consumption in subarctic Ephemeroptera, Plecoptera, and Simuliidae

    Energy Technology Data Exchange (ETDEWEB)

    Moore, J.W.

    1977-01-01

    Some of the factors influencing algal consumption in the mayflies Leptophlebia nebulosa, Cinygmula tarda, Baetis foemina and B. cf. bicaudatus, the plecopterans Arcynopteryx signata, Nemoura cinctipes and N. oregonensis and in the dipterans Simulium arcticum, S. venustum and S. decorum were investigated between June 1975 and June 1976 in several streams in the Canadian subarctic. Algae represented up to 65% of the gut contents of L. nebulosa but only 0--8% in the other mayflies. They were important in the plecopterans (85--90%) but less so (2--13%) in the simuliids. Most of the interspecies variability in algal consumption could be explained in terms of food availability. This factor was in turn dependent on the density and attachment characteristics of the flora and the strength of their cell wall. Feeding intensity in most species was low between October and April, reaching it peak in July and August. From 51 to 83% of intraspecies feeding variability was due to changing temperature, followed in importance by water velocity in the dipterans and food availability in the mayflies. All species in this latter group ceased feeding in the final instar stages.

  6. Influence of nonsystemic transmission on the epidemiology of insect borne arboviruses: a case study of vesicular stomatitis epidemiology in the western United States.

    Science.gov (United States)

    Lord, Cynthia C; Tabachnick, Walter J

    2002-05-01

    Nonsystemic transmission, where a pathogen is transmitted between infected and uninfected vectors without the vertebrate host becoming viremic, may provide an explanation for transmission in systems where the vertebrate hosts have been difficult to identify. This transmission pathway had been previously demonstrated for tick-borne viruses and bacteria, but the recent demonstration for Simulium and vesicular stomatitis virus is the first for a blood-feeding insect. The epidemiology of vesicular stomatitis viruses has been difficult to understand, and nonsystemic transmission may be important. We use mathematical formulations of the basic reproduction number, R(0), to compare systemic and nonsystemic transmission. The absence of a latent period before host infectiousness in nonsystemic transmission may allow a more rapid increase in prevalence in the biting flies early in the development of a new outbreak. Aggregation of flies between hosts and at favored feeding sites on hosts will be important, but further data on nonsystemic transmission as a function of space and time are required to fully assess this pathway. The data needed to compare the two pathways and their relative roles in virus epidemiology are discussed.

  7. One Hundred Years After Its Discovery in Guatemala by Rodolfo Robles, Onchocerca volvulus Transmission Has Been Eliminated from the Central Endemic Zone.

    Science.gov (United States)

    Richards, Frank; Rizzo, Nidia; Diaz Espinoza, Carlos Enrique; Monroy, Zoraida Morales; Crovella Valdez, Carol Guillermina; de Cabrera, Renata Mendizabal; de Leon, Oscar; Zea-Flores, Guillermo; Sauerbrey, Mauricio; Morales, Alba Lucia; Rios, Dalila; Unnasch, Thomas R; Hassan, Hassan K; Klein, Robert; Eberhard, Mark; Cupp, Ed; Domínguez, Alfredo

    2015-12-01

    We report the elimination of Onchocerca volvulus transmission from the Central Endemic Zone (CEZ) of onchocerciasis in Guatemala, the largest focus of this disease in the Americas and the first to be discovered in this hemisphere by Rodolfo Robles Valverde in 1915. Mass drug administration (MDA) with ivermectin was launched in 1988, with semiannual MDA coverage reaching at least 85% of the eligible population in > 95% of treatment rounds during the 12-year period, 2000-2011. Serial parasitological testing to monitor MDA impact in sentinel villages showed a decrease in microfilaria skin prevalence from 70% to 0%, and polymerase chain reaction (PCR)-based entomological assessments of the principal vector Simulium ochraceum s.l. showed transmission interruption by 2007. These assessments, together with a 2010 serological survey in children 9-69 months of age that showed Ov16 IgG4 antibody prevalence to be Guatemala declared onchocerciasis transmission as having been eliminated from the CEZ. © The American Society of Tropical Medicine and Hygiene.

  8. The role of flowering plant species in the survival of blackflies (Diptera: Simuliidae along the lower Orange River, South Africa

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    E. Myburgh

    2001-07-01

    Full Text Available This study is an investigation of the role that plants play in the survival of adult blackflies by providing shelter and carbohydrate food. A detailed phenological study of the 29 most abundant plant species in the Augrabies Falls National Park showed that throughout the year the percentage of plant species flowering was remarkably constant. It is therefore unlikely that the availability of carbohydrates would limit adult Simulium survival at any time of the year. Blackflies were recorded feeding on the flowers of Pappea capensis. Acacia karroo, A. mellifera, Tamarix usneoides, Ziziphus mucronata, Scholia afra and Sisyndite spartea. An additional survey showed that another 64 plant species flowered throughout the year, and these can be regarded as potential carbohydrate sources. Blackflies were observed sheltering in dense shrubs and trees that provide protection against predation and harsh environmental conditions. This study suggests that vegetated drainage lines are the means by which adult blackflies survive dispersal away from the river. It is concluded that carbohydrate scarcity cannot be considered a limiting factor to adult blackfly survival along the lower Orange River.

  9. Secondary production of benthic insects in three cold-desert streams

    Energy Technology Data Exchange (ETDEWEB)

    Gaines, W.L.

    1987-07-01

    Aquatic insect production was studied in three cold-desert streams in eastern Washington (Douglas Creek, Snively Springs, and Rattlesnake Springs). The size-frequency method was applied to individual taxa to estimate total insect production. production was also assessed for functional groups and trophic levels in each stream. Optioservus sp. (riffle beetles) and Baetis sp. (mayflies) accounted for 72% of the total insect numbers and 50% of the total biomass in Douglas Creek. Baetis sp. accounted for 42% of the total insect numbers and 25% of the total biomass in Snively Springs. Simulium sp. (blackflies) and Baetis sp. comprised 74% of the total insect numbers and 55% of the total biomass in Rattlesnake Springs. Grazer-scrapers (49%) and collectors (48%) were the most abundant functional groups in Douglas Creek. Collectors were the most abundant functional group in Snively Springs and Rattlesnake Springs. Herbivores and detritivores were the most abundant trophic level in Snively Springs and Rattlesnake Springs. Dipterans (midges and blackflies) were the most productive taxa within the study streams, accounting for 40% to 70% of the total community production. Production by collectors and detritivores was the highest of all functional groups and trophic levels in all study streams.

  10. Review of blackfly (Diptera : Simuliidae control in South Africa

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    E. Myburgh

    2003-11-01

    Full Text Available The medical, veterinary and economic importance of blackflies in South Africa, and the historical development of blackfly control programmes in various South African rivers, are reviewed in this paper. In 1996 it was estimated that blackflies can cause more than R 88 million damages per annum along the middle and lower Orange River where Simulium chutteri is considered the main pest species. A clear link between the construction of dams and the spread of the blackfly problem was shown. Four phases characterize the development of blackfly control in South Africa: (1 during the 1960s blackflies in the Vaal River were controlled with DDT; (2, during the 1970s and into the 1980s blackflies were controlled using water-flow manipulation; (3 when used at strategic times, water-flow manipulation could be used to enhance the effect of natural predator populations; and (4 during the 1990s the organophosphate temephos and toxins produced by the bacterium Bacillus thuringiensis var. israelensis were tested for their efficacy against blackflies. The larvicides temephos and B. thuringiensis proved to be effective and are still used in several control programmes. The latest research focuses on the factors that influence adult blackfly survival and annoyance, as well as the development of methods that can be used to protect sheep from blackfly attacks.

  11. Interruption of Transmission of Onchocerca volvulus in the Oaxaca Focus, Mexico

    Science.gov (United States)

    Rodríguez-Pérez, Mario A.; Unnasch, Thomas R.; Domínguez-Vázquez, Alfredo; Morales-Castro, Alba L.; Peña-Flores, Graciela P.; Orozco-Algarra, María E.; Arredondo-Jiménez, Juan I.; Richards, Frank; Vásquez-Rodríguez, Miguel A.; Rendón, Vidal García

    2010-01-01

    All endemic communities of the Oaxaca focus of onchocerciasis in southern Mexico have been treated annually or semi-annually with ivermectin since 1994. In-depth epidemiologic assessments were performed in communities during 2007 and 2008. None of the 52,632 Simulium ochraceum s.l. collected in four sentinel communities was found to contain parasite DNA when tested by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA), resulting in an upper bound of the infection rate in the vectors of 0.07/2,000. The prevalence of microfilariae (mf) in the cornea and/or anterior chamber of the eye was also zero (0 of 1,039 residents examined; 95%-UL = 0.35%). Similarly, all 1,164 individuals examined by skin biopsy were mf negative (95%-UL = 0.31%), and sera collected from 3,569 children from 25 communities did not harbor Ov16 IgG4-antibodies (95%-UL = 0.09%). These meet the criteria for absence of morbidity and parasite transmission in the Oaxaca focus. As a result mass treatments with ivermectin were halted in 2009. PMID:20595472

  12. Progress toward elimination of onchocerciasis in the Americas - 1993-2012.

    Science.gov (United States)

    2013-05-24

    Onchocerciasis (river blindness) is caused by the parasitic worm Onchocerca volvulus, transmitted to humans by the bite of infected black flies of the genus Simulium, and is characterized by chronic skin disease, severe itching, and eye lesions that can progress to complete blindness. Currently, among approximately 123 million persons at risk for infection in 38 endemic countries, at least 25.7 million are infected, and 1 million are blinded or have severe visual impairment. Periodic, communitywide mass drug administration (MDA) with ivermectin (Mectizan, Merck) prevents eye and skin disease and might interrupt transmission of the infection, depending on the coverage, duration, and frequency of MDA. The Onchocerciasis Elimination Program for the Americas (OEPA) was launched in response to a 1991 resolution of the Pan American Health Organization (PAHO) calling for the elimination of onchocerciasis from the Americas. By the end of 2012, transmission of the infection, judged by surveys following World Health Organization (WHO) guidelines, had been interrupted or eliminated in four of the six endemic countries in the WHO Americas Region. Thus, in 2013, only 4% (23,378) of the 560,911 persons originally at risk in the Americas will be under ivermectin MDA. Active transmission currently is limited to two foci among Yanomami indigenes in adjacent border areas of Venezuela and Brazil.

  13. Detection of Onchocerca volvulus (Nematoda: Onchocercidae) infection in vectors from Amazonian Brazil following mass Mectizan distribution.

    Science.gov (United States)

    Marchon-Silva, Verônica; Caër, Julien Charles; Post, Rory James; Maia-Herzog, Marilza; Fernandes, Octavio

    2007-05-01

    Detection of Onchocerca volvulus in Simulium populations is of primary importance in the assessment of the effectiveness of onchocerciasis control programs. In Brazil, the main focus of onchocerciasis is in the Amazon region, in a Yanomami reserve. The main onchocerciasis control strategy in Brazil is the semi-annually mass distribution of the microfilaricide ivermectin. In accordance with the control strategy for the disease, polymerase chain reaction (PCR) was applied in pools of simuliids from the area to detect the helminth infection in the vectors, as recommended by the Onchocerciasis Elimination Program for the Americas and the World Health Organization. Systematic sampling was performed monthly from September 1998 to October 1999, and a total of 4942 blackflies were collected from two sites (2576 from Balawaú and 2366 from Toototobi). The molecular methodology was found to be highly sensitive and specific for the detection of infected and/or infective blackflies in pools of 50 blackflies. The results from the material collected under field conditions showed that after the sixth cycle of distribution of ivermectin, the prevalence of infected blackflies with O. volvulus had decreased from 8.6 to 0.3% in Balawaú and from 4 to 0.1% in Toototobi.

  14. Geographical patterns of onchocerciasis in southern Venezuela: relationships between environment and infection prevalence.

    Science.gov (United States)

    Botto, C; Escalona, E; Vivas-Martinez, S; Behm, V; Delgado, L; Coronel, P

    2005-03-01

    Onchocerciasis is a chronic filarial infection transmitted by Simulium flies that has a focal geographical distribution in Latin America. The southern Venezuelan focus has a gradient of endemicity that includes the largest number of hyperendemic communities in the continent, many of them in remote forest and mountainous areas, where it is an important public health problem among the Yanomami indigenous population. The recent introduction of Geographical Information Systems (GIS) tools and a landscape epidemiology approach for study of vector borne diseases is helping to understand relationships between environment and transmission dynamics of onchocerciasis. Striking differences in the transmission dynamics of onchocerciasis between different river courses were detected. A significant relationship between onchocerciasis and temperature was also demonstrated. The geologic substrate, kind of landscape and vegetation seemed also to influence the transmission of onchocerciasis. In the Venezuelan Amazon, different kinds of landscapes associated with distinctive vector species, show different intensities of transmission of onchocerciasis. In this sense, landscape analysis aided by GIS, may prove to be a useful tool for better identification of the spatial distribution of onchocerciasis risk in the Orinoco basin.

  15. Detection of Onchocerca volvulus (Nematoda: Onchocercidae infection in vectors from Amazonian Brazil following mass Mectizan™ distribution

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    Verônica Marchon-Silva

    2007-03-01

    Full Text Available Detection of Onchocerca volvulus in Simulium populations is of primary importance in the assessment of the effectiveness of onchocerciasis control programs. In Brazil, the main focus of onchocerciasis is in the Amazon region, in a Yanomami reserve. The main onchocerciasis control strategy in Brazil is the semi-annually mass distribution of the microfilaricide ivermectin. In accordance with the control strategy for the disease, polymerase chain reaction (PCR was applied in pools of simuliids from the area to detect the helminth infection in the vectors, as recommended by the Onchocerciasis Elimination Program for the Americas and the World Health Organization. Systematic sampling was performed monthly from September 1998 to October 1999, and a total of 4942 blackflies were collected from two sites (2576 from Balawaú and 2366 from Toototobi. The molecular methodology was found to be highly sensitive and specific for the detection of infected and/or infective blackflies in pools of 50 blackflies. The results from the material collected under field conditions showed that after the sixth cycle of distribution of ivermectin, the prevalence of infected blackflies with O. volvulus had decreased from 8.6 to 0.3% in Balawaú and from 4 to 0.1% in Toototobi.

  16. Elimination of Onchocerca volvulus Transmission in the Huehuetenango Focus of Guatemala

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    Nancy Cruz-Ortiz

    2012-01-01

    Full Text Available In Latin America, onchocerciasis is targeted for elimination by 2012 through twice-yearly mass treatment of the eligible population with ivermectin. In Guatemala, two of the four historical endemic foci have demonstrated elimination of transmission, following World Health Organization guidelines. Using established guidelines ophthalmological, serological, and entomological evaluations were conducted in 2007-8 to determine the transmission status of onchocerciasis in the Huehuetenango focus. The prevalence of Onchocerca volvulus microfilariae in the anterior segment of the eye in 365 residents was 0% (95% confidence interval [CI] 0–0.8%, the prevalence of infection of O. volvulus in Simulium ochraceum among 8252 flies collected between November 2007 and April 2008 was 0% (95% CI 0–0.02%, and the prevalence of antibodies to a recombinant O. volvulus antigen in 3118 school age children was 0% (95% CI 0–0.1%. These results showed transmission interruption; thus, in 2009 mass treatment was halted and posttreatment surveillance began. To verify for potential recrudescence an entomological evaluation (from December 2010 to April 2011 was conducted during the 2nd and 3rd year of posttreatment surveillance. A total of 4587 S. ochraceum were collected, and the prevalence of infection of O. volvulus was 0% (95% CI 0–0.04%. Transmission of onchocerciasis in the Huehuetenango focus has been eliminated.

  17. The same ELA class II risk factors confer equine insect bite hypersensitivity in two distinct populations.

    Science.gov (United States)

    Andersson, Lisa S; Swinburne, June E; Meadows, Jennifer R S; Broström, Hans; Eriksson, Susanne; Fikse, W Freddy; Frey, Rebecka; Sundquist, Marie; Tseng, Chia T; Mikko, Sofia; Lindgren, Gabriella

    2012-03-01

    Insect bite hypersensitivity (IBH) is a chronic allergic dermatitis common in horses. Affected horses mainly react against antigens present in the saliva from the biting midges, Culicoides ssp, and occasionally black flies, Simulium ssp. Because of this insect dependency, the disease is clearly seasonal and prevalence varies between geographical locations. For two distinct horse breeds, we genotyped four microsatellite markers positioned within the MHC class II region and sequenced the highly polymorphic exons two from DRA and DRB3, respectively. Initially, 94 IBH-affected and 93 unaffected Swedish born Icelandic horses were tested for genetic association. These horses had previously been genotyped on the Illumina Equine SNP50 BeadChip, which made it possible to ensure that our study did not suffer from the effects of stratification. The second population consisted of 106 unaffected and 80 IBH-affected Exmoor ponies. We show that variants in the MHC class II region are associated with disease susceptibility (p (raw) = 2.34 × 10(-5)), with the same allele (COR112:274) associated in two separate populations. In addition, we combined microsatellite and sequencing data in order to investigate the pattern of homozygosity and show that homozygosity across the entire MHC class II region is associated with a higher risk of developing IBH (p = 0.0013). To our knowledge this is the first time in any atopic dermatitis suffering species, including man, where the same risk allele has been identified in two distinct populations.

  18. Aspectos da reprodução e alimentação de Neoplecostomus microps (Loricariidae, Neoplecostominae na microbacia do Ribeirão Grande, serra da Mantiqueira oriental (Estado de São Paulo = Reproduction and feeding aspects of Neoplecostomus microps (Loricariidae, Neoplecostominae in the Ribeirão Grande system, eastern Serra da Mantiqueira (São Paulo State

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    Francisco Manoel de Souza Braga

    2008-10-01

    Full Text Available A microbacia do Ribeirão Grande situa-se nas vertentes da serra da Mantiqueira e está circundada pela floresta Atlântica. Foram amostrados oito locais na microbacia do Ribeirão Grande, no inverno (julho de 2001, primavera (outubro de 2001, verão (fevereiro de 2002 e outono (abril de 2002. As amostras foram coletadas com um aparelho elétrico de pesca. A maturação das gônadas, os graus de repleção do estômago e de gordura visceral foram distribuídasem um ciclo anual. Neoplecostomus microps tem período de desova que vai da primavera ao verão. O tamanho da primeira maturação gonadal para machos foi de 5,9 cm de comprimento total e de 6,9 cm para as fêmeas. O alto valor em outubro e fevereiro para a relação gonadossomática e para o fator de condição relativo coincidiram com o período de desova. Foram encontradas, na dieta de N. microps, larvas de Diptera (Simulium, Chironomus, ninfas de Plecoptera e larvas deColeoptera aquáticas (Psephenus. O aumento da alimentação, do verão ao outono, proporcionou acúmulo de gordura visceral. Durante as estações seguintes, o peixe pode utilizar as reservas de gordura para a manutenção e reprodução. O padrão reprodutivo e o de alimentação foram interpretados como sendo adaptações em relação às variações temporais e espaciais no ambiente e na disponibilidade de alimento.The Ribeirão Grande system is located in the slope of the Serra da Mantiqueira and is surrounded by Atlantic forest. Eight sites were surveyed in the Ribeirão Grande system, during the winter (July 2001, spring (October 2001, summer (February 2002 and fall (April 2002. Samples were made with an electrofishing device. Gonad maturation, levels of stomach fullness and fat content were analyzed and their distributions reported in an annual cycle. Neoplecostomus microps has a spawning in the spring through to summer. The size at sexual maturity is about 5.9 cm total length for males and 6.9 cm for females. The

  19. Aspectos da reprodução e alimentação de Neoplecostomus microps (Loricariidae, Neoplecostominae na microbacia do Ribeirão Grande, serra da Mantiqueira oriental (Estado de São Paulo - DOI: 10.4025/actascibiolsci.v30i4.301 Reproduction and feeding aspects of Neoplecostomus microps (Loricariidae, Neoplecostominae in the Ribeirão Grande system, eastern Serra da Mantiqueira (São Paulo State - DOI: 10.4025/actascibiolsci.v30i4.301

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    Ursulla Pereira Souza

    2008-11-01

    Full Text Available A microbacia do Ribeirão Grande situa-se nas vertentes da serra da Mantiqueira e está circundada pela floresta Atlântica. Foram amostrados oito locais na microbacia do Ribeirão Grande, no inverno (julho de 2001, primavera (outubro de 2001, verão (fevereiro de 2002 e outono (abril de 2002. As amostras foram coletadas com um aparelho elétrico de pesca. A maturação das gônadas, os graus de repleção do estômago e de gordura visceral foram distribuídas em um ciclo anual. Neoplecostomus micropstem período de desova que vai da primavera ao verão. O tamanho da primeira maturação gonadal para machos foi de 5,9 cm de comprimento total e de 6,9 cm para as fêmeas. O alto valor em outubro e fevereiro para a relação gonadossomática e para o fator de condição relativo coincidiram com o período de desova. Foram encontradas, na dieta de N. microps, larvas de Diptera (Simulium, Chironomus, ninfas de Plecoptera e larvas de Coleoptera aquáticas (Psephenus. O aumento da alimentação, do verão ao outono, proporcionou acúmulo de gordura visceral. Durante as estações seguintes, o peixe pode utilizar as reservas de gordura para a manutenção e reprodução. O padrão reprodutivo e o de alimentação foram interpretados como sendo adaptações em relação às variações temporais e espaciais no ambiente e na disponibilidade de alimento.The Ribeirão Grande system is located in the slope of the Serra da Mantiqueira and is surrounded by Atlantic forest. Eight sites were surveyed in the Ribeirão Grande system, during the winter (July 2001, spring (October 2001, summer (February 2002 and fall (April 2002. Samples were made with an electrofishing device. Gonad maturation, levels of stomach fullness and fat content were analyzed and their distributions reported in an annual cycle. Neoplecostomus microps has a spawning in the spring through to summer. The size at sexual maturity is about 5.9 cm total length for males and 6.9 cm for females. The

  20. Interruption of onchocerciasis transmission in Bioko Island: Accelerating the movement from control to elimination in Equatorial Guinea.

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    Zaida Herrador

    2018-05-01

    Full Text Available Onchocerciasis, also known as river blindness, is a parasitic disease. More than 99 percent of all cases occur in Africa. Bioko Island (Equatorial Guinea is the only island endemic for onchocerciasis in the world. Since 2005, when vector Simulium yahense was eliminated, there have not been any reported cases of infection. This study aimed to demonstrate that updated WHO criteria for stopping mass drug administration (MDA have been met.A cross-sectional study was conducted from September 2016 to January 2017. Participants were 5- to 9-year-old school children. Onchocerciasis/lymphatic Filariasis (LF, only in endemic districts rapid diagnostic tests (RDTs were performed. Blood spots were collected from RDT positive children and 10 percent of the RDT negatives to determine Ov16 and Wb123 IgG4 antibodies through enzyme-linked immunosorbent assay (ELISA. Skin snips were collected from RDT positives. Filarial detection was performed by PCR in positives and indeterminate sera. Black fly collection was carried out in traditional breeding sites. A total of 7,052 children, ranging from 5 to 9 years of age, were included in the study. Four children (0.06% were Ov16 IgG4 RDT positives, but negative by ELISA Ov16, while 6 RDT negative children tested positive by ELISA. A total of 1,230 children from the Riaba and Baney districts were tested for LF. One child was Wb123 RDT positive (0.08%, but ELISA negative, while 3 RDT negative children were positive by Wb123 ELISA. All positive samples were negative by PCR for onchocerciasis and LF (in blood spot and skin snip. All fly collections and larval prospections in the traditional catching and prospection sites were negative.WHO criteria have been met, therefore MDA in Bioko Island can be stopped. Three years of post-treatment surveillance should be implemented to identify any new occurrences of exposure or infection.

  1. The interruption of Onchocerca volvulus and Wuchereria bancrofti transmission by integrated chemotherapy in the Obongi focus, North Western Uganda.

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    Lakwo Thomson Luroni

    Full Text Available Few studies have documented the interruption of onchocerciasis and Lymphatic Filariasis (LF by integrated chemotherapy in Uganda. The study describes the interruption of transmission of the two diseases co-endemic in Obongi focus, north western Uganda. Base line data for Onchocerciasis and LF were collected in 1994 and 2006, respectively. Annual mass drug administration for onchocerciasis (Ivermectin and Lymphatic Filariasis (Ivermectin + albendazole was conducted for 20 and 6 years, respectively. Thereafter, assessments by skin snip, larval searches in rivers and human landing catches were performed. Children 65% was achieved in the six treatment rounds. Household ownership of ITN's and utilization was 96% and 72.4%., respectively.Parasitological examinations conducted for onchocerciasis among 807 adults and children, revealed a reduction in mf prevalence from 58% in 1994 to 0% in 2012. Entomological monitoring conducted at the two sites had no single Simulium damnosum fly caught. Serological analysis using Ov16 ELISA for onchocerciasis revealed that out of the 3,308 children <10 years old screened in 2013, only 3/3308 (0.091% positive cases were detected. All Ov16 positive children were negative when tested for patent infection by skin snip PCR. A reduction in LF microfilaria prevalence from 2.5% (n = 13/522 in 2006 to 0.0% (n = 602 in 2014 was observed. LF TAS1 conducted in 2015 among 1,532 children 6-7 years, all were negative for antigens of W. bancrofti.The results concluded that interruption of onchocerciasis and LF has been achieved.

  2. Evaluation of Lymphatic Filariasis and Onchocerciasis in Three Senegalese Districts Treated for Onchocerciasis with Ivermectin.

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    Nana O Wilson

    2016-12-01

    Full Text Available In Africa, onchocerciasis and lymphatic filariasis (LF are co-endemic in many areas. Current efforts to eliminate both diseases are through ivermectin-based mass drug administration (MDA. Years of ivermectin distribution for onchocerciasis may have interrupted LF transmission in certain areas. The Kédougou region, Senegal, is co-endemic for LF and onchocerciasis. Though MDA for onchocerciasis started in 1988, in 2014 albendazole had not yet been added for LF. The objective of this study was to assess in an integrated manner the LF and onchocerciasis status in the three districts of the Kédougou region after ≥10 years of ivermectin-based MDA. The study employed an African Programme for Onchocerciasis Control (APOC onchocerciasis-related methodology. In the three districts, 14 villages close to three rivers that have Simulium damnosum breeding sites were surveyed. Convenience sampling of residents ≥5 years old was performed. Assessment for LF antigenemia by immunochromatographic testing (ICT was added to skin snip microscopy for onchocerciasis. Participants were also tested for antibodies against Wb123 (LF and Ov16 (onchocerciasis antigens. In two districts, no participants were ICT or skin snip positive. In the third district, 3.5% were ICT positive and 0.7% were skin snip positive. In all the three districts, Wb123 prevalence was 0.6%. Overall, Ov16 prevalence was 6.9%. Ov16 prevalence among children 5-9 years old in the study was 2.5%. LF antigenemia prevalence was still above treatment threshold in one district despite ≥10 years of ivermectin-based MDA. The presence of Ov16 positive children suggested recent transmission of Onchocerca volvulus. This study showed the feasibility of integrated evaluation of onchocerciasis and LF but development of integrated robust methods for assessing transmission of both LF and onchocerciasis are needed to determine where MDA can be stopped safely in co-endemic areas.

  3. Elimination of Onchocerciasis from Mexico

    Science.gov (United States)

    Rodríguez-Pérez, Mario A.; Fernández-Santos, Nadia A.; Orozco-Algarra, María E.; Rodríguez-Atanacio, José A.; Domínguez-Vázquez, Alfredo; Rodríguez-Morales, Kristel B.; Real-Najarro, Olga; Prado-Velasco, Francisco G.; Cupp, Eddie W.; Richards, Frank O.; Hassan, Hassan K.; González-Roldán, Jesús F.; Kuri-Morales, Pablo A.; Unnasch, Thomas R.

    2015-01-01

    Background Mexico is one of the six countries formerly endemic for onchocerciasis in Latin America. Transmission has been interrupted in the three endemic foci of that country and mass drug distribution has ceased. Three years after mass drug distribution ended, post-treatment surveillance (PTS) surveys were undertaken which employed entomological indicators to check for transmission recrudescence. Methodology/Principal findings In-depth entomologic assessments were performed in 18 communities in the three endemic foci of Mexico. None of the 108,212 Simulium ochraceum s.l. collected from the three foci were found to contain parasite DNA when tested by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA), resulting in a maximum upper bound of the 95% confidence interval (95%-ULCI) of the infective rate in the vectors of 0.035/2,000 flies examined. This is an order of magnitude below the threshold of a 95%-ULCI of less than one infective fly per 2,000 flies tested, the current entomological criterion for interruption of transmission developed by the international community. The point estimate of seasonal transmission potential (STP) was zero, and the upper bound of the 95% confidence interval for the STP ranged from 1.2 to 1.7 L3/person/season in the different foci. This value is below all previous estimates for the minimum transmission potential required to maintain the parasite population. Conclusions/Significance The results from the in-depth entomological post treatment surveillance surveys strongly suggest that transmission has not resumed in the three foci of Mexico during the three years since the last distribution of ivermectin occurred; it was concluded that transmission remains undetectable without intervention, and Onchocerca volvulus has been eliminated from Mexico. PMID:26161558

  4. Interruption of infection transmission in the onchocerciasis focus of Ecuador leading to the cessation of ivermectin distribution.

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    Raquel Lovato

    2014-05-01

    Full Text Available INTRODUCTION: A clinically significant endemic focus of onchocerciasis existing in Esmeraldas Province, coastal Ecuador has been under an ivermectin mass drug administration program since 1991. The main transmitting vector in this area is the voracious blackfly, Simulium exiguum. This paper describes the assessments made that support the decision to cease mass treatment. METHODOLOGY AND PRINCIPLE FINDINGS: Thirty-five rounds of ivermectin treatment occurred between 1991-2009 with 29 of these carrying >85% coverage. Following the guidelines set by WHO for ceasing ivermectin distribution the impact on parasite transmission was measured in the two vector species by an O-150 PCR technique standard for assessing for the presence of Onchocerca volvulus. Up to seven collection sites in three major river systems were tested on four occasions between 1995 and 2008. The infectivity rates of 65.0 (CI 39-101 and 72.7 (CI 42-116 in 1995 dropped to zero at all seven collection sites by 2008. Assessment for the presence of antibodies against O. volvulus was made in 2001, 2006, 2007 and 2008 using standard ELISA assays for detecting anti-Ov16 antibodies. None of total of 1810 children aged 1-15 years (between 82 and 98% of children present in the surveyed villages tested in the above years were found to be carrying antibodies to this antigen. These findings were the basis for the cessation of mass drug treatment with ivermectin in 2009. SIGNIFICANCE: This fulfillment of the criteria for cessation of mass distribution of ivermectin in the only known endemic zone of onchocerciasis in Ecuador moves the country into the surveillance phase of official verification for national elimination of transmission of infection. These findings indicate that ivermectin given twice a year with greater than 85% of the community can move a program to the final stages of verification of transmission interruption.

  5. Interruption of infection transmission in the onchocerciasis focus of Ecuador leading to the cessation of ivermectin distribution.

    Science.gov (United States)

    Lovato, Raquel; Guevara, Angel; Guderian, Ronald; Proaño, Roberto; Unnasch, Thomas; Criollo, Hipatia; Hassan, Hassan K; Mackenzie, Charles D

    2014-05-01

    A clinically significant endemic focus of onchocerciasis existing in Esmeraldas Province, coastal Ecuador has been under an ivermectin mass drug administration program since 1991. The main transmitting vector in this area is the voracious blackfly, Simulium exiguum. This paper describes the assessments made that support the decision to cease mass treatment. Thirty-five rounds of ivermectin treatment occurred between 1991-2009 with 29 of these carrying >85% coverage. Following the guidelines set by WHO for ceasing ivermectin distribution the impact on parasite transmission was measured in the two vector species by an O-150 PCR technique standard for assessing for the presence of Onchocerca volvulus. Up to seven collection sites in three major river systems were tested on four occasions between 1995 and 2008. The infectivity rates of 65.0 (CI 39-101) and 72.7 (CI 42-116) in 1995 dropped to zero at all seven collection sites by 2008. Assessment for the presence of antibodies against O. volvulus was made in 2001, 2006, 2007 and 2008 using standard ELISA assays for detecting anti-Ov16 antibodies. None of total of 1810 children aged 1-15 years (between 82 and 98% of children present in the surveyed villages) tested in the above years were found to be carrying antibodies to this antigen. These findings were the basis for the cessation of mass drug treatment with ivermectin in 2009. This fulfillment of the criteria for cessation of mass distribution of ivermectin in the only known endemic zone of onchocerciasis in Ecuador moves the country into the surveillance phase of official verification for national elimination of transmission of infection. These findings indicate that ivermectin given twice a year with greater than 85% of the community can move a program to the final stages of verification of transmission interruption.

  6. A study of onchocerciasis with severe skin and eye lesions in a hyperendemic zone in the forest of southwestern Cameroon: clinical, parasitologic, and entomologic findings.

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    Somo, R M; Enyong, P A; Fobi, G; Dinga, J S; Lafleur, C; Agnamey, P; Ngosso, A; Ngolle, E M

    1993-01-01

    Prior to the initiation of an onchocerciasis control program based on the mass administration of ivermectin in the rain forest of southwestern Cameroon, a preliminary baseline study of the area was conducted. The results of this study showed that onchocerciasis was hyperendemic in the area. Skin symptoms and signs were observed including pruritus (67.4% of the population examined), onchocerca nodules (51.6%), skin depigmentation (18.5%), and hanging groins (5.7%). Except for pruritus, the prevalence of these symptoms increased with age. Of the eyes examined, 44.9% had microfilariae in the anterior chamber, 33.5% had choroidoretinitis, 28.0% had punctate keratitis, 8.3% had papillary abnormalities, and 3.6% had sclerosing keratitis. Vision in 10.5% of the eyes examined was classified as blind or very poor (visual acuity = 0-0.10), in 15.7% as poor (visual acuity = 0.11-0.39), and in 73.8% as good (visual acuity = 0.4-1.00). Unlike previous reports that have linked serious ocular damage mainly to savanna onchocerciasis, the present study showed that forest onchocerciasis also caused significant ocular pathology, including blindness. Parasitologically, positive skin snips were recorded for 92.7% of the persons examined, with both sexes being equally infected. The parasite load, expressed as the geometric mean number of microfilariae per skin snip, was 53.6, and was much higher in males than in females. The flv vector, Simulium squamosum, had a high infection rate of 7.5% infective females in Bakumba and 6.8% infective females in Ngbandi, the two fly-catching points. The transmission potential was 266 infective larvae per person per month in Bakumba and 189 in Ngbandi.

  7. Ongoing Transmission of Onchocerca volvulus after 25 Years of Annual Ivermectin Mass Treatments in the Vina du Nord River Valley, in North Cameroon

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    Eisenbarth, Albert; Achukwi, Mbunkah Daniel; Renz, Alfons

    2016-01-01

    Background Recent reports of transmission interruption of Onchocerca volvulus, the causing agent of river blindness, in former endemic foci in the Americas, and more recently in West and East Africa, raise the question whether elimination of this debilitating disease is underway after long-term treatment of the population at risk with ivermectin. The situation in Central Africa has not yet been clearly assessed. Methods and findings Entomologic data from two former endemic river basins in North Cameroon were generated over a period of 43 and 48 months to follow-up transmission levels in areas under prolonged ivermectin control. Moreover, epidemiologic parameters of animal-borne Onchocerca spp. transmitted by the same local black fly vectors of the Simulium damnosum complex were recorded and their impact on O. volvulus transmission success evaluated. With mitochondrial DNA markers we unambiguously confirmed the presence of infective O. volvulus larvae in vectors from the Sudan savannah region (mean Annual Transmission Potential 2009–2012: 98, range 47–221), but not from the Adamawa highland region. Transmission rates of O. ochengi, a parasite of Zebu cattle, were high in both foci. Conclusions/significance The high cattle livestock density in conjunction with the high transmission rates of the bovine filaria O. ochengi prevents the transmission of O. volvulus on the Adamawa plateau, whereas transmission in a former hyperendemic focus was markedly reduced, but not completely interrupted after 25 years of ivermectin control. This study may be helpful to gauge the impact of the presence of animal-filariae for O. volvulus transmission in terms of the growing human and livestock populations in sub-Saharan countries. PMID:26926855

  8. Elimination of Onchocerciasis from Mexico.

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    Mario A Rodríguez-Pérez

    Full Text Available Mexico is one of the six countries formerly endemic for onchocerciasis in Latin America. Transmission has been interrupted in the three endemic foci of that country and mass drug distribution has ceased. Three years after mass drug distribution ended, post-treatment surveillance (PTS surveys were undertaken which employed entomological indicators to check for transmission recrudescence.In-depth entomologic assessments were performed in 18 communities in the three endemic foci of Mexico. None of the 108,212 Simulium ochraceum s.l. collected from the three foci were found to contain parasite DNA when tested by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA, resulting in a maximum upper bound of the 95% confidence interval (95%-ULCI of the infective rate in the vectors of 0.035/2,000 flies examined. This is an order of magnitude below the threshold of a 95%-ULCI of less than one infective fly per 2,000 flies tested, the current entomological criterion for interruption of transmission developed by the international community. The point estimate of seasonal transmission potential (STP was zero, and the upper bound of the 95% confidence interval for the STP ranged from 1.2 to 1.7 L3/person/season in the different foci. This value is below all previous estimates for the minimum transmission potential required to maintain the parasite population.The results from the in-depth entomological post treatment surveillance surveys strongly suggest that transmission has not resumed in the three foci of Mexico during the three years since the last distribution of ivermectin occurred; it was concluded that transmission remains undetectable without intervention, and Onchocerca volvulus has been eliminated from Mexico.

  9. Status of forest onchocerciasis in the Lower Cross River basin, Nigeria: entomologic profile after five years of ivermectin intervention.

    Science.gov (United States)

    Opara, Kenneth N; Fagbemi, Olakunle B; Ekwe, Asuquo; Okenu, Daniel M N

    2005-08-01

    In the Lower Cross River basin in Nigeria, no pre-control entomologic profile of Onchocerca volvulus infection in the local Simulium damnosum population was available prior to the initiation of an ivermectin control program in 1995. A longitudinal entomologic study was therefore carried out over a 12-month period (January-December 2001) at the Agbokim waterfalls and Afi River, which are breeding sites of S. damnosum in the river basin. A total of 9,287 adult S. damnosum were caught on human bait; 9,048 (97.43%) were dissected, of which 313 (3.46%) were infected. Annual biting rates (ABRs) of 42,419 and 28,346 bites per persons per year were recorded at the Agbokim Waterfalls and Afi River, respectively. The annual transmission potential (ATP) was 419 infective larvae per person per year at the Agbokim Waterfalls and 427 at the Afi River. Monthly biting rate and monthly transmission potential varied significantly (P < 0.05) at the two sites. Transmission was highly seasonal from April to September, corresponding to the peak biting period of the vector. The high ATP and ABR values are a measure of the mesoendemicity of onchocerciasis in the river basin. There was a significant F(0).05 (1, 10) (P < 0.05) variation in the relative fly abundance from both sites. It was observed that human activities such as farming, fishing, timber cutting, and hunting are done in the early morning and late afternoon, which corresponds to the peak diurnal biting period of the vector. Changes in these practices and attitudes may markedly affect the disease intensity and transmission.

  10. Interruption of transmission of Onchocerca volvulus in the Southern Chiapas Focus, México.

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    Mario A Rodríguez-Pérez

    Full Text Available BACKGROUND: The Southern Chiapas focus of onchocerciasis in Southern Mexico represents one of the major onchocerciasis foci in Latin America. All 559 endemic communities of this focus have undergone semi-annual mass treatment with ivermectin since 1998. In 50 communities of this focus, ivermectin frequency shifted from twice to four times a year in 2003; an additional 113 communities were added to the quarterly treatment regimen in 2009 to achieve a rapid suppression of transmission. METHODOLOGY/PRINCIPAL FINDINGS: In-depth epidemiologic and entomologic assessments were performed in six sentinel communities (which had undergone 2 rounds of ivermectin treatment per year and three extra-sentinel communities (which had undergone 4 rounds of ivermectin treatment per year. None of the 67,924 Simulium ochraceum s.l. collected from this focus during the dry season of 2011 were found to contain parasite DNA when tested by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA, resulting in an upper bound of the 95% confidence interval (95%-ULCI of the infective rate in the vectors of 0.06/2,000 flies examined. Serological assays testing for Onchocerca volvulus exposure conducted on 4,230 children 5 years of age and under (of a total population of 10,280 in this age group revealed that 2/4,230 individuals were exposed to O. volvulus (0.05%; one sided 95% confidence interval = 0.08%. CONCLUSIONS/SIGNIFICANCE: The in-depth epidemiological and entomological findings from the Southern Chiapas focus meet the criteria for interruption of transmission developed by the international community.

  11. Successful Interruption of Transmission of Onchocerca volvulus in the Escuintla-Guatemala Focus, Guatemala

    Science.gov (United States)

    Gonzalez, Rodrigo J.; Cruz-Ortiz, Nancy; Rizzo, Nidia; Richards, Jane; Zea-Flores, Guillermo; Domínguez, Alfredo; Sauerbrey, Mauricio; Catú, Eduardo; Oliva, Orlando; Richards, Frank O.; Lindblade, Kim A.

    2009-01-01

    Background Elimination of onchocerciasis (river blindness) through mass administration of ivermectin in the six countries in Latin America where it is endemic is considered feasible due to the relatively small size and geographic isolation of endemic foci. We evaluated whether transmission of onchocerciasis has been interrupted in the endemic focus of Escuintla-Guatemala in Guatemala, based on World Health Organization criteria for the certification of elimination of onchocerciasis. Methodology/Principal Findings We conducted evaluations of ocular morbidity and past exposure to Onchocerca volvulus in the human population, while potential vectors (Simulium ochraceum) were captured and tested for O. volvulus DNA; all of the evaluations were carried out in potentially endemic communities (PEC; those with a history of actual or suspected transmission or those currently under semiannual mass treatment with ivermectin) within the focus. The prevalence of microfilariae in the anterior segment of the eye in 329 individuals (≥7 years old, resident in the PEC for at least 5 years) was 0% (one-sided 95% confidence interval [CI] 0–0.9%). The prevalence of antibodies to a recombinant O. volvulus antigen (Ov-16) in 6,432 school children (aged 6 to 12 years old) was 0% (one-sided 95% IC 0–0.05%). Out of a total of 14,099 S. ochraceum tested for O. volvulus DNA, none was positive (95% CI 0–0.01%). The seasonal transmission potential was, therefore, 0 infective stage larvae per person per season. Conclusions/Significance Based on these evaluations, transmission of onchocerciasis in the Escuintla-Guatemala focus has been successfully interrupted. Although this is the second onchocerciasis focus in Latin America to have demonstrated interruption of transmission, it is the first focus with a well-documented history of intense transmission to have eliminated O. volvulus. PMID:19333366

  12. Interruption of Infection Transmission in the Onchocerciasis Focus of Ecuador Leading to the Cessation of Ivermectin Distribution

    Science.gov (United States)

    Lovato, Raquel; Guevara, Angel; Guderian, Ronald; Proaño, Roberto; Unnasch, Thomas; Criollo, Hipatia; Hassan, Hassan K.; Mackenzie, Charles D.

    2014-01-01

    Introduction: A clinically significant endemic focus of onchocerciasis existing in Esmeraldas Province, coastal Ecuador has been under an ivermectin mass drug administration program since 1991. The main transmitting vector in this area is the voracious blackfly, Simulium exiguum. This paper describes the assessments made that support the decision to cease mass treatment. Methodology and Principle Findings: Thirty-five rounds of ivermectin treatment occurred between 1991–2009 with 29 of these carrying >85% coverage. Following the guidelines set by WHO for ceasing ivermectin distribution the impact on parasite transmission was measured in the two vector species by an O-150 PCR technique standard for assessing for the presence of Onchocerca volvulus. Up to seven collection sites in three major river systems were tested on four occasions between 1995 and 2008. The infectivity rates of 65.0 (CI 39–101) and 72.7 (CI 42–116) in 1995 dropped to zero at all seven collection sites by 2008. Assessment for the presence of antibodies against O. volvulus was made in 2001, 2006, 2007 and 2008 using standard ELISA assays for detecting anti-Ov16 antibodies. None of total of 1810 children aged 1–15 years (between 82 and 98% of children present in the surveyed villages) tested in the above years were found to be carrying antibodies to this antigen. These findings were the basis for the cessation of mass drug treatment with ivermectin in 2009. Significance: This fulfillment of the criteria for cessation of mass distribution of ivermectin in the only known endemic zone of onchocerciasis in Ecuador moves the country into the surveillance phase of official verification for national elimination of transmission of infection. These findings indicate that ivermectin given twice a year with greater than 85% of the community can move a program to the final stages of verification of transmission interruption. PMID:24853587

  13. Onchocerca volvulus-neurotransmitter tyramine is a biomarker for river blindness.

    Science.gov (United States)

    Globisch, Daniel; Moreno, Amira Y; Hixon, Mark S; Nunes, Ashlee A K; Denery, Judith R; Specht, Sabine; Hoerauf, Achim; Janda, Kim D

    2013-03-12

    Onchocerciasis, also known as "river blindness", is a neglected tropical disease infecting millions of people mainly in Africa and the Middle East but also in South America and Central America. Disease infectivity initiates from the filarial parasitic nematode Onchocerca volvulus, which is transmitted by the blackfly vector Simulium sp. carrying infectious third-stage larvae. Ivermectin has controlled transmission of microfilariae, with an African Program elimination target date of 2025. However, there is currently no point-of-care diagnostic that can distinguish the burden of infection--including active and/or past infection--and enable the elimination program to be effectively monitored. Here, we describe how liquid chromatography-MS-based urine metabolome analysis can be exploited for the identification of a unique biomarker, N-acetyltyramine-O,β-glucuronide (NATOG), a neurotransmitter-derived secretion metabolite from O. volvulus. The regulation of this tyramine neurotransmitter was found to be linked to patient disease infection, including the controversial antibiotic doxycycline treatment that has been shown to both sterilize and kill adult female worms. Further clues to its regulation have been elucidated through biosynthetic pathway determination within the nematode and its human host. Our results demonstrate that NATOG tracks O. volvulus metabolism in both worms and humans, and thus can be considered a host-specific biomarker for onchocerciasis progression. Liquid chromatography-MS-based urine metabolome analysis discovery of NATOG not only has broad implications for a noninvasive host-specific onchocerciasis diagnostic but provides a basis for the metabolome mining of other neglected tropical diseases for the discovery of distinct biomarkers and monitoring of disease progression.

  14. Effects of an oil spill on leafpack-inhabiting macroinvertebrates in the Chariton river, Missouri

    Science.gov (United States)

    Poulton, B.C.; Callahan, E.V.; Hurtubise, R.D.; Mueller, B.G.

    1998-01-01

    Artificial leaf packs were used to determine the effects of an oil spill on stream macroinvertebrate communities in the Chariton River, Missouri. Plastic mesh leaf retainers with approximately 10 g of leaves from five tree species were deployed at five sites (two upstream of the spill and three downstream) immediately after the spill and one year later. Four macroinvertebrate species dominating the community at upstream sites were virtually eliminated below the spill, including the stonefly Isoperla bilineata, the caddisfly Potamyia flava, the midge Thienemanniella xena, and blackfly larvae (Simulium sp.). Density of collector and shredder functional groups, and number of shredder taxa differed between upstream sites and the two furthest downstream sites during the 1990 sample period (Kruskal-Wallis w/Bonferroni paired comparisons, experiment wise error rate = 0.05). With one exception, no differences between sites were detected in the 1991-1992 sample period, indicating that the benthic community had at least partially recovered from the oil spill after one year. The odds of obtaining a sample with a small abundance of shredders (abundance < median) in 1990 was significantly greater downstream of the spill than upstream, and the odds of obtaining a sample with a small abundance of shredders at downstream sites was greater in 1990 than in 1991-1992. A similar pattern was observed in abundance and taxa richness of the collector functional group. No significant differences between the two sampling periods were detected at upstream sites. Observed effects appeared to be associated with oil sorption and substrate coating, creating conditions unsuitable for successful colonization.

  15. Interruption of Transmission of Onchocerca volvulus in the Southern Chiapas Focus, México

    Science.gov (United States)

    Rodríguez-Pérez, Mario A.; Domínguez-Vázquez, Alfredo; Unnasch, Thomas R.; Hassan, Hassan K.; Arredondo-Jiménez, Juan I.; Orozco-Algarra, María Eugenia; Rodríguez-Morales, Kristel B.; Rodríguez-Luna, Isabel C.; Prado-Velasco, Francisco Gibert

    2013-01-01

    Background The Southern Chiapas focus of onchocerciasis in Southern Mexico represents one of the major onchocerciasis foci in Latin America. All 559 endemic communities of this focus have undergone semi-annual mass treatment with ivermectin since 1998. In 50 communities of this focus, ivermectin frequency shifted from twice to four times a year in 2003; an additional 113 communities were added to the quarterly treatment regimen in 2009 to achieve a rapid suppression of transmission. Methodology/Principal findings In-depth epidemiologic and entomologic assessments were performed in six sentinel communities (which had undergone 2 rounds of ivermectin treatment per year) and three extra-sentinel communities (which had undergone 4 rounds of ivermectin treatment per year). None of the 67,924 Simulium ochraceum s.l. collected from this focus during the dry season of 2011 were found to contain parasite DNA when tested by polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA), resulting in an upper bound of the 95% confidence interval (95%-ULCI) of the infective rate in the vectors of 0.06/2,000 flies examined. Serological assays testing for Onchocerca volvulus exposure conducted on 4,230 children 5 years of age and under (of a total population of 10,280 in this age group) revealed that 2/4,230 individuals were exposed to O. volvulus (0.05%; one sided 95% confidence interval = 0.08%). Conclusions/Significance The in-depth epidemiological and entomological findings from the Southern Chiapas focus meet the criteria for interruption of transmission developed by the international community. PMID:23556018

  16. Onchocerciasis in the Amazonian focus of southern Venezuela: altitude and blackfly species composition as predictors of endemicity to select communities for ivermectin control programmes.

    Science.gov (United States)

    Vivas-Martinez, S; Basáñez, M G; Grillet, M E; Weiss, H; Botto, C; García, M; Villamizar, N J; Chavasse, D C

    1998-01-01

    In preparation for an ivermectin distribution programme, the prevalence and intensity of infection due to Onchocerca volvulus as well as the species composition and abundance of Simulium vectors were investigated in 22 Yanomami communities situated along 2 altitudinal transects in the southern Venezuelan onchocerciasis focus. These transects corresponded to the Ocamo-Putaco and Orinoco-Orinoquito river systems, covering a range of elevation between 50 m and 740 m above sea level (asl). A total of 831 people underwent parasitological examination in this survey and an additional 196 patients from a previous study, at an altitude of 950 m, were included in the analysis. A total of 92,659 man-biting blackflies were collected and identified to morphospecies. S. oyapockense s.l. was the predominant simuliid up to 150 m asl, whereas S. guianense s.l. and S. incrustatum s.l. prevailed above 150 m. Communities located below 150 m were found to range from hypo- to mesoendemic; all villages above 150 m proved to be hyperendemic (> 60% microfilarial prevalence) and mass ivermectin treatment should be implemented. Age above 10-14 years, altitude of the village and biting rate of S. guianense s.l. up to 200 m asl were found to be statistically significant independent predictors of infection by multivariate logistic regression using a spline model. There were no differences in infection status according to sex. Above 200 m, microfilarial rate and density remained approximately constant, prevalence averaging 79% regardless of blackfly abundance. For the implementation of ivermectin-based onchocerciasis control programmes in the Amazonian focus, altitude and species composition of the blackfly population might be adopted as useful indicators aiding selection of the most affected communities. However, below 200 m additional parasitological indicators may also be necessary. As a direct result of this study, regular mass-ivermectin delivery to meso- and hyperendemic communities is now

  17. [The Brazilian focus of onchocerciasis: new observations in the areas of the Mucajaí and Catrimâni rivers, Territory of Roraima].

    Science.gov (United States)

    Moraes, M A; Shelley, A J; Luna Dias, A P

    1986-01-01

    A recent survey for onchocerciasis conducted among the Yanomami Indians living on the middle reaches of the Mucajaí and Catrimâni Rivers (Territory of Roraima) has failed to show any alteration in the local pattern of the disease. In fact, after a decade from the first surveys in these areas located at the periphery of the Yanomami focus, the prevalence and the intensity of infection have not experienced a significant change. Considering only the residents in the villages inside the surveyed areas, the prevalence varied from zero in the neighbourhood of the Catrimâni mission to 3.1 per cent near the Mucajaí mission. Had there been a competent vector of Onchocerca volvulus in the region higher rates might be expected due to the Yanomami custom of periodic visits among the groups of the tribe. In some of these visits, numbers of highly infected Indians from the central and mountainous part of the Yanomami territory--where more than 90 per cent of the adults have onchocerciasis--come to the villages in the lowland area, attracted by the facilities offered by the mission posts. As the visitors stay in the host villages for several days or weeks, the residents could become exposed to the disease. Simulium oyapockense s.1., a man-biting species of black fly, widely distributed in Northern Brazil, is the only possible vector of O. volvulus in the investigated areas, on the grounds of its local abundance.(ABSTRACT TRUNCATED AT 250 WORDS)

  18. Human onchocerciasis in the Amazonian area of southern Venezuela: spatial and temporal variations in biting and parity rates of black fly (Diptera: Simuliidae) vectors.

    Science.gov (United States)

    Grillet, M E; Basáñez, M G; Vivas-Martínez, S; Villamizar, N; Frontado, H; Cortez, J; Coronel, P; Botto, C

    2001-07-01

    We investigated some entomological factors underlying altitudinal prevalence variation in the Venezuelan Amazonia human onchocerciasis focus. Spatial and temporal variation in relative abundance, daily biting rate, proportion of parous flies, and monthly parous biting rate were studied for the three main simuliid vectors (based on their vectorial competence: Simulium oyapockense s.l. Floch & Abonnenc approximately = S. incrustatum Lutz Yanomami villages were selected among sentinel communities of the ivermectin control program, representing hypo- to hyperendemicity conditions of infection. Spatial variation was explored via increasing village altitude on two river systems (A: Ocamo-Putaco and B: Orinoco-Orinoquito). Temporal variation was studied between 1995 and 1999 by sampling the biting population during dry and rainy mouths. Environmental variables included monthly rainfall and maximum river height. Simuliid species composition itself varied along the altitudinal and prevalence gradient. S. oyapockense s.l. prevailed below 150 m. Above this altitude and up to 240 m, S. incrustatum and S. guianense s.l. became more frequently and evenly collected along A but not along B, where S. incrustatum remained absent. The daily biting rate of S. oyapockense s.l. was higher during the dry season along A, whereas the converse took place along B. Daily biting rate of S. incrustatum was lowest during early rains. By contrast, the daily biting rate of S. guianense s.l. was highest during this period. There was a significant negative cross-correlation between proportion of parous of S. oyapockense s.l. and river height (2 and 3 mo lagged), whereas this variable (1 and 2 mo lagged) was positively correlated with the proportion of parous flies for S. incrustatum. Monthly parous biting rate values suggest that the months contributing most to onchocerciasis transmission in the area are likely to be the dry season and the transition periods between seasons.

  19. Evidence of suppression of onchocerciasis transmission in the Venezuelan Amazonian focus.

    Science.gov (United States)

    Botto, Carlos; Basañez, María-Gloria; Escalona, Marisela; Villamizar, Néstor J; Noya-Alarcón, Oscar; Cortez, José; Vivas-Martínez, Sarai; Coronel, Pablo; Frontado, Hortencia; Flores, Jorge; Graterol, Beatriz; Camacho, Oneida; Tovar, Yseliam; Borges, Daniel; Morales, Alba Lucia; Ríos, Dalila; Guerra, Francisco; Margeli, Héctor; Rodriguez, Mario Alberto; Unnasch, Thomas R; Grillet, María Eugenia

    2016-01-27

    The World Health Organization (WHO) has set goals for onchocerciasis elimination in Latin America by 2015. Most of the six previously endemic countries are attaining this goal by implementing twice a year (and in some foci, quarterly) mass ivermectin (Mectizan®) distribution. Elimination of transmission has been verified in Colombia, Ecuador and Mexico. Challenges remain in the Amazonian focus straddling Venezuela and Brazil, where the disease affects the hard-to-reach Yanomami indigenous population. We provide evidence of suppression of Onchocerca volvulus transmission by Simulium guianense s.l. in 16 previously hyperendemic Yanomami communities in southern Venezuela after 15 years of 6-monthly and 5 years of 3-monthly mass ivermectin treatment. Baseline and monitoring and evaluation parasitological, ophthalmological, entomological and serological surveys were conducted in selected sentinel and extra-sentinel communities of the focus throughout the implementation of the programme. From 2010 to 2012-2015, clinico-parasitological surveys indicate a substantial decrease in skin microfilarial prevalence and intensity of infection; accompanied by no evidence (or very low prevalence and intensity) of ocular microfilariae in the examined population. Of a total of 51,341 S. guianense flies tested by PCR none had L3 infection (heads only). Prevalence of infective flies and seasonal transmission potentials in 2012-2013 were, respectively, under 1% and 20 L3/person/transmission season. Serology in children aged 1-10 years demonstrated that although 26 out of 396 (7%) individuals still had Ov-16 antibodies, only 4/218 (2%) seropositives were aged 1-5 years. We report evidence of recent transmission and morbidity suppression in some communities of the focus representing 75% of the Yanomami population and 70% of all known communities. We conclude that onchocerciasis transmission could be feasibly interrupted in the Venezuelan Amazonian focus.

  20. Initial study of arthropods succession and pig carrion decomposition in two freshwater ecosystems in the Colombian Andes.

    Science.gov (United States)

    Barrios, Maria; Wolff, Marta

    2011-10-10

    Entomological succession and trophic roles of arthropods associated with different stages of carcass decomposition were studied to estimate the post-mortem submersion interval in two freshwater ecosystems in the Colombian Andes, at an altitude of 2614 m. Pig carcasses were employed as models placed 68 m apart, one in a stream (lotic) and another in an artificial lake (lentic). Decomposition time to skeletal remains was 74 days in the lake and 80 days in the stream. Six phases of decomposition were established: submerged fresh, early floating, floating decay, bloated deterioration, floating remains and sunken remains. A total of 18,832 organisms associated with the carcasses were collected: 11,487 in the lake (four orders, 19 families and 33 species) and 7345 in the stream (eight orders, 15 families and 25 species). Organisms were classified in the following ecological categories: shredders, collectors, predators, necrophagous, sarcosaprophagous and opportunists. Physical and chemical properties of the habitats, such as water temperature, CO(2) and conductivity, varied according to rainfall. In the lake, shredders (Coleoptera: Tropisternus sp. and Berosus sp.) and collectors (Diptera: Chironomus sp.) were found to be associated with submerged phases. Predators (Odonata) were only present during the first phases. Coleoptera (Dytiscidae) were found during floating decay and bloated deterioration stages. In the stream, shredders (Hyalella sp.) and collectors (Simulium sp.) were found during all stages, whereas the predator Oxelytrum discicolle was found exclusively during the floating stages, during which body temperature increased in a fashion similar to active decay in terrestrial environments. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  1. The mitochondrial genome of the entomoparasitic green alga helicosporidium.

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    Jean-François Pombert

    Full Text Available BACKGROUND: Helicosporidia are achlorophyllous, non-photosynthetic protists that are obligate parasites of invertebrates. Highly specialized, these pathogens feature an unusual cyst stage that dehisces inside the infected organism and releases a filamentous cell displaying surface projections, which will penetrate the host gut wall and eventually reproduce in the hemolymph. Long classified as incertae sedis or as relatives of other parasites such as Apicomplexa or Microsporidia, the Helicosporidia were surprisingly identified through molecular phylogeny as belonging to the Chlorophyta, a phylum of green algae. Most phylogenetic analyses involving Helicosporidia have placed them within the subgroup Trebouxiophyceae and further suggested a close affiliation between the Helicosporidia and the genus Prototheca. Prototheca species are also achlorophyllous and pathogenic, but they infect vertebrate hosts, inducing protothecosis in humans. The complete plastid genome of an Helicosporidium species was recently described and is a model of compaction and reduction. Here we describe the complete mitochondrial genome sequence of the same strain, Helicosporidium sp. ATCC 50920 isolated from the black fly Simulium jonesi. METHODOLOGY/PRINCIPAL FINDINGS: The circular mapping 49343 bp mitochondrial genome of Helicosporidium closely resembles that of the vertebrate parasite Prototheca wickerhamii. The two genomes share an almost identical gene complement and display a level of synteny that is higher than any other sequenced chlorophyte mitochondrial DNAs. Interestingly, the Helicosporidium mtDNA feature a trans-spliced group I intron, and a second group I intron that contains two open reading frames that appear to be degenerate maturase/endonuclease genes, both rare characteristics for this type of intron. CONCLUSIONS/SIGNIFICANCE: The architecture, genome content, and phylogeny of the Helicosporidium mitochondrial genome are all congruent with its close

  2. Onchocerciasis in West Africa after 2002: a challenge to take up

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    Hougard J.M.

    2002-06-01

    Full Text Available Initially planned for a 20 year life time, the Onchocerciasis Control Programme in West Africa (OCP will have finally continued its activities for nearly three decades (vector control alone from 1975 to 1989, then vector control and/or therapeutic treatment until 2002. Although onchocerciasis is no longer a problem of public health importance nor an obstacle to socioeconomic development in the OCP area, the control of this filariasis is not over because OCP never aimed at eradication, neither of the parasite (Onchocerca volvulus, nor of its vector (Simulium damnosum s.l.. In 2003, the eleven Participating countries of OCP will take over the responsibility of carrying out the residual activities of monitoring and the control of this disease. This mission is of great importance because any recrudescence of the transmission could lead in the long run to the reappearance of the clinical signs of onchocerciasis, if not its most serious manifestations. For epidemiological and operational reasons, and given the disparity in national health policies and infrastructures, the capacities of the countries to take over the residual activities of monitoring and control of onchocerciasis are very unequal. Indeed, the interventions to be carried out are very different from one country to another and the process of integrating the residual activities into the national health systems is not taking place at the same pace. This inequality among the countries vis-a-vis the challenges to be met does not, however, prejudge the epidemiological situation after 2002 whose evolution will also depend on the effectiveness of the provisions made before that date by OCP, then after 2002, by the Regional Office for Africa of the World Health Organization which is currently setting up a sub-regional multidisease surveillance centre.

  3. Historia natural del virus de la estomatitis vesicular en zonas enzoóticas de Antioquia

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    John Arboleda

    2003-01-01

    Full Text Available

    La Estomatitis Vesicular (EV es una enfermedad producida
    por el virus de la Estomatitis Vesicular, serotipos New Jersey (VSV-NJ e Indiana (VSV-IN, afecta bovinos y equinos, porcinos y causa infección natural en humanos, principalmente granjeros, ordeñadores y personal de laboratorio.
    Se caracteriza por producir vesículas en las membranas mucosas
    de la boca (epitelio de la lengua y el paladar, bandas coronarias,
    pezones y tejidos blandos de los cascos; hay pérdida de peso y decrecimiento en la producción de leche. Está clasificada en la Lista A de la Organización Internacional de Epizootias, debido a su gran poder de difusión, a las graves consecuencias socioeconómicas y a las restricciones comerciales. Además, clínicamente la EV es indistinguible de la Fiebre Aftosa (FA (1.
    La enfermedad se presenta por ciclos estacionales; la mayoría
    de ellos ocurre en las épocas de transición de los períodos de lluvias a los de verano y viceversa (2. Estudios serológicos realizados en áreas endémicas han demostrado que VSV-NJ y VSV-IN infectan en forma natural una amplia variedad de animales silvestres, los cuales están posiblemente implicados en la ecozootiología de la EV, bien como hospederos portadores, amplificadores o reservorios. Igualmente, dos especies de artrópodos, Lutzomyia shannoni y Simulium vittatum son infectados naturalmente, replican y transmiten experimentalmente
    el VSV, convirtiéndolos en posibles vectores y/o reservorios.
    Sin embargo, en ningún animal se produce la viremia necesaria para infectar los artrópodos hematófagos. El reservorio natural nunca ha sido encontrado entre los animales domésticos y silvestres investigados (3.

    El objetivo es identificar los factores ecológicos (cobertura
    vegetal, temperatura promedio, pluviosidad y humedad relativa, los vectores artrópodos y los mamíferos reservorios asociados con el antenimiento y transmisión de la VSV en

  4. Gain and loss of polyadenylation signals during evolution of green algae

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    Glöckner Gernot

    2007-04-01

    Full Text Available Abstract Background The Viridiplantae (green algae and land plants consist of two monophyletic lineages: the Chlorophyta and the Streptophyta. Most green algae belong to the Chlorophyta, while the Streptophyta include all land plants and a small group of freshwater algae known as Charophyceae. Eukaryotes attach a poly-A tail to the 3' ends of most nuclear-encoded mRNAs. In embryophytes, animals and fungi, the signal for polyadenylation contains an A-rich sequence (often AAUAAA or related sequence 13 to 30 nucleotides upstream from the cleavage site, which is commonly referred to as the near upstream element (NUE. However, it has been reported that the pentanucleotide UGUAA is used as polyadenylation signal for some genes in volvocalean algae. Results We set out to investigate polyadenylation signal differences between streptophytes and chlorophytes that may have emerged shortly after the evolutionary split between Streptophyta and Chlorophyta. We therefore analyzed expressed genes (ESTs from three streptophyte algae, Mesostigma viride, Klebsormidium subtile and Coleochaete scutata, and from two early-branching chlorophytes, Pyramimonas parkeae and Scherffelia dubia. In addition, to extend the database, our analyses included ESTs from six other chlorophytes (Acetabularia acetabulum, Chlamydomonas reinhardtii, Helicosporidium sp. ex Simulium jonesii, Prototheca wickerhamii, Scenedesmus obliquus and Ulva linza and one streptophyte (Closterium peracerosum. Our results indicate that polyadenylation signals in green algae vary widely. The UGUAA motif is confined to late-branching Chlorophyta. Most streptophyte algae do not have an A-rich sequence motif like that in embryophytes, animals and fungi. We observed polyadenylation signals similar to those of Arabidopsis and other land plants only in Mesostigma. Conclusion Polyadenylation signals in green algae show considerable variation. A new NUE (UGUAA was invented in derived chlorophytes and replaced

  5. Elimination of onchocerciasis from Colombia: first proof of concept of river blindness elimination in the world.

    Science.gov (United States)

    Nicholls, Rubén Santiago; Duque, Sofía; Olaya, Luz Adriana; López, Myriam Consuelo; Sánchez, Sol Beatriz; Morales, Alba Lucía; Palma, Gloria Inés

    2018-04-11

    Onchocerciasis is a chronic parasitic infection originally endemic in 13 discrete regional foci distributed among six countries of Latin America (Brazil, Colombia, Ecuador, Guatemala, Mexico and Venezuela). In Colombia, this disease was discovered in 1965 in the Pacific Coast of the country. The National Onchocerciasis Elimination Program was established in 1993 with the aim of eliminating disease morbidity and infection transmission. In 2013, the World Health Organization (WHO) verified Colombia as free of onchocerciasis, becoming the first country in the world to reach such a goal. This report provides the empirical evidence of the elimination of Onchocerca volvulus transmission by Simulium exiguum (s.l.) after 12 years of 6-monthly mass drug administration of Mectizan® (ivermectin) to all the eligible residents living in this endemic area. From 1996 onwards, a biannual community-based mass ivermectin administration programme was implemented, complemented by health education and community participation. In-depth parasitological, serological and entomological surveys were conducted periodically between 1998 and 2007 to evaluate the impact of ivermectin treatment according to the 2001 WHO guidelines. When the interruption of parasite transmission was demonstrated, the drug distribution ceased and a three-year post-treatment surveillance (PTS) period (2008-2010) was initiated. After 23 rounds of treatment, parasitological and ophthalmological assessments showed absence of microfilariae in skin and anterior chamber of the eyes. Serological tests proved lack of antibodies against O. volvulus in children under 10 years-old. A total of 10,500 S. exiguum flies tested by PCR had no L3 infection (infectivity rate = 0.0095%; 95% CI: 0.0029-0.049) during 2004, indicating interruption of parasite transmission. However, biannual ivermectin treatments continued until 2007 followed by a 3-year PTS period at the end of which 13,481 flies were analyzed and no infective flies were

  6. Estructura de la comunidad de macroinvertebrados del arroyo Achiras (Córdoba, Argentina: análisis previo a la construcción de una presa

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    Cristina Mabel Gualdoni

    2012-06-01

    Full Text Available La regulación de ríos y arroyos mediante diques modifica parámetros que influyen directamente sobre la biota. En la cuenca endorreica Achiras-del Gato ha finalizado recientemente la construcción de una presa de mediana envergadura que alterará las características limnológicas del sistema y la estructura de las comunidades bentónicas. Este estudio aporta los primeros registros del macrobentos de este sistema lótico y analiza la variación espacio-temporal de la estructura de la comunidad en tramos pedemontanos del arroyo Achiras. Durante un año, antes de la construcción de la presa, se colectaron muestras de zoobentos y se registraron variables abióticas en correderas y rabiones de dos sitios del arroyo, uno situado río arriba del área del dique y otro aguas abajo de la misma. Para cada sitio, hábitat y estación del año se determinó abundancia, frecuencia, riqueza taxonómica, Índice de Shannon y equidad, y se analizaron mediante ANOVA de una y tres vías. Los atributos de las comunidades de referencia se complementaron con la determinación de taxa exclusivos e indicadores y detectores ecológicos. En el primer sitio se registraron 73 taxa, Simulium fue más abundante y Leptohyphes eximius Eaton, 1882, más frecuente. En el segundo se hallaron 75 taxa, Caenis fue más abundante y Cricotopus sp. 3 más frecuente. La abundancia y la riqueza fueron significativamente mayores en primavera, y la diversidad en rabiones de invierno. Se determinó que los atributos de la comunidad estuvieron afectados por la época de muestreo. El arroyo Achiras posee un régimen hídrico freático-pluvial, con caudales bajos en invierno y altos en verano, por lo que se esperan cambios en la biota nativa y la integridad del sistema en respuesta a la reducción de la variabilidad hidráulica cuando el funcionamiento de la presa altere el caudal natural.

  7. Invertebrados bentônicos: relação entre estrutura da fauna e características do mesohabitat

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    Virginia Sanches Uieda

    2016-06-01

    Full Text Available Em ecossistemas lóticos é comum a formação de diferentes mesohabitats intercalados ao longo do rio, como poções, corredeiras e rápidos, frequentemente acompanhados de alterações na estrutura da fauna bentônica associada. No trabalho analisamos a fauna de invertebrados bentônicos em rápidos e corredeiras de um trecho de serra do Rio Capivara (Bacia do Médio Rio Tietê. A análise das características ambientais e a coleta da fauna foram realizadas em três corredeiras e três rápidos, em um mês da estação chuvosa (cinco réplicas de cada. Os mesohabitats se diferenciaram quanto ao maior porcentual de blocos nos rápidos e maiores valores de profundidade, correnteza e porcentual de matacões nas corredeiras. Do total de 57 Unidades Taxonômicas Operacionais (UTO's amostradas, 75% foram comuns aos dois mesohabitats (Similaridade de Morisita = 0,86. Quando analisado o porcentual de abundância, a similaridade espacial se manteve e dois grupos se sobressaíram em abundância: Hexapoda (>80%, sendo a maioria Ephemeroptera, Diptera e Trichoptera e Annelida (10%. As análises exploratórias (cluster e NMDS também apontaram para uma elevada similaridade espacial, porém os resultados da Análise de Similaridade (ANOSIM indicaram uma diferença significativa entre os mesohabitats (p<0,1%, seja analisando o total de UTO's ou retirando as UTO's raras. Cinco grupos tiveram uma maior contribuição para a média de dissimilaridade entre os mesohabitats: Simulium e Baetodes mais abundantes nas corredeiras, Traveryphes, Hagenulopsis e Macrelmis nos rápidos. Assim, os resultados da ANOSIM salientaram a importância do refinamento na identificação para a interpretação mais precisa acerca da relação entre a fauna e a estrutura do habitat.

  8. Status of Onchocerciasis transmission after more than a decade of mass drug administration for onchocerciasis and lymphatic filariasis elimination in central Nigeria: challenges in coordinating the stop MDA decision.

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    Darin S Evans

    2014-09-01

    Full Text Available This study was undertaken in five onchocerciasis/lymphatic filariasis (LF co-endemic local government areas (LGAs in Plateau and Nasarawa, Nigeria. Annual MDA with ivermectin had been given for 17 years, 8 of which were in combination with albendazole. In 2008, assessments indicated that LF transmission was interrupted, but that the MDA had to continue due to the uncertain status of onchocerciasis transmission. Accordingly, assessments to determine if ivermectin MDA for onchocerciasis could be stopped were conducted in 2009.We evaluated nodule, microfilarial (mf skin snip, and antibody (IgG4 response to OV16 prevalence in adults and children in six sentinel sites where baseline data from the 1990s were available. We applied the 2001 WHO criteria for elimination of onchocerciasis that defined transmission interruption as an infection rate of <0.1% in children (using both skin snip and OV16 antibody and a rate of infective (L3 blackflies of <0.05%.Among adult residents in sentinel sites, mean mf prevalence decreased by 99.37% from the 1991-1993 baseline of 42.95% (64/149 to 0.27% (2/739 in 2009 (p<0.001. The OV16 seropositivity of 3.52% (26/739 among this same group was over ten times the mf rate. No mf or nodules were detected in 4,451 children in sentinel sites and 'spot check' villages, allowing the exclusion of 0.1% infection rate with 95% confidence. Seven OV16 seropositives were detected, yielding a seroprevalence of 0.16% (0.32% upper 95%CI. No infections were detected in PCR testing of 1,568 Simulium damnosum s.l. flies obtained from capture sites around the six sentinel sites.Interruption of transmission of onchocerciasis in these five LGAs is highly likely, although the number of flies caught was insufficient to exclude 0.05% with 95% confidence (upper CI 0.23%. We suggest that ivermectin MDA could be stopped in these LGAs if similar results are seen in neighboring districts.

  9. A new methodology for sampling blackflies for the entomological surveillance of onchocerciasis in Brazil.

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    Érika S do Nascimento-Carvalho

    Full Text Available The effectiveness of the MosqTent® trap was evaluated in endemic area to onchocerciasis in Brazil. This study seeks to provide subsidies for the monitoring of the onchocerciasis transmission in the country. The study was carried out at the Homoxi and Thirei villages, located in the Yanomami Indigenous Land, in the state of Roraima. This area presents hyperendemicity, high blackflies densities, large population migrations and mining activities. The Homoxi and Thirei villages are assisted by the Brazilian Ministry of Health. To conduct the present study, the village leader, health leaders and the Brazilian Ethics Committee were consulted. Blackflies captures were carried out simultaneously at the Homoxi and Thirei, using systematized methods to allow for comparisons between the traditional Human Landing Catch (HLC and HLC protected by the MosqTent®. The female blackflies were captured at two equidistant capture stations per locality, by two collectors per station, for five consecutive days. Individuals captured by interval/station/day were counted, identified and maintained at -20°C. The underlying probability distributions and the differences between the methods for the independent sample data were verified in a comparative statistical analysis between the use of the MosqTent® and the HLC. A total of 10,855 antropophilic blackflies were captured by both methodologies. A total of 7,367 (67.87% blackflies belonging to seven species were captured by MosqTent® -Simulium incrustatum s.l (99.06%; S. guianense s.l (0.74%, S. oyapockense s.l (0.01%, S. exiguum (0.10%, S. metallicum (0.05%, S. ochraceum (0.03% and S. minusculum s.l (0.01%. Moreover, 3,488 (32.14% blackflies belonging to four species were captured by HLC-S. incrustatum s.l (98.33%; S. guianense s.l (1.38%, S. oyapockense s.l (0.26% and S. metallicum (0.03%. The MosqTent® was more effective and efficient when compared to HLC. When comparing total blackflies captured/day, the Mosq

  10. A new methodology for sampling blackflies for the entomological surveillance of onchocerciasis in Brazil.

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    Nascimento-Carvalho, Érika S do; Cesário, Raquel de Andrade; do Vale, Vladimir Fazito; Aranda, Arion Tulio; Valente, Ana Carolina Dos Santos; Maia-Herzog, Marilza

    2017-01-01

    The effectiveness of the MosqTent® trap was evaluated in endemic area to onchocerciasis in Brazil. This study seeks to provide subsidies for the monitoring of the onchocerciasis transmission in the country. The study was carried out at the Homoxi and Thirei villages, located in the Yanomami Indigenous Land, in the state of Roraima. This area presents hyperendemicity, high blackflies densities, large population migrations and mining activities. The Homoxi and Thirei villages are assisted by the Brazilian Ministry of Health. To conduct the present study, the village leader, health leaders and the Brazilian Ethics Committee were consulted. Blackflies captures were carried out simultaneously at the Homoxi and Thirei, using systematized methods to allow for comparisons between the traditional Human Landing Catch (HLC) and HLC protected by the MosqTent®. The female blackflies were captured at two equidistant capture stations per locality, by two collectors per station, for five consecutive days. Individuals captured by interval/station/day were counted, identified and maintained at -20°C. The underlying probability distributions and the differences between the methods for the independent sample data were verified in a comparative statistical analysis between the use of the MosqTent® and the HLC. A total of 10,855 antropophilic blackflies were captured by both methodologies. A total of 7,367 (67.87%) blackflies belonging to seven species were captured by MosqTent® -Simulium incrustatum s.l (99.06%); S. guianense s.l (0.74%), S. oyapockense s.l (0.01%), S. exiguum (0.10%), S. metallicum (0.05%), S. ochraceum (0.03%) and S. minusculum s.l (0.01%). Moreover, 3,488 (32.14%) blackflies belonging to four species were captured by HLC-S. incrustatum s.l (98.33%); S. guianense s.l (1.38%), S. oyapockense s.l (0.26%) and S. metallicum (0.03%). The MosqTent® was more effective and efficient when compared to HLC. When comparing total blackflies captured/day, the MosqTent® was

  11. Gain and loss of polyadenylation signals during evolution of green algae.

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    Wodniok, Sabina; Simon, Andreas; Glöckner, Gernot; Becker, Burkhard

    2007-04-18

    The Viridiplantae (green algae and land plants) consist of two monophyletic lineages: the Chlorophyta and the Streptophyta. Most green algae belong to the Chlorophyta, while the Streptophyta include all land plants and a small group of freshwater algae known as Charophyceae. Eukaryotes attach a poly-A tail to the 3' ends of most nuclear-encoded mRNAs. In embryophytes, animals and fungi, the signal for polyadenylation contains an A-rich sequence (often AAUAAA or related sequence) 13 to 30 nucleotides upstream from the cleavage site, which is commonly referred to as the near upstream element (NUE). However, it has been reported that the pentanucleotide UGUAA is used as polyadenylation signal for some genes in volvocalean algae. We set out to investigate polyadenylation signal differences between streptophytes and chlorophytes that may have emerged shortly after the evolutionary split between Streptophyta and Chlorophyta. We therefore analyzed expressed genes (ESTs) from three streptophyte algae, Mesostigma viride, Klebsormidium subtile and Coleochaete scutata, and from two early-branching chlorophytes, Pyramimonas parkeae and Scherffelia dubia. In addition, to extend the database, our analyses included ESTs from six other chlorophytes (Acetabularia acetabulum, Chlamydomonas reinhardtii, Helicosporidium sp. ex Simulium jonesii, Prototheca wickerhamii, Scenedesmus obliquus and Ulva linza) and one streptophyte (Closterium peracerosum). Our results indicate that polyadenylation signals in green algae vary widely. The UGUAA motif is confined to late-branching Chlorophyta. Most streptophyte algae do not have an A-rich sequence motif like that in embryophytes, animals and fungi. We observed polyadenylation signals similar to those of Arabidopsis and other land plants only in Mesostigma. Polyadenylation signals in green algae show considerable variation. A new NUE (UGUAA) was invented in derived chlorophytes and replaced not only the A-rich NUE but the complete poly

  12. The vector control operations in the onchocerciasis control programme in West Africa

    International Nuclear Information System (INIS)

    Hougard, Jean-Marc

    2000-01-01

    Onchocerciasis is a dermal filariasis transmitted to man by a blood sucking blackfly belonging to the Simulium genus. The most serious manifestations of the disease are blindness and debilitating skin lesions. Africa is by far the most affected continent both in terms of distribution and severity of the clinical manifestations of the disease. That is the reason why an ambitious regional onchocerciasis control project, the Onchocerciasis Control Programme in West Africa (OCP), was launched in 1974 (Molyneux 1995). The objective is to eliminate onchocerciasis as a public health problem and as an obstacle to socio-economic development and to ensure that the countries are in a position to maintain these achievements. Seven countries were concerned at the beginning of the programme), delimiting the 'initial area' (Benin, Burkina Faso, Cote d'Ivoire, Ghana, Mali, Niger and Togo). In 1988, the OCP began operations in the 'western extension', an additional four countries in the West (Guinea, Guinea Bissau, Senegal and Sierra Leone) and extended operations into the 'southeastern extension' (south Benin, Ghana and Togo). The rationale for these extensions related to findings that the vectors were able to migrate and hence re-invade controlled areas over several hundred kilometres (Garms et al. 1979). Until 1989, in the absence of a non-toxic drug which could be used on a wide scale to kill the adult worm, the vector control strategy was the only method to interrupt the transmission of the blinding form of the parasite until the adult worm in the human body was eliminated (the maximum duration of the adult worm is estimated to be about fourteen years). In the late 1980s, ivermectin, a microfilaricide which is the only drug available to date, became an integral part of the OCP control strategy (Webbe 1992). In the extension areas, larviciding is still going on with satisfaction, combined with the distribution of ivermectin. In pursuing this combined therapeutic and vector

  13. O foco brasileiro de oncocercose: novas observações feitas nas áreas dos rios Mucajaí e Catrimâni, Território de Roraima The brazilian focus of onchocerciasis: new observations in areas of the Mucajaí and Catrimâni, Territory of Roraima

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    Mário Augusto Pinto de Moraes

    1986-03-01

    Full Text Available Um novo inquérito para oncocercose, realizado em 1984, entre índios Yanomami da parte média dos rios Mucajaí e Catrimâni (Território de Roraima, mostrou que, decorridos vários anos das primeiras investigações - uma década no caso do rio Mucajaí - os índices de prevalência, nesses dois locais da periferia do foco brasileiro, não haviam sofrido alteração significativa. Levando-se em conta apenas os residentes nas aldeias ou malocas abrangidas pelo inquérito, a prevalência atingiu 3,1% nos índios do rio Mucajaí, enquanto ficou em zero nos do rio Catrimâni. Dada a presença contínua, nas referidas aldeias, de índios visitantes, altamente infectados, oriundos da parte central e mais elevada do território indígena - onde cerca de 90% doa adultos têm oncocercose - seria de esperar o achado de valores bem maiores (acima pelo menos daqueles encontrados anteriormente, caso um vetor apropiado estivesse presente na região. Simulium oyapockense s.1. é a única espécie antropofílica de simulídeo, em toda zona inferior da área ocupada pelos Yanomami (altitude ao redor de 200 metros, abundante o suficiente para constituir-se em transmissor da oncocercose. Sem dúvida, no entanto, trata-se de um mau vetor (como aliás já foi demonstrado experimentalmente para Mansonella ozzardi ou, até mesmo, de espécie não vetora de Onchocerca volvulus, pois, de outra forma, os índices de prevalência na parte média dos rios Mucajaí e Catrimâni já teriam crescido durante o período assinalado. Para explicar as altas taxas alcançadas pela endemia na porção central e cheia de acidentes (altitude superior a 900 metros do território Yanomami, há que se admitir a presença aí de um outro vetor, muito eficiente, cujos hábitos estariam ligados à região montanhosa da fronteira entre o Brasil e a Venezuela.A recent survey for onchocerciasis conducted among the Yanomami Indians living on the middle reaches of the Mucajaí and Catrim

  14. Assessment and monitoring of onchocerciasis in Latin America.

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    Rodríguez-Pérez, Mario A; Unnasch, Thomas R; Real-Najarro, Olga

    2011-01-01

    Onchocerciasis has historically been one of the leading causes of infectious blindness worldwide. It is endemic to tropical regions both in Africa and Latin America and in the Yemen. In Latin America, it is found in 13 foci located in 6 different countries. The epidemiologically most important focus of onchocerciasis in the Americas is located in a region spanning the border between Guatemala and Mexico. However, the Amazonian focus straddling the border of Venezuela and Brazil is larger in overall area because the Yanomami populations are scattered over a very large geographical region. Onchocerciasis is caused by infection with the filarial parasite Onchocerca volvulus. The infection is spread through the bites of an insect vector, black flies of the genus Simulium. In Africa, the major vectors are members of the S. damnosum complex, while numerous species serve as vectors of the parasite in Latin America. Latin America has had a long history of attempts to control onchocerciasis, stretching back almost 100 years. The earliest programmes used a strategy of surgical removal of the adult parasites from affected individuals. However, because many of the adult parasites lodge in undetectable and inaccessible areas of the body, the overall effect of this strategy on the prevalence of infection was relatively minor. In 1988, a new drug, ivermectin, was introduced that effectively killed the larval stage (microfilaria) of the parasite in infected humans. As the microfilaria is both the stage that is transmitted by the vector fly and the cause of most of the pathologies associated with the infection, ivermectin opened up a new strategy for the control of onchocerciasis. Concurrent with the use of ivermectin for the treatment of onchocerciasis, a number of sensitive new diagnostic tools were developed (both serological and nucleic acid based) that provided the efficiency, sensitivity and specificity necessary to monitor the decline and eventual elimination of

  15. Catalogue of Tenebrionidae (Coleoptera of North America

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    Yves Bousquet

    2018-01-01

    angustula Casey, 1890, Stethasida stricta Casey, 1912, Stethasida muricatula languida Casey, 1912, Stethasida pertinax Casey, 1912, Stethasida socors Casey, 1912, Stethasida angustula inepta Casey, 1912, Stethasida tenax Casey, 1912, and Stethasida vegrandis Casey, 1912 [= Stenomorpha muricatula (LeConte, 1851]; Stethasida obsoleta expansa Casey, 1912, Stethasida obsoleta opacella Casey, 1912, Stethasida brevipes Casey, 1912, Stethasida torpida Casey, 1912, Stethasida convergens Casey, 1912, Stethasida discreta Casey, 1912, Stethasida longula Casey, 1912, Stethasida adumbrata Casey, 1912, Stethasida occulta Casey, 1912, Stethasida tarsalis Casey, 1912, Stethasida unica Casey, 1912, and Pelecyphorus laevigatus Papp, 1961 [= Stenomorpha obsoleta (LeConte, 1851]; Trichiasida eremica Wilke, 1922 [= Stenomorpha difficilis (Champion, 1884]; Trichiasida lineatopilosa Casey, 1912 [= Stenomorpha hirsuta (LeConte, 1851]; Trichiasida tenella Casey, 1912 [= Stenomorpha hispidula (LeConte, 1851]; Trichiasida duplex Casey, 1912 [= Stenomorpha villosa (Champion, 1884]; Alaudes squamosa Blaisdell, 1919, Alaudes testacea Blaisdell, 1919, and Alaudes fallax Fall, 1928 [= Alaudes singularis Horn, 1870]; Edrotes barrowsi Dajoz, 1999 [=Edrotes ventricosus LeConte, 1851]; Nyctoporis tetrica Casey, 1907 and Nyctoporis maura Casey, 1907 [= Nyctoporis aequicollis Eschscholtz, 1831]; Nyctoporis pullata Casey, 1907 [= Nyctoporis sponsa Casey, 1907]; Eleodes tibialis forma oblonga Blaisdell, 1909 [= Eleodes tibialis Blaisdell, 1909]; Eleodes (manni var. variolosa Blaisdell, 1917 [= Eleodes constrictus LeConte, 1858]; Eleodes cordata forma sublaevis Blaisdell, 1909, Eleodes cordata forma intermedia Blaisdell, 1909, Eleodes cordata forma oblonga Blaisdell, 1909, Eleodes cordata forma elongata Blaisdell, 1909, and Eleodes (cordata var. adulterina Blaisdell, 1917 [= Eleodes cordata Eschscholtz, 1829]; Eleodes hornii var. monticula Blaisdell, 1918 and Eleodes manni sierra Blaisdell, 1925 [= Eleodes fuchsii

  16. The occurrence of trace elements in bed sediment collected from areas of varying land use and potential effects on stream macroinvertebrates in the conterminous western United States, Alaska, and Hawaii, 1992-2000

    Science.gov (United States)

    Paul, Angela P.; Paretti, Nicholas V.; MacCoy, Dorene E.; Brasher, Anne M.D.

    2012-01-01

    . Generally, Hg concentrations were below the sediment-quality guideline for this trace element but appeared elevated in urbanized areas and at sites contaminated by historic mining practices. Lastly, although there was no distinctive pattern in Se concentrations with land use, median bed-sediment concentrations were slightly elevated in urbanized areas.Macroinvertebrate community structure was influenced by topographic, geologic, climatic, and in-stream characteristics. To account for inherent distribution patterns resulting from these influences, samples of macroinvertebrates were stratified by ecoregion to assess the influence of trace elements on community structure. Cumulative toxic units (CTUs) were used to evaluate gradients in trace-element concentrations in mixture. Correlation analyses among the trace elements under different land-use conditions indicate that trace-element mixtures vary among bed sediment and can have a marked influence on CTU composition. Macroinvertebrate response to bed-sediment trace-element exposure was evident only at the most highly contaminated sites, notably at sites classified as contaminated by the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) as a result of historic mining activities. Results of this study agree with the findings of other studies evaluating trace-element exposure to in-stream macroinvertebrate community structure in that generally lower richness metrics and taxa dominance occur in streams where high trace-element enrichment occurs; however, not all streams in all areas have the same characterizing taxa. In the mountain and xeric ecosystems, the mayfly, Baetis sp.; the Diptera, Simulium sp.; caddisflies in the family Hydropsychiidae; midges in the family Orthocladiinae; and the worms belonging to Turbellaria and Naididae all demonstrated resilience to trace-element exposure and, in some cases, possible changes in physical habitat within stream ecosystems. The taxa characteristics within