Allen Julie M
Full Text Available Abstract Background Sucking lice (Phthiraptera: Anoplura are obligate, permanent ectoparasites of eutherian mammals, parasitizing members of 12 of the 29 recognized mammalian orders and approximately 20% of all mammalian species. These host specific, blood-sucking insects are morphologically adapted for life on mammals: they are wingless, dorso-ventrally flattened, possess tibio-tarsal claws for clinging to host hair, and have piercing mouthparts for feeding. Although there are more than 540 described species of Anoplura and despite the potential economical and medical implications of sucking louse infestations, this study represents the first attempt to examine higher-level anopluran relationships using molecular data. In this study, we use molecular data to reconstruct the evolutionary history of 65 sucking louse taxa with phylogenetic analyses and compare the results to findings based on morphological data. We also estimate divergence times among anopluran taxa and compare our results to host (mammal relationships. Results This study represents the first phylogenetic hypothesis of sucking louse relationships using molecular data and we find significant conflict between phylogenies constructed using molecular and morphological data. We also find that multiple families and genera of sucking lice are not monophyletic and that extensive taxonomic revision will be necessary for this group. Based on our divergence dating analyses, sucking lice diversified in the late Cretaceous, approximately 77 Ma, and soon after the Cretaceous-Paleogene boundary (ca. 65 Ma these lice proliferated rapidly to parasitize multiple mammalian orders and families. Conclusions The diversification time of sucking lice approximately 77 Ma is in agreement with mammalian evolutionary history: all modern mammal orders are hypothesized to have diverged by 75 Ma thus providing suitable habitat for the colonization and radiation of sucking lice. Despite the concordant timing of
Pakeer, O; Jeffery, J; Mohamed, A M; Ahmad, F; Baharudin, O
Four cases of pediculosis, two in adults and two in children, caused by the crab-louse, Pthirus pubis Linnaeus, 1758 (Diptera: Anoplura) is reported from peninsular Malaysia. This is the second report of the problem to be documented from the country. Although P. pubis is closely associated with genital hairs, it is, however, also found to occur on the eyelashes, eyebrows, hairs of the body, head and axilla. The few reported cases of pthiriasis probably do not reflect the true situation.
Light, Jessica E; Hafner, Mark S
Although most studies of codivergence rely primarily on topological comparisons of host and parasite phylogenies, temporal assessments are necessary to determine if divergence events in host and parasite trees occurred contemporaneously. A combination of cophylogenetic analyses and comparisons of branch lengths are used in this study to understand the host-parasite association between heteromyid rodents (Rodentia: Heteromyidae) and their sucking lice of the genus Fahrenholzia (Phthiraptera: Anoplura). Cophylogenetic comparisons based on nucleotide substitutions in the mitochondrial COI gene reveal a significant, but not perfect, pattern of cophylogeny between heteromyids and their sucking lice. Regression analyses show a significant functional relationship between the lengths of analogous branches in the host and parasite trees, indicating that divergence events in hosts and parasites were approximately contemporaneous. Thus, the topological similarity observed between heteromyids and their lice is the result of codivergence. These analyses also show that the COI gene in lice is evolving two to three times faster than the same gene in their hosts (similar to the results of studies of other lice and their vertebrate hosts) and that divergence events in lice occurred shortly after host divergence. We recommend that future studies of codivergence include temporal comparisons and, when possible, use the same molecular marker(s) in hosts and parasites to achieve the greatest insight into the history of the host-parasite relationship.
Gutiérrez, María Mercedes; Werdin-González, Jorge Omar; Stefanazzi, Natalia; Bras, Cristina; Ferrero, Adriana Alicia
The human head louse, Pediculus humanus capitis (Anoplura: Pediculidae), is an ectoparasite confined to the scalp and human hairs. The repeated use of insecticides for the control of head lice during past decades has resulted in the development of marked levels of resistance. Natural compounds such as essential oils (EOs) have been suggested as alternative sources for insect control agents. In order to introduce a new pediculicide based on EOs, the effectiveness of the product and their effects on human being must be analyzed. In consequence, the biological activity of EOs from the leaves and fruits of Schinus areira (Anacardiaceae) and the leaves of Thymus vulgaris (Lamiaceae), Aloysia polystachya and Aloysia citriodora (Verbenacea) were evaluated against the eggs and adults of P. humanus capitis by fumigant and contact toxicity bioassays. Additionally, dermal corrosion/irritation tests were performed on New Zealand albino rabbits. In a fumigant bioassay, EOs from the leaves and fruits of S. areira were the most toxic against P. humanus capitis adults while these EOs and T. vulgaris were the most effective against the eggs. In contact bioassay, the EO from T. vulgaris was the most toxic against both stages. In the corrosion/irritation tests, the EOs did not produce dermal effects. According to the results, the essential oils from the leaves of T. vulgaris would be a valid tool for the management of P. humanus capitis. This EO produces a high knockdown effect in adults (followed by mortality) and toxicity in the eggs when it is applied for 21 min at a low concentration.
Dolores del Carmen Castro
Full Text Available The ultrastructure of Proechinophthirus zumpti Werneck, 1955, mainly the external chorionic features of the egg, is described through electronic microscopy techniques. This species was first cited in Argentina, infesting Arctocephalus australis (Zimmermann, 1873. The morphological adaptations of adults and nymphs are described in both species of Proechinophthirus parasitic on Otariidae: P. fluctus (Ferris, 1916 and P. zumpti.
Castex, M; Suárez, S; de la Cruz, A M
In order to determine the frequency of pediculosis in persons living with children diagnosed as positive to Pediculus capitis in educational institutions of the "Carmelo" People's Council, the houses of 58 children who repeatedly had pediculosis from May to September, 1997 were visited. 14.54% of the 237 examined persons were positive (40 individuals). 82.5% were females. The mother was the most affected relative (32.5%). 30 positive children were matched by age, sex and grade with 30 negative children. People living together with the cases had a higher frequency of pediculosis (12.4%) than those living with the controls (1.8%) (t = 3.49; p < 0.001). The examination and treatment, if necessary, of those persons living together with the school children with pediculosis was recommended.
Burkhart, C N; Burkhart, C G
Pediculosis capitis is a prevalent and highly communicable condition infesting millions of elementary school students annually. Topical insecticides are the present standard treatment for this condition. Because resistance of head lice to insecticides is a growing concern, assessment of efficacy of pediculicidal and ovicidal activity of the various agents is needed for public health interests. Given the number of anecdotal and market-driven reported studies, assessment of topical lice therapies requires standardized testing. Evaluations based on adaptations of World Health Organization guidelines are not ideal, whereas a protocol reflecting clinical exposure to insecticides is preferable.
Bowles, Vernon M; Yoon, Kyong Sup; Barker, Stephen C; Tran, Christopher; Rhodes, Christopher; Clark, Marshall J
Studies were undertaken to determine the ovicidal efficacy of 5,5'-dimethyl-2,2'-bipyridyl (abametapir) against eggs of both human head and body lice. Head lice eggs of different ages (0-2, 3-5, and 6-8-d-old eggs) were exposed to varying concentrations of abametapir in isopropanol and concentration-dependent response relationships established based on egg hatch. One hundred percent of all abametapir-treated eggs failed to hatch at the 0.74 and 0.55% concentrations, whereas 100% of 6-8-d-old head louse eggs failed to hatch only at the 0.74% concentration. The LC50 value for abametapir varied, depending on the age of the head lice eggs, from ∼0.10% recorded for 0-2-d-old eggs and increasing to ∼0.15% for 6-8-d-old eggs. Abametapir was also evaluated once formulated into a lotion referred to as Xeglyze (0.74% abametapir) and serial dilutions made. Ovicidal efficacies were determined against head lice eggs 0-8-d-old. Results indicated 100% ovicidal activity at the 0.74, 0.55, 0.37, and 0.18% concentrations. Additional studies undertaken using body lice eggs also demonstrated that abametapir was 100% ovicidal against eggs of all ages when evaluated at a concentration of 0.37 and 0.55%. Given that ovicidal activity is a critical component of any effective treatment regime for louse control, the data presented in this study clearly demonstrate the ability of abametapir to inhibit hatching of both head and body louse eggs as assessed in vitro.
Yang, Young-Cheol; Choi, Han-Young; Choi, Won-Sil; Clark, J M; Ahn, Young-Joon
The toxic effects of Eucalyptus globulus leaf oil-derived monoterpenoids [1,8-cineole, l-phellandrene, (-)-alpha-pinene, 2-beta-pinene, trans-pinocarveol, gamma-terpinene, and 1-alpha-terpineol] and the known Eucalyptusleaf oil terpenoids (beta-eudesmol and geranyl acetate) on eggs and females of the human head louse, Pediculus humanus capitis, were examined using direct contact and fumigation bioassays and compared with the lethal activity of delta-phenothrin and pyrethrum, two commonly used pediculicides. In a filter paper contact bioassay with female P. h. capitis, the pediculicidal activity was more pronounced with Eucalyptus leaf oil than with either delta-phenothrin or pyrethrum on the basis of LT(50) values (0.125 vs 0.25 mg/cm(2)). 1,8-Cineole was 2.2- and 2.3-fold more toxic than either delta-phenothrin or pyrethrum, respectively. The pediculicidal activities of (-)-alpha-pinene, 2-beta-pinene, and (E)-pinocarveol were comparable to those of delta-phenothrin and pyrethrum. l-Phellandrene, gamma-terpinene, and 1-alpha-terpineol were relatively less active than delta-phenothrin and pyrethrum. beta-Eudesmol and geranyl acetate were ineffective. 1-alpha-Terpineol and (E)-pinocaveol were highly effective at 0.5 and 1.0 mg/cm(2), respectively, against P. h. capitis eggs. At 1.0 mg/cm(2), (-)-alpha-pinene, 2-beta-pinene, and gamma-terpinene exhibited moderate ovicidal activity, whereas little or no ovicidal activity was observed with the other terpenoids and with delta-phenothrin and pyrethrum. In fumigation tests with female P. h. capitis at 0.25 mg/cm(2), 1,8-cineole, (-)-alpha-pinene, (E)-pinocarveol, and 1-alpha-terpineol were more effective in closed cups than in open ones, indicating that the effect of the monoterpenoids was largely due to action in the vapor phase. Neither delta-phenothrin nor pyrethrum exhibited fumigant toxicity. Eucalyptus leaf oil, particularly 1,8-cineole, 1-alpha-terpineol, and (E)-pinocaveol, merits further study as potential pediculicides or lead compounds for the control of P. h. capitis.
Durden, L A
A new species of sucking louse, Neohaematopinus sundasciuri, collected from the tree squirrel, Sundasciurus juvencus, is described from Palawan Island, Philippines. An updated world list of the genus Neohaematopinus is presented; this documents descriptive citations, known hosts, and geographical distributions with interpretive annotations for each of the 32 species now included in the genus. The geographical distributions of Neohaematopinus sciuri and N. sciurinus are discussed.
González Audino, P; Barrios, S; Vassena, C; Mougabure Cueto, G; Zerba, E; Picollo, M I
We studied the profile of permethrin resistance in populations of head lice infesting children 6-12 yr old in schools and their homes in and around Buenos Aires, Argentina. Five permethrin-resistant populations with different levels of resistance were collected: Hogar Loyola (HL), Republica de Turquia (RT), Hogar Mitre (HM), Guardia de Honor (GH), and Ricardo Guiraldes (RG). One susceptible population, Bandera Argentina (BA), also was collected. Their level of resistance was evaluated, and results showed resistance ratios of 13 for HL, 16 for RT, 22 for HM, 61 for GH, and 69 for RG. To elucidate the possible involvement of the cytochrome P450 monooxygenase system in conferring permethrin resistance, ethoxycoumarin-O-deethylase (ECOD) activity was measured in abdomens of individual third instars and adults by using a fluorometric assay. The ECOD activity was lower in the susceptible BA population (4.7 ng per louse) than in the resistant ones (13.7 ng per louse for RG, 12.3 ng per louse for GH, 8.6 ng per louse for RT, and 8.2 ng per louse for HL). ECOD activity was significantly correlated with the level of resistance in the field populations (r = 0.97, P = 0.0009), suggesting a role for cytochrome monooxygenase P450 system in permethrin resistance by head louse, Pediculus humanus capitis De Geer.
Yang, Young-Cheol; Lee, Hoi-Seon; Lee, Si Hyeock; Clark, J Marshall; Ahn, Young-Joon
The toxicity of cinnamon, Cinnamomum zeylanicum, bark essential oil compounds against eggs and adult females of human head louse, Pediculus humanus capitis, was examined using direct contact and vapour phase toxicity bioassays and compared with the lethal activity of their related compounds, benzyl alcohol, cinnamic acid, cinnamyl acetate, 4-hydroxybenzaldehyde and salicylaldehyde, as well as two widely used pediculicides, d-phenothrin and pyrethrum. In a filter-paper contact toxicity bioassay with female lice at 0.25 mg/cm(2), benzaldehyde was 29- and 27-fold more toxic than pyrethrum and d-phenothrin, respectively, as judged by median lethal time (LT(50)) values. Salicylaldehyde was nine and eight times more active than pyrethrum and d-phenothrin, respectively. Pediculicidal activity of linalool was comparable with that of d-phenothrin and pyrethrum. Cinnamomum bark essential oil was slightly less effective than either d-phenothrin or pyrethrum. Benzyl alcohol and (E)-cinnamaldehyde exhibited moderate pediculicidal activity. After 24h of exposure, no hatching was observed with 0.063 mg/cm(2) salicylaldehyde, 0.125 mg/cm(2) benzaldehyde, 0.5mg/cm(2)Cinnamomum bark essential oil, 1.0 mg/cm(2) (E)-cinnamaldehyde, and 1.0 mg/cm(2) benzyl cinnamate. Little or no ovicidal activity was observed with d-phenothrin or pyrethrum. In vapour phase toxicity tests with female lice, benzaldehyde and salicylaldehyde were much more effective in closed containers than in open ones, indicating that the mode of delivery of these compounds was largely due to action in the vapour phase. Neither d-phenothrin nor pyrethrum exhibited fumigant toxicity. Cinnamomum bark essential oil and test compounds described merit further study as potential pediculicides or ovicides for the control of P. h. capitis.
Vahabi, A; Shemshad, K; Sayyadi, M; Biglarian, A; Vahabi, B; Sayyad, S; Shemshad, M; Rafinejad, J
Human head lice, Pediculus (humanus) capitis, infest people worldwide and are most prevalent in children. The aim of this study was to determine the prevalence of head lice, in relation to socioeconomic status of the family and hygienic practices in the home. The prevalence rate was determined in 27 primary schools that had 810 students in Sanandaj city who were selected by multistage, systematic random sampling. A total of 38 students from all grades were infested with different rates of infestations. In addition, standard questionnaire recorded information about demographic features of each student were fulfilled. Children aged 10-11 years were the most frequently affected, there was a significant relationship between head louse infestation, family income and parents education level (α=5%). Pediculosis is a public health problem in many parts of the world. Pediculosis was found to be more prevalent among children of fathers with lower level of education and socioeconomic status, it is necessary to give health education to families in order to prevent pediculosis in this area.
Leonardi, M Soledad; Crespo, Enrique A; Raga, Juan Antonio; Fernández, Mercedes
Antarctophthirus microchir was originally described from Phocarctos hookeri on the basis of 1 female and 1 male only. We redescribe adults and describe, for the first time, the 3 nymphal stages from specimens collected from Otaria flavescens from Patagonia, using light and scanning electron microscopy. The present material can be distinguished from other Antarctophthirus species by the presence of a fringe of setae on the back of the head, only present in Antarctophthirus trichechi and Antarctophthirus callorhini. However, A. trichechi also possess a prominent proboscis with large hooks, and A. callorhini presents less abundant and nonuniform abdominal scales in shape and size. Other differential features of A. microchir are the pattern of ovoid and uniform scales and longitudinal grooves in the surface of spines. Nymphal stage 1 differs from 2 and 3 mainly by the absence of scales and thorax without ventral spines or hairs. Nymphal stages 2 and 3 may be distinguished by the disposition of the occipital apophyses. Antarctophthirus microchir has been reported from 5 sea lion species from both hemispheres. Considering the conservative morphology, and ecological and evolutionary features of sucking lice, we raise the question of whether A. microchir from different sea lion hosts may represent a complex of cryptic species.
Aznar, F J; Leonardi, M S; Berón Vera, B; Vales, D G; Ameghino, S; Raga, J A; Crespo, E A
We analysed population dynamics of the louse Antarctophthirus microchir in pups of the South American sea lion, Otaria flavescens, at the Punta León rookery (Argentina) over a period of 2 years. A total of 136 pups were aged and marked at the beginning of the lactation period ashore, then sampled for lice at different times within 30 days. Sampling was restricted to the chest and belly, two sites where lice were especially abundant. This concentration on ventral areas might protect lice from thermal stress in the austral summer. Infestation patterns in pups 3 days old suggested that the potential for transmission increased from first nymphs to adults. Population trends of each instar with pup age, based on standardised values of abundance, were conserved between years, reflecting the basic dynamics of recruitment and reproduction. However, trends based on log-transformed abundances varied significantly between years; apparently, environmental conditions affected growth of lice populations differently each year. Stage-based deterministic models for population growth of A. microchir suggested generation times from 18 to 23 days. Accordingly, only 2 lice generations might be produced before pups start going to the sea. Shortening the cycle to accommodate a third generation might be risky, whereas a 2-generation cycle might at least result in larger females producing higher numbers of viable offspring.
Beaucournu, J-C; Pisanu, B; Chapuis, J-L
A new sucking louse is recorded for the French Anopluran fauna, Enderleinellus tomiasis found on the introduced Sciurid Tamias sibiricus. This observation highlights the maintenance of parasites when introduced with their hosts and when their hosts settle into a novel environments. It suggests a common origin for two out of four populations of Siberian chipmunks examined. The authors describe the morphological criteria that allow the distinction between the two species of Enderleinellus and each infecting a sciurid host found in our country.
Full Text Available Head lice are endemic worldwide. Resistance to permethrin and doubts about the safety of pesticides promoted the use of physical therapies (wet-combing, dry-on suffocation. The aim of our study was to test the pediculicidal and ovicidal effects of one application of a silicon-oil complex composed of dimethiconol and castor oil. The study was a prospective cohort of 108 infested patients (11 males, 97 females; 58 children, 50 adults, in Sri-Lanka. Pediculicidal efficacy was evaluated as the percentage of patients free of live lice one hour after the application of the treatment and at day 1 (wet combing. Ovicidal efficacy was calculated as the proportion of subjects without larval stages at days 1 and 7 among subjects followed up all over the study. In normal conditions of use, in this open cohort, a pediculicidal effect of a dimethiconolcastor- oil lotion was shown one hour after application in 99/108 (91.7 % treated subjects and at day 1 in 86/99 (87 % subjects and an ovicidal effect at day 7 in 79/108 (73.2 % treated subjects. A second application of the same product was necessary to increase the cure rate to 79.6 % (86/108 at day 8. In our study, the second application of the same product was performed seven days later, but the best time for additional applications should be defined in further studies. However, the efficacy of this safe physical treatment was similar to that of chemical pediculicides (malathion, permethrin.
Full Text Available The authors described a new species Hoplopleura zentaensi sp. n. based on specimens collected on Andinomys edax Thomas, l902, from Sierra de Zenta, Jujuy province, Argentina. Descriptions involve the holotype female; three nymphal instar, external architecture of eggs and sites of oviposition, providing differences with its close relative Hoplopleura hirsuta Ferris, l916 and Hoplopleura oxymycteri Ferris, l921. Comments on distribution of these species on their hosts are presented and they are included in the “erratica” group.Describimos en esta contribución a Hoplopleura zentaensi sp. n., a partir de la hembra, sus tres estadios ninfales y las características coriónicas externas del huevo de la referida especie parásita de Andinomys edax Thomas, 1902 (Rodentia, Cricetidae, capturado en Sierra de Zenta, Jujuy, Argentina. Hoplopleura zentaensi sp. n. es afín a Hoplopleura hirsuta Ferris, 1916 y de Hoplopleura oxymycteri Ferris, 1921, integrando junto a estas especies el grupo “erratica”.
孟艳芬; 郭宪国; 门兴元; 吴滇
目的 测定云南省主要小型哺乳动物(小兽)宿主体表寄生的优势吸虱的生态位指数及其与小兽宿主的协同进化关系.方法 将云南省17县f市)30种小兽宿主作为30级资源序列,22种优势吸虱在小兽宿主体表的分布数量构成比作为其对各级资源的利用比例,测定生态位宽度、生态位相似性比例指数及其生态位重叠指数.应用SPSSl3.0统计软件对22种吸虱的生态位重叠指数原始数据矩阵进行系统聚类分析.绘制树形聚类图.结果 22种吸虱的生态位均较窄,其中最宽的太平洋甲胁虱(Hoplopleura pacifica)仅为0.1536.大多数吸虱生态位相似性比例指数较小(0.0005～0.4695).对生态位重叠矩阵进行系统聚类分析,当A=5.5时.将22种吸虱分为16个生态位重叠群. 结论 吸虱的宿主特异性高,不同种类吸虱对宿主的选择性表现为明显的生态位分离.吸虱与小兽宿主协同进化程度较高.
Ectoparasitos de roedores da região urbana de Belo Horizonte, MG: III. Indices pulicidianos, anoplurianos e acarianos em Rattus Norvegicus norvegicus Ectoparasites in rodents of the urban region of Belo Horizonte, MG: III. Fleas, anoplura and acari indices in Rattus norvegicus norvegicus
Pedro Marcos Linardi
Full Text Available Indices pulicidianos, anoplurianos e acarianos, globais e específicos foram determinados para os ectoparasitos de Rattus norvegicus norvegicus capturados em zona urbana de Belo Horizonte, Minas Gerais, Brasil, no período de junho de 1980 a setembro de 1982. Tendo-se em vista os valores limites ou críticos atribuídos aos índices pulicidianos, sobretudo ao índice "cheopis" e propostos por diversos autores como medida complementar de vigilância epidemiológica para peste bubônica, a comunidade de Belo Horizonte poderia ter estado exposta a esta infecção, uma vez que os índices globais anuais de 0,3 a 2,4 e a pulga prevalente foi Xenopsylla cheopis (99,2%, com os maiores índices coincidindo com o final da estação seca-fria. Em duas ocasiões, a comunidade poderia ter permanecido altamente exposta à infecção, já que os índices-limites tolerados foram suplantados: 8,8 (outubro 1980 e 6,2 (setembro 1982. Sugere-se que medidas profiláticas como anti-ratização e desinsetização sejam eficazmente aplicadas ao final da estação seca-fria, ou anteriormente à chegada das chuvas, sendo sucedidas pela desratização. Informações sobre índices anoplurianos e acarianos são importantes para que se possa, no exclusivas de roedoresThe total and specific indices of fleas, lice and mites were determined for ectoparasites on Rattus norvegicus norvegicus capture in urban areas of Belo Horizonte, Minas state, Brazil, from June 1980 to September 1982. In view of the limiting or critical values attributed to flea indices above all the [quot ]cheopis[quot ] index, proposed by several authors as a complementary measure for bubonic plague surveillance, the community of Belo Horizonte would have been exposed to this infection. The annual total indices ranged from 0.3 to 2.4 and the prevalent flea was Xenopsylla cheopis (99.2%, with the highest indices coinciding with the late dry-cool season. On two occasions, in this period, the community would have remained highly exposed to infection, since the index-limits were superseded: 8.8 (October 1980 and 6.2 (September 1982. It is suggested that preventive measures, such as protection against rat insecticide treatment may be efficiently applied in the late dry-cool season, or previous to the rainy season, before the elimination of rats. Reports on indices of lice and mites are important as they may establish index-limits for certain infections exclusive to rodents.
Among the many complex relationships between insects and microorganisms such as viruses, bacteria and parasites, some have resulted in the establishment of biological systems within which the insects act as a biological vector for infectious agents. It is therefore advisable to understand the identity and biology of these vectors in depth, in order to define procedures for epidemiological surveillance and anti-vector control. The following are successively reviewed in this article: Anoplura (lice), Siphonaptera (fleas), Heteroptera (bugs: Cimicidae, Triatoma, Belostomatidae), Psychodidae (sandflies), Simuliidae (black flies), Ceratopogonidae (biting midges), Culicidae (mosquitoes), Tabanidae (horseflies) and Muscidae (tsetse flies, stable flies and pupipara). The authors provide a rapid overview of the morphology, systematics, development cycle and bio-ecology of each of these groups of vectors. Finally, their medical and veterinary importance is briefly reviewed.
Full Text Available Background: Pediculus capitis (Anoplura: Pediculidae or head louse is an obligate ectoparasite transmitted mainly through physical contact. This study was conducted to survey the prevalence of head lice infestation rate and some risk factors in Primary School pupils, in Khajeh City East Azerbaijan Province, IranMethods: We selected 20 primary schools of Khajeh City during 2008 and 2009. Totally 500 pupils including 200 boys and 300 girls from all grade 1-5 were selected by multistage, systematic random sampling in rural areas of Khajeh City and were examined for lice. In addition, a standard questionnaire recorded information about demographic features of each pupil. Results were analyzed by SPSS software.Results: The total prevalence of head lice infestation in this study was 4.8%. and the prevalence rate was significantly higher in girls (6.66% than in boys (2%. Epidemiological factors such as: sex, school grade, family size, parent's education, type of house, hair washing (per week, number of using comb per day, were evaluated and results showed significant difference in head lice infestation and sex, school grade ,family size ,father education ,and type of house (P< 0.05.Conclusion: Pediculosis is a public health problem in many parts of the world, and due to the higher prevalence of pediculosis in crowded families, family by lower levels of father's education and socioeconomic status in our study and rural area, it is necessary to give health education for families to prevent of pediculosis in this area.
Lehnert, K.; Raga, J. A.; Siebert, U.
Parasites were collected from 107 harbour seals ( Phoca vitulina) found on the coasts of Schleswig-Holstein, Germany, between 1997 and 2000. The prevalence of the parasites and their associated pathology were investigated. Eight species of parasites, primarily nematodes, were identified from the examined organs: two anisakid nematodes ( Pseudoterranova decipiens (sensu lato) , Contracaecum osculatum (sensu lato)) from the stomach, Otostrongylus circumlitus (Crenosomatidae) and Parafilaroides gymnurus (Filaroididae) from the respiratory tract, one filarioid nematode ( Acanthocheilonema spirocauda) from the heart, two acanthocephalans, Corynosoma strumosum and C. semerme (Polymorphidae), from the intestine and an ectoparasite, Echinophthirius horridus (Anoplura, Insecta). Lungworm infection was the most prominent parasitological finding and secondary bacterial bronchopneumonia the most pathogenic lesion correlated with the parasites. Heavy nematode burdens in the respiratory tract were highly age-related and more frequent in young seals. A positive correlation was observed between high levels of pulmonary infection and severity of bronchopneumonia. The prevalence of lungworms in this study was higher than in seals that died during the 1988/1989 Phocine Distemper Virus epidemic, and the prevalence of acanthocephalans and heartworms had decreased compared to findings from the first die-off.
Durden, L A; Webb, J P
Both sexes of Abrocomaphthirus hoplai, new genus and new species (Anoplura: Polyplacidae), are described and illustrated. The endemic Chilean chinchilla rat Abrocoma bennetti Waterhouse (Rodentia: Abrocomidae) is the type host. The definition of the family Polyplacidae is amended to accommodate the new genus. Polyplax longa (Werneck), also referred to in the literature as Neohaematopinus longus Werneck, is reassigned to Abrocomaphthirus. The host of A. longus comb.n., is Abrocoma cinerea Thomas, another chinchilla rat, which inhabits parts of Argentina, Bolivia, Chile and Peru. The erection of Abrocomaphthirus as a distinct genus has important zoogeographical and evolutionary implications. The tenuous anomaly of P. longa being the sole native representative of the genus Polyplax in South America, possibly with African affinities, is now refuted. Instead, partial colonization of the neotropics by native species of both Polyplax and Neohaematopinus appears to have been relatively recent and from North America. The phylogenetic affinities of Abrocomaphthirus are unknown, but it appears to be closely related to other, more ancient, native South American polyplacid louse genera, such as Cuyana, Eulinognathus, Galeophthirus, and Lagidiophthirus. Arguments are presented in support of an ancestral zoogeographical link to Africa for these louse genera.
Julie M. Allen
Full Text Available Phylogenetic trees can reveal the origins of endosymbiotic lineages of bacteria and detect patterns of co-evolution with their hosts. Although taxon sampling can greatly affect phylogenetic and co-evolutionary inference, most hypotheses of endosymbiont relationships are based on few available bacterial sequences. Here we examined how different sampling strategies of Gammaproteobacteria sequences affect estimates of the number of endosymbiont lineages in parasitic sucking lice (Insecta: Phthirapatera: Anoplura. We estimated the number of louse endosymbiont lineages using both newly obtained and previously sequenced 16S rDNA bacterial sequences and more than 42,000 16S rDNA sequences from other Gammaproteobacteria. We also performed parametric and nonparametric bootstrapping experiments to examine the effects of phylogenetic error and uncertainty on these estimates. Sampling of 16S rDNA sequences affects the estimates of endosymbiont diversity in sucking lice until we reach a threshold of genetic diversity, the size of which depends on the sampling strategy. Sampling by maximizing the diversity of 16S rDNA sequences is more efficient than randomly sampling available 16S rDNA sequences. Although simulation results validate estimates of multiple endosymbiont lineages in sucking lice, the bootstrap results suggest that the precise number of endosymbiont origins is still uncertain.
Burgess, Mark N; Brunton, Elizabeth R; Burgess, Ian F
Nit combing and removal of head louse, Pediculus humanus capitis De Geer (Anoplura: Pediculidae), eggs is a task made more difficult because "nit combs" vary in efficiency. There is currently no evidence that the binding of the eggshell to the hair can be loosened chemically and few hair treatments improve the slip of the louse eggs along the hair. Ultrasound, applied through the teeth of a nit comb, may facilitate the flow of fluids into the gap between the hair shaft and the tube of fixative holding louse eggs in place to improve lubrication. Ultrasound alone had little effect to initiate sliding, requiring a force of 121.5 ± 23.8 millinewtons (mN) compared with 125.8 ± 18.0 mN without ultrasound, but once the egg started to move it made the process easier. In the presence of a conditioner-like creamy lotion, ultrasound reduced the Peak force required to start movement to 24.3 ± 8.8 mN from 50.4 ± 13.0 mN without ultrasound. In contrast, some head louse treatments made removal of eggs more difficult, requiring approximately twice the Peak force to initiate movement compared with dry hair in the absence of ultrasound. However, following application of ultrasound, the forces required to initiate movement increased for an essential oil product, remained the same for isopropyl myristate and cyclomethicone, and halved for 4% dimeticone lotion. Fixing the nit comb at an estimated angle of 16.5° to the direction of pull gave an optimum effect to improve the removal process when a suitable lubricant was used.
Asiry, Khalid A; Fetoh, Badr El-Sabah A
Ectoparasitic arthropods are a diverse element of the Saudi fauna. Due to this, a survey of ectoparasites associated with rodents was conducted as a preliminary study in five districts of Hail region of northern Saudi Arabia for the first time. Ectoparasites extracted from 750 rodents were sampled and identified by recording their frequency of appearance. Results revealed that 1,287 ectoparasites infested 316 of the captured rodent hosts. These ectoparasites parasitized on four species of rodents including three species of rats Rattus rattus rattus, Rattus rattus frugivorus, and Rattus rattus alexandrinus and one species of mouse Acomys dimidiatus (Rodentia: Muridae). The ectoparasites belong to four different groups: ticks, fleas, lice, and mites. Ticks were the highest in the number, while fleas were the lowest among all the extracted ectoparasite groups. The collected ectoparasitic arthropods consisted of seven species. Ticks were of two species: Rhipicephalus turanicus and Rhipicephalus sanguineus (Acari: Ixodidae), fleas were of two species: Xenopsylla cheopis and Xenopsyllus conformis mycerini (Siphonaptera: Pulicidae), lice was a single species: Polyplax serrata (Anoplura: Hoplopleuridae), and mites were of two species: Laelaps nuttali and Laelaps echidninus (Mesostigmata: Laelapidae). The findings of the study showed that the intensity of infestation was varied between rodent host sexes, wherein females had the highest rate of parasitic infestation, and the parasitic index of appearance was very high for one group of parasites (i.e., ticks). The parasitic prevalence was 42.13 % on rodents, and mites were the most prevalent parasite species. Overall, this study was carried out to establish baseline data for ectoparasite-infested rodents in Hail region, Saudi Arabia, and may help for appropriate planning to control zoonotic diseases in this area.
董文鸽; 郭宪国; 门兴元; 钱体军; 吴滇
An investigation of sucking lice on the body surface of small mammals was carried out in the surrounding areas of Erhai Lake in Dali, Yunnan from 2003 to 2004.From investigation sites, 3 303 small mammal hosts were captured and identified into 7families, 15 genera and 21 species in 4 orders (Rodentia, Insectivora, Scandentia and Carnivora), while 14 635 individuals of sucking lice collected from the body surface of the small mammal hosts are identified into 5 families, 6 genera and 21 species in the Order Anoplura. The sites stand alongside three cordilleras surrounding the Erhai Lake, namely Eastern Wuliang Mountain, Southern Ailao Mountain and Western Cangshan Mountain.The three confined oriented areas are different landscapes within the same zone where the longitude, latitude, altitude and fauna are homologous but isolated by Erhai Lake as inartificial barrier. The aim of this study was to recognize features of the species diversity,abundance, community structure, similarity and distribution of sucking lice in different landscapes within the same zone. The results showed the species diversity of sucking lice was very low with a very simple community structure. The distribution of sucking lice and their corresponding hosts are quite uneven among different oriented areas and this may imply that ecological environment influences the species composition and distribution of sucking li ce and their corresponding hosts. A certain species of hosts usually have theirfixed louse species. The similarity of sucking louse communities is highly consistent with the affinity of small mammal hosts in taxonomy. Species of sucking lice on the same small mam mal host in different oriented areas of Erhai Lake are homologous. The results stronglysuggest a close relationship of co-evolution between sucking lice and their hosts.
Leonardi, Maria Soledad; Aznar, F Javier; Crespo, Enrique A; Lazzari, Claudio R
Despite the incredible success of insects in colonizing almost every habitat, they remain virtually absent in one major environment--the open sea. A variety of hypotheses have been raised to explain why just a few insect species are present in the ocean, but none of them appears to be fully explanatory. Lice belonging to the family Echinophthiriidae are ectoparasites on different species of pinnipeds and river otters, i.e. they have amphibious hosts, who regularly perform long excursions into the open sea reaching depths of hundreds of meters (thousands of feets). Consequently, lice must be able to support not only changes in their surrounding media, but also extreme variations in hydrostatic pressure as well as breathing in a low oxygen atmosphere. In order to shed some light on the way lice can survive during the diving excursions of their hosts, we have performed a series of experiments to test the survival capability of different instars of Antarctophthirus microchir (Phthiraptera: Anoplura) from South American sea lions Otaria flavescens, when submerged into seawater. These experiments were aimed at analyzing: (a) immersion tolerance along the louse life; (b) lice's ability to obtain oxygen from seawater; (c) physiological responses and mechanisms involved in survival underwater. Our experiments showed that the forms present in non-diving pups--i.e. eggs and first-instar nymphs--were unable to tolerate immersion in water, while following instars and adults, all usually found in diving hosts, supported it very well. Furthermore, as long as the level of oxygen dissolved in water was higher, the lice survival capability underwater increased, and the recovery period after returning to air declined. These results are discussed in relation to host ecology, host exploitation and lice functional morphology.
Leonardi, M S; Crespo, E A; Vales, D G; Feijoo, M; Raga, J A; Aznar, F J
Among Anoplura, the family Echinophthiriidae includes species that infest pinnipeds and otters. Previous evidence obtained from pinnipeds infested by echinophthiriids, specifically from seals, indicates that flippers are the preferred infestation sites, while lice from fur seals select areas in the pelage. We studied habitat selection of Antarctophthirus microchir on South American sea lion pups (Otaria flavescens Shaw, 1800) from Patagonia, Argentina, during the austral summer of 2009. We found a clear pattern of habitat selection: eggs are laid on the dorsal surface; nymphs 1 hatch there and then migrate to the belly, where they develop into adults and copulate; and then ovigerous females return to the dorsal surface. On the one hand, nymphs 1 are characterised by their low locomotory ability; therefore, the fact that they migrate as soon as they hatch suggests a clear pressure leading to microhabitat restriction. On the other hand, the described pattern of microhabitat selection seems to respond to the physiological requirements of each stage, which vary according to the physiological process considered, e.g. oviposition, morphogenesis, hatching and development. Accordingly, it appears that A. microchir would prefer the host's ventral area for development and copulation and the dorsal area for oviposition. However, the causes of this pattern are not clear, and many factors could be involved. Considering that sea lion pups periodically soak at high tides, and that prolonged immersion and very high humidity are known to be lethal for lice eggs, selecting the dorsal area would be advantageous for oviposition because it dries much faster. Furthermore, because humidity should be retained for longer periods on the ventral surface of the pup, wetter conditions on the sea lion would prevent desiccation of the nymphs in the very arid environment where O. flavescens breeds.
Laurie R. Godfrey
Full Text Available The mouse lemur Microcebus griseorufus at the Beza Mahafaly Special Reserve and general vicinity in southwestern Madagascar were surveyed for ectoparasites as part of a year-long behavioral and ecological study. Of 249 individual mouse lemurs examined, 74 were positively identified as hosting ectoparasites. Ticks from 20 mouse lemurs and lice in a subset of two individuals captured in a 90 ha gallery forest (Parcel 1 were preserved in 70 % ethanol or EDTA and stored for analysis and for identification. Two species of Haemaphysalis ticks are represented in the sample, H. lemuris and possibly H. simplex, a tick previously reported on tenrecs, birds and rats. Synchronous development of ticks may pose a risk for vector - borne diseases at the reserve especially during the dry season. The louse represented in the sample belongs to the order Anoplura (sucking lice, and resembles Lemurpediculus verruculosus, previously reported on Microcebus rufus in eastern Madagascar. RÉSUMÉUn inventaire d’ectoparasites a été réalisé dans le cadre d’une étude de longue durée portant sur le comportement et l’écologie de Microcebus griseorufus dans trois parcelles forestières de Beza Mahafaly et ses environs. Sur les 249 microcèbes observés, 74 individus étaient infestés d’ectoparasites. La majorité de ces individus infestés, soit 97,3 %, provenait de la parcelle 1 de la réserve. Des poux et des tiques recensés sur ces animaux ont été immédiatement retirés puis préservés dans l’éthanol 70 % ou dans l’EDTA à des fins d’analyse et d’identification. Deux espèces de tiques ont été identifiées, Haemaphysalis lemuris et probablement H. simplex, cette dernière n’était préalablement connue que pour infester les tenrecs, les oiseaux et les rats.Les rongeurs jouent un rôle significatif en tant qu’hôtes pour près de la moitié des larves et des nymphes d’ixodes de tiques du monde, y compris H. simplex. Les rats sont connus