Prevalence Of Lice Research Articles

Prevalence of Myrsidea salimalii (Amblycera: Phthiraptera) on striated babblers (Turdoides earlei) (Timaliidae: Passeriformes: Aves)

Survey of literature showed that the population characteristics of the phthirapterans parasitizing striated babblers deserved investigation. Hence, 30 birds were examined during 2007-2009 in district Rampur U.P. The prevalence of an amblyceran louse, Myrsidea salimalii on striated babblers was 40%. The mean intensity of infestation and the sample mean abundance were 33.5 and 13.4, respectively. The variance to mean ratio of the population exceeded unity (36.24). The frequency distribution pattern of the louse was aggregated but did not conform to the negative binomial model. Females outnumbered the males in natural condition (M:F-1:1.4) while the nymphal population had an edge over adult population (A:N-1:1.3).

The Prevalence and Intensity of Louse (Phthiraptera, Mallophaga) and Tick (Acarina: Ixodidae) Infestation of Birds in South African Grasslands

The Prevalence and Intensity of Louse (Phthiraptera, Mallophaga) and Tick (Acarina: Ixodidae) Infestation of Birds in South African Grasslands A total of 270 birds represented by 12 species were examined for the presence of lice and ticks. Birds were collected in South African grasslands. Extensity of louse and tick infestation ranged from 10% to 80% and from 3% to 33% respectively. Average number of lice per host species ranged from 1 to 15, while average number of ticks per host species ranged from 1 to 5. Only single specimens (0.4%) were heavily parasited by lice and ticks respectively. Lice infested birds more often during the dry season, while ticks infested birds mainly during the rain season.

Evidence of farm-induced parasite infestations on wild juvenile salmon in multiple regions of coastal British Columbia, Canada

Salmon farms are spatially concentrated reservoirs of fish host populations that can disrupt natural salmonid host–parasite dynamics. Sea lice frequently infect farm salmon and parasitize sympatric wild juvenile salmonids, with negative impacts on survival in Europe and Pacific Canada. We examined louse parasitism of wild juvenile chum salmon ( Oncorhynchus keta ) and pink salmon ( Oncorhynchus gorbuscha ) from three salmon farming regions in British Columbia (Finlayson, Broughton Archipelago, and Georgia Strait). We compared sites of low and high exposure to farms and included an area without farms (Bella Bella) to assess baseline infection levels. Louse prevalence and abundance were lowest and most similar to natural baseline levels at low-exposure sites and highest at high-exposure sites in all farm regions. A significantly greater proportion of the lice were Lepeophtheirus salmonis at high-exposure sites. Exposure to salmon farms was the only consistently significant factor to explain the variation in prevalence data, with a secondary role played by salinity. Our results support the hypothesis that salmon farms are a major source of sea lice on juvenile wild salmon in salmon farming regions and underscore the importance of using management techniques that mitigate threats to wild stocks.

Ringing Procedure Can Reduce the Burden of Feather Lice in Barn SwallowsHirundo rustica

Chewing lice (Insecta: Phthiraptera) are the most widespread obligate ectoparasites living in the plumage of birds. Lice have to cope with unusual mechanical effects during ringing, and they could fall off their hosts. We assumed that trapping birds in nets, taking measurements and estimating condition could reduce their louse burdens. Lousiness affects life expectancy and reproductive success, so if ringing causes remarkable louse loss, the fitness of ringed birds could be altered. Lice are usually collected at ringing sites, and ringing precedes parasite sampling. This may therefore lead to an underestimation of louse prevalence and intensity. Here we tested whether ringing reduces the louse burden. We allocated Barn Swallows Hirundo rustica in the breeding season to two experimental groups — the birds were subject to either a standard ringing procedure (recording biometry, fat and other condition scores, feather hole counts), or a reduced one (only feather hole counts). We used feather holes (traces of louse chewing) as a measure of louse loads. Holes were recounted after a month. Significantly more new holes appeared in the reduced ringing procedure group, indicating tat the usual ringing procedures effectively reduce louse loads. We believe this is the first evidence that bird ringing affects ectoparasite infestations.

Risk of ectoparasitism and genetic diversity in a wild lesser kestrel population

Parasites and infectious diseases are major determinants of population dynamics and adaptive processes, imposing fitness costs to their hosts and promoting genetic variation in natural populations. In the present study, we evaluate the role of individual genetic diversity on risk of parasitism by feather lice Degeeriella rufa in a wild lesser kestrel population (Falco naumanni). Genetic diversity at 11 microsatellite loci was associated with risk of parasitism by feather lice, with more heterozygous individuals being less likely to be parasitized, and this effect was statistically independent of other nongenetic parameters (colony size, sex, location, and year) which were also associated with lice prevalence. This relationship was nonlinear, with low and consistent prevalences among individuals showing high levels of genetic diversity that increased markedly at low levels of individual heterozygosity. This result appeared to reflect a genome-wide effect, with no single locus contributing disproportionably to the observed effect. Thus, overall genetic variation, rather than linkage of markers to genes experiencing single-locus heterosis, seems to be the underlying mechanism determining the association between risk of parasitism and individual genetic diversity in the study host-parasite system. However, feather lice burden was not affected by individual heterozygosity; what suggest that differences in susceptibility, rather than variation in defences once the parasite has been established, may shape the observed pattern. Overall, our results highlight the role of individual genetic diversity on risk of parasitism in wild populations, what has both important evolutionary implications and major consequences for conservation research on the light of emerging infectious diseases that may endanger genetically depauperated populations.

Patterns in the distribution of avian lice (Phthiraptera: Amblycera, Ischnocera) living on the great grey shrike Lanius excubitor

The lice parasite community of great grey shrike Lanius excubitor collected in NE Slovakia during 1962-1974 was quantitatively studied. Lice fauna comprised of three species: Docophorulus coarctatus, Bruelia cruciata (Ischnocera) and Lanicanthus camelinus (Amblycera). All these species were previously indicated as characteristic for that host. The prevalence of lice was high--lice were recovered from 96.3% (n=108) host specimens. Distributions of lice on the great grey shrike, a strictly territorial bird, were aggregated, indicating substantial variation in the abundance of lice. Sex ratios of lice were biased towards females and not correlated with the subpopulation size of lice on individual hosts.

Ectoparasites of northern fulmars Fulmarus glacialis (Procellariiformes: Procellariidae) from the Canadian Arctic

We studied the prevalence and intensity of infestation of ectoparasites on northern fulmars (Fulmarus glacialis L.) from a breeding colony in Arctic Canada in June–August 2003. No fleas or ticks were found on any fulmars, but three species of chewing lice (Phthiraptera) were recorded: Ischnocera: Perineus nigrolimbatus (Giebel 1874), Ischnocera: Saemundssonia occidentalis (Kellogg 1896), and Amblycera: Ancistrona vagelli (Fabricius 1787). Non-breeding birds had a higher prevalence of lice than breeding birds, and prevalence varied markedly among louse species. Our study is an important baseline for the occurrence of ectoparasites on northern fulmars in the high Arctic, a region undergoing extensive environmental change due to global warming, and an area where parasites are expected to extend ranges or increase in prevalence under changing annual temperature regimes.

The prevalence of lice on sheep and control practices in South Australia.

To assess the prevalence of infestations of lice in sheep flocks and to survey control practices for lice in South Australia A total of 201 managers of sheep flocks, 75 chosen randomly from the high rainfall zone (HR), 76 from the cereal sheep zone (CS) and 50 from the pastoral zone (PA), were surveyed by telephone interview. Interviews were conducted between May 19 and May 25, 1999, according to a set questionnaire. Information was collected on presence of lice at last shearing, control practices for lice, factors important for gaining good effect from chemical treatments, sources of information on control practices and property details. Survey results were analysed by agricultural region. The apparent state prevalence of flocks infested with lice was 21%, with 13% infested in the HR, 21% in the CS and 25% in the PA. Ninety one percent of managers claimed to take precautions to prevent the introduction of lice and 91% routinely checked their flocks for lice. Seventy eight percent treated their sheep for lice annually and 85% had treated within the last 12 months. Of those treating in the last year, 69% had used a backline application, 16% had used a shower dip and 17% had used plunge dipping. Only 4% of producers used a long wool treatment. Synthetic pyrethroid (SP) based products were used by 50% of producers who used backline treatments in the preceding 12 months, compared to 42% and 8% for insect growth regulator and organophosphorous (OP) based products, respectively. Only 34% of managers identified SP-based products as having potential resistance problems. Of those producers who used shower or plunge dips in the last 12 months, 75% used an OP based product. Rural newspapers and magazines were by far the most commonly noted source of information for the control of lice on sheep.

Chewing Louse Distributions on Two Neotropical Thrush Species

Abstract We sampled lice from 2 species of Neotropical thrushes, Turdus assimilis, the white-throated robin, and T. grayi, the clay-colored robin, to document the prevalence, intensity, abundance, and species richness on each host. Sampling was conducted in 1999 in the Coto Brus Valley of southern Costa Rica using a modified dust-ruffling technique. The prevalence of lice was high—lice were recovered from 93% (n = 14) of T. grayi and 86% (n = 22) of T. assimilis individuals sampled. Observed prevalence and generic-level louse diversity were similar to those reported for T. migratorius, the American robin, in Newfoundland, Canada, although T. assimilis and T. grayi tended to have higher proportions of lice belonging to the suborder Amblycera. Turdus grayi hosted marginally more louse species (mean = 1.6, SD = 0.8) and had marginally higher louse abundance (mean = 33.9, SD = 27.9) than T. assimilis (mean = 1.1, SD = 0.6 and mean = 16.5, SD = 17.3, respectively), although T. grayi and T. assimilis are closel...

The prevalence of lice and fleas of chicken in Bokkos local government area of plateau State, Nigeria

The prevalence of lice and fleas of chicken in Bokkos local government area of plateau State, Nigeria

Variation in the Level of Grain Defect Light Flecks and Spots on Cattle Hides

The occurrence of hide damage light flecks and spots was determined on tanned hides from 28 herds during a period of 8 to 12 months. Light flecks and spots are described as small areas of grain loss up to 3 mm in diameter that are seen on dyed crust cattle leather. Damage was found on 75.8% of all hides. The neck and shoulders were the anatomical region with the highest prevalence of damage. Sixty-eight per cent of all hides had light flecks and spots in this region. The forelimbs and dewlap were the anatomical region with the second highest occurrence with a prevalence of 39.1%. This distribution corresponded to the known distribution of lice in cattle. No significant differences were observed in age, sex, prevalence of lice in the herd assessed in March or infestations with different lice species. The frequency of light flecks and spots varied significantly during the year. The frequency was highest in the late winter and early spring, decreased significantly during the summer and was lowest in the autumn. This variation supported the importance of lice in the development of light flecks and spots and suggested a relatively long healing period for the damages induced by lice.

Prevalence of lice on dairy cattle in England and the bordering counties of Wales

A postal questionnaire was used to collect information on the prevalence of lice on cattle on a random sample of dairy farms in England and the bordering counties of Wales....

Prevalence and clustering of louse infestation in Queensland sheep flocks

Information provided by wool growers in Queensland, Australia between 1995 and 1997 was used to assess the prevalence and spatial distribution of louse ( Bovicola ovis) infestation in sheep flocks. The estimated prevalence of louse-infested flocks was 40% (95% confidence interval, 35–46%). Although the prevalence of infestation was higher in western regions (41–50%) compared to the south region of Queensland (31%), the difference was not statistically significant ( P > 0.05). Significant ( P = 0.02) clustering of infested flocks was detected in the south region where two foci were apparent. We conclude that Queensland sheep flocks have a moderate prevalence of louse infestation, and that clustering of infestation is not strong. The control of lice is an industry-wide issue that needs to be addressed by most wool growers in Queensland.

Simultaneous-equation bias adjustment of the binary regression coefficients of farm-level risk factors for lice ( Bovicola ovis) in sheep flocks in Queensland, Australia

Simultaneous-equation bias adjustment of the binary regression coefficients of farm-level risk factors for lice ( Bovicola ovis) in Queensland sheep flocks was undertaken to control for the interdependency between lice prevalence and their control. Using probit analysis and a two-stage estimation procedure, the correlation between the error terms and the explanatory variables was removed — resulting in coefficient estimates that were asymptotically unbiased. The data for the study were derived from a cross-sectional study of 342 Queensland farms obtained by postal questionnaire in February 1993. The outcome variable of interest was the frequency of flock lice infestation which was classified into two groups: nil versus lice each of the last 3 years. Probit analysis was used to estimate the regression coefficients of the binary explanatory variables chosen for examination: ability to maintain sheep-proof boundary fences and method of post-shearing lice treatment (backliner or dip). Removal of the simultaneous-equation bias (SEB) importantly reduced the calculated probability of a farm being infested with lice. No change in associated probabilities for farms using backliner or relative to the fencing practice occurred when the SEB was removed. A table is presented that shows all possible combinations of the explanatory variables and can be used to assess the probability of lice infestation.

Louse Loads of Pied Flycatchers: Effects of Host's Sex, Age, Condition and Relatedness

This study documents patterns of variation in abundance and prevalence of Docophorulus capillatus (Insecta: Ischnocera, Philopteridae) on the crown feathers of Pied Flycatchers Ficedula hypoleuca in relation to host sex, age, survival, physical condition, expression of secondary sexual traits and genetic relatedness. Louse populations were relatively stable over a 3-year period, with low prevalences in the range 15-30%. Pair mates had similar louse loads, indicating the possible role of direct contact between birds as an agent of louse dispersal. Females were consistently more heavily and frequently infested than males at almost all ages. Louse prevalence and abundance tended to decrease or oscillate with advancing age, with a major peak late in life which was much more marked in females; no surviving birds older than five years had lice on their crown. Although bird condition in a given year seemed not to be affected by louse infestations, there were decreases in individual condition between years which were linked to increases in louse infestations in females. Individual birds of both sexes had similar louse loads in successive years. Within-family resemblance in louse loads was only detected between mothers and daughters and, to a lesser extent, between females and their male offspring. We discuss different hypotheses to account for intersexual differences in parasite infestation.

The prevalence of lice (Bovicola ovis) infested sheep flocks in Western Australia (1987–1993)

The proportion of wool bale brands with a positive test for sheep lice in baled wool decreased from 29.5% in 1987/88 to 23.2% in 1990/91 before increasing to 38.2% in 1992/93. Changes in the proportion of wool bale brands with a positive test for lice were highly correlated with changes in the Wool Market Price Indicator. The increase in the proportion of positive lice tests since 1990/91 was associated with an increase in failures to eradicate lice from flocks. These failures were partly a consequence of the reduced use of lousicidal treatments, the development of resistance to synthetic pyrethroid chemicals and an increase in the transmission of lice between flocks.

The prevalence of head louse infestation among urban and rural children in Korea

The prevalence of head louse (Pediculus hamanus var. capitis) infestation in preschool and school children in 9 urban and 8 rural areas of Korea, was investigated. Of 11,865 children who were examined for head lice and nits, 2,900(24.4%) were found infested. The over-all infestation rate of rural children, 58.9%, was higher than that of urban children, 14.4%. There also existed significant differences in the infestation rate among various regions of urban as well as rural areas. Females were more infested than males. But there was no differences in infestation rate in either sex of preschool age. The infestation rate increased gradually from the age of 6, reached a plateau between 9-12 years of age and thereafter slowly decreased. The infestation rate of an orphanage children was higher than that of general childhood population. Health education and mass-delousing attempt are urgently required to lower such a high prevalence of head louse infestation in Korea.

Head louse infestation among school children in Sanbuk-myon, Mungyong-gun, Kyongsangbuk-do (1985)

In order to know the prevalence of head louse among the school children in rural area, we visited 3 primary schools and a kindergarten in Sanbuk-myon, Mungyong-gun, Kyongsangbuk-do in July 1985, and examined the children to identify the adult worms of head louse and/or its nits on the hair. The overall infestation rate was 91.9% among 420 children examined, and there was a difference between schools (P< 0.05). the school girls' rate, 96.1% was higher than that of bods' 88.9%(P< 0.05). By grade, the rate of infant school was 88.5% and 1st to 6th grade were 100, 100, 95.8, 90.4 89.7, 80.0% respectively. Above result indicates that the head louse is an important health problem in this community. Therefore, the chemotherapy and the effort to improve the hygiene are necessary in this community by physicians, teachers and health administrators.

Carbaryl against lice

Carbaryl is a broad-spectrum insecticide effective against lice, with little toxicity to man. It is available as a lotion (Carylderm) and a shampoo (Carylderm; New Suleo; Derbac). Carbaryl was developed because lice began to show resistance to organochlorine insecticides such as DDT and gamma benzene hexachloride (Quellada; Lorexane). It was introduced in the late 1960s particularly for the control of head lice; it is less effective against mites, and not recommended for scabies. Together with the organophosphate malathion (Prioderm lotion and shampoo; Derbac Liquid), it has contributed to the substantial reduction in the prevalence of lice in this country; in a recent survey of 12,000 school children in England, 9% had head lice.1 Several pyrethroid compounds are also used for head lice, such as Parlice which contains bioallethrin and piperonyl butoxide, but only as prophylactic.