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Query: UMLS:C0851341 (infestation)
 10,121 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Red veld rats (Aethomys chrysophilus) and bushveld gerbils (Tatera leucogaster) were trapped at monthly intervals, when possible, over a 2-year period, in the southern Kruger National Park, Mpumalanga Province. Forty-six specimens of each species were caught, euthenased and microscopically examined for fleas, lice, ticks and mites. Clear differences existed between the two rodent hosts in infestation intensity and also parasite species. The flea, Xenopsylla brasiliensis, commonly and exclusively utilized red veld rats, whereas Xenopsylla frayi was common and specific to bushveld gerbils. T. leucogaster were commonly infested with the lice Hoplopleura biseriata and Polyplax biseriata, while only a single A. chrysophilus hosted the louse, Hoplopleura patersoni. Red veld rats harboured small numbers of the immature stages of Haemaphysalis leachi/spinulosa and relatively large numbers of Rhipicephalus simus. The larvae of R. simus were irregularly collected from February to September and the nymphs from March to November. Bushveld gerbils hosted fewer ticks than did the rats, with a single specimen of H. leachi/spinulosa and low numbers of immature Hyalomma truncatum, the latter erratically present from June to October. Miles were abundant on both rodent hosts, A. chrysophilus hosting 13 species in six families, and T. leucogaster hosting 12 species representing seven families, with clear differences in mite assemblages between the two rodents. As the rats and gerbils were collected from the same trap lines at the same times, the differences in species composition and infestation intensity of their parasites, suggest that immunological behavioural or other segregating mechanisms are in operation to maintain discrete parasite assemblages.
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PMID:The comparative host status of red veld rats (Aethomys chrysophilus) and bushveld gerbils (Tatera leucogaster) for epifaunal arthropods in the southern Kruger National Park, South Africa. 885 64

In two homeless men aged 38 and 32 years, who suffered from itching, infestation with body lice (Pediculus humanus var. corporis, a.k.a. clothes lice) was diagnosed. This infestation is rare in the Netherlands. In 1993 and 1994 and infection with body lice was registered 41 times in 31 patients at the clinic for homeless of the Community Health Service of Utrecht. The body louse can be seen by the naked eye. Treatment is by hygienic measures, pediculicides if necessary, and by prevention. Important to recognize is that P. humanus can be the vector of trench fever (Bartonella quintana), relapsing fever and typhus.
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PMID:[Back again: the clothes louse (Pediculus humanus var. corporis)]. 892 69

The efficacy of doramectin, a novel avermectin, was assessed against both naturally-acquired and experimentally-induced infections of gastrointestinal roundworms, lungworms, kidneyworms, lice and mites in studies conducted across North America and Europe. Twenty-two studies evaluated efficacy against fourth larval and adult stages of the following nematode species: Hyostrongylus rubidus, Ascaris suum, Strongyloides ransomi, Oesophagostomum dentatum, Oesophagostomum quadrispinulatum, Trichuris suis, Metastrongylus spp. and Stephanurus dentatus. Efficacy was evaluated against the louse Haematopinus suis in six studies and against the mite Sarcoptes scabiei in four studies. A common study design was employed for each study type. In all studies, animals were allotted at random to a doramectin-treated or a saline-treated group. The doramectin-treated group received the drug at 300 micrograms kg-1 by intramuscular injection while the saline-treated group received saline by the same route. In the nematode studies, worm burdens were determined for each animal at slaughter 14-16 days after treatment. Efficacy against each nematode species/stage was assessed on the basis of percentage reduction in geometric mean worm burden in doramectin-treated animals compared with saline-treated controls. In louse and mite studies, counts were made immediately before treatment and then at weekly intervals for four weeks. Efficacy was based on a comparison of the level of infestation on the day of treatment with that on the last day of test. Data from individual studies were combined to derive a single estimate of efficacy against each of the parasite species represented in the study program. Efficacy of doramectin was 98% or greater against all nematode species except T. suis for which the efficacy was 87% and 79% against adult and fourth larval stage, respectively. Efficacy was 100% against both Haematopinus suis and Sarcoptes scabiei.
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PMID:Activity of doramectin against nematode and arthropod parasites of swine. 898 59

The obligation to prove pediculicides efficacy is relatively recent. Two tests are required by the authorities to obtain registration. In vitro test (with Pediculus humanus humanus) is the first step to evaluate the efficacy of new molecules. It must be followed by bio-clinical tests (with infested children by Pediculus humanus capitis). For those tests the authors advise to respect the "three units rule": unit of time (no more than 2 days for the test), unit of place (same environment) and unit of action (only one team to apply and evaluate products). This type of tests is possible only in countries with high infestation (at least 60% of prevalence). A third test is consequently advised, the ex vivo test using Pediculus humanus capitis obtained from infested children in France. This test can be useful also to re-evaluate current products in the light of increased resistance or decreased sensitivity of the lice. Finally some other tests can be advised to prove some other activities like remanence or repellent properties or to estimated lice resistance.
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PMID:[Tests for evaluating the effectiveness of pediculicides: importance and limitations]. 899 12

Groups of ten louse-naive lambs were infested with one, ten or 100 female Bovicola ovis and killed 84 days later when an examination of their pelts was made to detect cockle. In a second experiment groups of ten lambs were infested with ten or 100 female B. ovis and groups of lambs were killed every fortnight up to 84 days post-infestation. The pelts were examined in order to detect the earliest time at which cockle could be detected following a louse infestation. Cockle is a nodular condition of the skin arising in response to infestation with B. ovis and is possibly a hypersensitivity on the part of some sheep to antigens of louse origin. In the first experiment cockle did not develop in lambs that had remained louse free or which had been initially infested with one louse. However, five of ten lambs that had been infested with ten lice and all lambs that had been infested with 100 lice developed cockle. In general cockle severity was positively related to the size of the terminal louse population. Group mean louse counts only slightly exceeded the initial infestation in the lambs infested with either ten or 100 lice, and were less than the initial infestation in lambs given only one louse. In the second experiment cockle was first seen 54 days post-infestation, but only in sheep infested initially with 100 lice.
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PMID:The development of cockle, a sheep pelt defect, in relation to size of infestation and time of exposure to Bovicola ovis, the sheep-biting louse. 901 73

Hair casts are often misdiagnosed because of their close resemblance to nits from an infestation with pediculosis capitis. In their clinical presentation both of these disorders may appear to have white keratinous material adherent to hair shafts and can look very similar. Microscopic examination provides the definitive and correct diagnosis. We report a case of hair casts, also referred to as pseudonits.
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PMID:Hair casts: a case of pseudonits. 940 44

The protective efficacy of doramectin against sucking lice was evaluated under natural challenge conditions in Canada. Two studies with a similar experimental design were conducted in sequence. In each study, two groups of louse-free cattle received either doramectin at a dose of 200 micrograms/kg by subcutaneous injection or no treatment and were then mixed with louse-infested animals for the winter housing period. All animals were examined for lice on treatment day and thereafter at weekly intervals for 13 weeks. In the preliminary study, acquisition of infestation in the face of a very mild challenge of Linognathus vituli was delayed by a mean period of 49 days in doramectin-treated animals compared with untreated controls. The difference in the delay between the groups was significant (P < or = 0.04). In the second study, test animals experienced a moderate challenge of a mixed infestation of L. vituli and Solenopotes capillatus. Acquisition of infestation was delayed by a mean period of 25.6 days in doramectin-treated animals compared with controls, the difference between the two groups being highly significant (P < or = 0.0001). These studies confirmed the protective efficacy of doramectin against sucking lice under natural challenge conditions showing that infestation is prevented for a period of about 4 weeks following administration of the drug at its recommended dose.
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PMID:Evaluation of the protective efficacy of doramectin against sucking lice of cattle. 940 80

From the 1950s to 1974 R.prowazekii infection was registered on the territory of Russia, mainly in the form of Brill's disease, represented by some individual cases in the focus of infection. In 0.25% of all of cases rickettsiosis was linked with group outbreaks of the family character (14 events), reflecting the epidemic form of the disease. From 1974 until the present time the correlation between the sources of infection and the infestation of the population with lice dropped below the critical level, ensuring the transmission of the infective agent among the susceptible human population. This led to the steady disappearance of rickettsiosis (a decrease in the number of rickettsiosis cases from several thousand in the 60s to less than 100 in 1991) due to natural demographic processes. After the disintegration of the USSR, the migration of the population from some regions, especially from those where military conflicts took place, did not affect this process. The return of the epidemic form of rickettsiosis in Russia is impossible.
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PMID:[A prognostic assessment of louse-borne typhus (Rickettsia prowazekii infection) in Russia]. 946 Aug 61

In order to contribute to a better knowledge of the pediculosis capitis and scabies during March-December 1995, 1122 primary schoolchildren under 14 years of age in the city-port of Antofagasta in northern Chile (20 degrees South lat.), were examined. A total of 285 (25.4%) were found to be infested with Pediculus humanus capitis and only 20 (1.8%) with Sarcoptes scabiei. In general the rates of infestation to both ectoparasitic diseases were higher in groups of younger schoolchildren, also higher in women than in men and in those groups with high indexes of crowding and ignorance of the transmission mechanism of pediculosis capitis and scabies.
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PMID:[Epidemiological study of pediculosis capitis and scabies in schoolchildren from Antofagasta, Chile, 1995]. 949 38

This study examined the relationships among louse density, pruritus and dermal response to insect antigens in sheep infested with Bovicola ovis. Polypay and Columbia ewes were allocated to two groups, infested and naive, and louse densities and pruritus were monitored for 15 months. Ten months after the initial infestation, all sheep were tested for hypersensitivity on the midside and ears by intradermal injection of soluble extracts of B. ovis, Stomoxys calcitrans and Musca autumnalis. The areas of skin reactions were measured at 20 min, 1, 3 and 24 h after injection and skin thickness was measured at 24 h. Louse densities on Polypays were approximately 10 times greater than on Columbias, and pruritus was correlated with louse numbers at most inspections. Most pruritic behaviour was directed to the sides of infested sheep. Wheal and flare reactions developed rapidly to all extracts in both infested and naive ewes. Reactions to louse extract were larger in infested than naive sheep at all four times after injection. In the infested Polypays, reactions to louse extract were greater than to the fly extracts, but in naive sheep there was little difference among extracts. Reactions in naive Columbias were larger than in naive Polypays at 20 min, 1 and 3 h, but had almost completely abated in both groups at 24 h. Reactions in infested Columbias were greater than in infested Polypays at 20 min, but at 24 h reactions in the Polypays were larger. Louse numbers and pruritus were correlated with wheal areas and skin thickness at 24 h, but there was little relationship with the size of reactions at earlier times. These findings are consistent with the development of a hypersensitive response to B. ovis and suggest that dermal reactions to lice may influence sheep susceptibility.
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PMID:Pruritus and dermal response to insect antigens in sheep infested with Bovicola ovis. 955 60


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