Infestation

About: Infestation is a research topic. Over the lifetime, 8308 publications have been published within this topic receiving 82305 citations.

Parasites of domestic and wild animals in South Africa. I. Oestrus ovis in sheep.

Abstract: Separate groups of 3 oestrid-free lambs were exposed to infestation on irrigated pasture for periods of approximalely 33 days each over30 months, and on dry-land pasture for approxomately 42 days over a period of 18 months. With some exceptions, the lambs slaughtered from October-June were found to be infested with Oestrus ovis while, with one exception, those slaughtered from July-September were free. A minimum of 4 sheeps' heads, obtained weekly over 24 months from the Pretoria Municipal Abattoir, was examined for infestation. Of a total of 542 heads examined, 73,4% were infested, having a mean burden of 15,2 larvae. Mean larval burdens were slightly greater in hornless than in horned sheep in Dorper-type than in Merino-type sheep, and in lambs than in sheep with 2 or more permanent incisors. The largest larval burdens were recovered from sheep slaughtered during May and June and the smallest during September and October. The greatest number of 1st instar larvae were recovered during May and June and the smallest during September, but those recovered during the latter month were the largest. With one exception, mature larvae which pupated after 21 March or before 16 August failed to hatch as viable flies. Those which pupated after 16 August hatched as flies after a pupal stage of approximately 50 days and the first flies to hatch were invariably recovered during the first 2 weeks of October. The pupal stage decreased to approximately 25 days during December and January and increased again to approximately 50 days for flies hatching during May. No flies hatched between 18 May and 1 Cctober. The following life cycle ofr Oestrus ovis is suggested: sheep are repeatedly infested from October-June; thereafter infestation survives in the sheeps' heads until August, mainly as 1st instar larvae, then as pupae and larvae until fresh infestation takes place during October.

Group-living and infestation by ectoparasites in passerines

Abstract: Using data from an 1 l-year field study, I determined whether group-living passerine species showed greater infestation by contact-transmitted ectoparasites (feather mites) than sympatric, solitary species. Differences in infestation by mobile hippoboscid flies between group-living and solitary passerine species were also examined. Among the 45 species included in the analysis, feather mite prevalence was significantly greater on group- living species than on solitary ones. Two other factors investigated, bird size and migratory habit, had no effect on infestation levels. Similar results were obtained when the analysis was performed on all species outside the most species-rich family (Fringillidae), or only within the family Fringillidae itself. An analysis at the family level also suggested greater feather mite infestations in families made up only of group-living species as opposed to families including only solitary species; however, the difference was not significant. No differences were observed in hippoboscid fly abundance between group-living and solitary passerines, in all analyses at either the species or family level. These results suggest that individuals of group-living species incur a greater risk of acquiring contact-transmitted ectoparasites than individuals of solitary species, a cost which may not be negligible.