Echinococcus granulosus larvae in the livers of sheep in Tunisia: the effects of host age.
A baseline survey of hepatic hydatid disease in sheep in Tunisia was undertaken. Prevalence and intensity (i.e. the number of cysts/liver) were both found to increase with age. The age-specific trends in these two parameters indicate that Echinococcus granulosus is in an endemic equilibrium steady-state in Tunisia and therefore amenable to control. The distribution of parasites within the livers of the hosts followed a negative binomial distribution. The negative binomial constant, k, increased with age, indicating that there was a lower propensity for aggregation of parasites in the hosts as the sheep became older.
Lahmar
S
S
Service de Parasitologie, Ecole Nationale de Médecine Vétérinaire, Sidi Thabet, Tunisia.
Kilani
M
M
Torgerson
P R
PR
Gemmell
M A
MA
D000367:Age Factors; D000818:Animals; D004444:Echinococcosis, Hepatic / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D004446:Echinococcus / Q000276:immunology; D008099:Liver / Q000469:parasitology; D015995:Prevalence; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology / Q000469:parasitology*; D014416:Tunisia / Q000453:epidemiology