The extraparasitic life cycle of Toxocara vitulorum in the village environment of Sri Lanka

Abstract

The extraparasitic life cycle of Toxocara vitulorum of buffalo in the villages of Sri Lanka is related to observations on buffalo behaviour, experimental studies on the development and persistence of the eggs in soil and in wallows and the presence of eggs in village locations. Calf faeces on soil were rapidly incorporated by insect activity and the eggs developed only slightly slower than in the laboratory. Some infective eggs persisted 3-4 cm deep for 17 months, finally dying during a prolonged hot, dry period. Eggs in a wallow developed intermittently over 16 months as it was flushed with rain water, and eventually died when the wallow dried out. When infected faeces were placed in water, decomposition caused some material to rise to the surface and eggs developed. In villages, eggs are ubiquitous where young calves are kept but survive best where there is moisture and shade around animal pens and wallows. Cows and calves acquire infection from infective eggs in wallow water, soil and pasture, while calves may also be infected from contamination on the udder and teats of the cow. The larvae resulting from this infection do not mature until the infection is passed to the calf through the milk of the cow. At least 72% of village calves have patent infections and current treatment procedures do not reduce the prevalence. The possibility that T. vitulorum is a cause of human visceral larva migrans is discussed.

Incidence of Toxocara vitulorum in Creole calves of Guadeloupe

“…Adult nematodes develop only in the small intestines of young calves, and female worms can lay up to 100 000 eggs per day (Roberts 1990a). Cattle acquire larval infection from infective eggs in wallow water, soil and pasture, while calves may also be infected from contamination of the udder and teats of the cow (Roberts 1989a). Infective eggs hatch and larvae migrate through different organs, most of them staying in the liver.…”

Helminths Identified by Coprological Examination in Cattle Raised in Bartin Region

“…Toxocara vitulorum dünyanın tropik ve subtropik bölgelerinde sığır ve mandalarda enfeksiyona neden olan bir askarittir (35,36 Hakem değerlendirmesi: Dış bağımsız.…”

Ocorrência dos principais agentes bacterianos e parasitários em fezes diarreicas de bezerros búfalos nos estados de São Paulo e Paraná

“…Este nematoide é citado no Paquistão, Ceilão (atual Sri Lanka), Índia, Malásia, Egito, Filipinas, Tailândia e Brasil como sendo o principal agente parasitário causador da mortalidade de bubalinos jovens (Warren, 1970). O T. vitulorum adulto parasita a primeira porção do intestino delgado de ruminantes (Smith, 1994), e principalmente de búfalos d'água (Bubalus bubalis) (Roberts, 1989). Este parasita está em primeiro lugar na ordem de prevalência e patogenicidade para bezerros búfalos bem jovens, nos primeiros quatro meses de vida (Patnaik;Pande, 1963;Starke et al, 1983).…”