Ovine internal parasitism in the Yemen Arab Republic.

Internal parasitism was studied in five flocks in different regions of the Yemen Arab Republic. Ewes and lambs were faeces sampled from the spring of 1977 to the spring of 1978 and helminth-free tracer lambs were subsequently run with three of the flocks from October 1978 to November 1979. The findings indicated that ovine helminthiasis and fascioliasis may be of importance with the following regional variations: Haemonchosis all the year round in the Tihammah coastal plain. Haemonchosis and trichostrongylosis in the periparturient period in the Southern Uplands and Western Foothills. Fascioliasis and nematodiriasis in the Inter-Montane Plains of the Highlands. Possible control regimes are suggested for further investigation.