| helminth infections of sheep in north sumatra, indonesia. | gastrointestinal tracts of 73 indigenous sheep were obtained from the medan abattoir in north sumatra, indonesia, and examined for the presence of helminths. a total of 13 species of helminths, eight nematodes, one cestode and four trematodes were encountered. all sheep were infected by more than one species of nematodes. trichostrongylus colubriformis, t. axei and haemonchus contortus were the most common species. the intensity of the nematode infections was very high: the average burden was ov ... | 1996 | 8720574 |