Infectivity and pathogenicity of Fasciola gigantica in West African dwarf sheep and goats.

The infectivity and pathogenicity of Fasciola gigantica for sheep and goats were investigated in animals infected with single doses of between 200 and 2,000 metacercariae. Acute fascioliasis occurred in sheep infected with 1,000 to 2,000 cysts in which 10 to 17% of the cysts became established. The infected animals died 80 to 90 days after infection. In goats given the same infective doses death from acute fascioliasis occurred earlier (70 to 83 days after infection) and 12 to 38% of cysts became established. Subacute fascioliasis could occur in both hosts with an infective dose of 200 cysts, the animals surviving for more than 100 days. It therefore appears that F. gigantica is more infective for goats and that the disease was more severe in this host than in sheep.