FASCIOLA IN HORSES IN THE REPUBLIC OF SOUTH AFRICA: A SINGLE NATURALCASEOF FASCIOLAHEPATICA ANDTHEFAILURETOINFESTTEN HORSES EITHER WITH F. HEPATICA OR FASCIOLA GIGANTICA

Republic of South Africa: a single natural case of Fasciola hepatica and the failure to infest ten horses either with F. hepatica or Fasciola gigantica. Onderstepoort Journal ofVeterinary Research, 55, 157-163 (1988). The faeces of 11 horses were examined for Fasciola spp. eggs. One of them was positive for Fasciola hepatica, a finding which was confirmed post-mortem. The 10 negative horses were subsequently infested with either F. hepatica or Fasciola gigantica, each animal receiving orally from 500--9 500 metacercariae. No clinical signs were observed and no fluke eggs were detected in the faeces, and neither immature nor adult Fasciola worms were recovered from the horses slaughtered 16-26 weeks post-infestation with F. hepatica and 28-34 weeks post-infestation with F. gigantica, respectively. The results indicate that horses have a high level of resistance to both South African Fasciola spp. Factors which can probably explain the conflicting reports for the prevalences of fascioliasis in horses throughout the world and the varying results obtained in experimental infestations are briefly considered. INTRODUCfiON Control of fascioliasis of domestic ruminants implies a sound knowledge of what reservoirs of infestation may exist and interfere with effective control, since these potential reservoir hosts commonly share the grazing with cattle and/or sheep. One domesticated animal species of which Fasciola infestation has been recorded on numerous occasions is the horse, but very little is known about the occurrence of fascioliasis in horses in the Republic of South Africa. According to Neitz (1965), Fasciola hepatica occurs sporadically in horses in the eastern Cape Province. Fur-thermore, we found a single record of fascioliasis of a horse from Kokstad in Natal in 1929; and since 1960 fascioliasis has occasionally been recorded as a cause for the condemnation of equine organs at the Johannesbur