Fasciola in horses in the 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.

This research article investigates the occurrence of Fasciola, a type of liver fluke, in horses in South Africa. Only one out of 11 horses was found to be naturally infested with Fasciola hepatica, while the attempt to artificially infest ten other horses with either F. hepatica or Fasciola gigantica was unsuccessful. This result suggests that horses have a high level of resistance to these two species of Fasciola.

Introduction and Methodology

• The research examined the faeces from 11 horses for the presence of Fasciola species eggs. Fasciola are parasitic flatworms that infest the liver, causing a disease known as fascioliasis.
• One horse tested positive for Fasciola hepatica, and this diagnosis was confirmed post-mortem.
• The remaining ten horses, who had tested negative, were then deliberately infested with either F. hepatica or Fasciola gigantica. The method of infestation was through oral ingestion of metacercariae, a larval form of the parasite. The number of metacercariae given to each horse varied between 500 and 9,500.

Results and Findings

• Despite the artificial infestation, no clinical symptoms were observed in these horses.
• Furthermore, no fluke eggs were detected in their feces, indicating a failure of the parasites to reproduce.
• Bound within a time range of 16-26 weeks after infestation with F. hepatica and 28-34 weeks after infestation with F. gigantica, the horses were slaughtered. Neither immature nor adult Fasciola worms were found in these horses, indicating that the parasites had not survived.
• The research results therefore indicate that horses have a high level of resistance to Fasciola hepatica and Fasciola gigantica.

Discussion

• Finally, the authors attempt to explain why there are conflicting reports about the prevalence of fascioliasis in horses across the globe, and the varying results of previous experimental infestations.
• Though these factors are not detailed in this abstract, the understanding is that they could be key to understanding the parasite’s life cycle, as well as developing effective control and treatment strategies.