Fasciola hepatica in UK horses

Area of Science:

• Veterinary Parasitology
• Equine Health
• Zoonotic Diseases

Background:

• Fasciola hepatica (liver fluke) is a parasite affecting grazing animals, including horses.
• The prevalence and impact of liver fluke in the UK horse population were previously unknown.

Purpose of the Study:

• To determine the prevalence of Fasciola hepatica infection in UK horses.
• To investigate the association between liver fluke exposure and liver disease in horses.
• To characterize liver fluke populations in horses.

Main Methods:

• Validated an excretory-secretory antibody detection ELISA for Fasciola hepatica.
• Conducted an abattoir study to estimate prevalence.
• Performed a case-control study comparing fluke exposure in horses with and without liver disease.
• Collected clinical and hematological data from sero-positive horses.
• Utilized multilocus genotyping to analyze adult fluke populations.

Main Results:

• Estimated sero-prevalence of Fasciola hepatica in UK horses at 8.7%.
• Abattoir sampling found adult flukes in 2.2% of horses.
• Horses with signs of liver disease showed significantly higher odds of Fasciola hepatica ELISA positivity.
• Clinical signs in sero-positive horses were non-specific, with one-third showing no symptoms.
• Genotyping confirmed liver flukes in horses originate from the same population as those in ruminants.

Conclusions:

• Fasciola hepatica exposure is frequent in UK horses and may be an under-recognized cause of liver disease.
• Liver flukes found in horses are epidemiologically linked to those in sheep and cattle.
• Parasite control strategies for horses should incorporate consideration of liver fluke, with testing recommended when appropriate.