NEW STUDY REVEALS SEASONAL TAPEWORM RISKS FOR UK HORSES
05 October 2025
AND HIGHLIGHTS THE ROLE OF SALIVA TESTING
A new UK study has provided valuable insights into how horses are exposed to tapeworm infection through tiny pasture dwelling mites, revealing seasonal patterns that could help owners make more informed decisions about parasite control.
Understanding Tapeworm Transmission
The study tracked horses, pastures, and mites over a 14-month period across three equine yards in the UK to examine how Anoplocephala perfoliata, the most common equine tapeworm, spreads in grazing environments. This parasite lives at the junction of the small and large intestines and is known to contribute to colic, a serious and potentially life-threatening condition in horses.
Tapeworms rely on oribatid mites, microscopic creatures living in soil and on pasture, to complete their life cycle. Horses become infected when they accidentally ingest these mites while grazing. The research monitored mite populations across the seasons, assessing both their presence and the occurrence of tapeworm DNA to understand when infection risk is highest.
Seasonal Risk Patterns Identified
The study found that oribatid mites were present on paddocks year-round, but their activity dropped significantly in winter compared to summer. Tapeworm DNA was most frequently detected in mites collected between March and September, pinpointing this as the highest-risk period for transmission.
This finding has important implications for parasite control, suggesting that spring is one of the key times to test horses for tapeworm infection. Early testing allows for informed treatment decisions before contaminated horses begin shedding tapeworm eggs, reducing the risk of infecting paddocks at a time when mites are most active.
Saliva Testing and Management Insights
To monitor exposure, the researchers used the EquiSal Tapeworm Test, a saliva-based diagnostic that measures tapeworm-specific antibodies in horses. The study revealed that horses turned out for only half the day were less likely to test positive than those grazing full-time, highlighting the link between grazing management and infection risk.
Interestingly, infections were detected throughout the year, reinforcing the value of routine testing as part of an evidence-based worming strategy. None of the yards in the study carried out recommended paddock hygiene practices, such as regular dung removal, factors that are crucial in breaking the parasite’s life cycle and preventing re-infection.
Implications for Horse Owners
The findings underscore the importance of seasonally targeted parasite control and support the move towards tailored deworming plans based on testing rather than routine treatment. This approach not only helps protect horses from tapeworm-associated disease but also supports sustainable parasite control by reducing unnecessary use of worming products.
By combining regular saliva testing, good pasture hygiene, and strategic treatment timing, horse owners can take effective steps to minimise infection risks and maintain herd health throughout the year.
The full research paper is available Open Access here: A study of the epidemiology of Anoplocephala perfoliata infection in horses and the oribatid mite vector in southern England - ScienceDirect
About the Study
The study was conducted in collaboration with The Royal Veterinary College between June 2016 and August 2017 across three UK equine premises. It involved regular sampling of pastures and mites, DNA testing for Anoplocephala species and EquiSal Tapeworm testing in horses. Statistical analyses explored links between management practices, mite activity, and tapeworm exposure to provide a clearer picture of how infection dynamics vary with season and turnout.