A saliva-based test has proved its worth by drastically reducing the use of tapeworm treatments in the management of 237 horses in Britain.
Experts in worm control, in a push to minimise increasing worm resistance, have been pushing for targeted treatments for parasites in horses rather than the traditional calendar-based approach.
Targeted selective treatment strategies use diagnostic tests to reduce drug use by treating individuals with worm burdens or egg-shedding levels above a set threshold.
Faecal egg counts are the mainstay of this approach, but cannot provide a reliable indication of tapeworm infection in horses.
Dr Kirsty Lightbody and her colleagues, writing in the Equine Veterinary Journal, have described their success in identifying tapeworm infections in horses, and in doing so reducing drug use.
The study team described their evaluation of the EquiSal tapeworm saliva test, developed by the firm Austin Davis Biologics Ltd, in 237 horses in the care of Bransby Horses, a British equine welfare group.
Owners can buy a test kit for each horse. A saliva swab is collected and returned to the laboratory in a prepaid envelope included in the kit. Test results and recommendations are reported by email within three days of the lab receiving the sample.
Saliva was collected from the horses from autumn 2015 to autumn 2016. Horses diagnosed as positive for naturally occurring tapeworm infection were given an appropriate dewormer according to weight.
The number of horses that received anthelmintic treatment based on the test results was compared with an all-group treatment approach and the reduction in drug use calculated.
A total of 143 incoming horses were also tested and the information used to inform quarantine treatments. A total of 41% of these horses required tapeworm treatment.
Analysis showed that, in autumn 2015, 85% of the 237 horses tested received no tapeworm drug and most (71%) remained below the treatment threshold throughout the study.
Of the 69 horses that received treatment, seven required treatment following three subsequent tests, while more than half of the horses treated fell below the treatment threshold at the following test.
No increase in tapeworm prevalence within the 237 horses was observed during the study despite a substantial reduction in the application of anti-tapeworm treatments, the authors reported.
In all, the diagnostic-led approach reduced the use of anti-tapeworm treatments by 86% compared to six-monthly interval-treatment strategies.
Six monthly ongoing testing of the horses would identify horses acquiring new tapeworm infections, allowing treatment at an early stage, limiting paddock contamination and exposure of the rest of the herd. It would also identify those horses which may be more prone to reinfection.
The test kits are currently available in Britain and parts of Europe.
Lightbody, K. L., Matthews, J. B., Kemp-Symonds, J. G., Lambert, P. A. and Austin, C. J. (2017), Use of a saliva-based diagnostic test to inform on tapeworm infection in horses in the UK. Equine Vet J. DOI: 10.1111/evj.12742
The abstract can be read here.