Seasonal infectious diseases in Ontario horses (Lyme, Anaplasmosis, and Potomac Horse Fever)
Lyme borreliosis and anaplasmosis are diseases caused by infection with Borrelia burgdorferi and Anaplasma phagocytophilum respectively, and both are transmitted in Ontario by the deer tick, Ixodes scapularis. Unfortunately, the distribution of these infections in the horse is only speculative. Horses continue to be diagnosed with Lyme disease, with and without supporting evidence, resulting in potential misdiagnoses and health risks as well as inappropriate antibiotic treatment with tetracycline. Anaplasmosis is a new and emerging disease in Ontario with only one case officially diagnosed in the eastern part of the province. The distribution of A. phagocytophilum is assumed to resemble that of the dog, thus predominantly affecting the eastern counties. Assessing the seroprevalance of these tick borne infections in horses of Ontario can provide insight into the tick distribution presently and can be used as an indirect indication of tick spread when monitored over time. It would also assist equine practitioners in completing accurate diagnoses and treatments as well as in understanding the impact of infection by these organisms on the long term health and productivity of the horse.
Potomac Horse Fever (PHF) is a seasonal infectious disease caused by the bacterium Neorickettsia risticii. PHF occurs in Ontario, mainly during the summer months (July to September). The disease is usually sporadic in eastern and south-western Ontario. The severity of clinical signs varies between horses, but characteristic signs include depression, decreased appetite, fever, diarrhea and colic. A high percentage of cases (up to 40%) of horses suffering from PHF develop acute laminitis, which is the most serious and life-threatening complication leading to animal welfare issues due to chronic pain and euthanasia due to the severe nature of laminitis.
This study aims to isolate the endemic strain (s) of N. risticii from horses with clinical disease in Ontario for molecular analysis.
Funded by:
