Recently, a case of anaplasmosis was identified in a horse in Eastern Ontario.
People in some places may say “so what?”
The reason it’s noteworthy is that anaplasmosis has historically been a very rare disease in Ontario. It’s a infection caused by the bacterium Anaplasma phagocytophilum, which is primarily transmitted by the tick Ixodes scapularis – the same tick that spreads Borrelia burgdorferi (the cause of Lyme disease). Anaplasmosis is therefore something that we expect to see more of in areas where this tick (and Lyme disease) is becoming established. In Ontario, that’s the eastern part of the province, particularly along the north shore of Lake Ontario and the St. Lawrence River. The expansion of tick ranges over the last decade or more has been pretty impressive, and it’s likely to continue. So, as ticks spread, and pathogens spread with them, anaplasmosis is something that equine veterinarians and horse owners may need to be more aware of in coming years.
More information on the recent Ontario case can be found in a report by the Ontario Animal Health Network.