According to a May report in The Western Producer, there have been nine cases of equine infectious anemia in Saskatchewan and six in Alberta so far this year. What’s more troubling is that the Saskatchewan cases span four different regions: Meadow Lake, Big River, Lakeview and Beaver River. These recent cases of equine infectious anemia in Canada show that risk factors for the disease are present in very different types of climates. The many species of biting flies that transmit EIA can survive in a variety of environments, but they tend to thrive in certain conditions. In the U.S., some of the best conditions for these biting flies are found in the southeast with its combination of heat and swampland. Indeed, there is a good reason one of the nicknames for equine infectious anemia is swamp fever. But this isn’t the only region with conditions that let these biting flies thrive.
In Alaska, in Canada, and around the Great Lakes region, there are plenty of ponds and stagnant water that allow fly larvae to mature into adult flies. In much of the Great White North, there is also plenty of moose, caribou, and other livestock that allow these adult flies to feed, migrate, and potentially spread animal disease.
There are a couple broader lessons for horse owners and veterinary professionals, most of whom already know how to responsibly manage the risk of equine infectious anemia. The golden rule is to regularly test your horses for equine infectious anemia—at least as often as required by law—no matter the climate or region. It’s also important to get a Coggins test when traveling to and from different regions.
Reasonable efforts can be made to reduce or eliminate superfluous water sources on and around the property. For many farmers and agricultural producers, ponds are an important source of irrigation. Watering troughs for the horses themselves are just one example of the difficulty of eliminating standing water altogether. Not every piece of farmland has a river that provides drinking water for horses as well as enough current year-round to prevent the presence of biting flies. Plus, even when standing water and biting flies are around horses, cases of equine infectious anemia transmitted directly from biting flies without the presence of other infected equine animas are very rare.
Another big-picture lesson is that, despite years and decades of decline in cases of equine infectious anemia, there has been a modest increase this year in the rate of infection. Despite ongoing efforts to develop a vaccine or cure for the illness, it seems like screening and removal of infected animals is still the best solution we have to effectively manage the disease.