Can The US Be Piroplasmosis Free?
.jpg)
The ongoing large piroplasmosis outbreak on a Texas farm, following on the heels of a few other US outbreaks, raises concern that this infection is not really a "foreign" disease in the US (at least not anymore). Although the source of the earlier outbreaks was not identified, they did not raise too much concern because ticks capable of transmitting this bloodborne infection were not found (which reduces the risk of uncontrolled spread of the disease). However, the situation may be different in Texas. Following identification of the first case, 31 more positive horses were identified on the affected farm. That's a lot of infected horses, and given the number it's probably less likely that the infection was spread by human activity (e.g. reusing contaminated needles) than by ticks. Concern has been expressed over the past couple years that Boophilus microplus and Rhipicephalus microplus, ticks capable of transmitting this parasite, might be establishing themselves in the state of Texas. If this is the case, this may not be an easily controllable situation, and the US may lose its piroplasmosis-free status. Intensive investigation of the source of this outbreak, how it was spread on this farm, whether there are other affected horses in the region and whether these tick species are present, is urgently needed.
Image: A "hard tick" (male brown dog tick (Rhipicephalus sanguineus)) from the same genus as R. microplus, one of the tick species capable of transmitting piroplasmosis (Theileria equi) to horses. (CDC Public Health Image Library #7646)
