Also known as
equine sleeping sickness, this is an infection of the
central nervous system most commonly developed in horses, although humans can contract it as well. There are two basic strains,
Eastern (occuring on the east coast and midwest) and
Western (which has been found all over the US and
Canada). The infection is usually contracted through the
bite of a
mosquito carrying infected
blood. While other animals may contract it, it seems to be only
symptomatic in horses and people. It is also not
communicable from one animal to another except through direct blood
transmission such as through a mosquito bite.
Early symptoms generally include apathy and depression and may last for up to five days. In some cases this is all the horse will experience. If the disease progresses, the horse will experience tremors, agitation, loss of appetite, blindness, paralysis of the throat and tongue, stupor, or even a coma. Death from the Eastern strain is about 60-70% in cases where severe symptoms develop, but only about 15-20% in the Western strain.
There is no treatment once this has been contracted, only supporting care can be given to treat the symptoms and keep the animal relaxed. As a preventative measure, animals should be vaccinated for both strains yearly.