Sometimes known as "Sleeping Sickness," (or "African Sleeping Sickness"), Equine Encephalomyelitis is a disease that affects the nervous system. This disease is caused by at least three different types of equine encephalomyelitis viruses (Eastern, Western, and Venezuelan), which are carried by mosquitoes.
Signs include depression and a high fever, followed by a period when the horse appears blind, nervous and uncoordinated, which progresses to muscle tremors, yawning and eventually complete paralysis. Proper vaccination and good mosquito control are important to help prevent these diseases.
These three separate types of viruses all have common signs. Signs include:
The most common types of Equine Encephalomyelitis in the United States are Eastern Equine Encephalomyelitis (EEE) and Western Equine Encephalomyelitis (WEE). The EEE virus is found in eastern Canada, all states east of the Mississippi River, and Arkansas, Minnesota, South Dakota, and Texas. It also occurs in the Caribbean and regions of Central and South America, including along the Gulf coast. The WEE virus is found in western Canada, Mexico, parts of South America, and west of the Mississippi River in the United States. Venezuelan Equine Encephalomyelitis (VEE) viruses are endemic in South and Central America and Trinidad. Most epidemics of VEE occur in northern and western South America, but some may spread into adjacent countries, including the United States. According to APHIS (Animal and Plant Health Inspection Service, the U.S. governmental service that monitors disease in livestock and horses), the most recent outbreak of VEE in the United States was in the early 1970s.
Eastern Equine Encephalomyelitis (EEE)
After infection, equines may suddenly die or show progressive central nervous system disorders. The rapidity of deterioration and eventual outcome of infection vary among individual horses. The equine mortality rate due to EEE ranges from 75 to 90 percent.
Humans can also contract this disease. Healthy adults who become infected by the virus may experience flu-like symptoms such as high fevers and headaches. The young, the elderly, and people with weakened immune systems are most at risk for complications from this disease.
Because outbreaks of EEE are infrequent, the number of susceptible horses is often high, especially if they have not been vaccinated. Therefore, the disease often has a significant economic and social impact once it enters a specific area. When the disease appears in an area for the first time, there is a loss of horses and/or poultry, which can also contract the virus. The area may also experience an increase in human morbidity and mortality.
Western Equine Encephalomyelitis (WEE)
Venezuelan Equine Encephalomyelitis (VEE)
Protect your horse by vaccinating.