The focus of this section will be on Eastern, Western, and Venezuelan equine encephalomyelitis (EEE, WEE, VEE), with equine tetanus coming later. Starting with equine encephalomyelitis, it is a result of the Alphavirus in the family Togaviridae. This virus is spherical in shape and has an envelope (McClain & Schmaljohn, 1996). Through various study it has been determined that the most common reservoir for this disease is in birds and sometimes rodents. Arthropods, like mosquitoes, mites and lice, are the main vectors for EEE, WEE and VEE. These arthropods feed on the bird and rodent populations, which are the carriers, and transmit it to the victim animal, which are mainly horses. Interestingly enough, while not a vector for transmission, reptiles, such as snakes, have been known to be carriers over winter months. It is important to note that the arthropod vector is essential for spread of this disease. There are no known incidents of VEE or WEE being spreadable from a horse to another horse or human, and EEE is a dead end as well in this regard, except for in laboratory demonstrations. EEE is the most common of the three, especially in the U.S., with cases detected in east Canada and most of the southeast states. WEE has sporadically appeared in western states and VEE is extremely rare in the U.S., occurring primarily in South and Central America (Eastern/Western). EEE, WEE, and VEE can be very …show more content…
Once infected, the only treatment for any of these is supportive care. Permanent brain damage is common if the animal survives, but the mortality rate is very high, especially in EEE (the most common) at 75%-100% (Nadeau and Bushmich). As the name implies for these three viruses, the most susceptible species are horses, but birds and rodents who are reservoirs for this disease can also be afflicted. All three have zoonotic potential and strains of EEE and VEE in particular can cause very bad illnesses. The symptoms for the less common victims of these viruses is similar to those in horses. Birds can sometimes be very asymptomatic, however. It is also worth noting, particularly with EEE, mortality is always very high if neurological signs have developed. (Eastern,