Eastern equine encephalitis is a viral infection that is transmitted to humans, horses, other domestic animals (including dogs and pigs), and wild birds through the bite of an infected mosquito. Because of this “mosquito connection,” the eastern equine encephalitis virus (EEEV) is commonly referred to as an arbovirus (arthropod-borne virus). The EEEV has been reported throughout the eastern half of North America (which is the reason for its name), but is particularly prevalent in coastal cedar and hardwood swamps from New Hampshire to peninsular Florida.
The EEEV is normally transmitted between mosquitoes and wild birds in freshwater swamps. This bird-to-mosquito-to-bird transmission cycle is commonly referred to as amplification because it can result in a large number of infected mosquitoes and birds. During most years infected birds and mosquitoes remain in the swamps. During years with wet spring and summer conditions infected mosquitoes disperse from the swamps and carry the EEEV to horses and humans in distant locations. Most wild and domestic animals are not susceptible to infection and do not suffer clinical signs of infection. Some animals (particularly humans and horses) are highly susceptible to EEE infection and these individuals may suffer severe clinical symptoms, often ending in death.
Environmental conditions are extremely important to the EEEV cycle in nature and certain rainfall patterns predispose a region to EEEV transmission. At the University of Florida, Florida Medical Entomology Laboratory, we track these conditions and periodically issue releases explaining and updating the current EEEV situation in Florida. To view the most recent information about EEEV in Florida visit:
http://mosquito.ifas.ufl.edu/Documents/MWTD/EEE_Analysis_Florida_June_2009.pdf
and http://eis.ifas.ufl.edu/eis1.htm.
Best wishes for an enjoyable and healthy summer,
Jonathan F. Day, Ph.D.
Professor of Medical Entomology
University of Florida, Florida Medical Entomology Laboratory, Vero Beach
The EEEV is normally transmitted between mosquitoes and wild birds in freshwater swamps. This bird-to-mosquito-to-bird transmission cycle is commonly referred to as amplification because it can result in a large number of infected mosquitoes and birds. During most years infected birds and mosquitoes remain in the swamps. During years with wet spring and summer conditions infected mosquitoes disperse from the swamps and carry the EEEV to horses and humans in distant locations. Most wild and domestic animals are not susceptible to infection and do not suffer clinical signs of infection. Some animals (particularly humans and horses) are highly susceptible to EEE infection and these individuals may suffer severe clinical symptoms, often ending in death.
Environmental conditions are extremely important to the EEEV cycle in nature and certain rainfall patterns predispose a region to EEEV transmission. At the University of Florida, Florida Medical Entomology Laboratory, we track these conditions and periodically issue releases explaining and updating the current EEEV situation in Florida. To view the most recent information about EEEV in Florida visit:
http://mosquito.ifas.ufl.edu/Documents/MWTD/EEE_Analysis_Florida_June_2009.pdf
and http://eis.ifas.ufl.edu/eis1.htm.
Best wishes for an enjoyable and healthy summer,
Jonathan F. Day, Ph.D.
Professor of Medical Entomology
University of Florida, Florida Medical Entomology Laboratory, Vero Beach
