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TAHC 2.jpg For Immediate Release 


TAHC Encourages Equine Owners to Consult with Veterinarian Regarding Vaccinations

AUSTIN - With the recent rain and flooding across the state, mosquito activity is expected to increase. Texas Animal Health Commission (TAHC) officials encourage equine owners to consult with their private veterinary practitioner regarding vaccinating their horses against mosquito-borne illnesses such as Eastern Equine Encephalitis (EEE), Western Equine Encephalitis (WEE), Venezuelan Equine Encephalitis (VEE), and West Nile Virus.

Eastern, Western, and Venezuelan Equine Encephalitis are reportable diseases to the TAHC.

Eastern equine encephalomyelitis (EEE) is a mosquito-borne viral disease of all equine species. Infected horses may suddenly die or show progressive central nervous system disorders. Symptoms may include unsteadiness, erratic behavior and a marked loss of coordination.

Western equine encephalomyelitis (WEE) is a viral disease that mainly affects horses; mosquitoes primarily transmit this disease. Similar to EEE, WEE is characterized by central nervous system dysfunction.  

Venezuelan equine encephalomyelitis (VEE) is a viral disease that affects horses and causes illness in humans. It has not been seen in the United States for many years (however, a recent outbreak of VEE occurred in Mexico). Mosquitoes most often transmit the disease after the insects have acquired the virus from birds and rodents. Humans also are susceptible when bitten by an infected mosquito, but direct horse-to-horse or horse-to-human transmission is very rare. Symptoms in horses vary widely, but all result from the degeneration of the brain. Early signs include fever, depression and appetite loss.  

About 20 to 50 percent of horses infected with WEE die, and the death rate is 75-100% of animals infected with EEE. The mortality rate for VEE is 40 to 80 percent.

West Nile Virus, is a potentially deadly disease that can affect horses and humans. Like WEE, EEE and VEE, West Nile virus is transmitted to horses via the bite of an infected mosquito. While not a reportable disease to the TAHC, it is recommended that horse owners consult with their veterinarian about protecting their horses against this mosquito-borne illness as well.

"As part of routine equine health care, the TAHC recommends that owners visit with their local veterinarian to discuss a vaccination program to protect their horses against mosquito-borne diseases," said Dr. Dee Ellis, Texas State Veterinarian.

For more information on mosquito borne diseases visit:


Founded in 1893, the Texas Animal Health Commission works to protect the health of all Texas livestock, including: cattle, swine, poultry, sheep, goats, equine animals and exotic livestock.





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