Health departments throughout the United States along with veterinarians, are joining together to raise awareness about the dangers of Eastern Equine Encephalitis (EEE) West Nile virus (WNV)and other mosquito-borne illnesses that affect horses and humans as summer brings increases in the mosquito population in many parts of the country.
Preventing mosquito-borne diseases in horses and humans
Horse owners are advised to take steps to reduce the number of mosquitoes around their barns, stables, and homes, including eliminating standing water in farm yards.
EEE virus attacks the central nervous system and unvaccinated horses are very susceptible to the infection. The disease appears within five days after a mosquito transmits the virus to the horse. Onset of clinical symptoms are abrupt and infected horses often die within three days.
The fatality rate is 90% or higher and an animal that survives the disease may have brain damage.
The fatality rate for horses exhibiting clinical signs of West Nile Virus infection is approximately 33%. Data have supported that 40% of horses that survive the acute illness caused by WNV still exhibit residual effects, such as gait and behavioral abnormalities, 6-months post-diagnosis.
With more than 600 cases of equine West Nile virus (WNV)1 and more than 200 cases of Eastern Equine Encephalitis (EEE)2 reported in 2012, it was one of the worst years on record for mosquito-borne diseases.
Besides the alarming number of equine cases, more than 5,000 cases of WNV were reported in humans, resulting in 243 deaths. According to the Centers for Disease Control and Prevention, this was the highest on record since 2003.
In addition to making sure that all horses are vaccinated against mosquito-borne diseases, health officials recommend people protect themselves when outdoors by using mosquito repellent and wearing long pants and long sleeves.
Insect repellants containing oil of lemon eucalyptus should not be used on children under 3 years of age, and products containing DEET should not be used on infants under 2 months of age. For children older than 2 months, the American Academy of Pediatrics recommends products containing 10 percent to 30 percent DEET.
Horse owners are also advised to take steps to reduce the number of mosquitoes around their barns, stables, and homes, including eliminating standing water in yards and making sure all windows and doors have screens that are in good repair to prevent mosquitoes from getting inside. In addition, horse owners should:
- Dispose of used tires, tin cans, plastic containers, ceramic pots or similar containers in which water collects.
- Drill holes in the bottoms of recycling containers that are kept outdoors. Make sure roof gutters drain properly and clean clogged gutters in the spring and fall.
- Turn over plastic wading pools and wheelbarrows when not in use, and change the water in bird baths twice a week.
- Clean vegetation and debris from the edges of ponds.
- Clean and chlorinate swimming pools, outdoor saunas and hot tubs, anddrain water from pool covers.
In consultation with DOH, counties that are considered to be at high risk for EEE initiate mosquito control programs, which include the use of aerial spraying when it is determined to be necessary, to reduce public health risks. Residents may contact their local health departments to obtain up-to-date information on mosquito control efforts in their counties.