Standardbred Horse Tests Positive for EEE

A five-year-old Standardbred racing horse from the Frankford, Del., area has tested positive for Eastern equine encephalitis (EEE). Tests on the animal, which died last weekend, were performed this week at the Division of Public Health Laboratory in Smyrna, Del. 

The viral disease EEE, much like West Nile Virus, is spread through mosquitoes. EEE results in a ninety percent death rate for horses, but a vaccination is available. State Veterinarian Dr. H. Wesley Towers urges horse owners to contact their veterinarians and have their horses vaccinated for EEE and West Nile virus. The disease is usually apparent during the months of August, September, and October. Common symptoms of EEE in horses include loss of coordination, blindness, circling to the right or left, and aimless walking (walking through fences or into objects). The symptoms progress to inability to stand, convulsions, coma, and death.

Earlier this month, DNREC confirmed that two sentinel chickens from a DNREC Mosquito Control monitoring station in the Great Cypress Swamp in south-central Sussex County tested positive for EEE. DNREC monitors the sentinel chickens for EEE and West Nile virus. These chickens, located just five miles from the infected horse, tested negative for West Nile Virus.

A confirmed human case of EEE has not occurred in Delaware since 1979. According to the Delaware Division of Public Health, people should avoid mosquito bites by employing personal and household protection measures, such as using insect repellent containing DEET or Picaridin, wearing protective clothing, taking precautions from dusk to dawn when mosquitoes are most likely to bite, and controlling standing water that can provide mosquito-breeding sites. More information is available on mosquito bite avoidance at:

To reduce the spread of EEE, DNREC recommends controlling standing water that can provide mosquito-breeding sites. Residents should drain areas such as wheelbarrows, old tires and clogged gutters. Water in birdbaths and children’s wading pools should be changed frequently.

To report mosquito problems in Kent or Sussex Counties, call Mosquito Control at 302-422-1512.
To report mosquito problems in New Castle County, call Mosquito Control at 302-323-4492.
For questions about Mosquito Control practices, call DNREC at 302-739-3493.
For questions about EEE in horses, call DDA at 1-800-282-8685 (poultry/animal health).
For questions about EEE in humans, call DPH at 302-739-5617.

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