Eastern Equine Encephalitis (EEE) has made its way north. While mosquito tests in southern Massachusetts have shown the virus present there, no horse or human cases have been announced.

Compare that with rural St. Lawrence County in New York State. New York has not reported EEE in any mosquito testing, but a horse is already dead.

I spoke with David Smith, DVM, state veterinarian for New York, this afternoon and he confirmed that an eight-year-old Standardbred/draft cross in St Lawrence County has died. He also reported that while there have been no findings of EEE in mosquitoes in New York, there have been several mosquito testing projects that have found West Nile Virus (WNV) in the state this summer.

According to Dr. Smith, the owner of the dead horse reported that it had been acting sluggishly on Day One. By Day Two, the horse was acutely ill and a veterinarian was summoned. The horse had no Day Three, since it died that night. The horse had not traveled outside the county, so the virus must have infected it there.

The horse had never been vaccinated for EEE.

Smith remarked that this summer has been usually hot and dry in New York; in other words, the weather has not been conducive to hordes of mosquitoes.
He advised horse owners that it is not too late to have a horse vaccinated for EEE and WNV for 2012, since the mosquito season will go into the fall. Last year, he said, mosquitoes were active in New York until November.

Smith advised strongly that any horse owner who observes a horse with neurological symptoms contact a veterinarian immediately. EEE and WNV can be fatal, but neurological signs may also indicate rabies, as well as contagious disease like Equine Herpes Virus (EHV).

Looking back, 2011 was a fateful year for New York. By September, 12 horses and, in an unusual twist of the disease, two dogs were diagnosed with EEE in New York. Only one horse survived. A child also died from EEE in New York in 2011. Last year’s first case of EEE was reported on August 3.