Hall said the number of horses that have died as a result of the virus was not known, but that a mortality rate of 30 to 40 percent of those infected is considered typical.
Because the disease is a virus, there is no specific treatment other than to treat the symptoms such as fever, and to ensure that the person, or horse, receives plenty of fluids.
A vaccination is available for horses, but not for humans.
The number of human cases broke the record of 107 cases and nine deaths set in 2007, but Bradley said she's optimistic that 2013 will be a milder year for the disease.
“Based on what we've seen before is usually a season that follows a severe outbreak year is much milder,” Bradley said.
As for the rest of 2012, Bradley said residents should continue taking precautions when outdoors at least until there are several consecutive days of sub-freezing temperatures that drive the mosquito into hibernation.