By KEVIN WALKER
Michigan Correspondent
 
LANSING, Mich. — The Michigan Department of Community Health (MDCH) announced last week that a third person has been diagnosed with Eastern equine encephalitis (EEE), a rare but extremely deadly disease that usually afflicts horses.

The most recent case occurred in a 52-year-old woman from Barry County, in the southwestern portion of the state. She became sick in late July, was hospitalized and later went to a rehabilitation center to recover further.

Two other human cases have been diagnosed this year, both in individuals from Kalamazoo County. A 61-year-old man contracted it but is now home and recovering from the disease, while a 41-year-old man, also diagnosed with the disease, is in intensive care at a Kalamazoo County hospital.

“We don’t know what the prognosis is for the ones who have it,” said James McCurtis, a spokesman for the MDCH. “We’re monitoring it, but we don’t have any other cases out there right now.”

EEE is a mosquito-borne virus. Birds can carry it but often do not become sick. Mosquitoes pick up the virus from these birds and can transmit it to horses and humans. Horses can’t transmit EEE to humans.

Ninety percent of the horses that get the disease die, while the mortality rate in humans with EEE is one-third, but people who get the disease and survive can also end up with brain damage.

EEE can also affect poultry, such as chickens and emus, but people can only contract it from mosquitoes.

The disease may have affected as many as 80 horses, but it’s been confirmed in 26, according to Steven Halstead, Michigan’s state veterinarian. These cases have occurred in Barry, Calhoun, Kalamazoo, Cass and St. Joseph counties. Although veterinarians are required to report cases of EEE to the state, livestock owners are not; still, they are encouraged to do so.

All or almost all of the horses are dead by the time the state finds out about a possible case of EEE. Currently, livestock owners must pick up the tab for the test, so not everyone chooses to have their horse tested.

According to Halstead, reports of EEE in horses usually precede human cases, so it’s important to keep track of the disease in horses. Several factors have led to this outbreak, Halstead said.

The birds that can carry the disease have no immunity to the virus, since the birds that had immunity died off. Second, there was a wet spring, plus a summer with high heat and humidity; these conditions have all been favorable for a large mosquito population.

Third, people have not been getting their horses vaccinated for EEE. “Recent economic conditions have led to fewer horses being vaccinated,” Halstead said.

Moreover, the season isn’t over yet. There could be six more weeks before the area sees a night with a frost.

“When we get a good frost, this will all end,” he said.

Also, according to Halstead, the virus might not do much for several years after an outbreak. On the other hand, sometimes it comes back again for a second year.