New York State Confirms Death of Human Patient From EEE

New York State has confirmed its first human case of eastern equine encephalitis (EEE) since 2015, according to a press release from the New York State Department of Health. 

The individual, an adult resident of Ulster County, was hospitalized and has since died, and the epidemiology of the case is under investigation, according to the release. The death occurred 3 days after the case was confirmed on September 20 by the New York State Department of Health.

Consequently, the New York State Department of Health emphasizes that residents should take precautions to avoid mosquito bites and reduce the risk for EEE and other mosquito-borne diseases, and the state issued a Declaration of an Imminent Threat to Public Health for Mosquito-Borne Disease on September 23. This document outlines how local health departments can receive funding and take action to control mosquitoes in their areas.

“Eastern equine encephalitis is a serious and fatal mosquito-borne disease with no vaccine,” said State Health Commissioner James McDonald, MD, in the press release. “Even though temperatures are getting cooler, mosquito-borne illnesses are still a risk, and New Yorkers must be cautious,” he said.

Other states including Massachusetts, Vermont, New Jersey, Rhode Island, Wisconsin, and New Hampshire have reported human cases of EEE in 2024. Medscape Medical News previously reported on this surge, protective actions, and clinical guidance. 

The New York State Department of Health is unable to say whether the confirmed EEE patient had any particular risk factors or exposures that would have increased his or her risk for infection, said Danielle R. De Souza, MSc, public information officer for the New York State Department of Health, in an interview.

However, “EEE should be considered in any patient with fever or a neurologic illness who may have had recent exposure to mosquitoes, especially in areas where EEE virus activity has been reported,” De Souza said.

Although individuals of all ages are potentially vulnerable to EEE, those aged > 50 years and

Most cases of EEE are asymptomatic, but clinical signs of severe cases may include sudden onset of fever, as well as headache and meningismus (a triad of headache, fever, and stiff neck), sometimes accompanied by nausea and vomiting, according to the Centers for Disease Control and Prevention (CDC) website. In severe cases, patients may experience disorientation, seizures, and coma. Approximately one third of human EEE patients die, and half of those who survive experience long-term neurologic problems, according to the CDC.

No human vaccine is commercially available for EEE; therefore, the best protection is to prevent mosquito bites, according to the New York State Department of Health, which continues to recommend precautions to reduce the risk for infection from EEE or other 

mosquito-borne diseases. These recommendations include the use of insect repellants containing N,N-diethyl-meta-toluamide, ie DEET, when outdoors and washing treated skin after returning indoors. 

Other personal protection strategies include wearing long sleeves and tucking shirts into pants and pants into socks when outdoors at dusk or dawn. 

Environmental strategies to reduce mosquito contact include eliminating standing water from yards, emptying birdbaths, wading pools, and any other areas where water might collect, and ensuring that screens on doors and windows are secure and have no rips, tears, or holes. 

EEE has been confirmed in one horse in Ulster County, as well as in horses in Saint Lawrence, Madison, Oneida, Orange, Cayuga, Wayne, and Washington counties, according to another press release from the New York Department of Health. The virus does not spread from horses to humans, but horse owners are encouraged to have their horses vaccinated. 

De Souza had no financial conflicts to disclose.