Eastern Equine Encephalitis Cases Continue to Grow in United States

In a new commentary in The New England Journal of Medicine, officials from the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, discuss the emergence of eastern equine encephalitis (EEE) in the United States.

According to the article, there were 12 documented cases of EEE in the United States between 1831 and 1959, however, as of November 2019 there were already 36 confirmed cases for the year, with 13 of those being fatal.

In people infected with EEE, symptoms, including fever, malaise, intense headache, nausea, and vomiting, typically present within 3 to 10 days. Diagnostic testing can be difficult and testing for EEE antibodies may be negative. Approximately 96% of people infected with EEE do not develop symptoms. Of those who do develop symptoms, nearly 1/3 or more died and other have permanent neurologic damage.

Potential EEE vaccines may have trouble reaching advanced development due to the rarity of EEE outbreaks and the difficulty in identifying an appropriate target population for vaccination.

Mosquito-saliva vaccines are in early stages as well and would be effective against multiple mosquito diseases including EEE.

The authors state that monitoring horses, birds, and mosquitoes may provide an early warning of imminent human infections, but this surveillance can be limited by lack of funding.

The authors conclude that although it is not clear how to best address arboviruses, to “ignore them completely and do nothing would be irresponsible.”

Reference

Eastern equine encephalitis virus — Another emergent arbovirus in the United States. N Engl J Med. 2019;381:1989-1992. DOI: 10.1056/NEJMp1914328