Eastern equine encephalitis, a rare mosquito-borne illness, is becoming more common in North America due to climate change. In recent years, the disease has been reported in Wisconsin, New Jersey, Massachusetts, Vermont, and New Hampshire, where a 41-year-old man died last week after contracting the disease.
According to Theodore G. Andreadis, a researcher who studied mosquito-borne diseases at the Connecticut Agricultural Experiment Station, climate change is one of the factors spurring the spread of the disease, particularly into new regions. The first triple E outbreak on record occurred in Massachusetts in the 1830s in horses. However, it wasn’t until a full century later that mosquitoes were incriminated as potential vectors for the disease.
Researchers believe that climate change is contributing to the spread of the disease due to milder winters, warmer summers, and extremes in precipitation and drought. Warmer global average temperatures produce more mosquitoes, and warmer air temperatures shorten the amount of time it takes for mosquito eggs to hatch. Additionally, rainfall plays a role in mosquito breeding and activity, as mosquito eggs need water to hatch.
The disease is spread by two types of mosquito, the black-tailed mosquito and the perturbans mosquito. The melanura mosquito tends to live in hardwood bogs and feeds on birds, spreading the virus among them. However, the perturbans mosquito picks up the EEE virus when it feeds on birds and then infects the humans and horses that it bites.
The recent case of a 41-year-old man in New Hampshire contracting and dying from the mosquito-borne eastern equine encephalitis virus, also known as EEE or “triple E,” has raised concerns about the disease’s growing threat to public health. This rare and deadly illness has a high mortality rate, causing severe flu-like symptoms and seizures in humans four to 10 days after exposure.
As the planet warms, mosquitoes thrive in the hotter, wetter conditions, expanding their habitats and increasing the risk of disease transmission. According to Theodore G. Andreadis, a researcher who studied mosquito-borne diseases, “We’ve got milder winters, we’ve got warmer summers, and we’ve got extremes in both precipitation and drought,” which have a profound impact on mosquito populations.
The disease is spread by two types of mosquito, with the Coquillettidia perturbans mosquito primarily responsible for most of the human cases reported in the US. The outbreak has prompted state officials to begin spraying insecticide in Massachusetts, where 10 communities have been designated “critical” or “high risk” for triple E.