A 41-year-old man from New Hampshire He died last week. This marks the first human case in New Hampshire in 10 years after the patient was infected with a rare mosquito-borne disease called Eastern Equine Encephalitis Virus, also known as EEE or “Triple E.” Four other cases of human EEE have been reported in New Hampshire this year. Wisconsin, New Jersey, Massachusetts, Vermont.
While this outbreak is small and Triple E does not pose a risk to most people living in the United States, public health officials and researchers are concerned about the threat this deadly virus poses to the general public, both this year and in future summers. There is no known cure for the disease, which causes severe flu-like symptoms and seizures 4-10 days after infection and kills 30-40% of those infected. Half of those who survive a Triple E infection are left with permanent neurological damage. Due to the high mortality rate of EEE, state officials Pesticide spraying begins in MassachusettsTen communities are in the triple E “critical” or “high risk” category. It closed parks from dusk to dawn and warned people to stay indoors after 6 p.m.This is the time when mosquitoes are most active.
Like West Nile virus, another mosquito-borne disease that poses a risk to people in the United States each summer, Triple E is constrained by environmental factors that are rapidly changing as the planet warms, as mosquitoes thrive in the hotter and wetter conditions that climate change creates.
“Over the last decade or so, we’ve seen a resurgence of eastern equine encephalitis virus activity,” said Theodore G. Andreadis, a researcher who has studied mosquito-borne diseases for 35 years at the Connecticut Agricultural Experiment Station, a state government research and outreach agency. “And we’ve seen its expansion into northern areas where it hadn’t been detected before.” Researchers don’t know what causes the virus to surge and decline, but Andreadis said it’s clear that climate change is one factor that’s facilitating its spread, especially to new areas.
Illness from tomorrow onwards
of First recorded occurrence of Triple E It first appeared in horses in Massachusetts in the 1830s (hence the three E’s, one for “horse”). It wasn’t until a century later, in 1934, that mosquitoes were suspected as a potential vector for the disease. The first human cases of the disease also occurred in Massachusetts four years later, in 1938. That year, there were 38 cases in the state, including 25 deaths.Since then, human cases have They have been registered primarily in the Gulf Coast states, with an increasing number of cases in the Northeast.From 1964 to 2002, there was less than one case per year in the Northeast. From 2003 to 2019, the average number of cases in the region increased to four to five cases per year.
The disease is spread by two types of mosquitoes. The first is the Culiseta melanura, or black-tailed mosquito. This mosquito tends to live in deciduous wetlands, where it feeds on birds such as robins, herons, and wrens, spreading the virus among them. However, melanura mosquitoes do not often bite mammals. Another mosquito species, Coquillettidia perturbans, is the primary cause of the majority of reported human cases of the disease in the United States. The perturbans mosquito feeds on birds, picking up the EEE virus and transmitting it to humans and horses that it bites. Human cases begin to surge in late summer, when mosquito populations peak and compete for available blood.
Andreadis is Published a historical memoir International Health Organization (IHE) researchers studying the 2021 triple E outbreak in the northeastern US said climate change is emerging as a major cause of the disease.
“We’re seeing milder winters, warmer summers, and more extreme precipitation and drought,” he says. “The impact of this on mosquito populations is probably quite significant.”
Rising global average temperatures generally lead to an increase in mosquito populations, regardless of species.
Research has shown that C. melanura eggs take less time to hatch when temperatures rise above a certain threshold, around 90 degrees Fahrenheit. Warmer temperatures in the spring and fall give mosquitoes more days to breed and feed, and warmer temperatures in the summer encourage them to feed more frequently because mosquitoes are ectothermic and warmer temperatures speed up their metabolism.
Rainfall also affects mosquito breeding and activity, as mosquito eggs need water to hatch. Warm air Retains more moistureThis means that even small amounts of rainfall will dump more water than they did in the last century. More water will accumulate in roadside ditches, abandoned car tires, ponds, swamps and holes, creating more opportunities for mosquitoes to breed. And warmer water temperatures will shorten the incubation period for C. melanura eggs, A study They conclude that warmer-than-average water temperatures “increase the likelihood of EEE amplification.”
Climate change is not the only factor facilitating the spread of pathogens like mosquitoes. The slow reforestation of areas that were cleared for industry or agriculture decades ago is creating new habitats for insects. At the same time, Developers are increasingly building new homes in wooded and semi-forested areas.This brings humans even closer to the natural world and the insects that live there.
West Nile virus becomes deadly
At an individual level, the best way to protect yourself from EEE and other mosquito-borne diseases is to avoid being bitten: wear long sleeves and long trousers during dusk and dawn, when mosquitoes are most likely to bite; Use an effective mosquito repellent regularlyHowever, there are steps local health departments can take to protect public health, such as testing pool water for mosquito larvae and conducting public education and insecticide spraying campaigns when Triple E is detected. Massachusetts is one example of a state that has actively tested for Triple E in mosquitoes in recent summers.
The most effective way to protect people from the disease would be to develop a vaccine. A vaccine already exists for horses, but There are few incentives Because the disease is so rare, vaccine manufacturers will need to develop a preventative treatment for triple E in humans.
“While EEE is not yet a global health emergency, the recent rise in cases has highlighted our inadequate preparedness for unexpected infectious disease outbreaks.” A group of biologists wrote in the open-access scientific journal Frontiers last year.“In the face of these threats, it would be prudent to be proactive and take active control measures and exercise heightened vigilance.”
