A lethal, mosquito-borne virus that causes jap equine encephalitis (EEE) has contaminated an eighth particular person in Massachusetts, a state that the sickness has hit notably exhausting, the state’s public well being division introduced Sept. 13.
On common, simply seven instances of EEE are reported within the U.S. annually, in response to the Centers for Disease Control and Prevention (CDC). This 12 months, the virus has killed three folks, together with a Massachusetts lady. So why is Massachusetts taking the brunt of this virus?
The New England state has one of many densest concentrations of pink maple and white cedar swamps on the East Coast. “These swamps are the engines that drive EEE exercise,” mentioned Dr. Catherine Brown, the Massachusetts state epidemiologist.
Here’s why: Birds contaminated with the EEE virus migrate up from Florida, the place EEE can also be an issue, to New England yearly. These birds desire to stay within the pink maple and white cedar swamps, as does a selected species of mosquito that primarily feeds on birds. Taking up residence close to these swamps, the birds grow to be blood meals for the mosquitoes, which subsequently choose up the virus.
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Other species of mosquitoes that primarily feed on mammals will sometimes additionally feed on the birds, changing into the gateway for the virus to hop from birds to mammals, equivalent to horses and people. Humans and horses are “unintended” and “dead-end hosts,” and the virus has nowhere to go from there, Brown mentioned.
The virus would not kill the birds, and after a few years or so, these birds construct up an immunity to EEE. Once that occurs, the virus would not successfully transmit among the many birds and would not journey extensively, so the state has a lull in outbreaks.
But then the proportion of birds with immunity begins reversing itself, because the birds with immunity die off ultimately from previous age and hatchlings are left susceptible. What’s extra, sometimes, the migrating birds will convey with them a barely totally different pressure of EEE that not one of the birds are resistant to. Taken collectively, these components trigger outbreaks in Massachusetts each 10 to 20 years, and these can final for a number of years.
In people, the virus invades the central nervous system and causes irritation within the mind. About 30% of people that contract EEE die, and lots of of those that survive have ongoing neurological issues, in response to the CDC.
“At this time, there are not any particular drugs which might be identified to deal with EEE,” Brown mentioned. Even so, this illness could be very uncommon; each nonoutbreak 12 months there are sometimes solely a mean of seven instances recognized in all the U.S. Other states are additionally dealing with threats from the virus inflicting EEE – the opposite two fatalities occurred in Michigan (the place two different folks have been suspected of being contaminated) – and Rhode Island, the state’s solely confirmed human case since 2010.
Mosquito season in New England is winding down, and usually, EEE infections additionally drop to close zero by mid-September. However, “I believe all people is nervous about this 12 months” as a result of it is notably widespread, Brown mentioned. The state is spraying pesticides to eliminate mosquitoes in high-risk areas.
The finest prevention for EEE is to keep away from mosquito bites, Brown mentioned. She recommends utilizing mosquito repellents, carrying clothes that covers up the physique when outdoors and dumping out any standing water the place mosquito larvae can develop. In the highest-risk areas of Massachusetts, she recommends folks keep away from out of doors actions from nightfall to daybreak.