The spread of deadly mosquito-borne viruses to the United States from other parts of the world is beginning to pose a significant public health threat.
In recent years, the African West Nile virus, which began in New York City in 1999, has resulted in 2,000 deaths out of 30,000 total cases. No one seems to know why West Nile appeared in the Western Hemisphere in the first place, and cases are occurring at a growing rate – with half the cases reported since 2012.
Now there’s a new threat on the horizon, Eastern Equine Encephalitis, or EEE. Like West Nile, it’s considered an “arbo-virus,” which means it’s transmitted by anthropods (including mosquitoes and ticks) and results in yellow fever, dengue and in extreme cases, encephalitis (or brain swelling)
The symptoms and lethality of the two viruses differ. West Nile begins with fatigue and a fever, fever, headache, body aches, rash and swollen lymph nodes. About 80% of those infected do not display any symptoms at all, and less than 1% develop a more advanced neuro-invasive version of the disease that results in encephalitis or meningitis.
By contrast, about a third of those infected with EEE die. However, even those that survive often suffer mild to severe brain damage. In severe cases, about 20%, those infected suffer swelling of the brain that eventually results in death. The lucky ones end up with severe headaches and what seems like the flu.
Nine people have died from EEE in 2019, including three in New Jersey and Rhode Island in the early summer; the latest fatality was reported last week in Connecticut, it’s second so far. Overall, seven states have reported 28 cases of EEE so far this year, with Massachusetts — a historic hot spot for the virus — recording 10 cases and Michigan reporting eight. North Carolina and Tennessee have recorded one case each.
It is not clear why so many of the most recent cases are occurring in the mid-Atlantic and New England region. Some earlier cases back in 2016 were found in the Great Lakes region and the Gulf Coast.
According to the CDC, there have been more cases of EEE than at any time in the last half-century. The previous highpoint was 2005 when there were 21 cases.
The second “E” in EEE derives from the disease’s close relationship to horses, which are highly vulnerable to the spread of the disease. EEE can also strike birds and dogs. The good news – if there is any – is that animals, like humans, are “dead-end” hosts for EEE. We cannot spread the disease to each other.
However, there’s no FDA-approved vaccine available to the general public to combat EEE. Public health specialists do have access to an unlicensed vaccine developed in U.S. military laboratories but there are no plans to develop it commercially. The main issue is the small number of EEE cases – the market is simply too small for a company to try to profit from vaccine sales. (The same problem has plagued the West Nile virus, which is more widespread).
It’s worth noting that the Defense Department views EEE – and a less deadly sibling Western Equine Encephalitis or WEE — as a possible biological warfare weapon. The ailment is so severe and potentially incapacitating that in the wrong hands, it could wipe out large numbers of people quickly. DOD is also concerned to protect its troops, especially those stationed overseas. Without DOD interest, there wouldn’t be any funding to study EEE at all.
For most people mosquito bites are little more than a hot weather nuisance. Spray
yourself with insect repellent and you can enjoy the outdoors comfortably. For years, the main disease threats were malaria and dengue fever – and they were largely found in tropical climates and readily treatable with antibiotics.
Not so with the latest mosquito-borne threats. These can be fatal. Moreover, as EEE demonstrates, they are becoming more deadly. Current public health advisories seem hopelessly inadequate to protect the general public. Will it take a rising death count to finally move authorities to make more constructive action?