West Nile in RI and the Rise of Vector-borne Disease

Jul 19, 2012

The RI Department of Environmental Management says in a statement today that a weekly sampling of mosquitoes collected from a swamp in Westerly tested positive for West Nile virus. That doesn’t necessarily mean you have to hermetically seal yourself, your kids, and your pets inside until the first frost. But the presence of West Nile and other diseases transmitted by so-called “vectors” like mosquitoes and ticks in our area should mean you take a few precautions before venturing into the great outdoors.

Photo credit: tickencounter.org

First, about those diseases. While West Nile can cause really serious illness, it’s not nearly as prevalent in our state as the other vector-borne heavyweight, Lyme. West Nile arrived on the scene more recently, in the late ’90s. Lyme cases began popping up in the ’70s. Now, it’s the 5th most commonly reported notifiable infectious disease in the country (a “notifiable” disease is one the Centers for Disease Control wants to know about so it can stop its spread).

But there’s another tick-transmitted disease on the rise called babesiosis. It’s also spread by deer ticks in the nymph (or teenage) stage, and is mostly a problem in summer and in the Northeast and upper Midwest. In 2011, the U.S. Centers for Disease Control began requiring health care providers to report suspected cases of babesiosis. It can be more difficult to diagnose than Lyme and sometimes more serious. Plus, the symptoms are similar.

Your best bet for battling bugs is to wear repellant, check yourself for hangers-on, wear long pants and sleeves, and avoid infested areas. Find more  information from the state health department here about the disease. More great tips here on preventing tick bites, identifying ticks, and even a video on how to remove a tick safely, from the University of Rhode Island’s “tick guy,” Thomas Mather. (Mather told me recently how proud he is that this how-to video is the most popular on the topic on Youtube, which I confirmed. Nearly 1.5 million views!)

So what’s going on with the rise in vector-borne and other zoonotic diseases (vector-borne means the infectious agent is transmitted by a mosquito or tick, etc; zoonotic means the infection itself can be passed from animals to humans, like rabies or Plague)?

It’s complicated, of course. But one of the main drivers seems to be humans’ influence on the environment. We’re introducing new species and eradicating others, altering landscapes with sprawl and (mis)management, and warming the climate, and in the process giving rise to new opportunities for diseases to take root. There was a great piece by the NYT’s Jim Robbins on this recently.

I’ll be doing a story about the rise of babesiosis soon. Got experience with it? Let me know!