How Birds Could Make Lyme Disease a National Problem

Lyme disease: it's a pain for people both figuratively and physically. And for as long as the disease has been around, people have placed the blame squarely on the deer tick. Now new research has revealed that birds, of all things, should also be sharing a great deal of the blame, as they serve as ideal incubators and distributors of the disease. 

Causing approximately 30,000 cases annually, the bacterium Borrelia burgdorferi behind Lyme disease is mostly found in the United States' northeast and upper Midwest, according to the US Centers for Disease Control and Prevention (CDC).

Its main vector is the deer tick (Ixodes scapularis), but researchers have long known that the disease does not flourish within the tick. Instead, the Lyme bacterium circulates among wood rats, western gray squirrels, and other small mammals before being picked up by the ticks, who can then spread it to humans when feeding on their blood.

Researchers have long suspected that the nature of these 'incubators' - restricted to their respective habitats - is what has stopped the disease from becoming a national problem, even if was the 5th most common Nationally Notifiable disease in 2013.

However, it can already be found in California, and experts worry that if it ever were  to find its way to the rest of the west coast, health professionals could have a much bigger problem on their hands.

And, one such way this could happen is on feathered wings.

"The role of birds in the maintenance of Lyme disease bacteria in California is poorly understood," Erica Newman, a researcher with the University of California at Berkeley explained in a recent release. (Scroll to read on...)

Newman and her colleagues recently published a study in the journal PLOS One that investigates this very real concern. It is the first study of its kind to consider bird diversity, behavior, and habitats when identifying key carriers.

"Birds are much more capable of carrying diseases long distances than the small-mammal hosts typical of Lyme disease, and so may constitute an underappreciated component of Lyme disease ecology," added Morgan Tingley, an ornithologist who was not part of the study. "In the same way that airplanes can help spread disease across nations, birds do the same thing for our ecosystems."

So what did this new study uncover? In an analysis of samples from 14 sites, 623 birds representing 53 species, and 284 juvenile ticks found on the birds, the researchers found that well over half the birds collected were carriers. Goldfinch, oak titmouse, and dark-eyed junco birds were all found to harbor the most varied subtypes of the bacterium, meaning that they are more likely to hand off bacterium to a tick that could eventually find its way into a human.

Stunningly, the researchers also identified the bacterium Borrelia bissettii that has been known to cause a Lyme disease-like illness in people in central and southern Europe. Study co-author Robert Lane added that what's most intriguing about this is that B. bissettii has never before been identified in birds, never mind in a US species.

"The fact that we found this particular bacterium for the first time in birds in California is notable because of the ease with which birds can distribute spirochetes to different regions," said Lane. "It is worth watching to see if this spirochete expands in this state."

Still, it's important to remember that Lyme disease and its cousin illness are not exactly doomsday material. If caught early enough, it can be treated and eliminated in a matter of days or weeks. If caught later, the disease can still be suppressed, with it only often causing joint pain and exhaustion - serious problems, but ones that people can endure to live otherwise healthy lives.

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