Lyme is not the only disease deer ticks can transmit. Scientists now know of four other pathogens the tick can transmit to humans. The oganisms are less prevalent that Lyme, but in some cases can make people much sicker.
Babesiosis, caused by microscopic parasites that infect red blood cells, can result in a range of symptoms, including fever, aches, chills, and in rare cases, death in the elderly or those with a weakened immune system or without a spleen. It is often treated using antimalaria-like drugs.
The illness is a growing problem in the nation’s blood supply, in part because some people may feel fine if they have it and unwittingly contaminate blood when they donate. There were 159 transfusion-associated cases from 1979-2009, with more than three-quarters of the cases reported after 2000, according to a 2011 paper in the Annals of Internal Medicine. Scientists are working on blood-screening tests.
Anaplasmosis, caused by bacteria, can deliver flu-like symptoms, confusion, malaise, and in very rare cases, death. Researchers earlier this year announced they discovered another strain of tick-borne bacteria in the Northeast — so new it has no name — that can make people sick.
The bacteria can cause flu-like symptoms, and in one case, an immune-compromised elderly woman became confused and withdrawn, lost weight, and developed hearing difficulty and a wobbly gait until she was treated. Both diseases, like Lyme, are treated with antibiotics.
Yale University researchers estimate 1 percent of the population in areas where Lyme disease is widespread may be infected with the bacteria.
A far rarer disease, deer tick virus, can cause fatigue, fever, stiff neck and neurological issues, and also death. There is no known treatment for it, according to Sam R. Telford III, an infectious disease professor and tick specialist at the Cummings School of Veterinary Medicine at Tufts University. Less than one percent of nymphal ticks are likely to be infected with it.
While the bacteria that causes Lyme disease is consistently found in about 20 to 30 percent of deer tick nymphs and about 50 percent of adults in the Northeast, rates of infection of the other pathogens vary from place to place, according to Stephen Rich, a University of Massachusetts Amherst microbiologist who runs the school’s Laboratory of Medical Zoology.
His lab conducts DNA analyses of ticks people discover — on their body or pets, outdoors or indoors. For a fee, the lab tests mailed-in or dropped-off ticks for pathogens.
The results won’t tell you whether a tick transmitted a disease to a person — that depends on the amount of pathogen in the tick and how long it has fed — but people like to know the answer. Scientifically, it gives insight into the level and spread of disease in specific regions.
The almost 4,000 ticks the lab has analyzed in the last seven years have revealed interesting information: The bacteria that cause anaplasmosis and babesiosis are more prevalent, for example, in ticks on Cape Cod than ones in the Pioneer Valley in Western Massachusetts.
“What we are seeing in anaplasmosis and babesiosis is what Lyme disease looked like 30 years ago — it hugs the coast,” Rich said. “It is vital we figure out what are the ecological factors that allowed Lyme to spread and what, if anything, is limiting the spread of [these two diseases].”