Professors study ticks to help prevent Lyme disease

Most people avoid the tiny, vampire-like bugs or remove them as quickly as possible, but Keith Clay collects ticks in plastic vials off of his dog or even off his wife's pants. \nThe tick vials end up at work where Clay and his colleagues are examining how harmless and disease-causing bacteria interact inside ticks. Their work could lead to methods of limiting the spread of diseases like Lyme disease to humans and other animals.\nClay, Curt Lively, Michael Wade and Clay Fuqua -- all IU biology professors -- and Robert Pinger from Ball State University recently received a $1.88 million grant from the National Science Foundation and National Institutes of Health to fund the research over the next five years.\nTo carry out the work, they are collecting samples of hundreds of ticks from 40 to 50 sites, mostly in central and southern Indiana. They then grind up individual ticks and sequence the genetic material. The genetic data allows them to identify bacteria by molecular fingerprinting, comparing their data to a database of known microbes. \n"I think of (the sequencing approach) as an engine telling us what kind of diversity is present," Fuqua said. "Then with these huge data sets, when we get lots of information on these individual ticks, then we can start statistically analyzing them and asking what patterns occur."\nSo far they have found a total of 10 to 15 different bacteria that live in their tick samples, some of which cause disease and others that live harmlessly in the ticks. Almost all the ticks contain at least one type of harmless bacteria, and others might contain two or more different microbes, including some of the pathogenic microbes. \nBy analyzing which ticks contain which microbes, Clay said they hope to find patterns of bacteria that are compatible or incompatible with one another. If they could find a case where a harmless microbe was incompatible with a microbe like the one that causes Lyme disease, the harmless microbe could provide a way to inoculate a tick population against the disease, according to Clay.\nTicks feed on animal blood once at each stage of their life cycle, and they can acquire or transmit disease-causing bacteria during these blood meals. They inherit harmless bacteria through their eggs.\nCompared to other parts of the U.S., Indiana sees few cases of tick-borne diseases such as Lyme disease, Rocky Mountain spotted fever, tularemia and ehrlichiosis. Twenty-three cases of Lyme disease were reported in Indiana in 2000, according to the Indiana State Department of Health, compared to CDC reports of more than 15,000 cases of Lyme disease nationwide.\nIn addition to a greater understanding of bacterial interactions in ticks, Fuqua said he sees the research as an opportunity to study human disease before humans become infected.\n"I think this whole program is a recognition that we need to know the ecology of pathogens when they're not causing disease in order to really fully understand patterns of the disease and population prevalence," he said.