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Press Release for Monday, June 10, 2013

UNF Professor Discovers Two Lyme Bacterial Species Can Infect Humans

Media Contact: Joanna Norris, Associate Director

Department of Public Relations

(904) 620-2102


For the first time ever, Dr. Kerry Clark, University of North Florida associate professor of public health, and his colleagues have found two species of Lyme disease bacteria previously unknown to infect humans in patients.



These two Lyme disease species, Borrelia americana and Borrelia andersonii, were found in symptomatic patients living in the Southeastern United States. The commonly found lone star tick, formerly believed by many to be incapable of transmitting Lyme disease, was implicated in some of these cases.


His research, published in the May issue of The International Journal of Medical Sciences, is extremely significant for several reasons. First, only oneLyme bacterial species, Borrelia burgdorferi sensu stricto, was previously recognized to cause disease in North America. Current testing methods and interpretation criteria, designed to detect just one species, may explain many of the complaints involving the unreliability of Lyme disease tests in the U.S.


This study’s findings suggest that multiple Borrelia species may be causing Lyme disease in the Southeast, another tick species may also be transmitting it in the Southeast and that it may be much more common here than was previously thought,” said Clark. “Additional evidence presented suggests that some people may develop chronic infections, and the current antibody testing approach for Lyme disease may not identify the infections.”


The belief that only black-legged “deer ticks” can transmit Lyme disease has been widely publicized for decades. Lyme disease risk has been calculated largely based upon the prevalence and infection rate of these “deer ticks. Clark’s findings, together with past studies implicating lone star ticks associated with Lyme disease, strongly suggest otherwise.


Clark and his team identified lone star ticks removed from humans who tested positive for Lyme bacteria, including the species of Borrelia burgdorferi, already known to cause the disease in North America. Some of the ticks removed from the patients tested positive, too.


Lone star ticks are the most commonly found species biting humans in the Southeastern U.S. These aggressive ticks are found almost halfway across the nation, from the Deep South and as far north as Canada. This groundbreaking research may clarify why so many humans living outside of the Northeastern U.S. claim they have contracted Lyme disease, regardless of the presence of infected black-legged “deer ticks.”


The new findings significantly expand the geographic area where Lyme disease should be considered by medical providers and citizens alike. “If only one percent of these ticks are able to transmit Lyme disease, it poses a tremendous threat to public health because lone star ticks are known to bite humans so frequently,” said Liz Schmitz, president of the Georgia Lyme Disease Association (GALDA), which provided both technical assistance and funding in support of Clark’s research.


Additionally, Clark’s work may help millions of chronically ill people living in areas where Lyme disease wasn’t previously recognized. Called The New Great Imitator, Lyme disease is often mistaken for illnesses such as fibromyalgia, chronic fatigue syndrome, lupus, multiple sclerosis, rheumatoid arthritis, Lou Gehrig's disease, Parkinson’s, ADHD and even Alzheimer’s.


GALDA is an all-volunteer patient advocacy group that is dedicated to the prevention of and education about Lyme disease and other tick-borne diseases. The non-profit organization recently kicked off a fundraising campaign to support Clark’s research. To find out more, visit .


In addition to research and teaching, Clark serves as a board member for the Northeast Florida Lyme Association (NEFLA), with whom he collaborates in Lyme disease education and awareness activities. “NEFLA has also been significant in raising funds to support my research over the past several years,” said Clark.


UNF, a nationally ranked university located on an environmentally beautiful campus, offers students who are dedicated to enriching the lives of others the opportunity to build their own futures through a well-rounded education.