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Thu August 1, 2013
Dr. Kerry Clark, University of North Florida – Expanding the Lyme Disease Zone
In today’s Academic Minute, Dr. Kerry Clark of the University of North Florida explains why Lyme disease is a threat in areas beyond the northeastern United States.
Kerry Clark is an associate professor of public health at the University of North Florida in Jacksonville, Florida. His area of expertise includes the ecology and epidemiology of tick-borne diseases such as Lyme borreliosis, human ehrlichiosis, babesiosis, rickettsiosis, anaplasmosis, and others. He holds a Ph.D. from the University of South Carolina School of Public Health.
Dr. Kerry Clark – Expanding the Lyme Disease Zone
Lyme disease is by far the most common vector-borne disease in the United States, but it is still erroneously considered as rare in most areas of the Southeast. Under-recognition and misdiagnosis are common in southern states. Often, infections are diagnosed as Southern Tick Associated Rash Illness (a.k.a. STARI), believed to be a separate disease, but for which no cause has been identified. Also, controversy exists over the tick species responsible for transmitting Lyme disease in the South. The aim of my study was to determine the cause of illness in several human patients in Florida and Georgia who, based on signs or symptoms, were suspected of having Lyme disease.
Patients in my study received a variety of diagnoses by their physicians, including chronic fatigue syndrome, fibromyalgia, multiple sclerosis, and others. We tested patients’ blood, skin samples from rashes, or ticks removed from patients with polymerase chain reaction (PCR) tests to detect DNA of Lyme disease bacteria. This was followed by DNA sequence analysis. We found three different Lyme Borrelia species in patient samples, including the known Lyme disease species Borrelia burgdorferi, and two other species never before found in human LD patients. We also identified Lyme Borrelia DNA in lone star ticks removed from several patients.
This study confirmed LD infection in 10 patients from Florida and Georgia, and lone star ticks were implicated as potential vectors for several cases. Other cases of Lyme-like illness sometimes referred to as STARI in the southern U.S. may also be attributable to actual Lyme disease from previously undetected species of the bacteria.