From 1990 through 1995, 913 ticks removed from 460 human patients in Georgia or South Carolina were identified and recorded. The majority of these specimens (758, 83.0%) were lone star ticks, Amblyomma americanum. One hundred and four (11.4%) American dog ticks Dermacentor variabilis, 36 (3.9%) blacklegged ticks Ixodes scapularis, 9 (1.0%) Gulf coast ticks Amblyomma maculatum, and 6 (0.7%) brown dog ticks Rhipicephalus sanguineus were also recovered. All active stages (larvae, nymphs, and adults) of A. americanum were represented, whereas nymphs and adults of D. variabilis and I. scapularis and only adults of A. maculatum and R. sanguineus were recorded. Compared with data published for other regions in the U.S.A., A. americanum was a much more prevalent parasite of humans in the current survey. Only 1 (3%) of the I. scapularis collected was a nymph. Because these tick species are vectors of zoonotic pathogens or cause tick paralysis in humans, the data have epidemiological significance.

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From June 1995 through January 1998, 677 tick specimens were submitted by 521 humans from 14 states. Analysis was limited to specimens originating in Georgia and South Carolina, representing 87.3% of total submissions. Attachment sites were specified in 367 specimens (62.3%). The American dog tick, Dermacentor variabilis (Say), a vector of the agent of Rocky Mountain spotted fever, favored the head and neck in 59% of attached specimens. The lone star tick, Amblyomma americanum (L.), a strongly implicated vector of the agent of human monocytic ehrlichiosis, favored the lower extremities, buttocks, and groin in 54% of specimens. The blacklegged tick, Ixodes scapularis Say, the main eastern vector of the Lyme disease spirochete, had widely distributed attachment sites with no apparent site preference. The Gulf Coast tick, A. maculatum Koch, parasitized humans in too few instances for analysis. In the southeastern United States, prevention of tick bites and tickborne illnesses such as Rocky Mountain spotted fever, ehrlichiosis, and Lyme disease may be enhanced by personal practices and public health measures based on knowledge of preferred attachment sites of potentially infectious tick species.

We investigated the use of the polymerase chain reaction (PCR) to detect Borrelia burgdorferi strain B-31 in human blood and urine experimentally inoculated with 5 and 1 borreliae/cm³, respectively, and to biotinylate a DNA probe specific for B. burgdorferi in the dot blot and Southern blot assays. When the blood and urine samples were subjected to PCR, a 370-bp amplified product was consistently visible on agarose gel electrophoresis after 30 and 45 cycles, respectively. The total human genomic DNA extracted from a 1-cm³ sample of inoculated blood was approximately 6.25 µg, and the total amount of B. burgdorferi DNA was estimated to be 0.01 pg/6.25 µg of the human DNA. For PCR, 2.5 µg of human DNA which contained the equivalent of 0.004 pg of borrelia DNA (approximately two borreliae) were used for enzymatic amplification. When 1/20 or 1/10 of the PCR-amplified products were used either for dot blot or Southern blot hybridization, the accessible copies of amplified B. burgdorferi DNA were sufficient for detectable hybridization to occur. PCR amplification of B. burgdorferi DNA in clinical specimens followed by dot blot hybridization may be a valuable adjunct or alternative to current but inadequate laboratory methods for the diagnosis of Lyme disease.