Lyme disease prevention--knowledge, beliefs, and behaviors among high school students in an endemic area

We surveyed 153 high school students in an area highly-endemic for Lyme disease. All students were familiar with Lyme disease; 14 students reported having had the disease. Ninety per cent of students believed tick-avoidance behavior could prevent Lyme disease, but fewer than half reported practicing any preventive behaviors. Students who believed a specific behavior was preventive were 3-6 times more likely than others to practice that behavior. Schools in endemic areas should educate students about Lyme disease.

Lyme disease. The hidden pandemic

Physicians will recognize Lyme disease faster if they maintain a high index of suspicion in a young patient with arthritis accompanied by negative rheumatoid factor and antinuclear antibody in combination with cardiac conduction problems or lymphocytic meningitis. The Lyme spirochete (Borrelia burgdorferi) has notable sensitivity to tetracycline, penicillin, and erythromycin; therefore, proper and complete treatment of the disease, once it is identified, can be easily achieved. Finkel observed that Lyme disease manifests itself as a "great imitator," as do many disorders caused by a spirochete. The total impact of Lyme disease on public health will be known only when the disease is fully recognized, consistently reported, and adequately managed.

Surveillance for Lyme disease in Alabama

To estimate the frequency of occurrence of Lyme disease in Alabama, in September 1988 the Department of Public Health requested physicians and laboratories to begin voluntary reporting of cases of Lyme disease. Thirteen cases, 5 confirmed, 1 probable, 4 presumptive and 3 possible, were reported for the years 1986-1988. Counties in which tick exposure likely occurred included Calhoun, Cleburne, Mobile, Monroe, Shelby, Talladega and Tallapoosa. Lyme disease occurs in Alabama but appears to be uncommon.

Ticks parasitizing humans in a Lyme disease endemic area of southern New York State

A total of 126 tick specimens were submitted by tick bite victims to the Westchester County Department of Health, White Plains, New York, and to the New York Medical College, Medical Entomology Laboratory, Armonk, New York, during 1985. These included 96 (76.2%) Ixodes dammini, 26 (20.6%) Dermacentor variabilis, and two (1.6%) Amblyomma americanum. I. dammini parasitism was reported during all months of the year except December and February and involved all life stages. Only D. variabilis adults parasitized humans, with all cases occurring in the spring and summer. The mean age of I. dammini victims was 24.5 years, with 39.0% under age 10 years. This age group also accounted for 52.0% of all D. variabilis victims (mean age, 16.8 years). The majority of I. dammini and D. variabilis were though to be acquired in the victims' yards (68.6 and 64.7%, respectively). Attachment sites for these species were significantly different, with I. dammini nymphs found most frequently on the lower extremities and I. dammini adults and D. variabilis adults found primarily on the head. Prophylactic antibiotic treatment was prescribed by a physician for 40.8% of I. dammini victims, compared with 4.5% of the D. variabilis victims. Lyme disease was reported by two patients during the course of the study. Neither had received prophylactic therapy at the time of the reported tick bite.

Prospects for suppressing transmission of Lyme disease

A variety of methods have been developed to prevent human infection by the Lyme disease spirochete in the northeastern United States, mainly based on the observations that nymphal Ixodes dammini serve as vector, that deer serve as hosts for the reproductive stage of this tick, that white-footed mice serve as the reservoir of infection, and that nymphs are most abundant in early summer and must attach for 2 days before infection is transmitted. Methods for personal protection included seasonal avoidance of infested sites, the use of repellants, and prompt removal of attached ticks. Destruction of mouse habitat, but not of mice, was locally effective. Nondestructive acaricidal treatment of deer proved ineffective, but the elimination of these hosts resulted in reduced transmission after several years. Treatment of mice by means of acaricide-impregnated bedding material effectively reduced transmission.

Vector tick populations and Lyme disease. A summary of control strategies

Although many aspects of Lyme disease have been intensely studied for over a decade, little research has been directed toward control of the principal tick vector, Ixodes dammini. Ecological and epidemiological investigations have provided not only an ample understanding of tick biology and behavior, they have also identified the types of areas at risk for disease transmission. The advantages and limitations of previous attempts to control I. dammini by host reduction, habitat modification, and acaricide applications have been discussed in relation to overall control strategies for high-risk areas, and an integrated approach to control proposed.

Lyme disease and babesiosis: acaricide focused on potentially infected ticks

Permethrin-treated cotton, intended as rodent nesting material, was distributed in wooded sites in which the agents of Lyme disease and babesiosis were enzootic, in order to kill immature Ixodes dammini, the ticks that transmit these human pathogens. Such ticks feed most abundantly on white-footed mice (Peromyscus leucopus), apparently the main reservoir hosts of these agents, and tend to concentrate in mouse burrows. Mice captured after permethrin-treated cotton was distributed, were infested by a tenth as many ticks as were those captured in adjacent nontreated sites, a difference that continued throughout the 4-month period of observation. On average, 72% of all mice captured in treated sites were free of ticks, while virtually all mice captured in nontreated sites were infested. Voles (Microtus pennsylvanicus), however, were tick-infested, regardless of site of capture. Laboratory-reared I. dammini failed to attach to mice captured in treated sites, and most such exposed ticks died. Distribution of permethrin-treated cotton appears to be a means for preventing transmission of the pathogens that cause human babesiosis and Lyme disease.

Active immunization of hamsters against experimental infection with Borrelia burgdorferi

The immunogenicity of a single dose of a whole-cell vaccine of inactivated Borrelia burgdorferi HSF (human spinal fluid isolate) was evaluated. Syrian hamsters were vaccinated subcutaneously and challenged by the intraperitoneal injection of 1,000 50% infectious doses of B. burgdorferi HSF 30 or 90 days postvaccination. Animals were sacrificed 14 days after challenge, and the kidneys and spleens were examined for spirochetes by cultural procedures. At 30 days postvaccination, 86 to 100% protection against infection was achieved in hamsters receiving 50 and 100 micrograms (dry weight) of vaccine. Protection was decreased to 60% with 25 micrograms of vaccine and was absent with 10 micrograms of vaccine. Resistance to infection decreased to 25, 40, and 5% for the 100-, 50-, and 25-micrograms vaccine doses, respectively, at 90 days postvaccination.

Vaccination of hamsters against experimental infection with Borrelia burgdorferi

Vaccination of Syrian hamsters with a single dose of 50 micrograms to 100 micrograms dry weight of a whole cell preparation of Borrelia burgdorferi provided 75% to 86% protection against infection.