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MORBIDITY AND MORTALITY WEEKLY REPORT

From 1984 through 1986, CDC received an average of 1,500 reports of Lyme disease annually, making it the most common tick-borne disease reported to CDC. The disease takes its name from Lyme, Connecticut, where the full spectrum of illness

riny-one percent of patients with Lyme disease were male, and all but one of the 372 patients with known race reported in 1984 were white. Racial information was not gathered in 1985. Age-specific incidence was tabulated by 5-year age groups for patients reported in 1985. The incidence ranged from 11/100,000 for persons aged 20 to 24 years, to 39/100,000 for those aged 5 to 9 years (Figure 1).

Overall, 83% of the patients studied had erythema migrans; 24% had arthritis; 8% had neurologic manifestations; and 2% had cardiac involvement. For those with arthritis, affected joints were the knee (89%), hip (9%), shoulder (9%), ankle (7%), and elbow (2%). In 1985, persons under 20 years of age were 1.6 times more likely to have *A distinctive skin lesion that characterizes the first stage of the disease.

*Neurologic and cardiac manifestations characterize the second stage of the disease, and arthritic manifestations, the third. These later stages can occur weeks or years after the initial tick bite and without evidence of an earlier skin lesion.

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES/PUBLIC HEALTH SERVICE

From 1984 through 1986, CDC received an average of 1,500 reports of Lyme disease annually, making it the most common tick-borne disease reported to CDC. The disease takes its name from Lyme, Connecticut, where the full spectrum of illness was first described in 1975. To further study the incidence of disease among its residents, Connecticut conducted a laboratory-based program of surveillance for Lyme disease from July 1, 1984, to March 1, 1986.

Indirect immunofluorescence antibody (IFA) and enzyme-linked immunosorbent assays (ELISA) were used to detect antibodies to Borrelia burgdorferi, the spirochete that causes the disease. Serologic testing was offered to Connecticut physicians without cost for all residents with suspected Lyme disease if the serum was accompanied by a case report form. Residents who, in 1984 or 1985, had onset of erythema migrans* and/or neurologic, cardiac, or arthritic manifestations* characteristic of Lyme disease and a positive serologic test (IFA >1:128 or ELISA 1:160 with a polyvalent conjugate) were included in the study.

Thirty-seven percent of the 3,098 patients reported met the criteria for inclusion in the study (460 in 1984 and 689 in 1985). In 1985, the first complete year of reporting, 66% of the patients studied had onset of symptoms from June through August. Twenty-four percent more patients had onset of symptoms from July through December 1985, than from July through December 1984 (492 compared with 397). Serologic testing was equally available during these time periods.

The incidence of Lyme disease for all Connecticut residents in 1985 was 22/100,000. Town-specific incidences ranged from zero to 1,156/100,000. Towns with the highest incidences were in southern Connecticut, east of the Connecticut River. Fifty-one percent of patients with Lyme disease were male, and all but one of the 372 patients with known race reported in 1984 were white. Racial information was not gathered in 1985. Age-specific incidence was tabulated by 5-year age groups for patients reported in 1985. The incidence ranged from 11/100,000 for persons aged 20 to 24 years, to 39/100,000 for those aged 5 to 9 years (Figure 1).

Overall, 83% of the patients studied had erythema migrans; 24% had arthritis; 8% had neurologic manifestations; and 2% had cardiac involvement. For those with arthritis, affected joints were the knee (89%), hip (9%), shoulder (9%), ankle (7%), and elbow (2%). In 1985, persons under 20 years of age were 1.6 times more likely to have *A distinctive skin lesion that characterizes the first stage of the disease.

*Neurologic and cardiac manifestations characterize the second stage of the disease, and arthritic manifestations, the third. These later stages can occur weeks or years after the initial tick bite and without evidence of an earlier skin lesion.

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES/PUBLIC HEALTH SERVICE