U.S. Lyme Disease Cases Doubled Since Early 1990s

Lyme disease now the most common vector-borne disease in United States

FRIDAY, June 15 (HealthDay News) -- Over 20,000 new cases per year of Lyme disease were reported from 2003-2005, making it the most common vector-borne disease in the United States, officials from the U.S. Centers for Disease Control and Prevention report in the June 15 issue of the Morbidity and Mortality Weekly Report. Reported cases have more than doubled since 1991, the agency said.

Overall, 64,382 cases of Lyme disease were reported to the CDC from 2003-2005, of which 93 percent occurred in 10 states where the disease is endemic (Connecticut, Delaware, Maryland, Massachusetts, Minnesota, New Jersey, New York, Pennsylvania, Rhode Island and Wisconsin).

The average annual incidence of Lyme disease in the 10 states during this period was 29.2 cases per 100,000 population, about triple the target annual incidence of 9.7 per 100,000 set by Healthy People 2010, according to CDC officials. The target was based on expected widespread use of a Lyme disease vaccine that was licensed in 1999 but withdrawn from the market in 2002 due to poor sales.

Seventy-four percent of cases where the date of illness was available occurred from May through August, and 54 percent of cases occurred in males. Although the median patient age was 41 years, 61 percent of cases occurred in children aged 5 to 14 years. The most common symptoms were erythema migrans and arthritis.

"Although no Lyme disease vaccine is available, persons can lower their risk for the disease and other tickborne illnesses by avoiding tick-infested areas when possible, using insect repellents containing DEET (N,N-diethyl-m-toluamide), and performing daily self-examination for ticks," CDC officials write.

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