Cases of Lyme Disease Remain Elevated

Abstracts & commentary

Synopsis: Nine states accounted for 90% of cases, including (in descending order) Connecticut, Rhode Island, New York, Pennsylvania, Delaware, New Jersey, Maryland, Massachusetts, and Wisconsin. Disease incidence exceeded 100 cases per 100,000 population in 24 counties located in these states.

Sources: MMWR Morb Mortal Wkly Rep. 2001;50:181-185; Parola P, Raoult D. Clin Infect Dis. 2001;32:897-928.

As suburban sprawl pushes communities deeper into wooded areas, cases of Lyme disease in the United States have risen. Overall, 16,801 and 16,273 cases were reported to the CDC in 1998 and 1999, respectively, up 27-30% from 1997 and more than double the figures for 1990. Nine states accounted for 90% of cases, including (in descending order) Connecticut, Rhode Island, New York, Pennsylvania, Delaware, New Jersey, Maryland, Massachusetts, and Wisconsin. Disease incidence exceeded 100 cases per 100,000 population in 24 counties located in these states.

The highest disease incidence (950.7) was reported in Nantucket County, Mass. Only 139 cases were reported from California, one of which I know to have been imported from Wisconsin.1 Five states reported no cases (Alaska, Georgia, Hawaii, Montana, and South Dakota). More than half of the cases were reported in June and July.

Comment by Carol A. Kemper, MD, FACP

Lyme disease can generally be prevented with a few simple measures. Growing up in Minnesota, we were trained at an early age to observe good tick practices: 1) Avoid tick-prone areas, or if you must camp or hike in an area with ticks, wear long sleeved shirts and long pants with socks rolled up over the cuffs; 2) Use insect repellant; 3) Do a tick check every night before bed during peak season—check all hairlines, and around breasts and under arms where the skin is soft and warm; 4) Remove any tick within 24 hours of attachment in order to reduce the risk of transmission; and 5) check your pets before letting them back in the house.

People living in areas of greatest risk should consider vaccination. But vaccination is no substitute for good tick practices. Primary care physicians in endemic areas should consider posting recommendations for good tick practices in their waiting rooms, especially during spring and summer months. (Dr. Kemper is Clinical Associate Professor of Medicine, Stanford University, Division of Infectious Diseases, Santa Clara Valley Medical Center, Redwood City, Calif.)

Reference

1. Kemper CA. Infectious Disease Alert. 2001;20:77-79.