New CDC Estimate: 300K Americans Diagnosed With Lyme Disease Each Year

If you follow Lyme disease at all, you know that there's no question that the official prevalence figures fail to capture the true extent of the toll those nasty little disease-spreading deer ticks take. The only question is just how far the official figures fall short of reality.

WBUR's Lyme Disease series last summer cited these official figures for Massachusetts: 2-4,000 confirmed cases each year. But everyone knows those numbers are laughably low. Dr. Catherine Brown of the Massachusetts Department of Public Health said a more realistic figure might be the 12-14,000 positive lab tests for Lyme disease reported statewide each year. But that's clearly still low. A leading tick expert estimated that in much of Massachusetts, about 1 percent of the population contracts Lyme each year.

Now, at a major conference on Lyme disease and other tick-borne illnesses under way in Boston, federal health authorities have just released their own more realistic estimate, and it's about ten-fold their old one. From the CDC press release:

Preliminary estimates released by the Centers for Disease Control and Prevention indicate that the number of Americans diagnosed with Lyme disease each year is around 300,000. The preliminary estimates were presented Sunday night in Boston at the 2013 International Conference on Lyme Borreliosis and Other Tick-Borne Diseases.

This early estimate is based on findings from three ongoing CDC studies that use different methods, but all aim to define the approximate number of people diagnosed with Lyme disease each year. The first project analyzes medical claims information for approximately 22 million insured people annually for six years, the second project is based on a survey of clinical laboratories and the third project analyzes self-reported Lyme disease cases from a survey of the general public.

Each year, more than 30,000 cases of Lyme disease are reported to CDC, making it the most commonly reported tick-borne illness in the United States. The new estimate suggests that the total number of people diagnosed with Lyme disease is roughly 10 times higher than the yearly reported number. This new estimate supports studies published in the 1990s indicating that the true number of cases is between 3- and 12-fold higher than the number of reported cases.

“We know that routine surveillance only gives us part of the picture, and that the true number of illnesses is much greater,” said Paul Mead, M.D., M.P.H, chief of epidemiology and surveillance for CDC’s Lyme disease program. “This new preliminary estimate confirms that Lyme disease is a tremendous public health problem in the United States, and clearly highlights the urgent need for prevention.”

CDC continues to analyze the data in the three studies to refine the estimates and better understand the overall burden of Lyme disease in the United States and will publish finalized estimates when the studies are complete. Efforts are also underway at CDC and by other researchers to identify novel methods to kill ticks and prevent illness in people.

Readers, given your own anecdotal experience among the circles of people you know, what do you think the estimate ought to be?