Lyme disease cases double in five years

Since UNDER OUR SKIN has been released, Lyme disease cases have continued to rise, with the U.S. Centers for Disease Control (CDC) posting a final tally of 38,468 reported cases in 2009 [1], a 9% increase over the previous year. Over the past five years, Lyme cases increased by 94%, almost doubling from 2004 to 2009.

According to CDC epidemiologists, these reported cases are underestimated 6- to 12-fold in endemic regions due to inherent flaws in its passive reporting system. [2] Consequently, the actual number of new Lyme cases in 2009 could be as high as 461,616.

The large gap between reported and actual cases is caused by a number of factors, including:
1. Inaccurate Lyme tests [3]
2. Failure of physicians to report cases
3. A labor-intensive process that requires local health officials to contact individual physicians to confirm details of many of the case reports [4]
4. Cases rejected because they don’t fit the conservative surveillance definition of Lyme disease

The Lyme disease surveillance process was changed in 2008, with the goal of reducing the burden of the CDC/CTSE complex mandatory Lyme reporting process on resource-strapped state and local health departments. [4] Unfortunately, the resulting revision, which was held behind closed doors with no provision for public comment, did nothing to address the fundamental flaws in the surveillance criteria—it is still based on an inaccurate blood test, an outdated list of Lyme disease symptoms, and a cumbersome reporting process that places an undue burden on state and local health departments.

Instead, the CDC/CTSE revision added more complexity and less transparency to the reporting system, creating three categories for Lyme cases – confirmed, probable and suspected.

The problem with the “suspected” category of Lyme cases is that it allows state health workers who don’t have time to follow up on valid cases, with positive test results or the classic Lyme bulls eye rash, to place them in a list that the CDC never publishes. In addition, the CDC only reports the confirmed cases to the media, never mentioning the probable and suspected cases, or the fact that CDC epidemiologists say that the actual case count could be ten times higher than the reported cases.

The tragedy of this new process is that physicians make diagnostic decisions based on the CDC case numbers, and when cases in their states are underestimated, more Lyme patients will be misdiagnosed. Congress allocates research funding based on the CDC case numbers, too, and by underestimating these numbers by a factor of ten, grants will go to other diseases.

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[1] CDC. Reported Lyme disease cases by state, 1995-2009. Reported cases in this chart include both “confirmed” and “probable” cases for 2008 and 2009.
http://www.cdc.gov/ncidod/dvbid/lyme/ld_rptdLymeCasesbyState.htm
2009 reported Lyme cases = 29,959 confirmed + 8509 probable = 38,468
2008 reported Lyme cases = 28,921 confirmed + 6277 probable = 35,198
2009 annual increase = (38,468 – 35,198)/35,198 = 9.3%

[2] CDC. Cases are “under-reported by 6- to 12-fold.” http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5317a4.htm

[3] Coulter, P, et. al. 2005. Two-Year Evalution of Borrelia burgdoferi Culture and Supplemental Test for Definitive Diagnosis of Lyme Disease, Clin. J. Clin. Microbiol. 41: 5080-5084. “…no single test is optimal for Lyme disease diagnosis”

[4] CDC. Burden of Lyme Reporting. http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5702a4.htm
In New Jersey, for example, the health department found that each Lyme case took health officials an average of 2 months to close; 24% of Lyme cases were never closed or counted; and the Lyme reporting process in New Jersey alone required 5 full-time employees to handle.