Public health impact of strain specific immunity to Borrelia burgdorferi.
BACKGROUND
Lyme disease, caused by Borrelia burgdorferi, is the most common tick-borne infection in the United States. Although humans can be infected by at least 16 different strains of B. burgdorferi, the overwhelming majority of infections are due to only four strains. It was recently demonstrated that patients who are treated for early Lyme disease develop immunity to the specific strain of B. burgdorferi that caused their infection. The aim of this study is to estimate the reduction in cases of Lyme disease in the United States that may occur as a result of type specific immunity.


METHODS
The analysis was performed based on three analytical models that assessed the effects of type specific immunity. Observational data on the frequency with which different B. burgdorferi strains cause human infection in culture-confirmed patients with an initial episode of erythema migrans diagnosed between 1991 and 2005 in the Northeastern United States were used in the analyses.


RESULTS
Assuming a reinfection rate of 3 % and a total incidence of Lyme disease per year of 300,000, the estimated number of averted cases of Lyme disease per year ranges from 319 to 2378 depending on the duration of type specific immunity and the model used.


CONCLUSIONS
Given the assumptions of the analyses, this analysis suggests that type specific immunity is likely to have public health significance in the United States.
Evolution and Ecology of Disease Systems Laboratory, Department of Biology, University of Pennsylvania, Philadelphia, PA, USA. camilok@sas.upenn.edu.
Camilo E
CE
Khatchikian
Division of Infectious Diseases, Department of Medicine, New York Medical College, Valhalla, NY, USA. robert_nadelman@nymc.edu.
Robert B
RB
Nadelman
Division of Infectious Diseases, Department of Medicine, New York Medical College, Valhalla, NY, USA. john_nowakowski@nymc.edu.
John
J
Nowakowski
Department of Microbiology and Immunology, New York Medical College, Valhalla, NY, USA. ira_schwartz@nymc.edu.
Ira
I
Schwartz
Department of Biostatistics and Epidemiology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA. mzlevy@mail.med.upenn.edu.
Michael Z
MZ
Levy
Evolution and Ecology of Disease Systems Laboratory, Department of Biology, University of Pennsylvania, Philadelphia, PA, USA. dbrisson@sas.upenn.edu.
Dustin
D
Brisson
Division of Infectious Diseases, Department of Medicine, New York Medical College, Valhalla, NY, USA. gwormser@nymc.edu.
Gary P
GP
Wormser
D025065:Borrelia burgdorferi / Q000276:immunology / Q000472:pathogenicity*; D015748:Borrelia burgdorferi Group; D006801:Humans; D015994:Incidence; D008193:Lyme Disease / Q000453:epidemiology / Q000276:immunology* / Q000382:microbiology*; D009518:New York / Q000453:epidemiology; D011634:Public Health; D014481:United States