Although Lyme disease is the most common vector-borne disease reported in humans in the United States, many researchers feel that it may actually be underreported. This study demonstrated that the seroprevalence in dogs may provide a public health surveillance tool. Many veterinarians in Maine use an ELISA (SNAP 3Dx-IDEXX Laboratories, Westbrook, ME) to screen dogs for Borrelia burgdorferi and heartworm infection. Sixty-nine clinics in Maine participated in the study. They recorded the results of all Lyme disease tests that were done as part of routine health screens. Samples from more than 9000 dogs were collected. Where dogs lived and if they had received Lyme disease vaccines were also recorded. If a dog had received the vaccine, its results were not included in the prevalence rates. These data were compared with 2 years of data of Lyme disease reported in humans in the same areas. The overall seroprevalence for unvaccinated dogs was 8%. Canine seroprevalence rates were congruent with the presence of the vector, Ixodes scapularis, and human Lyme disease reports. Geographic patterns of distribution were observed, showing a concentration of infected dogs in southern and coastal areas of Maine. There were also some high-risk foci in sparsely populated inland areas, suggesting that canine serosurveillance may identify new areas of disease transmission.

COMMENTARY: One reason this study may have been so successful in data collection was that screening was already being done. This test could be a useful tool in parts of the country where Lyme disease is not as prevalent, but collecting the data would also have to be simple and consistent.

Antibody testing and Lyme disease risk. Stone EG, Lacombe EH, Rand PW. EMERG INFECT DIS 11:722-724, 2005.