The distribution of canine exposure to Borrelia burgdorferi in a Lyme-Disease endemic area.

OBJECTIVES: A serosurvey of canine exposure to Borrelia burgdorferi, the causative agent of human Lyme disease, was conducted in Westchester County, New York, to determine the distribution of exposure in an area endemic for Lyme disease. METHODS: A total of 1446 blood samples was collected from resident dogs and tested by modified enzyme-linked immunosorbent assay. Equivocal samples were further tested by immunoblot. A mean number of 57.8 samples was collected from each of 25 towns and cities. RESULTS: Seroprevalence rates for municipalities ranged from 6.5% to 85.2%. County seroprevalence was 49.2%. There was a significant difference among the rates for the northern (67.3%), central (45.2%), and southern (17.3%) regions. Multiple range analysis indicated homogeneity between the southern and central regions and the central and northern regions. CONCLUSIONS: Canine exposure to B burgdorferi increases in a south to north gradient within the county. Intensity of exposure, measured by enzyme-linked immunosorbent assay titers, indicates a similar pattern. The close association between dogs and humans suggests that human risk of acquiring Lyme disease within Westchester County is equally disparate and is inversely related to the degree of urbanization.

Bacteriocin production by Neisseria gonorrhoeae.

Seventeen apparently unrelated isolates of Neisseria gonorrhoeae out of 2,123 tested produced a diffusible growth-inhibitory substance against other gonococci. The inhibitor was destroyed by trypsin, not blocked by bovine serum albumin, and not soluble in chloroform-methanol; each isolate was resistant to the inhibitor it produced. Thus, the substance differs from previously described gonococcal inhibitors, and since it fits the description of a bacteriocin we designated it gonocin. The use of gonocin for typing was complicated by the observation that susceptibility to gonocin appears to depend on the gonococcal colony type.