Borreliosis in equids in northeastern United States.

This research study monitored the prevalence of Borreliosis, caused by the bacterium Borrelia burgdorferi, in equids (horses, donkeys, etc.) in the northeastern United States between 1982 and 1985. Researchers identified a link between areas with the presence of the primary tick vector Ixodes dammini and higher rates of Borrelia burgdorferi antibodies in equids.

Methodology

• The researchers collected blood samples from 705 equids between the years 1982 and 1985.
• These samples were examined for antibodies to Borrelia burgdorferi. These antibodies indicate the equids’ immune response to the bacterium.
• They used a technique called indirect immunofluorescence staining to detect the presence of IgM and total immunoglobulin (IgM and IgG) antibodies.
• The geometric mean titer for the IgM antibody and the total immunoglobulin was calculated for different months, revealing seasonal variations in the antibody response.

Results

• Out of all the studied equids, 37 (5.3%) had IgM antibodies and 90 (12.8%) had total immunoglobulin antibodies to Borrelia burgdorferi.
• The highest geometric mean titer for the IgM antibody (140.4) was observed in July.
• The total immunoglobulin ranged from 94.1 in October to 338 in May, showing a variable response throughout the year.
• Out of the 86 equids that had total immunoglobulin to B burgdorferi, most lived in areas of Connecticut where the primary tick vector, Ixodes dammini, was present.
• Nine equids from Lyme, Connecticut and Westchester County, New York not only had Borrelia burgdorferi antibodies but also developed limb or joint disorders that caused lameness. This indicates a possible correlation between the bacterium and these health issues.

Implications

• The research provides crucial information about the incidence of Borrelia burgdorferi in equids located in the northeastern United States.
• It pinpoints the primary tick vector, Ixodes dammini, as a main transmitter of the bacterium in these areas.
• The data suggests a possible link between Borrelia burgdorferi infection and joint disorders leading to lameness in equids, although more research may be necessary to establish a definitive causal relationship.