Serologic evidence of equine leptospirosis in the northeast United States.

The study investigates the prevalence of leptospirosis in horses in the northeast United States using serologic testing. It found that 5% of the tested samples from healthy horses displayed significant reactions to at least one of the five leptospiral serotype antigens.

Methodology

• The researchers employed the macroscopic agglutination test, a serologic test, to identify the presence of leptospiral antibodies which signify previous or current infection.
• The study included 1,346 equine serum samples. These were all collected from clinically healthy horses across 123 purebred herds in the Northeast.

Findings

• Out of all the tested samples, 68 (which makes up around 5% of the tested population) showed significant reactions to one or more of the five serotype antigens that were tested.
• The samples with significant reactions represented 38 herds – around 31% of all the tested herds.

Reactions to Different Serotypes

• The serotype antigens used in the test included pomona, canicola, icterohemorrhagiae, grippotyphosa, and hardjo.
• The most common reaction was to the pomona serotype, with 72% of the 38 reactive herds showing this.
• Some herds showed reactions to other serotypes, namely canicola, icterohemorrhagiae, and grippotyphosa.
• No significant reactions were detected for the hardjo serotype in the study.

The study reveals the presence of leptospirosis in horse populations in the northeastern United States. The most predominant leptospiral serotype detected was pomona, which potentially provides valuable insights into the most common strain of leptospirosis present among the equine population in this region.