Prevalence and serovars of leptospira involved in equine abortions in central Kentucky during the 1990 foaling season.

This research investigates the occurrence and types of leptospira, a bacteria causing abortions in horses, found in central Kentucky’s horse population during the 1990 breeding season. Out of 726 tested instances, 4.4% were diagnosed with leptospirosis, and two specific types of leptospira – serovar kennewicki and serovar grippotyphosa – were identified.

Study Background and Methodology

• This research was orchestrated to find the level of leptospira-induced abortions in the equine population based in central Kentucky during the 1990 foaling season. It further aimed to identify the leptospira serovars, or distinct variations, responsible for these abortions.
• The study was conducted over one year, from July 1, 1989 to June 30, 1990.
• The research utilized submissions of fetal tissues, stillborn foals, and placentas; out of 726 submissions, 32, accounting for 4.4%, were diagnosed with leptospirosis.
• Diagnosis of leptospirosis was based on either the fluorescent antibody test or the microscopic agglutination test, two common methods for identifying the presence of specific bacteria.

Research Findings

• In 31 out of the 32 leptospirosis cases, attempts were made to isolate the leptospira from the fetal tissues and the dam’s urine.
• Of these cases, Leptospira interrogans serovar kennewicki was isolated in 11 cases, accounting for 35.5%, and serovar grippotyphosa was found in 2 cases, representing 6.5%.
• Additionally, in 12 cases where cultures came back negative but fetal fluids tested positive serologically (by blood test), variations of leptospira were identified: eight cases had titers, or concentrations of antibodies, against serovar pomona; one titer was found against each of serovar bratislava, grippotyphosa, and hardjo; and one case was against both bratislava and pomona.

Conclusion

• The study concluded that leptospirosis, caused by various serovars of leptospira, was indeed present and contributing to equine abortions during the 1990 foaling season in central Kentucky.
• Further, it isolated and identified specific serovars responsible, providing valuable information for future preventive and treatment measures.