Titer Concentration Testing for Leptospirosis in Equine

Project Abstract

Managing disease in the equine population is daily battle for horse owners. One of the most common management practices to combat diseases are vaccinations. Vaccines provide animals with immunity or help to reduce the effects of certain diseases. Vaccinations contain weakened or killed forms of different diseases, and by administering the vaccine, it causes an immune response in the animal. This immune response creates antibodies to protect them against contracting the disease in the future.

Unfortunately, this immunity only last for a certain period of time. Depending on the vaccine, immunity can last months to years. This is important to consider when developing a vaccination timeline. One common way to help determine duration of immunity is to test titer concentration in the blood. Titers reflect the concentration of antibodies found in the blood and can be used to determine if the animal still has protection against a disease after being vaccinated. In equine, research on titers is limited and therefore most vaccines are given on an annual basis, regardless of the titer levels. The Leptospirosis vaccine is one of the these given yearly.

Leptospirosis is a less common, but still impactful, disease that can cause recurrent uveitis, abortion, and acute renal failure in horses. There is only one approved vaccine available for horses called the Lepto EQ Innovator®. It is a risk-based vaccination that is said to give the animal immunity for up to one year after initial administration and booster. Titer testing for this disease can be done using the microscopic agglutination test (MAT), but there is not enough information available to specify what levels are required to guarantee immunity against the disease. Because of this, many animals could be left unprotected if an exact duration of immunity is not determined.

The objective of this study is to determine the current titer levels for Leptospirosis in a group of horses, and to then evaluate their immune response after administering the Lepto EQ Innovator®. Data will be collected to evaluate their titer concentrations before and after the vaccination and will track how their titer levels increase or decrease over the course of the study. This data may then aid in confirming or developing a more accurate timeline for the leptospirosis vaccine administration.

Funding Type

Research Grant

Academic College

Jesse D. Jones College of Science, Engineering and Technology


Equine Science


BS in Ag, Pre-Chiropractic




Shea Porr, PhD.

Academic College

Hutson School of Agriculture

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