Identification of pathogenic Leptospira strains in tissues of a premature foal by use of polymerase chain reaction analysis.

The research article delves into a study aiming at discerning the cause of death in a premature Thoroughbred foal who died 24 hours post-birth. It was established that the foal died due to a Leptospira infection, confirmed through various polymerase chain reaction (PCR) assays and histologic examinations.

About the Research

• The research was driven by an endeavor to identify the reason behind the sudden death of a prematurely born Thoroughbred foal. The foal had died merely 24 hours after birth, spurring the researchers to explore the causes.
• The investigation was conducted post-mortem, and a necropsy was conducted on the foal. The necropsy signaled indications of septicemia, a severe infection of the bloodstream.

Findings from PCR Assay

• The researchers utilized Polymerase Chain Reaction (PCR), a prevalent molecular biology method, for the examination. A commercial Leptospira PCR assay was employed particularly for this study, aiming at amplifying the hemolysis-associated protein 1 (hap1) gene exclusively present in pathogenic Leptospira strains.
• The test unveiled the presence of Leptospira DNA in various tissues of the foal, suggesting the likelihood of a Leptospira infection.

Revelations from Histologic Examination

• On examining tissue sections of lung, liver, kidney, and myocardium (heart muscle), the researchers observed numerous spirochetes (a type of bacteria causing diseases like syphilis and Lyme disease).
• These spirochetes were detected clearly in Warthin-Starry-stained tissue sections, finalizing the presence of a bacterial infection.

Final Inference

• The researchers concluded through the PCR analysis and histologic examination results that a leptospiral infection was present in the newborn foal. This infection coexisted with aspiration bronchopneumonia associated with Streptococcal bacteria, as well as postpartum septicemia, when the foal passed away.
• The research underscored the effectiveness of the PCR assay. It was found beneficial for the amplification of the hap1 gene, proving vital for detecting specific pathogenic leptospira in samples collected from horses in the field.