Isolation and molecular identification of Leptospira santarosai and Leptospira interrogans in equines from eastern Mexico.

This study aims to investigate the presence of Leptospira bacteria in horses from Veracruz, Mexico, by analyzing their blood and urine samples. The researchers documented that an infectious disease called Leptospirosis, affecting horses’ health and caused by Leptospira bacteria, was present in the majority of the sampled equids.

Research Methodology

• The research involved the collection of blood and urine samples from 28 horses and a mule from three locations within Veracruz, Mexico.
• To promote the growth of any Leptospira bacteria present, the urine samples were introduced into a specific culture medium called Ellinghausen-McCullough-Johnson-Harris (EMJH).
• Following incubation, the collected isolates were type identified using Multi Locus Sequence Typing (MLST), a molecular typing method employed to determine the genetic variability among bacterial species.
• DNA amplifications from these isolations were sequenced, and these sequences were compared to reference ones listed in the GenBank, a genetic sequence database, using the Basic Local Alignment Search Tool (BLAST).
• A method known as phylogenetic reconstruction was used to clarify the evolutionary relationship and lineage of the bacteria.
• The researchers also performed a Microscopic Agglutination test on the serum samples to identify any anti-Leptospira antibodies, thus indicating exposure to the bacteria.

Results and Conclusion

• Out of the samples tested, 16 urine samples were positive for the Leptospira DNA, confirming the presence of this bacteria.
• The subsequent analyses revealed various genotypes of two Leptospira species, Leptospira interrogans and Leptospira santarosai, within the samples.
• The serological test revealed that an overwhelming majority of the sampled equids (97.1%) had anti-Leptospira antibodies in their system, indicating high levels of exposure to the bacteria.
• These findings denote the first record of Leptospira bacteria’s presence in equids in Mexico, establishing its existence across this region and emphasizing the need for preventive measures in animal healthcare.