Seroprevalence and risk factors associated with equineleptospirosis in the metropolitan region of Salvador and Recôncavo Baiano region, Bahia state (NE Brazil).

This research investigates the prevalence and risk factors linked with equine leptospirosis in parts of Northeast Brazil, revealing it as a significant concern in many cattle farms due to factors like semi-extensive livestock farming, farm topography, interactions with neighboring animals, and cohabitation with goats.

Understanding the Research

• The study focussed on equine leptospirosis, a disease that usually does not show symptoms in horses, but when it does, it can cause serious health issues such as recurrent uveitis, abortion, and other systemic signs. These conditions have the potential to cause major economic loss within the equine agribusiness sector.
• The research involved the investigation of anti-Leptospira spp. agglutinins (substances that cause organisms to clump together) in 1200 serum samples from horses. These were collected from 27 municipalities in the Recôncavo Baiano region, Bahia state in Northeast Brazil. Part of this study was understanding which factors were most likely to lead to the presence of this disease, both regarding the specific animals and to their farms. The analysis instrument used was the microscopic agglutination test (MAT).

Results of the Study

• A total of 8% of the horses tested were found positive to the disease, with a titre (concentration) of 200 or higher. Furthermore, from a total of 28 properties, 22 (78.6%) had at least one affected horse.
• The most frequent serogroup was Australis (serovar Bratislava), which accounted for 67% of cases in animals raised in stables, while among mounted police animals, the Sejroe (serovar Wolffi and Hardjobovis) serogroup was most common (50%). Among equestrian animals, serogroups Australis (serovar Bratislava) and Icterohaemorrhagiae (serovar Copenhageni) were equally prevalent, each accounting for 25% of cases.

Identified Risk Factors

• Several significant risk factors were identified as main contributors to the disease’s prevalence. Semi-extensive livestock farming practices, where animals are allowed to freely roam and graze, increase their odds of exposure to the Leptospira bacterium by enabling direct contact with an infected animal or through a contaminated water or soil source.
• The geographical layout, or topography, of a farm also plays a crucial role. Farms with wet, marshy, or flooded areas are more likely to retain contaminated water and thus, increase the risk of Leptospira infection in animals.
• Horses that have contact with animals from neighboring properties are also at a higher risk of infection due to the potential exposure to infected animals.
• Lastly, it was found that horses cohabitating with goats have a higher risk of contracting leptospirosis. This may be due to goats being potential carriers of Leptospira bacteria.

All these findings highlight a significant presence of equine leptospirosis in the studied regions and point at the need for effective strategies in controlling and preventing this disease to avoid potential economic losses in the equine agribusiness sector.