Evidence and implications of pigs as genital carriers of Leptospira spp. in the Caatinga biome

The Caatinga biome is unique to Brazil, with unfavorable environmental characteristics for the survival of Leptospira spp. However, recent studies have shown high positivity at PCR (polymerase chain reaction) in small ruminants. There are no Leptospira spp. studies based on sample calculation in pigs in the Caatinga. The aim of this study was to assess the importance of pigs in the spread of leptospirosis in the Caatinga biome. Overall, 200 biological samples (urine, blood, vaginal fluid, and tissues of reproductive and urinary tracts) were collected from 40 slaughtered sows, and MAT (microscopic agglutination test) and PCR tests were carried out to detect anti- Leptospira spp. antibodies and the agent's DNA, respectively. The serological analysis showed a positivity rate of 5% (2/40), and the PCR identified Leptospira spp. DNA in 62.5% (25/40) of the animals. Only 2.5% (1/40) of the animals were positive for both techniques. The detected serogroups were Australis (50%) and Bataviae (50%), with antibody titers of 25 and 50. Leptospira spp. DNA was detected in 40% (16/40) of the reproductive tract samples, 32.5% (13/40) of the urinary tract, 32.5% (13/40) of the vaginal fluid and 30% (12/40) of the urine. There was no agreement (Kappa <0) between PCR samples from the genital tract vs. urinary tract or serological results. Genetic sequencing of one urine and one urinary tract tissue sample revealed 99% identity with L. borgpetersenii. . The results indicate that leptospirosis is a concern in pigs in the context of Caatinga, with a high prevalence of infection detected by different diagnostic methods. The molecular analysis revealed a considerable proportion of infected animals. The findings emphasize the importance of a multifaceted approach in the diagnosis of leptospirosis in pigs, with a focus on the use of genital tract samples for the diagnosis of leptospirosis in this animal species, providing valuable insights for the control and prevention of this disease in both animals and the zoonotic context. Finally, the detection of leptospires in the genital tract indicates a possibility of male-female transmission in the venereal context.