Seroprevalence and determination of the serogroup-specific antibodies of Leptospira in Cattle and Buffaloes in Karnataka, India

Abstract

This study sought to evaluate the seroprevalence and distribution of Leptospira serovars among bovines experiencing reproductive disorders across various divisions in the state of Karnataka, India. A total of 582 serum samples, consisting of 314 cows and 268 buffaloes, were collected from Bengaluru, Belgaum, Gulbarga, and Mysore divisions of Karnataka. The gold standard serological test, the Microscopic Agglutination Test (MAT) was employed to assess these samples against the reference panel of serovars comprised of eight pathogenic Leptospira namely Hardjo, Pomona, Canicola, Icterohaemorrhagie, Hebdomadis, Grippotyphosa, Pyrogenes, and Autumnalis. The findings indicated an overall seroprevalence rate of 28% (163/582), revealing serogroup-specific antibodies against the employed serovars among others: Hardjo (34.35%), Pomona (16.56%), Canicola (11.66%), Icterohaemorrhagie (10.43%), Hebdomadis (9.81%), and Autumnalis (6.74%) with no specific positive reactions were observed for Grippotyphosa and Pyrogenes serovars.  Further, Buffaloes exhibited a higher seropositivity (29%) compared to cattle (27%) and additionally, serovar Hebdomadis was identified as the most prevalent in both cattle and buffaloes. Furthermore, among the 163 MAT reactive positive samples, the majority (62.58%) were linked to a history of abortion, followed by repeat breeding (28.22%), while the remaining cases (9.2%) were associated with other reproductive disorders. The Bengaluru, Mysore, and Belgaum divisions displayed higher seropositivity and a greater diversity of serovars, potentially due to increased risk factors in these regions compared to Gulbarga division of Karnataka. These results underscore the necessity for enhanced surveillance and diagnostic efforts, particularly in animals with a history of abortion, to address leptospirosis in bovines. Furthermore, identifying prevalent serovars emphasizes the importance of targeted interventions in particular geographical areas, and may be of use in the reference panels of antigens in the MAT in disease diagnostic laboratories which pay the way for more accurate, efficient, and timely diagnosis of leptospirosis, to ultimately contributing to the management of 'One Health' concerns and to combat the challenges in public health