Mapping serogroup distribution and seroprevalence of leptospirosis in livestock of Assam, Northeastern State of India: Unveiling uncommon Leptospira serogroups.

Leptospirosis is a significant zoonotic disease affecting livestock, leading to reproductive issues and economic losses. Despite its endemic status in India, research has predominantly focused on coastal regions, leaving the North Eastern Region (NER) underexplored. This study aims to investigate the seroprevalence and serogroup distribution of leptospirosis in livestock across Assam, a major state in the North Eastern Region (NER) of India. Serum samples (n=811) from cattle, buffalo, sheep, goats, and pigs were collected between 2016 and 2019 and screened using the Microscopic Agglutination Test (MAT) for 24 serogroups. The overall seroprevalence was 22.9 % (186/811), with highest prevalence in cattle (26.2 %) and buffalo (25 %), followed by small ruminants (19.8 %) and pigs (18.6 %) . Notably, uncommon serovars such as Mini (28.8 %), Manhao (12.4 %), and Cynopteri (7.5 %) were identified, indicating a unique epidemiological pattern in Assam. High seroprevalence was observed in districts like Bongaigaon (66.7 %), Kamrup Metropolitan (50.0 %), and Nalbari (40.0 %), emphasizing the need for targeted intervention strategies. The presence of these uncommon serogroups, typically found in neighbouring countries and other regions, suggests potential transboundary transmission from these countries. This study provides valuable insights into the seroprevalence and serogroup distribution of leptospirosis in Assam's livestock, highlighting the need for region-specific surveillance and control measures. These findings underscore the importance of understanding the local epidemiological landscape to develop effective disease management and prevention strategies, ultimately reducing the impact of leptospirosis in the NER of India.

Comparative diagnostic efficacy of Avidin-Biotin recombinant nucleoprotein competitive ELISA for serosurveillance and monitoring of peste des petits ruminants in sheep and goats.

In this study extensive evaluation of Avidin-Biotin recombinant nucleoprotein competitive ELISA (ABrC-ELISA) was carried out by mass screening of a large number of sera to make use of this assay for serosurveillance and seromonitoring of peste des petits ruminants (PPR) in sheep and goats to evaluate its diagnostic efficacy value and strengthen findings associated with the assay. The recombinant PPR virus (PPRV) nucleoprotein was over-expressed in E. coli, Ni-NTA affinity-purified, and characterized and used as coating diagnostic antigen in ABrC-ELISA, and evaluated using the field sera from animals. On evaluation of the diagnostic performance or efficacy of this assay using the pre-vaccinated and post-vaccinated sera of sheep and goats (n = 1437), the ABrC-ELISA showed a relative diagnostic sensitivity of 87.2% (95% CI: 84.1-90%) and diagnostic specificity of 92.0% (95% CI: 90-93.7%), against well-established existing indigenous H protein-specific PPR competitive ELISA kit with an accuracy of 90.1% (95% CI: 88.5-91.7%) and good or substantial agreement of Cohen's Kappa value of 0.79 ± 0.017 SE (95% CI: 0.76 to 0.82). These findings suggest that the ABrC-ELISA is a potential additional diagnostic tool of a rapid, sensitive, and specific assay for the detection of the PPRV nucleoprotein antibodies in sera of sheep and goats. This PPR Ab Chek kit can be used extensively under field conditions for serosurveillance, and seromonitoring of PPR in sheep and goats at the eradication /post-eradication phase in disease-controlled countries or PPR non-enzootic countries.