Prevalence and molecular confirmation of Campylobacter species in small ruminants, humans and water sources in Borno State, Nigeria: A One Health approach.

Campylobacter species are among the leading bacterial causes of gastroenteritis worldwide, yet epidemiological data from northeastern Nigeria remain scarce. This study applied a One Health framework to investigate the prevalence, identification and characterization of Campylobacter spp. in small ruminants, humans, and water sources in Borno State. Additionally, we identified the risk factors associated with Campylobacter infection in small ruminants. A cross-sectional study was conducted between January and September 2023 across the six agricultural zones of Borno State, Nigeria. Rectal swabs were collected from 396 small ruminants (sheep and goats) and 98 humans, alongside 175 water samples. Samples were analyzed using selective culture and biochemical identification, with PCR confirmation targeting the 16S rRNA gene and species-specific markers (hipO and ceuE) for C. jejuni and C. coli. Associations between potential risk factors and Campylobacter positivity were assessed using Fisher's exact tests and odds ratios. Campylobacter spp. was detected in 2.78% of small ruminants, 2.04% of humans, and 3.43% of water samples, with C. jejuni identified as the predominant species across all sample types. Exploratory association analysis suggested that young animals (OR = 5.89; p < 0.01), extensive management systems (OR = 5.35; p < 0.05), and contaminated water sources (OR = 7.78; p < 0.01) were associated with higher positivity. Overall, Campylobacter circulates among humans, livestock, and water sources in Borno State, presenting a clear One Health challenge.