One Health Assessment of Leptospirosis Burden in Humans, Livestock, and Environment in Delta State, South South Nigeria

This study conducts a One Health assessment of leptospirosis burden across human, livestock, and environmental reservoirs in Delta State, located in Nigeria's South South geopolitical zone. Leptospirosis is a neglected tropical disease caused by pathogenic Leptospira spp., transmitted through contact with urine of infected animals or contaminated water, and is likely highly endemic in the flood-prone Delta State, yet systematic human-animal-environment prevalence data from the state are absent. Using a cross-sectional One Health design, serum samples were collected from 200 cattle, 150 pigs, 120 domestic dogs, and 200 human occupational contacts (farmers, abattoir workers, and flood relief workers) in four local government areas during and after seasonal flooding. Microscopic agglutination test (MAT) was performed using a panel of 16 Leptospira serovars. Environmental water samples from flooded agricultural areas were tested by PCR for pathogenic Leptospira DNA. Serovar-specific epidemiological linkages between animal and human positives were explored. The study provides the first multi-host leptospirosis prevalence dataset from Delta State. Findings revealed seroprevalence of 41 percent in pigs, 34 percent in dogs, 22 percent in cattle, and 19 percent in humans, with Leptospira icterohaemorrhagiae as the predominant serovar. Environmental PCR confirmed Leptospira presence in 48 percent of flood water samples. The study recommends integrated leptospirosis control targeting animal reservoirs, flood-period human protection measures, and inclusion in Nigeria's neglected tropical disease programme. Keywords: leptospirosis, One Health, Delta State, seroprevalence, flood-associated zoonosis.