Virological Survey of Lassa Fever Virus Seropositivity Among Healthcare Workers in Ondo State

Lassa fever is an acute viral hemorrhagic fever endemic to Nigeria, with healthcare workers representing a disproportionately exposed occupational group due to nosocomial transmission. This cross-sectional seroepidemiological study determined the seroprevalence of Lassa virus IgG antibodies among healthcare workers at Ondo State University Teaching Hospital and Ondo State General Hospitals, in the South West geopolitical zone of Nigeria. Blood samples were collected from 220 consenting healthcare workers, including physicians, nurses, laboratory staff, and health attendants. Lassa virus IgG was detected by enzyme-linked immunosorbent assay (ELISA) using commercially validated test kits. The overall seroprevalence of Lassa virus IgG antibodies was 11.8 percent. Laboratory scientists and nurses had the highest positivity rates. Healthcare workers who had cared for febrile hemorrhagic patients without full personal protective equipment had significantly higher odds of seropositivity. Geographic analysis showed that healthcare workers posted in rural facilities with higher Mastomys natalensis rat density had elevated risk. These findings confirm significant occupational Lassa virus exposure in Ondo State healthcare settings and justify urgent strengthening of standard precautions, provision of full PPE, Lassa surveillance training, and healthcare worker vaccination once a licensed vaccine becomes available. Keywords: Lassa fever, seroprevalence, healthcare workers, Ondo State, viral hemorrhagic fever.