Abstract:
Background: Lassa fever remains a major public health threat in West Africa, with Nigeria accounting for the highest burden of disease. The Lassa fever virus infection continues to affect many communities, yet demographic, household, and behavioural factors that influence people’s chances of exposure are not fully understood. However, the true extent of population-level exposure is poorly defined, particularly in North-Central Nigeria. The study aimed investigated of IgG IgM, antibodies and associated population-based risk factors with LASV exposure and infection patterns in an understudied endemic region.
Methods: A community-based cross-sectional seroprevalence of LASV was conducted across five states in North Central Nigeria (Benue, Kogi, Nasarawa, Plateau, and the Federal Capital Territory-FCT) between January and July 2024. Ethical approval was obtained from the National Health Research Ethics Committee of Nigeria (NHREC/01/01/2007-01/09/2023). The study Permission was also secured from the respective State Ministries of Health. Before community entry, we obtained informed consent from traditional leaders and other community gatekeepers following established community engagement protocols. A total of 958 participants were enrolled using a multistage sampling method. Serum samples were tested for LASV-specific IgG and IgM antibodies using a validated recombinant nucleoprotein enzyme-linked immunosorbent assay. All IgM-positive samples and a random subset of IgM-negative samples underwent RT-PCR testing for the detection of active infection. Standardized questionnaires captured sociodemographic, environmental, and behavioral exposures. Multivariable logistic regression was used to identify factors independently associated with seropositivity.
Results: The prevalence of Lassa virus IgG was 19%, while IgM positivity was 1.15%, and all 91 samples tested by RT-PCR were negative. In multivariable analysis, participants from FCT (adjusted odds ratio [aOR] 0.07, 95% CI 0.03–0.15), Kogi (aOR 0.05, 95% CI 0.02 0.14), Nasarawa (aOR 0.18, 95% CI 0.09–0.40), and Plateau (aOR 0.22, 95% CI 0.10–0.49) had significantly lower odds of IgG seropositivity compared to Benue State. Living in non-concrete houses was associated with increased odds of seropositivity (aOR 2.66, 95% CI 1.79–3.95). In contrast, rodent consumption was associated with reduced odds of seropositivity (aOR 0.23, 95% CI 0.12–0.44).
Conclusion: These results highlighted that the exposure to LASV is prevalent yet unevenly spread throughout North-Central Nigeria, significantly influenced by geographical, demographic, and housing-related factors. This indicates a necessity to enhance rodent control at the community level and implement household-based prevention strategies, which could aid in minimizing exposure
Biography:
Professor Joseph Anejo-Okopi, is a Medical Microbiologist specializing in infectious disease research and public health virology. He holds a PhD in medical Microbiology from Ahmadu Bello University Zaria. Prof Okopi has worked with US PEPFAR HIV implementation program and has published extensively on public health related pathogens including: HIV drug resistance, HBV, arboviruses and Lassa fever virus diseases. He is currently the Director of the Research and Innovation at the Federal University of Health Sciences Otukpo, Nigeria.
