Pattern and Outcome of Lassa Fever cases in Nasarawa State, Nigeria (2017-2022)

Background: Lassa Fever (LF), an endemic zoonotic disease requires a 'One Health approach'. Introduction: A prior study in Nasarawa state (2013) showed a high seroprevalence range of 10-25%, having a serious impact on the health care system and families with significant socioeconomic losses to the state which necessitated this study Methods: This retrospective cross sectional study in Nasarawa State over five years (2017-2022) utilized all secondary data from all the Local Government Areas. Results: showed a Case Fatality Rate of 61% indicating high viral virulence, with the highest prevalence over the past 6 years in Keffi LGA. The trend analysis shows a fluctuating pattern of LF cases with 2 reported deaths of health workers (2021) indicating an evolving epidemiological pattern of the virus. With 38 LF positives out of 343 cases, high period prevalence of 11%, and increased number of 'suspected' and 'probable' cases, it shows sub-optimal quality of care or presence of other diseases that mimic LF and hence a need to review case definition. Conclusion: There is a need for increased in-country laboratory testing/diagnostic capacities and events-based surveillance.