Epidemiological investigation of Lassa fever outbreak in a resource limited setting: Lessons learnt. (January to March 2018)

Abstract

Background: An outbreak of Lassa Fever (LF) reported and confirmed in Ebonyi state, Southwest Nigeria in January 2018 was investigated. This article provides the epidemiology of the LF and lessons learnt from the investigation of the outbreak. Methods and materials: The Emergency operational centre (EOC) model was used for the outbreak coordination. Cases and deaths were identified through the routine surveillance system using standard definitions for suspected and confirmed cases and deaths respectively. Blood specimens collected from suspected cases were sent for confirmation at the virology centre Abakaliki. Active case search was intensified, and identified contacts of confirmed cases were followed up for the maximum incubation period of the disease. Other public health responses included infection prevention and control, communication and advocacy as well as case management. Data collected were analysed using Epi info, by time, place and persons and important lessons drawn were discussed. Results: We identified 89 suspected LF cases of which 61 were confirmed with mean age of 35 ± 16.2. More than half (59.7%) of the confirmed cases were females and the age group mostly affected was 30–39 years. Majority of the cases presented late. The Case Fatality Rate (CFR) was 68.5% among the laboratory confirmed cases. Among the health care workers 5 confirmed cases died. Three hundred and twenty-five contacts of the confirmed cases were identified, out of which 304(99.7%) completed the follow-up without developing any symptoms and 1(0.3%) developed symptoms consistent with LF and was confirmed by the laboratory. Conclusion: Key lessons learnt from the investigation were: high fatality rate in those presenting late to the hospital and especially in those presenting with complications underscore the need for intensive public enlightenment that encourages early presentation to hospital, majority of the confirmed cases were primary cases hence efforts should be intensified in breaking the chain of transmission in the animal–man interphase, death of healthcare workers involved in management of Lassa fever raises the importance of providing life insurance. The presence of virology centre and the impact of both local and international partners contributed significantly in curbing the outbreak.