Lassa fever outbreak in Newaken Community, Grand Kru County, Liberia, September-October 2017

Abstract

Introduction: Lassa fever (LF) is an acute viral hemorrhagic febrile disease spread by infected multi-mammate rats and from person-to-person by direct contact with infected body fluids. On 4th October 2017, the surveillance focal person of Newaken clinic reported to the surveillance focal person of Grand Kru County a suspected case of Lf, who had presented with fever, headache, vomiting blood, and weakness. We investigated to confirm the outbreak, determine its scope, establish its source, and implement evidence-based control and prevention measures. Methods: We defined a suspected case as any person with an acute onset of fever (≥ 38° Celsius) and two or more of the following symptoms: bleeding, headache, vomiting, diarrhea, muscle weakness, and chest pain, who lived in Newaken Community from September 14, 2017 to October 25, 2017. A probable case as anyone who was epidemiological linked to a confirmed case, within 21 days of onset of symptoms while a confirmed case was either a suspected or probable case who was laboratory confirmed (positive IgM antibody, PCR or virus isolation). A contact was defined as anyone who associated with the confirmed case either by providing therapeutic care or living in the same household. We reviewed medical records, interviewed family, and community members to identify cases and contacts. We conducted active case search in the affected community to identify cases and contacts. We followed and monitored the contacts for 21 days. Results: We identified one confirmed case of LF, an 11-year old boy, whose onset of illness started with fever, cough, vomiting blood, and body weakness three days after he returned from Cote d'Ivoire where he had been residing for the past two years. He was isolated at hospital A. He was managed using anti-pyretic drugs and anti-viral drug (Ribavirin). Patient recovered after 30 days of intensive management. No other case was identified among the 21 contacts. The case-patient's resident community in Liberia was fond of storing food without covering it and also consuming bush meat. There was no documented LF outbreak in the Cote d'Ivoire community where the case-patient was residing before coming back to Liberia. Conclusion: This was LF outbreak whose source could not be established and no spread occurred among the human population beyond the index case. It was controlled by effective management and public education about infection prevention and the outbreak was declared over on the 25th of October 2017.