Lassa fever outbreak investigation in a Nigerian bakery - August, 2012

Background: Lassa fever (LF) is a severe hemorrhagic illness caused by Lassa virus and is associated with high mortality. |Endemic in West Africa with an estimated 300,000 to 500,000 cases/yearwith 5000 deaths. The virus is transmitted to humans by contact with excreta, urine or blood of rodents Mastomys natalensis. In 2012, LF outbreak affected 19 out of 36 states in Nigeria. In August 2012, a suspected case of LF was reported in a tertiary hospital at Ibadan. We investigated the outbreak to determine its magnitude, source, possible risk factors and to recommend control and preventive measures. Methods M including household contacts, bakery staff and health workers for serological tests. A suspected case was defined as any person resident in Ibadan or reported sick at the health facility between July and August 2012 with fever >38◦C (101◦F) and one or more of following: bleeding, chest pain, and not responding to appropriate anti-malarial or antibiotics treatment within 24-72hours of treatment. A confirmed case was a suspected case with positive ELISA IgM. Results: Two cases were identified; one confirmed case and a suspected casewith one death (case fatality rate of 50%). Therewas no epidemiological linkage between the two cases, and serological test for all high risk contacts were negative. There was evidence of rat infestation in the homeandbakery surroundings. Therewere no standardized protocols for the case detection and management of LF in all health facilities visited. Knowlege of mode of transmision of LF was poor in the bakery community Conclusion: The outbreak of Lassa fever was confirmed. The possible mode of spread was rodent to human. Fumigation of the Bakery, Pre-positioning of standard PPE and health workers/community awareness was carried out. We recommended further research into prevalence of infected Mastomys spp. rat in this locality, and training of health workers on early detection and case management.