Containing a Lassa fever epidemic in a resource-limited setting: outbreak description and lessons learned from Abakaliki, Nigeria (January-March 2012)

Abstract

Objectives: Despite the epidemic nature of Lassa fever (LF), details of outbreaks and response strategies have not been well documented in resource-poor settings. We describe the course of a LF outbreak in Ebonyi State, Nigeria, during January to March 2012.

Methods: We analyzed clinical, epidemiological, and laboratory data from surveillance records and hospital statistics during the outbreak. Fisher's exact tests were used to compare proportions and t-tests to compare differences in means.

Results: The outbreak response consisted of effective coordination, laboratory testing, active surveillance, community mobilization, contact and suspected case evaluation, and case management. Twenty LF cases (10 confirmed and 10 suspected) were recorded during the outbreak. Nosocomial transmission to six health workers occurred through the index case. Only 1/110 contacts had an asymptomatic infection. Overall, there was high case fatality rate among all cases (6/20; 30%). Patients who received ribavirin were less likely to die than those who did not (p=0.003). The mean delay to presentation for patients who died was 11 ± 3.5 days, while for those who survived was 6 ± 2.6 days (p<0.001).

Conclusions: The response strategies contained the epidemic. Challenges to control efforts included poor local laboratory capacity, inadequate/poor quality of protective materials, fear among health workers, and inadequate emergency preparedness.

Keywords: Case report; Epidemiology; Infection control; Lassa fever; Nigeria; Outbreak report.