Descriptive characterization of the cerebrospinal meningitis outbreak in Zamfara State, 2017-18

Abstract

Introduction: Cerebro-spinal meningitis (CSM) is an epidemic-prone disease characterized by inflammation of the meninges. From epidemiological week 36, 2017 through epidemiological week 21, 2018, Zamfara State reported an outbreak of CSM that affected all the 14 Local Government Areas (LGAs). Therefore, we conducted a descriptive analysis of the outbreak to determine its epidemiology. Methods: We line-listed all suspected cases during the outbreak between September 4th 2017, and May 22nd 2018. We described the outbreak in time, place and person and calculated the attack rates by LGA and the age- and sex-specific case fatality rates (CFR). Results: A total of 1125 cases were reported with an overall attack rate and CFR of 25.2 cases/100,000 population and 7.6%, respectively. The age-specific CFR was highest among individuals aged 5-9 years (9.7%), while the sex-specific CFR was almost equal in males and females. The epidemiologic curve showed an increasing number of weekly reported cases with several peaks, the highest in week 12, 2018. A clustering of cases was seen in 2 contiguous LGAs, Bungudu and Gusau; while the highest attack rate was recorded in Shinkafi LGA (51 cases/100,000 population). Only 24% of suspected cases had their cerebrospinal fluid collected, and Neisseria meningitidis C accounted for 77.1% of causative agents. Conclusion: Zamfara State has experienced an outbreak of CSM. Training health workers and improving their skills on sample collection and treatment protocol will improve profiling of causative agents and outcomes. The use of Vaccines containing serogroup C will help to prevent future outbreaks.