Endemicity of Diphtheria in Some Regions of Nigeria: Chronology of a Fourteen Month Sustained Outbreak

Abstract

Diphtheria in humans is caused by exotoxin produced by Corynebacterium diphtheriae which is a gram positive bacteria. The sustained endemicity of diphtheria amongst Nigerian population from May 2022 to July 2023 is significant and has not been widely reported. Secondary data was collected from the recent data base of Nigeria Centre for Disease Control, Federal Ministry of Health, and Federal Ministry of Information then analyzed applying standard procedure. The result shows in overall a total of 4,160 suspected cases of diphtheria which spanned through a period of May 2022 to July 2023. Out of these suspected cases, 1,534 were positive, yielding a total prevalence of 36.9% and mortality of 137(8.9%). In the Northern states alone, 4,061 individuals were recorded as suspected diphtheria cases; out of which 1,525(36.6%) individuals were confirmed positive with 132(8.7%) death cases. Conversely, in the southern states, a total of 40 suspected cases were recorded. Out of these, 9(22.5%) were confirmed positive with mortality of 5(55.6%). Only one state yielded a suspected case without any conclusive confirmatory evidence. The result further showed that a total of 15 states were grouped as “others”. In this group a total of 59 cases were suspected, but none yielded positive result. The prevalence was high (36.6%) in the North when compared to the south (22.5%), and mortality was high (55.6%) in the south when compared to the North where a total mortality rate of 8.7% was recorded. Amongst the Northern states affected, prevalence was highest (75.9%; 41/54) in Bauchi and least (5.0%;5/101) in Kaduna state. This present result shows that diphtheria is endemic in some parts of Nigeria leading to sporadic outbreaks overtime, predominantly in the Northern part. High spread and prevalence in the North may be that herd immunity in the North is low or inadequate. Thus, urgent attention of Government and relevant stake holders is necessitated to eliminate this negative trend.