Six-Year Retrospective Analysis of Buruli Ulcer Diagnosis via Real-Time PCR at the Nigerian Institute of Medical Research

Abstract

Buruli ulcer, caused by Mycobacterium ulcerans, is a neglected tropical disease that affects the skin, resulting in serious disfigurement and long-term disability. The World Health Organization has set at least 70% Polymerase Chain Reaction confirmation rate for countries to meet. The Control Program in Nigeria faced significant challenges due to lack of in country molecular confirmation laboratories. Nigerian Institute of Medical Research, supported by WHO/TDR, established a unit in 2016 for the molecular diagnosis laboratory which assists the national program and eventually joined the Buruli Ulcer Laboratory Network in Africa. Clinical samples from 18 states and the Federal Capital Territory were analyzed between 2018 and 2023. Sample collection was predominantly done using dry swabs (92%), from which DNA was extracted using Ethanol -Sodium Hydroxide DNA extraction solution and Genolyse kit. The DNA was screened using qPCR, targeting the IS2404 sequence. Out of the 1386 samples screened, only 58 (4.2%) were positive, indicating low prevalence. More male samples were screened (52.4%) as compared to women (47.6%). Most of the samples came from the age group 21-40 years (32%) (P<0.001). Infection rates in males and females were not significantly different (p>0.05), but age group < 50 years were significantly more infected than those above (p<0.001). Most samples were from southern Nigeria. The low number of samples from states and prevalence calls for more governmental sensitization efforts at the grassroots level. The Buruli Ulcer Laboratory Network in Africa ensures reliability of results from member countries, hence the need for inclusion of more countries.