Non-exanthematous mpox infections in Nigeria: a possible explanation of the sporadic outbreaks in city centers?

Abstract

Introduction: non-exanthematous presentations in mpox infection are increasingly reported, posing a risk of underestimating the true burden of the disease. In Nigeria, border towns play a unique role in shaping the dynamics of mpox transmission, yet they have received relatively little research attention. This study aims to address this gap by investigating the prevalence of mpox infection in a potential hotspot region of Nigeria. Methods: a cross-sectional study was conducted during a free medical outreach in Iboko, Izzi Local Government Area, Ebonyi State, Nigeria, from April 15 to May 20, 2024. Participants were educated on the study objectives and provided informed consent for clinical evaluation and sample collection. Blood samples from 75 participants were tested for the mpox virus using quantitative PCR. Socio-demographic data and clinical presentations were also recorded. Results: the mean age of participants was 51.3 ± 18.0 years, and 73.3% were female. Most participants (78.7%) were farmers, and 52.0% had no formal education. Headache (69.3%) and body pain (37.3%) were the most common clinical symptoms, with only 3.6% presenting with fever. Mpox virus DNA was detected in two participants (2.67%) designated K3 and K4. Both cases lacked exanthematous lesions but reported headache and body pain. Conclusion: this study identified the presence of non-exanthematous mpox infections in Nigeria, emphasizing the need to recognize and address "subclinical" spreaders to mitigate sporadic outbreaks of mpox infection. In addition, the findings highlight the importance of integrating targeted awareness campaigns to enhance surveillance and improve case detection of asymptomatic mpox in Nigeria.