Outbreak of human monkeypox in Nigeria in 2017–18: a clinical and epidemiological report

By A. Yinka-Ogunleye, O. Aruna, M. Dalhat, D. Ogoina, A. McCollum, Y. Disu, Ibrahim Mamadu, Afolabi Akinpelu, Adama Ahmad, J. Burga and 35 more. Lancet. Infectious Diseases (Print), 2019

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Background In September, 2017, human monkeypox re-emerged in Nigeria, 39 years after the last reported case. We aimed to describe the clinical and epidemiological features of the 2017–18 human monkeypox outbreak in Nigeria. Methods We reviewed the epidemiological and clinical characteristics of cases of human monkeypox that occurred between Sept 22, 2017, and Sept 16, 2018. Data were collected with a standardised case investigation form, with a case definition of human monkeypox that was based on previously established guidelines. Diagnosis was confirmed by viral identification with real-time PCR and by detection of positive anti-orthopoxvirus IgM antibodies. Whole-genome sequencing was done for seven cases. Haplotype analysis results, genetic distance data, and epidemiological data were used to infer a likely series of events for potential human-to-human transmission of the west African clade of monkeypox virus. Findings 122 confirmed or probable cases of human monkeypox were recorded in 17 states, including seven deaths (case fatality rate 6%). People infected with monkeypox virus were aged between 2 days and 50 years (median 29 years [IQR 14]), and 84 (69%) were male. All 122 patients had vesiculopustular rash, and fever, pruritus, headache, and lymphadenopathy were also common. The rash affected all parts of the body, with the face being most affected. The distribution of cases and contacts suggested both primary zoonotic and secondary human-to-human transmission. Two cases of health-care-associated infection were recorded. Genomic analysis suggested multiple introductions of the virus and a single introduction along with human-to-human transmission in a prison facility. Interpretation This study describes the largest documented human outbreak of the west African clade of the monkeypox virus. Our results suggest endemicity of monkeypox virus in Nigeria, with some evidence of human-to-human transmission. Further studies are necessary to explore animal reservoirs and risk factors for transmission of the virus in Nigeria. Funding None.

Subfields: Epidemiology, Infectious Diseases, Virology

View Paper: https://www.semanticscholar.org/paper/684c392646cdd6a36739138c09fbeb768c52d52e

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Citations in the corpus

The changing epidemiology of human monkeypox—A potential threat? A systematic review (2021, background): “Commonly reported occupations included traders [44], students [44], artisans [44], healthcare professionals [35,44,56], farming [23,44,49], hunting [15], and transportation [35].”
Monkeypox Virus Infection in Humans across 16 Countries - April-June 2022. (2022, background): “with rash reported (%) Vesiculopustular 291/500 (58) Macular 19/500 (4) Single ulcer 54/500 (11) Multiple ulcers 95/500 (19) Other 41/500 (8) No rash 28”
Clinical features and management of human monkeypox: a retrospective observational study in the UK (2022, neutral): “…However, we did not identify any oral lesions; only two of seven patients reported a sore throat; pruritis was common in the 2018 Nigerian outbreak, 8 but it was rare in our cohort; and gastrointestinal and respiratory symptoms were reported by a minority of patients in the 2003 US outbreak but…”
Monkeypox Virus in Nigeria: Infection Biology, Epidemiology, and Evolution (2020, methodology): “Routine detection of MPXV DNA from clinical and veterinary specimens, as well as from MPXV-infected cell cultures, is accomplished by RT-PCR targeting conserved regions of extracellular-envelope protein gene (B6R) [59], DNA polymerase gene, E9L [60].”