Investigation of a mpox outbreak in Central African Republic, 2021-2022

Abstract

Human monkeypox virus is spreading globally, and more information is required about its epidemiological and clinical disease characteristics in endemic countries. We report the investigation of an outbreak in November 2021 in Central African Republic (CAR). The primary case, a hunter, fell ill after contact with a non-human primate at the frontier between forest and savannah. The ensuing investigation in a small nearby town concerned two families and four waves of inter-human transmission, with 14 confirmed cases, 11 suspected cases and 17 non-infected contacts, and a secondary attack rate of 59.5% (25/42). Complications were observed in 12 of the 19 (63.2%) confirmed and suspected cases with available clinical follow-up data: eight cases of bronchopneumonia, two of severe dehydration, one corneal ulcer, one abscess, two cutaneous superinfections, and six cutaneous sequelae (cheloid scars, or depigmentation). There was one death, giving a case fatality ratio of 1/25 (4.0%) for confirmed and suspected cases. This outbreak, with the largest number of confirmed cases ever described in CAR, confirms the potential severity of the disease associated with clade I monkeypox viruses, and highlights the need for rapid control over virus circulation to prevent the further national and international spread of infection.

Keywords: Central African Republic; Emerging infectious diseases; Monkeypox virus; Outbreak investigation; Surveillance; Zoonosis; mpox.

Fig. 1

Geolocalization of the site of contamination (primary case), and of current and previous mpox outbreaks, CAR, 2021–2022.

Fig. 2

Hypothetic pattern of monkeypox virus transmission during the Bania outbreak, CAR 2021–2022. Circles correspond to female individuals, squares to male individuals, and triangles to suspected cases. Case 0 is the primary case. Cases are organized according to the date of illness onset and the four waves of transmission (first wave: green, second wave: yellow, third wave: coral, fourth wave: brown). The numbers indicate the number of days between disease onset in two consecutive patients in the line of transmission (rash-to-rash interval). The dotted lines correspond to less reliable presumed chains of transmission. The solid lines correspond to more reliable chains of transmission. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)

Fig. 3

Signs and symptoms in the confirmed and suspected cases of mpox, Bania, CAR 2021–2022 (MD missing data).

Fig. 4

A. Cutaneous abscess in a confirmed case of mpox, Bania, CAR, 2021–2022. B. Axillary adenopathy in a different confirmed case of mpox, Bania, CAR, 2021–2022. Photo credits: Dr. Festus Mbrenga.