Mapping the distribution and describing the first cases from an ongoing outbreak of a New Strain of mpox in South Kivu, Eastern Democratic Republic of Congo between September 2023 to April 2024

BackgroundIn September 2023, an outbreak of mpox was reported in the eastern part, South Kivu Province, of Democratic Republic of the Congo. This paper aims to provide a summary from several ongoing and completed studies to share initial insights into the time trend and spatial distribution, the links we have observed between level of mpox cases with population density and the presence of professional sex workers (PSW) in bars within affected heath areas of Kamituga health zone. We also seek to share our initial observations on the novel characteristics of this new and emergent strain. MethodsConsenting patients admitted with mpox-like symptoms to the Kamituga hospital were recruited to an observational cohort study to understand the clinical characteristics and household perceptions and treatment seeking behaviours. We mapped the demographic and clinical characteristics of all individuals between September 2023 and April 2024. Findings371 (suspected) mpox cases were admitted to the Kamituga hospital. There were slightly more female than male cases (192/371 [52%] versus 179/371, [48%], and cases were reported from 15 health areas. The majority of cases were reported in Mero (115/371 [31%]), followed by Kimbangu (65/371[18%]), Kabukungu (63/371[17%]), Asuku (47/371 [13%]), Soluluyu (19/371 [5,12%]), Katunga (17/371 [4,58%]), Kalingi, Poudriere (12/371 [3,23%]) respectively, and Poly Afia (7/371 [1,89%]). During this period, 4 deaths occurred and 4 out of 8 women who were pregnant had fetal loss . Three healthcare workers acquired infection when caring for patients. In depth case ascertainment showed that 88,4 % of patients reported recent visits to bars for (professional) sexual interactions as a likely source of infection. Our findings suggest that the epidemic in South Kivu is driven by transmission in a network of professional sex workers, working in bars. The continued spread of the mpox virus in Kamituga health zone and other health zones of South -Kivu points at a critical need for cross border surveillance, and the potential for rapid vaccination of sex workers as potential intervention. InterpretationThese data suggest that the rapid transmission of mpox virus is related to interactions with professional sex workers (PSW) in bars within densely populated health areas. The expanding number of cases and the recent spillover to 16 other nearby health zones of South -Kivu including a health district bordering Rwanda and Burundi stresses the need for cross border surveillance. In addition, enhanced response action is needed, including vaccination health education programmes to limit further escalation and stop this outbreak.