Mpox is endemic in western and central Africa, with the majority of cases occurring in the Democratic Republic of the Congo (DRC), where the disease is reportable.[1][2] There, the more virulent Congo basin virus type has been affecting some of the world's poorest and socially excluded communities.[3]
Mpox in the Democratic Republic of the Congo | |
---|---|
Disease | Mpox |
Virus strain | Monkeypox virus |
Source | Initially mainly animal contact in rainforest, later greater human-to-human transmission |
Location | Democratic Republic of the Congo |
Many cases occur sporadically or in small clusters, but large outbreaks also occur.[2]
Early cases
The world's first case of human mpox was detected in a nine-month old child in 1970 in the Democratic Republic of the Congo (then Zaire),[4][5] two years after it reported its last case of smallpox.[6] The onset of their rash was on 24 August.[7] That year, the disease was identified in another four children, including three in Liberia who were playmates.[8] At the time, evidence of the virus was found in non-human primates in Liberia and Sierre Leone.[8]
Active surveillance by the World Health Organization (WHO) between 1981 and 1986, identified 338 cases with a human-to-human transmission rate of 28%.[9][10] Until 1986, 95% of cases worldwide were identified in the DRC.[11] Cases were rare in people over the age of 15-years, and over two-thirds of infections could be traced to animal contact within the rainforests.[12] Initially it was uncommon for a family member to contract the infection unless they did not have a smallpox scar.[12]
1996 reemergence
A reemergence of the disease in the DRC in 1996 also saw a large number of reported but not all laboratory confirmed cases, with a high transmission rate and lower fatality rate; leading experts to believe a significant number may have actually been chicken pox.[10][13] Some likely had both mpox and chickenpox at the same time.[6] The DRC's Kasaï-Oriental region saw the largest number of cases during 1996–1997.[6]
Between 1996 and 2005, mpox cases appeared increasingly in gradually older people, with less than a quarter of cases being traced to rainforest animal contact, and with greater close contact infections.[12] Between January 2001 and December 2004, 2,734 cases of suspected human mpox were reported from the DRC.[10] However, civil war limited surveillance and only 171 clinical specimens were obtained from 136 suspected cases; less than 5% of all reported cases.[10]
- Mpox outbreak in DRC (1997)
- The US epidemiologic team after having landed at Lodja Airport - Zaire 1997
- Testing of Gambian rats (1997)
- Educational meeting DRC (1997)
2005 onwards
After 2005, the DRC was reporting more than 1000 suspected cases per year.[14] Between November 2005 and November 2007, 760 laboratory-confirmed human mpox cases were detected; particularly in people living in forested areas, males, age less than 15-years, and no previous smallpox vaccination.[15]
Many cases occur sporadically or in small clusters, but large outbreaks also occur.[2] The risk of human-to-human transmission within households in the DRC was noted to range from 50% to 100% during the 2013 outbreak.[6] The DRC's Bokungu Health Zone saw an increase in cases of 600-fold that year.[2] In 2019 the DRC reported 3,794 suspected cases and 73 deaths.[11] In the first nine-months of 2020, it reported over 4,500 suspected cases of mpox, including 171 deaths.[11]
Mpox is reportable in the DRC, where the disease is endemic, and disease burden remains high.[2][16] There, the more virulent Congo basin virus type has been affecting some of the world's poorest and socially excluded communities.[3] A regional surveillance system collects reports of all suspected mpox cases, and where possible, they may be investigated.[2]
2023-2024 outbreak
During 2023, a Clade I outbreak of mpox disease in the DRC resulted in 14,626 suspected cases being reported, with 654 associated deaths, making for a case-fatality rate (CFR) of 4.5%. The outbreak continued into 2024 with an additional 3,576 suspected mpox cases and 265 deaths being reported in the DRC through the first 9 weeks of the year, making for an estimated CFR of 7.4%.[17]
The outbreak appears to be of a primarily sexually transmitted nature and cases are occurring in areas without a history of mpox, such as South Kivu and Kinshasa. The outbreak seems to consist of two separate sub-variants of clade I, with one of the sub-variants having a novel mutation making detection with standard assays unreliable.[17]
The outbreak spread to the neighbouring country of the Republic of Congo, with 43 mpox cases being reported in March 2024.[17]