#17,779
We've been following the spread and evolution of MPox (Monkeypox) for well over a decade in this blog (see here, here, here), which until a few years ago was only endemic in Central Africa (DRC), although it had returned to Nigeria in 2017 after a nearly 40 years absence.The name `monkeypox’ - which is being phased out - is a bit of a misnomer. It was first detected (in 1958) in laboratory monkeys, but further research has revealed its host to be rodents or possibly squirrels. It produces a remarkably `smallpox looking' illness in humans, albeit not as deadly.
Until a couple of years ago there were only two distinct genetic groups (clades) of the Mpox virus—Central African (clade 1) and West African (clade II). West African monkeypox was associated with milder disease, fewer deaths, and limited human-to-human transmission.
In 2022, for the very first time, we saw international spread of Mpox Clade II, prompting a short-lived (10 month) PHEIC declaration by the WHO. Case reports peaked in the fall of 2022, but continue today at a much reduced level.
A little over a year ago, it was decided (see WHO: Expert Group Assigns New Names For Monkeypox Clades) to rename, and expand, the classification of Mpox viruses.
Consensus was reached to now refer to the former Congo Basin (Central African) clade as Clade one (I) and the former West African clade as Clade two (II). Additionally, it was agreed that the Clade II consists of two subclades.
Thus, the new naming convention comprises Clade I, Clade IIa and Clade IIb, with the latter referring primarily to the group of variants largely circulating in the 2022 global outbreak.
In many ways we got lucky, in that it was an offshoot of the milder Clade II Mpox virus that began its world tour in 2022. But Clade I viruses continue to circulate, and evolve, in Central Africa. And we've seen warnings for years that it has the potential to become more transmissible (see WHO: Modelling Human-to-Human Transmission of Monkeypox) over time.
Unlike Clade II, which as been largely spread internationally over the past couple of years by sexual activity, Clade I has not been linked to sexual transmission; that is, until now.
Yesterday the WHO published a lengthy DON report on the first confirmed cluster of sexually transmitted clade I Mpox in the DRC, which raises concerns over it following Clade II's recent example, and begin spreading internationally.
Due to its length, I've only posted some excerpts. Due to its importance, I urge you to follow the link to read it in its entirety. I'll have a postscript when you return.
Mpox (monkeypox)- Democratic Republic of the Congo
23 November 2023
Situation at a Glance
Mpox is an infectious disease caused by monkeypox virus (MPXV), which is endemic in densely forested regions of West, Central and East Africa, particularly in the northern and central regions of the Democratic Republic of the Congo. Eleven of the 26 provinces of the Democratic Republic of the Congo are identified as endemic for mpox, but in more recent years the total number of mpox cases and the number of provinces reporting mpox has been expanding, to 22 provinces as of November 2023.There are two known clades of MPXV: clade I, previously known as the Congo Basin clade; and clade II, previously called the West African clade; clade II further has two subclades: clade IIa and clade IIb. Before 2018, very few cases were reported outside of the African continent: eight international travellers returning from endemic countries and one outbreak related to imported animals. Since 2022, an epidemic of clade IIb MPXV has been ongoing globally, affecting many countries outside the African continent that had never reported mpox previously. The spread of this epidemic was mainly driven by transmission via sexual contact among men who have sex with men.The Democratic Republic of the Congo has not reported cases of mpox linked to clade IIb MPXV during the global outbreak to date; only MPXV clade I has been detected in the country. Before April 2023, no formally documented cases of sexual transmission of clade I MPXV were registered globally.The first known cases were reported when a man, resident in Belgium and with connections to the Democratic Republic of the Congo, tested positive for clade I in Kenge, Kwango province, during a visit to the Democratic Republic of the Congo. Thereafter, sexual contacts of this case in the Democratic Republic of the Congo also tested positive for clade I MPXV, with closely related viral sequences.This is the first time that reported clade I MPXV infection is linked to sexual transmission within a cluster. Another outbreak in the country is also being reported with multiple cases of mpox among sex workers. In the Democratic Republic of the Congo, human-to-human transmission of mpox through close contact has been reported since the 1970s, mostly in small household or community outbreaks, presumed to be primarily due to zoonotic transmission.Due to a lack of timely access to diagnostics, difficulties with linking cases to any contact with infectious animals, and incomplete epidemiological and contact tracing investigations over the years, the dynamics of MPXV clade I transmission in the Democratic Republic of the Congo are not well understood. These new features of sexual and unknown modes of transmission now raise additional concerns over the continuing rapid expansion of the outbreak in the country.In the global outbreak of mpox which began in 2022, clade IIb MPXV transmission between humans continues in most WHO regions. In addition, clade I MPXV community outbreaks occur regularly in three countries (Cameroon, Central African Republic, and the Democratic Republic of the Congo) and sporadically in others (e.g., Sudan, South Sudan). In some of these geographic areas in East, West and Central Africa, transmission from animals to humans is also presumed to occur. The natural reservoir of the virus is unknown; while various small mammals such as squirrels and monkeys are known to be susceptible, they have rarely been linked to outbreaks.
(SNIP)
WHO Risk Assessment
(Excerpt)
It is still unclear what proportion of mpox cases in the Democratic Republic of the Congo may be exposed through sexual contact; however, with outbreaks linked to sexual transmission documented in 2023 in three previously unaffected provinces, the potential additional public health impact of this new observation could be significant, particularly in under-resourced urban areas. The rapid evolution of the new outbreak in South Kivu, including among sex workers, is also concerning.
Additionally, the first case identified in Kinshasa had traveled to the city by boat on the Congo river. These boats constitute a potentially high exposure environment since people are often in proximity, transporting animals, selling and consuming wild game on board, and often traveling on the boats for weeks while sharing beds and sometimes engaging in sexual activities. Moreover, the human-to-human spread potential is amplified in urban settings such as Kinshasa and the implementation of containment measures is more challenging.
Response capacities for mpox remain limited in the country. Surveillance and laboratory capacities remain suboptimal: only 9% (1106 / 12 569, as of week 44) of suspected cases this year have been tested by PCR. There are no immunization programmes for populations at risk of mpox in the Democratic Republic of the Congo outside of research projects, and access to the antiviral medication tecovirimat also remains limited to a few clinical research studies in the country.
Risk communication and community engagement are therefore of critical importance to address the risk posed by modes of transmission traditionally reported as bushmeat consumption and community outbreaks, as well as for the newly described risk of sexual transmission, particularly among men who have sex with men. According to a recent WHO study, awareness of the risks associated with mpox is low in the Democratic Republic of the Congo. Additionally, anyone suffering from disfiguring skin conditions, including due to mpox, may face stigma, and the lack of health messages to date for men who have sex with men in the country exposes this population to a particular risk.
In summary, the reasons for concern about further spread of mpox in the Democratic Republic of the Congo are as follows:
- The Democratic Republic of the Congo is experiencing a significant increase in the number of suspected cases reported in 2023;
- Geographic expansion of the presence of mpox is underway in the newly affected southern and eastern provinces of the country;
- Epidemiological and scientific knowledge about mpox remains limited and modes of transmission in the country are poorly understood;
- In 2023, confirmed cases of mpox have been reported in the large urban area of Kinshasa and several other previously unaffected areas for the first time;
- Sexual transmission of mpox due to clade I MPXV is being documented for the first time and chains of transmission may have been missed;
- Key populations experience a higher prevalence of HIV infection than the general population;
- Awareness of mpox and the associated risks are insufficient in the general and key populations;
- National response capacities face challenges, including limited epidemiological information on exposure and infection risk factors, limited public awareness of mpox and prevention measures, and numerous competing priorities;
- Collaboration and coordination among partners are needed to sustain essential research and support a robust response at national as well as provincial and local levels.
The risk of mpox further spreading to neighbouring countries and worldwide appears to be significant. In addition to the features outlined above, arguments supporting the assessment of a high risk of international spread of mpox include the following:
- These first reported outbreaks of mpox due to clade I MPXV linked to sexual contact include a history of international travel within and across WHO regions;
- The introduction of clade I MPXV in different and possibly intersecting sexual networks could facilitate and amplify the spread of this historically more virulent clade of the virus;
- A concurrent outbreak of mpox is occurring in the neighbouring Republic of Congo along the Congo River ecosystem, whose links, if any, with cases in the Democratic Republic of the Congo remain unknown.
These factors pose an additional risk of mpox outbreaks with potentially more severe consequences than the one which has been affecting the world since 2022.
(Continue . . . )
While it remains to be seen how well, or how far, Clade I Mpox will spread it isn't as if we weren't warned that it could happen.
A 2016 study (see EID Journal:Extended H-2-H Transmission during a Monkeypox Outbreak) looked at a large 2013 outbreak of Monkeypox in the DRC and suggested that the virus's epidemiological characteristics may be changing (possibly due to the waning smallpox vaccine derived immunity in the community).
The DRC had reported a 600% increase in cases over both 2011, and 2012. The authors also cite a higher attack rate, longer chains of infection, and more pronounced community spread than have earlier reports.
Like all viruses, Monkeypox continues to evolve and diversify, as discussed in the 2014 EID Journal article Genomic Variability of Monkeypox Virus among Humans, Democratic Republic of the Congo, where the authors cautioned:
Small genetic changes could favor adaptation to a human host, and this potential is greatest for pathogens with moderate transmission rates (such as MPXV) (40). The ability to spread rapidly and efficiently from human to human could enhance spread by travelers to new regions.The takeaway from all of this is that we ignore global healthcare and infectious disease outbreaks – even in the remotest areas of the world – at our own peril. When a virus can hitch a ride on an airliner and be anywhere in the world in less than 24 hours, vast oceans and extended travel times no longer protect us they way they once did.
