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| Geographic Range of Monkeypox - Credit WHO |
#16,811
Although there is sudden awareness of Monkeypox over the past month, with more than 1,300 cases detected (so far) in non-endemic countries, we've been following outbreaks in Nigeria, the DRC, and other central African nations - and the occasional exported case - for well over a decade.
EID Journal: Reemergence of Human Monkeypox and Declining Population Immunity - Nigeria, 2017–2020
WHO: Modelling Human-to-Human Transmission of Monkeypox
EID Journal:Extended H-2-H Transmission during a Monkeypox Outbreak
Genomic Variability of Monkeypox Virus among Humans, Democratic Republic of the Congo
In 2019's CDC: 8 Zoonotic Diseases Of Most Concern In The United States, Monkeypox was ranked 29th; about halfway down their list. Similarly, in 2018's WHO List Of Blueprint Priority Diseases - while Monkeypox did not make the final list (n=8) - it was mentioned as a disease to watch.
At the same time, it has been apparent that surveillance and reporting of cases from endemic nations has been less than robust.
Based simply on the number of exported cases reported in the UK, and the U.S, over the past 3 years, far more cases would have to be occurring in these countries than have been officially reported.
Recently the Nigerian CDC acknowledged the following challenges with Monkeypox surveillance.
1. Sub-optimal monkeypox surveillance in all states of the Federation
2. Non- prioritisation of Monkeypox as a disease of public health importance due to low-risk perception
All of which means we probably know less than we think we do about Monkeypox; its prevalence in endemic nations, how it spreads, and even its full spectrum of clinical presentations. We are basing our assumptions and public health responses on incomplete, and potentially misleading data.
All of which brings us to a recent paper, published in the International Journal of Infectious Diseases, that highlight our knowledge gaps. First a link, the abstract, and a small excerpt - but you'll want to read it in its entirety.
I'll have a brief postscript when you return.
Najmul Haider. Javier Guitian. David Simons. Eskild Petersen, Richard Kock, Alimuddin ZumlaOpen AccessPublished:May 28, 2022DOI:https://doi.org/10.1016/j.ijid.2022.05.058Highlights• We present explanation for the 2022 monkeypox epidemic in the Western world• The true burden of MPX and the extent of animal reservoirs are not well known• The increased rodent-human interaction led to increased transmission of MPXV• The population has crossed a threshold for sustainable human-human transmission• A new estimation of basic and effective reproduction rate (R0 and Re) is requiredAbstractWe explain research gaps on Monkeypox (MPX) virus epidemiology in endemic countries and present hypotheses for the recent increase of MPX cases in West Africa as a possible explanation for the current epidemic in Europe, America, and Australia. The detection of >400 MPX cases in less than a month in May 2022, across many countries underscores the epidemic potential of MPX in humans and demonstrates several important research gaps.First, the true burden of MPX in West and Central Africa is poorly understood, although it is critical for prevention and control of future outbreaks. Second, the diversity and extent of the animal reservoir remain unknown.
- We hypothesize that the synanthropic rodent population has increased in recent years in Africa leading to more human-rodent interactions and thus increased transmission of MPXV.
- We further hypothesise that nearly 45 years after the end of routine smallpox vaccination, the larger and more interconnected immune-naïve population has crossed a threshold resulting in more sustainable human-to-human transmission of MPXV.
The current epidemic in the Western World is possibly a consequence of increased local transmission of MPXV in Africa. A new estimation of the basic and effective reproduction rate (R0 and Re) in different populations is required. National, regional, and international collaborations are needed to address research gaps related to MPX outbreaks.
(SNIP)
MPX case burden in Sub-Saharan Africa: the tip of the icebergNigeria reported the first case of MPXV in 1971 with no cases being formally reported between 1978 and 2017. Since 2017 outbreaks of MPX, are reported annually (Fig 1). The number of confirmed cases likely represents a small proportion of the true number of infections, due to lack of testing, cases not meeting healthcare services and incomplete reporting practices. Between 1st January 2017 and 30th April 2022, the Nigeria CDC has reported a total of 558 suspected MPX cases; 241 (43%) confirmed cases with 8 deaths giving an estimated case-fatality rate of 3.3% (NCDC 2022). Among confirmed cases, males (69%) and young adults ≤ 40 years old (84%) are over-represented (NCDC 2022).
For most infectious disease specialists, Monkeypox has been on their `short-list' of zoonotic diseases with epidemic potential for years. Along with (far worse) pathogens like Nipah, Hendra, Lassa Fever, MERS-CoV, a long list of avian flu subtypes, and Crimean-Congo Hemorrhagic Fever.
While Monkeypox may have jumped the line, it won't be the last to do so.
We either figure out how to deal with these exotic pathogens in the places where they are simmering quietly under the radar, or we can wait for them to evolve and show up on our doorstep.
Our choice.
