Saturday, March 16, 2024

Mpox Update From The CDC, A New Preprint On Transmission & Reports of Spread In Republic of Congo

#17,951

Although the declared global health emergency over the international spread of a new clade (IIb) of Mpox (formerly Monkeypox) was ended after only 10 months in the spring of 2023, we continue to see sporadic infections around the globe, while the more dangerous clade I mpox virus continues to rage (>12,000 cases in 2023) in the DRC,. 

Four months ago, the WHO Reported the 1st Confirmed Cluster Of Sexually Transmitted MPXV Clade 1 in the DRC, warning that `The risk of mpox further spreading to neighbouring countries and worldwide appears to be significant.'

Last week we looked at a report in Eurosurveillance: Ongoing Mpox Outbreak in South Kivu Province, DRC Associated With a Novel Clade I Sub-lineage, which contained the first genomic analysis of samples from a previously unaffected region of the DRC. 

This study revealed a novel clade I sub-linage had emerged - most likely from a zoonotic introduction - with changes that may render current CDC tests unreliable.

Over the past 48 hours there have been media reports from the DRC's neighbor, the Republic of Congo, of an outbreak of Mpox recorded in several regions not previously affected (see Republic of Congo reports its first mpox virus cases in several regions). 

Since I can find no confirmation on their Health Ministry website, we may have to wait for a WHO update. But spread beyond the DRC was one of the risks mentioned last November. 

Meanwhile, we've a new preprint on the medRxiv server, which further confirms last year's finding of (primarily heterosexual) sexual transmission of Mpox clade I in the DRC. 

Epidemiology, clinical characteristics, and transmission patterns of a novel Mpox (Monkeypox) outbreak in eastern Democratic Republic of the Congo (DRC): an observational, cross-sectional cohort study
Leandre Murhula Masirika, Jean Claude Udahemuka, Pacifique Ndishimye, Gustavo Sganzerla Martinez, Patricia Kelvin, Maliyamungu Bubala Nadine, Bilembo Kitwanda Steeven, Franklin Kumbana Mweshi, Léandre Mutimbwa Mambo, Bas B. Oude Munnink, Justin Bengehya Mbiribindi, Freddy Belesi Siangoli, Trudie Lang, Jean M. Malekani, Frank M. Aarestrup, Marion Koopmans, Leonard Schuele, Jean Pierre Musabvimana, Brigitte Umutoni, Ali Toloue, Benjamin Hewins, Mansi Dutt, Anuj Kumar, Alyson A. Kelvin, Jean-Paul Kabemba Lukusa, Christian Gortazar, David J Kelvin, Luis Flores
doi: https://doi.org/10.1101/2024.03.05.24303395

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Summary (abstract)

Background 

In August 2023, an outbreak of mpox was reported in the eastern part, South Kivu Province, of Democratic Republic of the Congo. In this study, we aimed to investigate the origin of this outbreak and to assess how monkeypox virus spread among humans in the city of Kamituga.

Methods 

We performed an observational cohort study by recruiting hospitalized patients with mpox-like symptoms. Furthermore, we compared structured, de-identified case report forms and interviews were conducted to determine the possible origins and modes of transmission of the mpox outbreak. We describe the clinical characteristics and epidemiology observed in reported infections.

Findings 

During the study period (24 September 2023 to 29 January 2024), 164 patients were admitted to the Kamituga hospital, 51 individuals were enrolled in the study and interviewed, and 37 (73%) of 51 individuals received a molecularly confirmed mpox diagnosis. 

The median age for males was 24 years (IQR 18-30; range 14-36) and 19 years for females (IQR 17-21; range 1-59). The cohort was comprised of 47 (92%) of 51 individuals who identified as heterosexual, and two (4%) of 51 as bisexual, with 31 (61%) of 51 individuals sexually active with more than one partner within the last six months. 

The direct transmission routes are unknown; however, it is expected that the majority of infections were transmitted via occupational exposures. Out of the 51 individuals, 24 (47%) were professional sex workers (PSWs), while five (10%) were gold miners, 6 (12%) were students, and four (8%) were farmers; the remaining individual occupations were unknown. 

The most common symptoms associated with clinical mpox diagnosis were fever, which was described in 38 (75%) of 51 individuals, and rash, which was described in 45 (88%) of 51 individuals. Among those with a rash, 21 (41%) of 51 individuals experienced oral lesions, and 32 (63%) of 51 presented anogenital lesions. Mpox viral DNA was detected by qPCR from vaginal, penile, and oral swabs in 37 (73%) of 51 enrolled individuals. Two deaths were reported.

Interpretation 

In this observational cohort study, mpox virus infection caused symptoms in a wide age range of participants with most cases presenting in sexually active individuals. Symptoms included fever, cough, lymphadenopathy, sore throat, chills, headache, back pain, muscle pain, vomiting, nausea, conjunctivitis, and rash (oral and anogenital). Heterosexual partners dominated human-to-human contact transmission suggesting that heterosexual close contact is the main form of transmission in this outbreak. Furthermore, Professional Sex Workers (PSWs) were the dominant occupation among infected individuals, indicating that PSWs and clients may be at higher risk for developing mpox virus infections.

The changing epidemiology and genetic evolution of mpox clade I in central Africa has sparked a number of risks assessments over the past few months, including:

There have been no cases of the type of mpox spreading in DRC reported in the United States at this time. The risk to the general public in the U.S. from the type of mpox circulating in the DRC is low.

But that assessment could change. Which is why the CDC continues to update their Mpox web page , adding the following guidance yesterday (March 15th).


Signs and Symptoms March 15, 2024

Mpox in Animals and Pets March 15, 2024

About Mpox March 15, 2024

During the decade leading up to Mpox clade IIb's world tour (Spring 2022), we saw repeated warnings that the virus was evolving into a more transmissible disease threat (see 2016's EID Journal:Extended H-2-H Transmission during a Monkeypox Outbreak).

A 2020 report, published by the Bulletin of the World Health Organization, warned that our waning immunity to smallpox put society at greater risks of seeing Monkeypox epidemics (see WHO: Modelling Human-to-Human Transmission of Monkeypox).

And in early 2023, in EID Journal: Monkeypox Virus Evolution before 2022 Outbreak, researchers suggested that` . . . the most likely scenario is that there has been silent and undetected circulation of MPXV, possibly including multiple non–MPXV-endemic countries outside Africa, since the 2017–2018 outbreak.'

While there are no guarantees that Clade I Mpox will follow suit, similar warning signs are there. Just as they are for novel or avian flu, Lassa Fever, Nipah, MERS-CoV, and an increasing array of other emerging infectious diseases.

A reminder that nature is nothing, if not persistent.
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