Epidemiology and public health response to monkeypox

Monkeypox is a zoonotic disease, ie. it can be transmitted between animals and humans through direct or indirect contact. After the eradication of smallpox and the end of universal smallpox vaccination, monkeypox is now the most common orthopoxvirus infection in humans.

Since May 2022, several countries around the world have reported a growing epidemic of monkeypox cases, mainly affecting young men who identify themselves as men who have sex with men. Four quick messages published in Euromonitoring today describe cases diagnosed in Italy, Portugal, the United Kingdom (United Kingdom) and Australia.

United Kingdom: one outbreak, three separate incidents

Vivancos et al. describe the epidemiology and public health response to an outbreak of monkeypox in the United Kingdom with 86 confirmed cases of monkeypox virus infection between 7 and 25 May 2022.

The authors grouped currently known cases into three separate incidents: an isolated laboratory-confirmed case after a trip to Nigeria, two confirmed cases of monkeypox from a separate household cluster, including one whose infections are already clinically resolved (without laboratory confirmation) and a third incident, 82 laboratory-confirmed cases of monkeypox, which are neither related to the other two incidents, nor patients report travel to areas where monkeypox is endemic.

While investigations are still ongoing to determine whether the incidents in 3 may have been infected outside the UK, sexual health stories have identified links to on-site sex, private sex parties and the use of geospatial dating apps, as in the UK. and in abroad. In the group related to the third incident, gender information was available for 79 cases, all men. Among them, the vast majority, 66 identified as gay, bisexual or other men who have sex with men.

So far, no case-related factors or exposures have been identified.

According to Vivanco et al., “The current epidemic signals a change in basic assumptions about the epidemiology of MPXV in Europe with profound implications for surveillance and control” and is the first reported long-term transmission of MPXV in the UK with evidence of human-human transmission. contact, including in sexual networks.

Possible undetected earlier spread of monkeypox in Portugal

Portugal confirmed the first case of human monkeypox in the country on May 17, 2022 and Duque et al. describe the discovery of an outbreak of 96 confirmed cases of monkeypox in the Lisbon region and the Tagus Valley. The onset of symptoms for the first cases in Portugal was reported on April 29, 2022.

Most of the patients were not part of the identified transmission chains, nor could a connection to travel or contact with symptomatic individuals or animals be established. According to the authors, this suggests a possible undiscovered spread of monkeypox.

Among the 23 confirmed cases, Duque et al. described, 14 were HIV positive and the most common symptoms were exanthema (n = 14), inguinal lymphadenopathy (n = 14), fever (n = 13), genital ulcers (n = 6). The authors suggest that “MPX circulates under the discovery of surveillance systems. Although some cases have a clear epidemiological link, the lack of identified exposure in others raises unanswered questions.”

Semen samples positive for monekypox in Italy

Vita et al. provide a clinical description of the four cases of smallpox reported in Italy in adult men presenting different clinical pictures from the existing literature, as skin lesions are asynchronous, ranging from single or grouped spot to umbilical papule with progressive central ulcer and finally to scabs. The lesions are localized mainly in the genital and perianal sites.

Biological semen samples were positive for monkeypox viral DNA in all four patients, with a quantification cycle of 27 to 30. Based on this, the authors suggest that “although these findings cannot be considered conclusive evidence of infectivity, they demonstrate the release of a virus whose transmission efficacy cannot be ruled out. “

Risk of bacterial superinfection

In their description, Hammerschlag et al. share data on a virus-suppressed HIV-positive patient who has a genital rash in Australia after a visit to Europe in May 2022, who was later hospitalized.

The clinical picture in this case is considered atypical given the presence of a rash exclusively at the site of sexual intercourse 3 days before the onset of fever and due to the predominance of lesions in the central distribution with the least lesions present on the face and limbs after the rash spread.

The authors emphasize that “the hospitalization of our patient was not for severe manifestations of viral infection with monkeypox, but to enable diagnostic assessment, pain management and treatment of bacterial superinfection” and that the normal number of CD4 + T cells of the patient and the suppressed HIV viral load of antiretroviral therapy “were potentially important factors in preventing more severe outcomes of his monkeypox infection”.


European Center for Disease Prevention and Control (ECDC)

Reference in the magazine:

Duke, MP, et al. (2022) Current outbreak of monkeypox virus, Portugal, 29 April to 23 May 2022 Euromonitoring. doi.org/10.2807/1560-7917.ES.2022.27.22.2200424.

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