Monkeypox is a zoonotic disease, meaning that it can be transmitted between animals and humans through direct or indirect contact. Following the eradication of smallpox and the end of universal smallpox vaccination, monkeypox is currently the most common orthopoxvirus infection in humans.
Since May 2022, an evolving outbreak of monkeypox cases has been reported by multiple countries around the world, primarily affecting young men who identify as men who have sex with men. Four rapid communications published in Eurosurveillance today describe cases diagnosed in Italy, Portugal, the United Kingdom (UK) and Australia.
United Kingdom: one epidemic, three separate incidents
Vivancos et al. describe the epidemiology and public health response to an outbreak of monkeypox in the UK with 86 confirmed cases of monkeypox virus infections between 7 and 25 May 2022.
The authors grouped the currently known cases into three separate incidents: an isolated laboratory-confirmed case from travel to Nigeria, two confirmed cases of monkeypox from a separate household cluster, including one case whose infections had been clinically resolved (no lab confirmation) and the third incident, 82 lab-confirmed cases of monkeypox that are neither related to the other two incidents, nor the patients reported travel to areas where monkeypox is endemic.
While investigations are still ongoing to determine whether the cases in Incident 3 may have been infected outside the UK, the sexual health history has identified links to on-site sex, private sex parties and the use of geospatial dating apps, both in the UK and overseas. In the cluster linked to the third incident, gender information was available for 79 cases, all male. Of these, a large majority, 66 identified as gay or bisexual or other men who have sex with men.
So far, no single factor or exposure that links the cases has been identified.
According to Vivanco et al., “the current outbreak signals a shift in basic assumptions about the epidemiology of MPXV in Europe with profound implications for surveillance and control” and is the first reported sustained transmission of MPXV in the UK. United with evidence of human-to-human transmission. – human transmission by close contact, including in sexual networks.
Possible undetected spread of monkeypox suspected in Portugal
Portugal confirmed the first-ever case of human monkeypox in the country on May 17, 2022 and Duque et al. describe the epidemic detection of 96 confirmed cases of monkeypox to date in the region of Lisbon and the Tagus Valley. The onset of symptoms of the first cases in Portugal was reported as early as April 29, 2022.
Most patients were not part of the identified chains of transmission, and no link to travel or contact with symptomatic people or animals could be established. According to the authors, this suggests a possible undetected spread of monkeypox.
Of the 23 confirmed cases, Duque et al. describe, 14 were seropositive and the most common symptoms were rash (n = 14), inguinal lymphadenopathy (n = 14), fever (n = 13), genital ulcers (n = 6). The authors hypothesize “that MPX circulated below the detection of surveillance systems. Although some cases have a clear epidemiological link, the lack of exposure identified in others raises unanswered questions.”
Seminal fluid samples in Italy positive for monekypox
Vita et al. provide the clinical description of the four cases of monkeypox reported in Italy, in adult men with different clinical pictures from the existing literature because the skin lesions were asynchronous, ranging from single or grouped spot to umbilical papule with progressive central ulceration and, finally, to the crusts. The lesions were mainly localized in the genital and perianal sites.
Biological samples of seminal fluid were positive for monkeypox viral DNA in all four patients, with a quantification cycle ranging from 27 to 30. Based on this, the authors hypothesize that “although these results cannot be considered definitive proof of infectivity, they demonstrate viral excretion, the effectiveness of which in terms of transmission cannot be ruled out.”
Risk of bacterial superinfection
In their case description, Hammerschlag et al. share data on a virally suppressed HIV-positive patient who presented with a genital rash in Australia following a visit to Europe in May 2022, who was subsequently hospitalised.
The clinical presentation in this case was considered atypical given the presence of a rash exclusively at the site of sexual contact 3 days prior to the development of fever and due to the preponderance of lesions in a central distribution with the least lesions present on the face and extremities after the rash. broadcast.
The authors point out that “our patient’s hospitalization was not for severe manifestations of monkeypox viral infection but to allow for diagnostic evaluation, pain management, and treatment of bacterial superinfection” and that the The patient’s normal CD4+ T-cell count and suppressed HIV viral load on antiretroviral therapy “were potentially important factors in preventing more serious consequences of his monkeypox infection.”
European Center for Disease Prevention and Control (ECDC)
Duke, deputy, et al. (2022) Ongoing monkeypox virus outbreak, Portugal, April 29 to May 23, 2022. Eurosurveillance. doi.org/10.2807/1560-7917.ES.2022.27.22.2200424.