Update: Since 28.11.2022, the WHO recommends using the term mpox for the disease "monkeypox" [1]. A new name for the monkeypox virus is currently being developed by the International Committee on the Taxonomy of Viruses (ICTV).
The monkeypox virus was discovered in monkeys as early as 1958 and has been spreading to humans in Central and West Africa since 1970 [2]. Reports from non-endemic countries have so far been rare but could be facilitated in the future due to the decreasing global population immunity after the cessation of smallpox vaccination. Since the beginning of May, reports of cases from non-endemic countries around the world have been increasing [3].
The disease mpox is caused by the so-called monkeypox virus (Orthopoxvirus simiae; genus Orthopoxvirus; enveloped virus). After an incubation period of 5 to 21 days, infected people usually first develop fever, headaches, muscle and back pain, and swollen lymph nodes. The typical eponymous skin alterations only appear after the onset of fever and are mainly found in the face as well as on the palms of the hands and the soles of the feet. However, they can also occur on other body parts such as the mouth, urogenital and anal areas, and the eyes. In the course of the disease (usually 2-4 weeks), the rash changes from a spot to a pustule, later becoming encrusted and falling off. The disease caused by the virus clade currently circulating in non-endemic countries is mostly mild and self-limiting in humans but can also result in complications such as bacterial superinfections in rarer cases [3].
Mpox can be transmitted from animals to humans as well as from human to human. However, human-to-human transmission is considered less common and usually requires close physical contact. The virus mainly uses tiny skin lesions or the mucous membranes (eyes, mouth, nose, genitals) to enter the body. Particularly high virus concentrations are found in the typical pustules, but other body fluids (secretions and excretions) most likely also contain virus particles. Droplet infection is possible but probably only occurs with prolonged face-to-face contact. In addition, the virus can be transmitted from pregnant women to the unborn fetus or to the child during birth [3,4].
Animal transmission can occur if the person has been in contact with infected animals or contaminated animal products, e.g. through bites, close contact, contact with secretions or excretions, consumption of contaminated, undercooked meat, etc.). Contrary to what the name suggests, the natural host of the monkeypox virus is probably not the monkey, which can also be infected. It is assumed that mainly rodent species and shrews form the wildlife reservoir for the virus [3,4].
In order to prevent further spread of mpox, it is important to educate the population about preventive behavioral measures. This includes, for example, avoiding close contact with (suspected) infected people. In addition, no items of laundry such as towels or bed linen should be shared. Since vaccination against human smallpox seems to offer some protection against mpox, smallpox vaccination can be carried out if there are special indications. In addition, it is important to quickly identify new cases [2]. In most countries, people with confirmed or suspected illness should isolate themselves (usually at home) until they have recovered or the suspicion no longer exists.
In order to avoid transmission of monkeypox in healthcare facilities, good hand hygiene using a hand disinfectant with at least a virucidal activity against enveloped viruses and changing gloves according to indications is recommended. Employees who directly care for infected people should also protect themselves with an FFP2 mask and personal protective equipment [5]. Disinfectants with at least limited virucidal activity should also be used for surface disinfection. Since the virus can persist for a long time, exposure times must be considered.
According to the World Health Organization (WHO), as of July 19 2022, 10,604 cases from 36 countries were reported. So far, this has only involved the clade circulating in West Africa, which causes less severe courses than the Central African clade [6]. On July 23 2022, the current mpox outbreak was declared a "Public Health Emergency of International Concern" (PHEIC) by WHO [7]. While the WHO currently assesses the risk on a global level as moderate, the risk for the European region is considered as high [7]. Individual countries may only see a low risk for the health of the general population.
The current monkeypox outbreak is a classic example of a zoonotic disease, as the monkeypox virus originally only appeared in wild animals. However, since humans are increasingly intruding and destroying the natural habitat of wild animals, zoonoses are becoming an increasing threat to humans [8].
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