Monkey pox B04.x0

Since monkeypox was first diagnosed in humans in the Democratic Republic of Congo (DRC) in 1970, the disease has spread to other regions of Africa (particularly West and Central Africa). Since 2003, import- and travel-related spread outside Africa has occasionally led to outbreaks. Interactions/activities with infected animals or people are risk behaviors associated with the acquisition of monkeypox. Recent research shows an escalation of monkeypox cases, particularly in the highly endemic Democratic Republic of Congo, a spread to other countries and an increase in the mean age of onset from young children to young adults. According to the RKI, the increase in infections observed in Germany in 2022 mainly affected men who have sex with men (RKI communication 2022).

Zoonosis that used to occur sporadically in rural areas of the tropical rainforest (Cameroon, Liberia, Nigeria, Sierra Leone, Gabon, Democratic Republic of Congo, Ivory Coast, Central African Republic) and is caused by an orthopoxvirus that triggers a smallpox-like disease in humans.

Orthopoxvirus that has evolved independently of the variola virus.

Incubation period: 5-21 days, usually 10-14 days.

Transmission occurs through direct contact or aerosols; 28 % human-to-human transmission (the chain of infection breaks down quickly), otherwise through contact with sick animals; approx. 65 reported infections per year. 30% of infections are subclinical; lethaloutcome possible; probably protected by smallpox vaccination. In 2022, an increased incidence of infection was observed in men with homosexual contact.

By 25.8.2022, the percentage of reported monkeypox cases was distributed as follows:

• 52% (24,172 cases in 29 countries and territories) reported in the WHO Region of the Americas
• 46% (21,246 cases in 43 countries) in the WHO European Region
• < 1% (445 cases in 9 countries) in the WHO African region
• < 1 percent (135 cases in 8 countries) in the WHO Western Pacific region
• < 1 percent (36 cases in 7 countries) in the WHO Eastern Mediterranean region
• < 1 percent (14 cases in 3 countries) in the WHO South-East Asia region

Of the confirmed cases with known information (n=22,154), 98.2% (21,757) are male.

The average age is 36 years.

In terms of sexual orientation, of the 10,785 cases with available information, 96% of men reported having same-sex sexual contact (MSM). Of the 10,963 cases for which information on HIV infection was available, 44 percent were HIV-positive.

The clinical picture is similar to variola infection. The incubation period is about 12 days. The clinical picture begins with fever, a patchy exanthema, severe headache and back pain and a severe feeling of illness. A typical smallpox exanthema breaks out almost simultaneously. Papules become pustules with typical central indentation. A high percentage of patients also develop an infestation of the mucous membranes. The disease lasts 2-4 weeks. The efflorescences heal with scarring. Once the efflorescences have dried up completely, the lesions are no longer infectious.

Monkeypox can be confirmed by polymerase chain reaction (PCR) (lesional smear) or immunohistochemistry. Pustule contents with electron microscopic detection of the 300x200nm monkeypox viruses. A skin biopsy of the vesiculopustular rash or from the roof of an intact vesiculopustule can be analyzed for this purpose.

A Tzanck smear can help to distinguish monkeypox from other non-viral diseases, but not from smallpox or herpes infections.

CBC, CRP, ESR, liver and kidney function. An examination for Lues, HIV or other STDs, especially in MSM, would also be important.

Risk of scarring. Secondary bacterial infections can occur.

The mortality rate in Africa is between 1% and 10.6% for people at high risk (e.g. immunodeficiency or malnutrition).

Quarantine (applies to the Federal Republic of Germany): according to the RKI, isolation is required for 3 weeks, as infected persons are infectious for the entire duration of the disease.

In immunocompetent patients, the disease is usually self-limiting after 2-4 weeks. Symptomatic and supportive measures (e.g. analgesia, topical antiseptic therapy - prevention of bacterial superinfection). Disinfection of surfaces and objects, appropriate washing of textiles.
Examination of partners. Vaccinations are available after risk exposure.
Special attention to HIV infection, immunosuppressed and malnourished patients. There is currently no specific treatment approved for monkeypox virus infections. However, antivirals developed for use in patients with smallpox may prove beneficial. The following medical countermeasures are currently available.

• Tecovirimate (also known as ^TPOXX®) is an antiviral medication approved by the United States Food and Drug Administration (FDA).
• Cidofovir(also known as Vistide®) is an antiviral drug approved by the FDA.
• Brincidofovir (also known as Tembexa) is an antiviral drug that was approved by the FDA on June 4, 2021 for the treatment of human smallpox disease in adult and pediatric patients, including newborns. Brincidofovir has been extended compared to cidofovir by a lipid that is cleaved inside the cell and metabolized to the active ingredient cidofovir diphosphate. There are no findings on its use in monkeypox. Although data from in-vitro studies suggest efficacy in monkeypox, animal or human data are still lacking. Brincidofovir was originally developed for the treatment and prophylaxis of cytomegalovirus infections in patients following stem cell transplantation. The broad-spectrum antiviral was also used during the Ebola epidemic in West Africa between 2014 and 2016.

The overall mortality rate was 8.7%, with a significant difference between the regional collectives:

• Central Africa 10.6% (95% CI: 8.4% - 13.3%) vs.
• West Africa 3.6% (95% CI: 1.7% - 6.8%).

A live vaccine (Imvanex®, 3rd generation) is available for the prophylaxis of monkeypox (from the age of 18). Imvanex® has been approved by the EMA for the prophylaxis of smallpox since 2013; the indication has been extended in 2022 following an increased incidence of monkeypox in Europe. Complete vaccination protection is achieved after two doses (at least 28 days apart).

Post-exposure prophylaxis: Vaccination with Imvanex® should be offered after a high-risk contact with close physical contact, especially in patients at risk of a severe course (e.g. HIV-infected patients).

For the monkeypox virus, there is both a medical reporting obligation and a laboratory reporting obligation in accordance with the Infection Protection Act (IfSG).

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2. Mukinda VB et al (1997) Re-emergence of human monkeypox in Zaire in 1996. monkeypox Epidemiologic Working Group. Lancet 349: 1449-50
3. Mukinda VB et al. (1997) Re-emergence of human monkeypox in Zaire in 1996. dermatologist 48:598.
4. Meyer H et al. (2002) Outbreaks of disease suspected of being due to human monkeypox virus infection in the democratic republic of congo in 2001. J Clin Microbiol 40: 2919-2921.