Disease, transmission and therapy

Read more about transmission routes, the symptoms and course of the disease, therapy for the disease and the history of monkeypox.

Transmission routes

The current outbreak mainly involves human-to-human transmission. Transmission can occur through close contact with an infected person via:

  • skin and mucous membranes (for example eyes, nose, mouth or genitals),
  • skin wounds (infected secretions or blood),
  • respiratory secretions or large respiratory droplets or
  • indirectly via recently contaminated objects (such as bedclothes, towels, clothes, toiletries and door handles).

At the moment it is not known for certain whether monkeypox can also spread via sperm or vaginal secretion. What is certain, however, is that the virus can be transmitted through direct contact with skin and mucous membranes, also during sexual activity. Sexual contact with an infected person may increase the likelihood of human-to-human transmission. Men who have sex with men (MSM, but not exclusively MSM) currently seem to be at a higher risk of infection.

The transmission routes in the current outbreak are currently being investigated scientifically.

Symptoms of the disease

Common symptoms of the disease are:

  • Acute rash or individual lesion (macules, then papules, vesicles, pustules and finally crusts, similar to pox).
  • Headache
  • Acute onset of fever (>38.5 C)
  • Swollen lymph nodes (lymphadenopathy)
  • Myalgia (muscle and body aches)
  • Back pain
  • Asthenia (pronounced weakness)
  • Proctitis (inflammation of the lining of the rectum)
  • Balanitis (inflammation of the glans of the penis)

A case is all the more probable if one or more or the following requirements are met:

  • An epidemiological link to a suspected or confirmed case of monkeypox in the 21 days preceding the onset of symptoms;
  • Close and prolonged physical contact in the last 21 days before the onset of symptoms, especially with different and/or anonymous sexual partners;
  • Direct, close physical contact in the last 21 days before the onset of symptoms with a man who has sex with men;
  • Participation in events with direct close physical contact (especially skin and mucous membrane contact).

Course of the disease

The incubation period of monkeypox is usually from five to 21 days The period of infectivity has not yet been conclusively determined. Infectivity probably begins with the onset of symptoms and declines sharply as soon as the skin efflorescences have healed and a new layer of skin has formed.

The symptoms and course of the disease are generally mild and may differ from the symptoms described in regions where the disease is endemic. It is not uncommon for cases to be oligosymptomatic without the typical skin rash described in earlier cases. Similarly, there may only be a small number or even a single lesion (initially appearing in the genital or perianal area, and not spreading), or lesions at various stages of development. Some patients may also have sexually-transmitted infections (STI) and should be tested and treated accordingly.

Currently there are no known long-term consequences of monkeypox infection. People with immune deficiency as well as infants, children and pregnant women seem to be at a higher risk of a severe course.

Therapy for disease

The antiviral drug Tecovirimat is available in Switzerland. In cooperation with the Armed Forces Pharmacy, the federal government is in the process of procuring a further 500 treatment units.

History of the disease

In 1970 the first human isolate of monkeypox virus was reported in a child in the Democratic Republic of the Congo. Subsequently sporadic cases were reported, primarily from central and western Africa. Until mid-May, monkeypox virus infections of humans were detected only rarely outside Africa, and the few cases detected had a history of travel in a risk area in central or western Africa.

The monkeypox virus is a zoonotic disease and member of the Orthopoxvirus genus in the family Poxviridae. Although the name suggests that monkeys are the primary host, the specific animal reservoir remains unknown. Native African rodents appear to be a natural reservoir for the virus.

The Orthopoxvirus genus also includes vaccinia virus, cowpox virus, variola virus and various other pox viruses.

Genomic sequencing has identified two phylogenetically distinct clades (variants) of monkeypox virus. Since 12 August 2022, these have been designated as clade I (Congo Basin, Central Africa) and clade II (West Africa) according to the WHO. Sequencing data show that clade II is predominantly circulating in the current outbreak in Europe and North America.

Last modification 14.10.2022

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