The Public Health Agency of Sweden
Updated 23 September 2022

Disease information about monkeypox

This information does not claim to be comprehensive or constantly updated, but aims to provide an overview of communicable diseases relevant to communicable disease prevention.

Monkeypox is a zoonosis, i.e. a disease that can be transmitted between animals and humans. The virus can be transmitted from animals to humans through close contact. It was first discovered in wild monkeys, and was therefore named monkeypox, but the virus has most likely spread through various rodents in central and western African rainforests. It is probably these rodents that maintain the virus in nature.

During spring 2022, an unusual number of cases have been observed in several countries. In these cases, transmission of the virus appears to have occurred mainly through sexual contacts between men who have sex with men.

What causes monkeypox and how does the disease spread?

Monkeypox is caused by monkeypox virus, a species of the Orthopoxvirus. The knowledge of how the disease spreads is incomplete. Contact with infected animals is a known route of transmission, but the disease can also spread between humans. Monkeypox is mainly transmitted through close physical contact with an infected person. It is likely that the virus can enter the body through the airways, through broken skin (even if not visible) or the mucous membranes (eyes, nose, or mouth).

The routes of transmission are not completely clear, but the virus is probably spread via large drops from the airways, via body fluids and fluid from blisters. It is not entirely clear whether the virus can also spread in other ways. Physical sexual contacts, or other close skin-to-skin contacts with an infectious person, pose a particularly high risk. 

The incubation period is usually 6–13 days but can vary between 5 and 21 days.

Symptoms and complications

Symptoms of monkeypox often include skin rash and blisters, and are often mild, but can be serious in persons in risk groups. In older studies, cases of serious disease and death have been reported in African countries, but not in the current outbreak in 2022.

The blisters can appear on the torso, arms, legs, hands, feet and face, and on parts of the body that were infected. E.g. blisters on and around the genitals, and around the anus and the mouth have been observed in infections after intimate contacts, such as sex. The blisters can itch and hurt.

Symptoms of monkeypox may also include fever and swollen lymph nodes.

Diagnostics and treatment

Suspicions of monkeypox may arise from the symptoms and if the person has been exposed to risk of being infected. The diagnosis is then confirmed by either detecting the genome of the virus in a molecular biological analysis or by electron microscopy.

There are medicines that appear to have some effect on monkeypox and that can be used in cases of serious illness.  

General preventive measures

It is possible to prevent infection by avoiding close contact with infected people. Sexual contact poses a particularly high risk of infection.

Infection is also prevented by avoiding infected animals in areas where monkeypox is present, especially in western and central Africa.

The monkeypox vaccine is used as a prophylaxis for people who are at high risk of being exposed to the disease. It is also used to prevent the course of infection or reduce its severity in unvaccinated people who have been exposed to the virus.

Measures in the event of cases or outbreaks

Monkeypox is a disease that is subject to mandatory contact tracing and is dangerous to public health according to the Swedish Communicable Diseases Act. All cases of infection with monkeypox should be reported to the county medical officer in the region and to the Public Health Agency of Sweden.

Further reading