Mpox (monkeypox)
What is mpox?
Mpox is an infectious disease caused by the mpox virus (MPXV). The MPXV belongs to the Orthopoxvirus genus. This genus also includes the cowpox virus, the molluscum contagiousum virus and the variola virus, which causes smallpox. The variola virus has been eradicated, and the disease no longer circulates among humans.
Mpox is not easily transmitted from person to person.
How common is mpox?
Mpox occurs in tropical rainforests in Central and West Africa. Two different strains of the virus are known. Of these, the virus found in the Congo Basin in Central Africa causes a more severe disease than the strain occurring in West Africa.
The disease occurs from time to time in Africa. Mpox was identified in 1970 and has been reported in the territories of eleven African countries since that year. An outbreak that began in Nigeria in 2017 caused more than 500 suspected and more than 200 confirmed cases of mpox.
Mpox has spread outside Africa through animals and tourism. It also caused an individual outbreak in the United States in 2003, in which 81 people were infected by wild animals originally imported from Africa. No human-to-human transmissions were found.
In May 2022, several cases of mpox have been found in Europe and North America. These infections have been diagnosed in persons who have not travelled in areas where mpox is usually present.
How is mpox transmitted?
Mpox is a zoonosis, or a disease primarily transmitted from animals to humans. Humans typically contract the virus from wild animals, especially rodents, on the African continent. Direct contact with an infected animal may result in transmission through blood, blisters or other secretions.
Mpox can also be transmitted from person to person. In particular, the transmission can take place in direct contact with an infected person’s skin changes and through droplets in prolonged face-to-face contact.
Environmental transmission is also possible, e.g., via bedclothes/linen contaminated by bodily secretions.
As a rule, mpox does not spread easily between people. The ECDC estimates that the risk of the disease spreading more widely among the population is low. Mpox is not typically transmitted in short everyday contacts.
The majority of the infections diagnosed outside Africa in 2022 have been transmitted through sexual contact. In particular, mpox has been diagnosed among men who have sex with men. Those who have multiple sexual partners are likely to have an increased risk of infection.
What are the symptoms of mpox?
The incubation period of mpox is typically 6 to 13 days, but may vary between 5 and 21 days.
The first symptoms of mpox may include
- fever
- headache
- swollen lymph nodes
- back pain
- muscle ache
- tiredness/fatigue.
While mpox has similar symptoms as smallpox, mpox causes a milder disease and is less contagious than smallpox.
Skin lesions usually begin to occur one to three days after the onset of fever. A blistering rash is formed, especially on the face as well as the hands and feet. As the disease progresses, the blisters can turn to pustules, which then form scabs. Blisters may also appear on mucous membranes of the mouth and the genital area.
The symptoms typically last two to four weeks. The disease usually heals spontaneously. Mpox can also cause a serious disease. The virus occurring in West Africa causes a milder disease (mortality below 1%), while the one found in Central Africa may cause mortality exceeding 10%.
Serious forms of the disease are possible especially in those immunocompromised due to underlying illnesses or medical treatment. In mpox outbreaks in Africa, more serious forms of the disease have been diagnosed especially in children and pregnant women.
The majority of the infections diagnosed outside Africa in 2022 have so far represented the milder form typical of West Africa. The first symptoms of the cases have been mild or non-existent. Skin changes have started from the genital area or the area surrounding the anus. Because of the route of transmission, cases have almost exclusively been diagnosed in adults.
When should I suspect mpox?
Mpox should be suspected when a person has a generalised or localised reddish, pinkish or blistering rash. The rash typically expands in a ring shape and can occur simultaneously with
- swollen lymph nodes and/or
- fever and/or
- headaches and/or
- fatigue.
Your risk of infection may be higher if
- you have had contact with a person infected with mpox in the last three weeks, or
- you have travelled in an area where mpox is present, or
- you have had multiple sexual partners.
How is a mpox diagnosed?
The mpox virus genome can be detected in laboratory tests of samples taken from skin changes using the gene amplification (PCR) method. In Finland, tests for the mpox virus are currently carried out at HUSLAB.
Orthopox virus (HUSLAB testing protocol)
A physician's referral is needed for the laboratory test.
How is mpox treated?
The treatment is symptomatic, and the disease usually heals spontaneously within a few weeks. New antivirals can be used with caution to treat serious cases of mpox. The availability of these drugs is limited, and the EU countries together with the European Commission are currently investigating the possibilities of procuring them.
How can mpox be prevented?
Mpox is not easily transmitted from person to person. Good hand hygiene and coughing hygiene reduce the risk of infection. Mpox has currently been transmitted from person to person in the population that has multiple sexual contacts, including sex between men.
If you think you may have mpox, it is important to report the suspected infection by phone before entering healthcare services. This way unprotected contacts between staff and the patient can be avoided, and a suitable room can be arranged for the patient for the visit, for example at the emergency clinic.
Is there a vaccine against mpox?
A close relative of the mpox virus, the variola virus, has been eradicated with the help of smallpox vaccinations. It is likely that the smallpox vaccine also gives protection against mpox. Vaccinating exposed persons with next-generation smallpox vaccines could be considered, but the availability of these vaccines is limited. The EU countries together with the European Commission are currently investigating the possibilities of procuring these vaccines.
Further information
Monkeypox multi-country outbreak (ECDC, pdf 599 kt)
Epidemiological update:Monkeypox outbreak
Multi-country monkeypox outbreak in non-endemic countries
Monkeypox cases diagnosed in Europe (in Finnish)
Multi-country monkeypox outbreak in non-endemic countries (WHO)
