Unusually, since mid-May 2022 a high number of cases of monkeypox infection have been detected in humans in Switzerland and Europe. What do you have pay attention to? Learn more here.
Disease and transmission
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.
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 and course of the disease
Symptoms
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)
Differential diagnosis
The following differential diagnoses (list not exhaustive) could also explain the clinical presentation of an acute exanthema:
- Allergic reaction (for example to plants)
- Bacterial skin infections
- Chancroid
- Chikungunya
- Dengue
- Disseminated gonococcal infection
- Granuloma inguinale
- Herpes simplex
- Herpes zoster
- Lymphogranuloma venereum
- Measles
- Molluscum contagiosum
- Primary or secondary syphilis
- Varicella zoster
- Zika
- Any other locally relevant frequent cause of maculopapular or vesicular efflorescences
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.
Measures in the event of suspected cases
Consider monkeypox infection as a possible cause in people with clinical symptoms and report your suspicion immediately to the competent cantonal authority.
Laboratory diagnosis by PCR is indicated when monkeypox infection is suspected.
To prevent infection when dealing with suspected cases, adhere to the protective measures from Swissnoso.
- When monkeypox infection is suspected, laboratory diagnosis by PCR is indicated.
- To prevent infection when dealing with suspected cases, adhere to the protective measures from Swissnoso.
- Instruct the person concerned so that they observe the behavioural recommendations for people who have tested positive until the test result is available. You will find information on this on the following site: Monkeypox > You have tested positive for monkeypox
Reporting
Monkeypox infections are subject to mandatory reporting. You will find information on reporting suspected cases at Infektionskrankheiten melden (reporting infectious diseases; German, French and Italian only).
Diagnosis
For laboratory diagnosis, take a sample by means of a swab or biopsy of skin efflorescences (exudate, pustule contents, crusts, etc.). Then send it to the reference centre for newly emerging viral infections (NAVI/CRIVE) in Geneva:
- 24/7 contact number 079 55 30 922;
- https://www.hug.ch/laboratoire-virologie/formulaires-informations
- Samples are shipped as a Category B (UN 3373) biological substance, (triple packed).
People who have tested positive
- To prevent infection when dealing with people who have tested positive, the protective measures from Swissnoso should be adhered to.
- Those affected will receive the necessary instructions and information from the competent cantonal authority,
- We recommend the following rules of behaviour for anyone who tests positive:
- - Avoid close contact with other people and animals for 21 days;
- - If close contact is necessary (for example to consult with a health professional), cover skin lesions and wear a hygiene mask;
- - Avoid sexual contact for 21 days after a positive test result;
- - Use a condom for eight weeks after a positive test result.
- - You will find more tips for people who have tested positive on this on the following site: Monkeypox > You have tested positive for monkeypox
You will find information on animal health in relation to monkeypox on the Swiss Federal Food Safety and Veterinary Office website: Monitoring of zoonotic diseases (in German, French and Italian only).
Prevention and therapy
Prevention
First- and second-generation smallpox vaccines provide effective protection. These were administered as part of the programme to eradicate smallpox – in Switzerland up until 1972.
A third-generation vaccine for immunisation against smallpox in adults (MVA-BN/Imvanex) has been authorised in Europe and the US. This likewise provides good protection against monkeypox, but is not currently authorised in Switzerland. The possibility of procuring vaccines is currently being looked into.
According to current knowledge, the use of condoms does not provide complete protection against monkeypox infection, as transmission occurs through contact with skin lesions.
Therapy
Treatment primarily targets the symptoms. In severe cases, following consultation with a specialist an antiviral therapy can be administered.
Last modification 18.08.2022
Contact
Federal Office of Public Health FOPH
Division Communicable diseases
Schwarzenburgstrasse 157
3003
Bern
Switzerland
Tel.
+41 58 463 87 06