Mpox is usually zoonotic but may spread between humans through close contact.
The clinical picture is usually mild but the virus may cause severe clinical pictures particularly in immunocompromised people, children and pregnant women.
In countries outside Africa, solitary typical skin lesions in the genital area and possibly elsewhere and general symptoms are typical for the clinical picture. The clinical picture differs from that in the endemic area.
In Europe, the most important route of infection is sexual transmission.
Find out about local policies concerning mpox and notifications of communicable diseases.
Epidemiology
The mpox virus belongs to the Orthopox genus. Other members of the genus include the variola virus, the molluscum contagiosum virus 2 and the cowpox virus.
Mpox occurs as an endemic disease in tropical rain forest regions in Central and West Africa.
In Africa, mpox is typically a zoonosis but it may also spread from person to person.
In Europe, many chains of infection are known to have started from sex between men but some cases of infection have also been reported in women and children.
Infection mainly occurs through contact with skin lesions in a symptomatic person. Close skin contact is required for infection. Infection through airborne droplets from oral mucosal lesions is also considered possible.
Any close contacts of patients with mpox should look for any emerging symptoms daily for 21 days following contact. Close contacts include people who have been in direct contact with the patient's skin lesions (through sexual contact with the patient, for example), as well as those living with the patient.
The incubation period is usually 5-21 days from contact.
The first symptoms may include fever, headache, swollen lymph nodes, back pain, muscle pain and fatigue.
Swollen lymph nodes typically occur in areas close to skin lesions but may also occur in other areas (neck, armpits, groin).
Skin symptoms usually begin 1 to 3 days after the onset of fever.
Patients may have only skin symptoms, or skin symptoms may appear before general symptoms.
There are typically solitary or clustered erythematous or skin-coloured lesions with central ulceration.
An originally erythematous macule develops in a few days into a papule with possibly a pustule forming on the top.
Skin lesions may occur in any skin area but the typical sites are the genital area, face, trunk and limbs.
The skin lesions typically cause few symptoms.
Symptoms usually continue for 2 to 4 weeks.
The duration of the clinical picture, extent of skin lesions and severity of general symptoms vary individually. Skin lesions usually heal more slowly than general symptoms.
Severe clinical pictures are possible particularly in immunocompromised patients, children and pregnant women.
Infected people are considered to be infectious from the beginning of symptoms until the skin lesions have healed completely. If there are only skin symptoms, the patient is contagious from one day before the appearance of skin symptoms.
Syphilis (in primary syphilis usually a solitary, painless ulcer in the genital area with raised edges; may also occur in other areas) Syphilis
Chickenpox (eruptive clinical picture, solitary papulopustules on the trunk and limbs, often lesions on the mucosa and on palms) Chickenpox
Hand, foot and mouth disease (solitary small vesicles on the palms and soles of the feet, often aphthae on oral mucosa, GI symptoms) Enterovirus Infections
Ulcerated skin tumours (e.g. keratoacanthoma, no acute clinical picture, no general symptoms, a solitary lesion) Squamous Cell Carcinoma
Based on clinical picture, enterovirus nucleic acid detection test from a skin lesion, VZV antibodies (chickenpox), Chlamydia trachomatis nucleic acid detection test (chancres), as necessary
Treatment and prevention
The disease usually resolves spontaneously within a few weeks.
Home treatment of mpox is symptomatic: rest, fluid administration and antipyretics.
People infected with the virus should avoid close contact and refrain from sex for 21 days (from symptom onset).
In severe cases, specialized care should be consulted.
Vaccination against smallpox probably provides protection against mpox, as well. Vaccination of exposed people with new generation smallpox vaccines could be considered.
There is limited availability of medication and vaccines.
References
Petersen E, Kantele A, Koopmans M et al. Human Monkeypox: Epidemiologic and Clinical Characteristics, Diagnosis, and Prevention. Infect Dis Clin North Am 2019;33(4):1027-1043. [PubMed]
Bunge EM, Hoet B, Chen L et al. The changing epidemiology of human monkeypox-A potential threat? A systematic review. PLoS Negl Trop Dis 2022;16(2):e0010141. [PubMed]
Benites-Zapata VA, Ulloque-Badaracco JR, Alarcon-Braga EA et al. Clinical features, hospitalisation and deaths associated with monkeypox: a systematic review and meta-analysis. Ann Clin Microbiol Antimicrob 2022;21(1):36. [PubMed]
Kaler J, Hussain A, Flores G et al. Monkeypox: A Comprehensive Review of Transmission, Pathogenesis, and Manifestation. Cureus 2022;14(7):e26531. [PubMed]