[11] Mpox is endemic in Central and Western Africa, where several species of mammals are suspected to act as a natural reservoir of the virus.

[12] Since then, the frequency and severity of outbreaks have significantly increased, possibly as a result of waning immunity since the cessation of routine smallpox vaccination.

[7][21] The WHO put forth its approval for the new name Mpox,[22] which was gradually adopted as the preferred term in the International Classification of Diseases (ICD) after December 2023.

[1][25] The rash comprises numerous small lesions, which may appear on the palms, soles, face, mouth, throat, genitals, or anus.

[28][29] The case fatality rate of the 2022–2023 global outbreak caused by clade IIb was very low, estimated at 0.16%, with the majority of deaths in individuals who were already immunocompromized.

[34] The disease has also been reported in a wide range of other animals, including monkeys, anteaters, hedgehogs, prairie dogs, squirrels, and shrews.

[39] Clinical differential diagnosis distinguishes between rash illnesses, such as chickenpox, measles, bacterial skin infections, scabies, poison ivy, syphilis, and medication-associated allergies.

The Alinity m MPXV assay enables the detection of the virus by laboratory testing swabs of skin lesions, giving a result in less than two hours.

[45] The MVA-BN vaccine, originally developed for smallpox, has been approved in the United States for use by persons who are either considered at high risk of exposure to mpox, or who may have recently been exposed to it.

These include that healthcare providers don a gown, mask, goggles, and a disposable filtering respirator (such as an N95), and that an infected person should be isolated a private room to keep others from possible contact.

[55] Those living in countries where mpox is endemic should avoid contact with sick mammals such as rodents, marsupials, non-human primates (dead or alive) that could harbour Orthopoxvirus monkeypox and should refrain from eating or handling wild game (bush meat).

[61] The review identified non-randomized controlled trials which evaluated the safety of therapeutics for mpox, finding no significant risks from tecovirimat and low certainty evidence that suggests brincidofovir may cause mild liver injury.

[8][62] People with mild disease should isolate at home, stay hydrated, eat well, and take steps to maintain their mental health.

An additional 2024 study on Siga Technologies’ antiviral drug, tecovirimat, found it ineffective in reducing lesion healing time or pain in adults with the clade II strain of mpox.

The trial, launched in September 2022 by the U.S. National Institute of Allergy and Infectious Diseases, involved patients from several countries, including the U.S., Argentina, and Japan, who had mpox symptoms for less than 14 days.

[73] The first documented human cases occurred in 1970, involving six unvaccinated children during the smallpox eradication efforts, with the first being a 9-month-old boy in the Democratic Republic of the Congo.

[12][74] From 1981 to 1986, over 300 human cases of mpox were reported in the Democratic Republic of the Congo (then known as Zaire), primarily due to contact with animals.

[77] Originally thought to be uncommon in humans, cases have increased since the 1980s,[78][12] possibly as a result of waning immunity following the cessation of routine smallpox vaccination.

[85] Clade Ib was linked to a reported mpox case in Sweden on August 15, 2024, which was related to traveling to an African country where the virus is found.

[88][89][90] In May 2003, a young child became ill with fever and rash after being bitten by a prairie dog purchased at a local swap meet near Milwaukee, Wisconsin.

All cases were traced to Gambian pouched rats imported from Accra, Ghana, in April 2003 by a Texas exotic animal distributor.

[99] The first case of clade I mpox in the United States was identified in November 2024; the California Department of Public Health reported that an unidentified individual outside San Francisco had tested positive following travel to and from East Africa.

Unlike previous outbreaks of this clade, infection was predominantly among young male adults and human-to-human transmission appears to have readily occurred.

[109] In May 2019, a 38-year-old man who traveled from Nigeria was hospitalized in an isolation ward at the National Centre for Infectious Diseases in Singapore, after being confirmed as the country's first case of mpox.

[112] The first case was detected in London, United Kingdom, on 6 May, in a patient with a recent travel history from Nigeria, where the disease is endemic.

This status was terminated in May 2023 due to steady progress in controlling the spread of the disease, attributed to a combination of vaccination and public health information.

[122] As of August 2024[update], clade IIb mpox cases outside of endemic regions in Africa continued to be reported at a low level.

[93] During 2023, a clade I outbreak of mpox disease in the Democratic Republic of the Congo resulted in 14,626 suspected cases being reported, with 654 associated deaths, making for a case-fatality rate of 4.5%.

The outbreak continued into 2024, with 3,576 suspected mpox cases and 265 deaths reported in the Democratic Republic of the Congo through the first nine weeks of the year, making for an estimated CFR of 7.4%.

[123] Transmission of the virus in the outbreak appears to be primarily through sexual and close familial contact, with cases occurring in areas without a history of mpox, such as South Kivu and Kinshasa.