Monkeypox virus (MPXV) is a zoonotic, double-stranded DNA virus belonging to the genus Orthopoxvirus of the family Poxviridae. It is one of the orthopoxviruses that infect humans, including smallpox virus (causing smallpox, which has been eradicated), cowpox virus and vaccinia virus (which has been used as an live vaccine and was a key tool in the eradication of smallpox achieved in 1980).
MPXV owes its name to the fact that it was initially detected in monkeys. This virus is mainly found in rodents, although further studies are needed to identify the exact reservoir of the virus and how it maintains circulation in nature.
Clinical signs of monkeypox usually include fever, rash and swollen lymph nodes and can lead to a variety of medical complications. The disease is usually self-limiting, with symptoms lasting two to four weeks, although it can cause severe disease.
MPXV is transmitted to humans by close contact with an infected person or animal, or with material contaminated by the virus. Person-to-person transmission occurs through close contact with lesions, body fluids, respiratory droplets and contaminated materials such as bedding.
Although monkeypox occurs mainly in rainforest areas of central and western Africa, it is sporadically exported to other non-endemic regions. From May 13 to June 10, 2022, the World Health Organization (WHO) received notification of 1,423 confirmed cases of monkeypox in 31 Member States that are not endemic for monkeypox. This outbreak is still ongoing and it is expected that more cases will be identified as surveillance and laboratory capacity is implemented in non-endemic countries.
For laboratory confirmation of samples from a suspect case, the World Health Organization recommends the use of nucleic acid amplification tests, such as real-time or conventional polymerase chain reaction (PCR). These tests can be generic for Orthopoxvirus or specific for monkeypox virus, preferably.