What is Monkeypox?

Monkeypox is a rare but potentially serious viral disease that was first identified in 1958 in monkeys in Africa. The disease was later discovered in humans in 1970 in the Democratic Republic of the Congo (DRC). Since then, outbreaks of monkeypox have occurred in several countries in Central and West Africa, including Cameroon, Central African Republic, Nigeria, Republic of the Congo, and Sierra Leone. In recent years, there have also been cases reported in the United States and the United Kingdom.

Monkeypox is caused by the monkeypox virus, which is a member of the Orthopoxvirus genus of the Poxviridae family. The virus is closely related to the variola virus, which causes smallpox, and the vaccinia virus, which is used in the smallpox vaccine. Like smallpox, monkeypox is a zoonotic disease, which means it can be transmitted from animals to humans.

Transmission

Monkeypox is typically transmitted to humans through contact with infected animals, usually rodents or monkeys, or with the bodily fluids of infected animals. Human-to-human transmission is also possible through direct contact with bodily fluids or lesion material from an infected person or through respiratory droplets from an infected person.

Symptoms

The symptoms of monkeypox are similar to those of smallpox, although usually milder. The incubation period of the virus is typically 5 to 21 days, and symptoms usually appear within 1 to 3 days of the onset of illness. The first symptoms of monkeypox are fever, headache, muscle aches, and fatigue. This is followed by the appearance of a rash, which begins on the face and then spreads to other parts of the body. The rash progresses to vesicles, which are small, fluid-filled blisters, and then to pustules, which are larger, pus-filled blisters. The lesions can take up to three weeks to heal, and scarring may occur.

In addition to the rash, other symptoms of monkeypox can include lymphadenopathy, or swelling of the lymph nodes, sore throat, cough, and gastrointestinal symptoms such as nausea, vomiting, and diarrhea. In severe cases, monkeypox can cause encephalitis, or inflammation of the brain, which can be fatal in up to 10% of cases.

Diagnosis

Diagnosis of monkeypox is based on clinical symptoms, including the appearance of a rash, as well as laboratory tests such as polymerase chain reaction (PCR) testing or viral culture. Serological testing can also be used to confirm a diagnosis or to determine whether a person has been previously infected with the virus.

Treatment

There is no specific treatment for monkeypox, and supportive care is the mainstay of treatment. This includes the administration of antipyretics, or fever-reducing medications, and analgesics, or pain-relieving medications. Antiviral medications such as cidofovir and brincidofovir have been used in some cases, but their effectiveness is uncertain.

Prevention

Prevention of monkeypox primarily involves avoiding contact with infected animals or animal products. This can include avoiding hunting or eating bushmeat, which is a common source of the virus in Africa. In addition, people should avoid contact with sick or dead animals, and they should wear protective clothing, such as gloves and masks, when handling animals or animal products. Vaccination with the smallpox vaccine can also provide some protection against monkeypox, although the vaccine is no longer routinely given in most countries.

Outbreaks

Monkeypox outbreaks occur sporadically in Africa, with the most recent outbreak occurring in Nigeria in 2017. There have also been occasional cases of monkeypox reported outside of Africa, including in the United States and the United Kingdom. In the United States, there have been a few imported cases of monkeypox in people who had traveled to Africa or had contact with animals from Africa. In 2003, a monkeypox outbreak occurred in the United States, with cases reported in six states. The outbreak was traced back to imported African rodents that had been sold as pets.

In the United Kingdom, there was a single case of monkeypox reported in September 2018, in a person who had traveled to Nigeria. The person was hospitalized but eventually made a full recovery. There were also two cases of monkeypox reported in Wales in December 2021, which were believed to be linked to the first case.

The emergence of monkeypox in new geographic locations highlights the need for continued surveillance and monitoring of the disease. The World Health Organization (WHO) has designated monkeypox as a priority disease for research and development, and efforts are underway to develop new vaccines and treatments for the disease.

Monkeypox is a rare but potentially serious viral disease that is typically transmitted from animals to humans. The disease can cause a range of symptoms, including fever, rash, and in severe cases, encephalitis. There is no specific treatment for monkeypox, and prevention primarily involves avoiding contact with infected animals or animal products. While monkeypox outbreaks occur sporadically in Africa, there have also been occasional cases reported in other parts of the world. Continued surveillance and monitoring of the disease, as well as research into new vaccines and treatments, are important to prevent and control future outbreaks.

References:

Centers for Disease Control and Prevention. Monkeypox. https://www.cdc.gov/poxvirus/monkeypox/index.html

World Health Organization. Monkeypox. https://www.who.int/news-room/questions-and-answers/item/monkeypox

Olson VA, Laue T, Laker MT, et al. Real-time PCR system for detection of orthopoxviruses and simultaneous identification of smallpox virus. J Clin Microbiol. 2004;42(5):1940-1946. doi:10.1128/JCM.42.5.1940-1946.2004

Nolen LD, Osadebe L, Katomba J, et al. Extended Human-to-Human Transmission during a Monkeypox Outbreak in the Democratic Republic of the Congo. Emerg Infect Dis. 2016;22(6):1014-1021. doi:10.3201/eid2206.151724