Rabbits and rodents typically present with fever, cough, runny nose, sore eyes and swollen glands. They develop small bumps that fill with yellow fluid and may have patches of hair loss and pneumonia. Spread among animals occurs via the fecal-oral route and through the nose, through wounds and eating infected meat. Death is more likely in baby monkeys. The CDC recommend that animals exposed to monkeypox be quarantined for six weeks. Causes
Monkeypox in both humans and animals is caused by infection with the monkeypox virus – a double-stranded DNA virus in the genus Orthopoxvirus, family Poxviridae. The virus was first identified in captive monkeys and is found mainly in tropical rainforest regions of Central and West Africa. The two subtypes of virus are clade I and clade II (formerly Congo Basin and West African clades, matching the geographical areas).In addition to monkeys, the virus has been identified in Gambian pouched rats (Cricetomys gambianus), dormice (Graphiurus spp.) and African squirrels (Heliosciurus, and Funisciurus). The use of these animals as food may be an important source of transmission to humans. Transmission
Humans can be infected by an animal via a bite or scratch, bush meat preparation, or by contact with an infected animal’s bodily fluids or lesion material. The virus is thought to enter the body through broken skin, the respiratory tract, or the mucous membranes of the eyes, nose, or mouth.Once a human is infected, transmission to other humans is common, with family members and hospital staff at particularly high risk of infection.
Although it was once thought to be uncommon in humans, cases increased since the 1980s, possibly as a result of waning immunity since the stopping of routine smallpox vaccination.Between 1981 and 1986  WHO surveillance in DRC/Zaire recorded 338 confirmed cases and 33 deaths (CFR 9.8%). In 1996–1997, a second outbreak of human illness was identified in DRC/Zaire and between 1991 and 1999, 511 cases were reported in DRC/Zaire. Clade I of disease remains endemic in DRC and has a higher CFR than the other genetic clade in Western Africa.By May 2022, the case fatality rate (CFR) of past outbreaks was around 3%–6%, while the CFR of the 2022 outbreak remains below 1%. No human-to-human transmission was documented until the 2022 monkeypox outbreak in Europe. Clade II had an outbreak – the first outbreak of monkeypox outside of Africa – in Midwestern United States among owners of pet prairie dogs in 2003. Seventy-one people were reportedly infected, of whom none died.As of 2018, monkeypox was traditionally restricted to the ecology of tropical rainforests. although the pattern was broken in 2005, when 49 cases were reported in Sudan (areas now South Sudan), with no fatalities. The genetic analysis suggested that the virus did not originate in Sudan but was imported, most likely from DRC.Many more monkeypox cases have been reported in Central and West Africa, and in the Democratic Republic of Congo in particular: 2000 cases per year are known between 2011 and 2014.