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.
An exostosis, also known as bone spur, is the formation of new bone on the surface of a bone. Exostoses can cause chronic pain ranging from mild to debilitatingly severe, depending on the shape, size, and location of the lesion. It is most commonly found in places like the ribs, where small bone growths form, but sometimes larger growths can grow on places like the ankles, knees, shoulders, elbows and hips. Very rarely are they on the skull. Exostoses are sometimes shaped like spurs, such as calcaneal spurs. Osteomyelitis, a bone infection, may leave the adjacent bone with exostosis formation. Charcot foot, the neuropathic breakdown of the feet seen primarily in diabetics, can also leave bone spurs that may then become symptomatic. They normally form on the bones of joints, and can grow upwards. For example, if an extra bone formed on the ankle, it might grow up to the shin. When used in the phrases "cartilaginous exostosis" or "osteocartilaginous exostosis", the term is considered synonymous with osteochondroma. Some sources consider the two terms to mean the same thing even without qualifiers, but this interpretation is not universal. Osteophytes
Osteophytes are bone spurs that develop on the margins of joints secondary to external stimuli such as osteoarthritis. However, these are not always distinguished from exostoses in any definite way. Fossil record
Evidence for exostosis found in the fossil record is studied by paleopathologists, specialists in ancient disease and injury.