Monkeypox virus is an enveloped double-strain DNA virus of the Poxviridae family. Orthopoxvirus genus. There are 2 distinct genetic clades, called the Central Africa and West African clades, depending on where they are originally described. The Central African clade causes more severe diseases. Various animal species are the natural hosts of this virus, mainly rodents, tree squirrels and some non-human primates.
The incubation period ranges from 5- 21 days. Initially the infection (lasting from 0-5 days) is characterized by fever and Lymphadenopathy. The rash or skin eruptions usually occurs 1-3 days after the onset of fever, affecting mainly the face, palms of the hands, soles of the feet, oral mucosa, genitalia and sometimes the conjunctivae.
The rash is initially maculopapular, then evolves into vesicles and thereafter into pustules which crust over with umbilication and finally desquamation and scarring. In contrast to chickenpox (VZV), the rash of Monkeypox is not painful or itchy and all lesions are in the same stage of evolution.