Monkeypox virus and smallpox virus are related. Monkeypox virus and smallpox virus are both DNA viruses, belonging to the same genus Orthopoxvirus, and the symptoms of human infection are similar, with common symptoms such as headache, fever and rash. However, the symptoms of monkeypox virus infection in humans are generally milder, and patients usually have an incubation period ranging from 6 to 16 days. Monkeypox virus was first found in green monkeys and is now known to infect monkeys, rodents, rabbits and humans. There are suspected or confirmed cases of monkeypox virus infection, so you should avoid contact with wild animals and seek medical advice if you develop symptoms to avoid delaying your condition.