Monkeypox is a viral infection caused by the monkeypox virus, an enveloped double-stranded DNA virus. It has an incubation period of 7 to 14 days, and symptoms may last from 14 to 16 weeks. It is endemic in several countries and occasionally causes smaller outbreaks.
Monkeypox infection usually starts with fever, malaise, weakness, headache, swollen lymph nodes and chills. It then progresses with a rash that may appear on the face, palms, soles, eyes, mouth, throat, groin or anal regions. The rash begins as a flat lesion or scratch-like wound, grows into fluid-filled vesicles, or blisters, before crusting and drying up. Most cases are mild and self-limiting but the virus can lead to severe illness or death in children, the elderly, or immunocompromised people. A live, attenuated virus vaccine has been developed for smallpox has been shown to be effective against Monkeypox and is offered to those who have been exposed to the virus.
Monkeypox is a type of zoonotic disease, which happens when infections occur between vertebrate animals and humans. Zoonoses can be viral, bacterial, parasitic, fungal in origin or transmitted by proteins known as prions, which can be further classified based on the transmission pattern. For example, rabies is a direct zoonosis between vertebrate animals to humans, while tapeworm is a cyclozoonosis between more than one vertebrate animal to humans. We also have infections like Lyme disease, which is a metazoonosis between both vertebrates and invertebrates to humans; and histoplasmosis, which is a saprozoonosis between vertebrate animals and an inanimate developmental site such as food or soil to humans.
Zoonoses are important to pay attention to because they are closely tied to emerging infectious diseases. Factors such as urbanisation, deforestation, climate change, travel and trade activities are the main drivers of emerging zoonotic infections. As the risk of spillover infections from natural animal reservoirs to humans is high, it is important to have proper preventive measures in place to prevent these spillover events.
Dr Khoo Yoong Khean
Scientific Officer, Duke-NUS Centre for Outbreak Preparedness