Monkeypox is a viral disease that can spread from animals to humans, known as a zoonotic disease. Understanding its discovery is important for comprehending its emergence and spread in human populations.
Discovery in Research Colonies
The monkeypox virus was first identified in 1958 during an outbreak in a research facility in Copenhagen, Denmark. Scientists observed a pox-like illness among crab-eating macaque monkeys (Macaca fascicularis) and rhesus macaques (Macaca mulatta) being used for polio vaccine research. These monkeys had arrived from Singapore and developed skin lesions resembling smallpox.
Danish medical doctor Preben von Magnus and his colleagues at Statens Seruminstitut in Copenhagen meticulously analyzed the virus. They cultivated it on chick embryo membranes and cell cultures, then performed observations using electron microscopy. Their work confirmed that the virus was a new type of poxvirus, distinct from smallpox, leading them to name it “monkeypox” due to its isolation from monkeys.
Despite its name, monkeys are not believed to be the primary natural hosts of the virus. Subsequent research suggests that various small mammals, particularly African rodents like squirrels and pouched rats, may serve as the main reservoir for the monkeypox virus in nature. The initial discovery in research monkeys, however, provided the first scientific recognition of this unique pathogen.
First Human Cases
The first documented human case of monkeypox occurred in 1970 in the Democratic Republic of Congo, then known as Zaire. A nine-month-old boy in the Equateur province was diagnosed with a smallpox-like illness, which was later confirmed as monkeypox by the World Health Organization. This marked the initial recognition of the virus as a human pathogen.
Following this initial case, other human infections were retrospectively attributed to monkeypox in 1970 and 1971 across countries like Ivory Coast, Liberia, Nigeria, and Sierra Leone. The initial symptoms observed in these early human cases included fever, headache, body aches, swollen lymph nodes, and a characteristic rash that progressed through various stages.
The confirmation of human cases established that monkeypox could transmit from animals to humans, and occasionally between humans. These early observations were crucial in understanding the disease’s epidemiology, particularly its presence in the rainforest regions of Central and West Africa.