The virus named for monkeys is actually hosted by smaller mammals

Health · Published 19 October 2026 Swipe more like this →

In short: Despite its name, the monkeypox virus isn't primarily hosted by primates. It is a zoonotic pathogen belonging to the Orthopoxvirus genus, making it a close relative of the eradicated smallpox virus. While it remains endemic in parts of Africa, recent global outbreaks have highlighted its complex transmission and varying severity.

Mpox (formerly monkeypox) is caused by a virus in the Orthopoxvirus genus, a family that includes the variola virus (smallpox), cowpox, and vaccinia. While it was named monkeypox after being isolated from monkeys, the natural reservoir remains unknown; however, various small mammals, such as squirrels and rodents like rats and mice, are known to be susceptible. The virus is a zoonotic pathogen, meaning it can spread from animals to humans through bites, contact with fur, skin, blood, or body fluids, or by consuming undercooked meat.

The virus exists in two distinct clades. Clade I is historically associated with the Congo Basin and is often more severe, with a historical fatality rate of around 10% (though recent outbreaks have seen rates below 3.3%). Clade II is historically associated with West Africa and was the driver of the global outbreak beginning in 2022. While Clade II is rarely fatal, it has spread widely across many countries. In contrast, Clade I is currently causing a significant upsurge in the Democratic Republic of Congo, where children under 15 make up more than half of the cases.

Transmission occurs primarily through close physical contact, including skin-to-skin contact, kissing, or prolonged face-to-face interaction that can generate infectious respiratory particles. It can also spread through contaminated materials like bedding or towels. Symptoms typically appear 5 to 21 days after exposure, beginning with flu-like signs—fever, headache, and swollen lymph nodes—followed by a rash of sores or blisters that can last two to four weeks. Because the virus is genetically similar to smallpox (96.3% identical in coding regions), research into smallpox has helped healthcare providers quickly implement vaccines and treatments for mpox.

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