239 species of RNA viruses known to infect humans have been cataloged as of December 2024—25 more than in 2018.
A study in Scientific Data presents an updated catalog of RNA viruses known to infect humans.
Most viruses cluster within a few families and are linked to mammalian hosts. Only a minority of spillover events lead to sustained human-to-human transmission or epidemic spread. Discovery rates increased from the mid-20th century, with peaks in the 1960s and 2000s. Geographically, first reported human cases occur across all inhabited continents, with clusters in regions with stronger surveillance.
Transmission and Risk
62% of viruses are strictly zoonotic without human-to-human transmission. 60 species are endemic or capable of epidemic spread; many maintain animal reservoirs. Vector-borne transmission (mosquitoes, ticks) is common, followed by inhalation and direct contact.
Implications
The dataset supports targeted surveillance of high-risk viral families, mammalian reservoirs, and under-surveyed regions. It provides a foundation for modeling discovery trends and identifying traits linked to epidemic potential.