No other emerging pathogen is known to have jumped so frequently from species to species.

A virus that killed a six-year-old boy in 1965 has also infected bonobos and chimpanzees in an unprecedented case of viral ‘ping-pong’ between species.

James Chodosh at Harvard Medical School in Boston, Massachusetts, Donald Seto at George Mason University in Manassas, Virginia, and their colleagues reconstructed the history of a long-stored sample of adenovirus, a type of virus that causes colds and other illnesses. By tracking the small changes that accumulated in the virus’s genome when it infected new species, the researchers found that it had previously lived in bonobos (Pan paniscus), chimpanzees (Pan troglodytes) and humans.

The analysis also showed that the pathogen was remarkably similar to an adenovirus recently identified in two groups of primates that had never come into contact with each other: bonobos in the San Diego Zoo in California and chimpanzees in a primate research facility in Louisiana.

The results suggest that the transmission of adenoviruses to humans from other animals might have an important role in the emergence of pathogens that could harm human health.