90-Second Read: How does Andes Hantavirus spread between people?

The cause of his death, while initially unclear, was determined to be Andes Hantavirus (ANDV), which he picked up prior to boarding the ship. When Hantaviruses do spill over into humans, and, in the case of ANDV, have the potential to spread between them, it would be valuable to have preventive and therapeutic tools at the ready to deal with them. Hantaviruses, which cause sporadic outbreaks, tend to fall under the radar compared to other more widespread public health threats. As of this writing, there have been 10 reported cases of ANDV infection from the ship, resulting in three deaths.

More than 40 species and strains of Hantaviruses exist in nature, and over half are known to be capable of spilling over into humans. It does transmit from rodents to people like other Hantaviruses, and that is how most infections start. Experts note that multiple evolutionary changes, particularly those that could help the virus transmit to and between humans more efficiently, would be required for ANDV or any recognized Hantaviruses to have pandemic potential. There are currently no licensed vaccines or antivirals for Hantaviruses, a family of single-stranded, negative-sense RNA viruses.

Rodents, like mice and rats, are the definitive hosts of Hantaviruses. The outbreak began when someone sick with ANDV attended a birthday party with 100 people; five people who were seated close to the individual later developed symptoms. While the presence of ANDV antigens is not direct evidence of viral infection or replication, the results support the fact that the virus may spread through respiratory and/or salivary pathways. Even so, proper containment and monitoring of infected or exposed individuals is important for minimizing the chances of ANDV transmitting to a larger pool of people where it could have more chances to spread and evolve.

It's worth noting that hamsters are similar to the virus' natural rodent reservoirs, which have co-evolved with Hantaviruses for 20 million years. Jonsson's lab showed in a suckling mouse model that treating animals infected with Hantaan virus (another type of Hantavirus) with the antiviral ribavirin reduced infectious virus levels but increased the virus's mutational frequency. Researchers also underscore the need to keep tabs on Hantaviruses and their genetic changes in reservoir hosts, particularly as climate and environmental changes increase the risk of animal-human contact and potential spillover events.