We hear a lot about animal diseases that make the jump to humans—swine flu, for instance. But this transfer goes the other way, too.
There are 786 mountain gorillas left in the wild, and three quarters of those animals are used to being around people. Partially, that's an OK thing. The tourism industry has played a key role in keeping these gorillas protected. On the other hand, though, tourism also means that a small, previously isolated population of primates is regularly being brought into contact with diverse primates from all over the world. It's the perfect set-up for us jet-setting humans to pass on diseases that are completely novel to the gorilla's immune system.
Human metapneumovirus is very common in people, and not terribly dangerous. Most kids have been exposed by the time they're 5. The only people who usually develop complications are elderly, very young, or have compromised immune systems. In gorillas, however, this virus can be deadly. During a 2009 outbreak among one group of gorillas, an adult female and an infant died
This issue is interesting to me, because of the dilemma it poses. As the journal Emerging Infectious Diseases notes: "Human proximity to mountain gorillas is essential for their conservation, also crucial is minimizing the risk for human-to-great ape transmission of respiratory pathogens." How to cover both concerns, at the same time, will be a real dilemma.