Since time immemorial, humans have had a knack for being complete and utter dicks to the other animals we share our planet with. Often, we even manage to screw things up for other species without meaning to. A study published earlier this month in the journal of Emerging Infectious Disease has retroactively uncovered one such incident: That time we gave a town of chimpanzees a cold bug that ultimately left five dead, including an adorable 2-year-old baby named Betty (pictured above).
Poor Betty, seen here in happier times. Photo: Richard Wrangham/University of Wisconsin-Madison
As the study explains, throughout much of 2013, starting in February, a community of more than 50 chimpanzees living in Uganda's Kibale National Park came down with a nasty and incredibly contagious respiratory illness. By the time the outbreak finally ended, in September, most had caught it and four adult chimps, as well as the adorable Betty, had died of it.
Luckily, an Ugandan vet was able to recover Betty's body soon after her death and take samples. That allowed the scientists studying the outbreak to eventually discover, to their great surprise, what had caused it: A germ known as rhinovirus C, one of the hundreds of viruses that cause the common cold in people.
"It was completely unknown that rhinovirus C could infect anything other than humans," senior study author Tony Goldberg, a professor in the University of Wisconsin — Madison's School of Veterinary Medicine, said in a statement. "It was surprising to find it in chimpanzees, and it was equally surprising that it could kill healthy chimpanzees outright."
As far as scientists had known from experiments in the 1960s, the most that other rhinoviruses (A and B) could do to chimps was cause a mild case of the sniffles. But rhinovirus C, first identified in 2006, is a meaner beast than other kinds of cold. For one, it seems to hit kids especially hard. And in children with asthma, it can raise the risk of a serious attack that could even lead to ongoing respiratory problems in adulthood.
Part of what makes the rhinovirus C virus so harsh is that some of us are genetically vulnerable to it. The surface of every one of our cells is dotted with receptors that allow them to interact with other molecules, like hormones and nutrients. But viruses hijack these receptors to break into a cell and take it over. Some people, thanks to one tiny genetic variation, carry a version of a receptor on the cells of their respiratory system that makes it way easier for rhinovirus C to infiltrate. Sure enough, when the researchers looked at the genetic makeup of the Kibale National Park chimps — via poop samples — they found this same genetic variation.
What that likely means is that wild chimps have only rarely ever come across rhinovirus C before, which made the Kibale chimps sitting ducks when it crossed their paths. The strain of rhinovirus C found in Betty also looked indistinguishable from those found in people, making it almost certain some unsuspecting human was the original source.
"There's a species-wide susceptibility of chimps to this virus," said Goldberg.
The bright side to this story is that, thanks to this and earlier outbreaks seemingly caused by human cold germs, it's become standard practice for tourists and researchers to wear facemasks when interacting with apes in the wild. And with any luck, the researchers wrote, the rhinovirus experiments we performed with chimps in the lab decades ago might just help scientists figure out how to protect their wild counterparts in the future.