As African countries struggle to fight the worst outbreak of Ebola in history, a team at UC Davis is working to identify the next disease like Ebola, before it becomes a pandemic.
Jonna Mazet runs the early warning project, called Predict, based at the School of Veterinary Medicine. Many of today’s emerging diseases come from animals. Scientists believe Ebola, for example, is transmitted when people eat fruit bats that carry the virus. So Mazet is searching around the globe for new viruses carried by animals that humans may not have had much contact with before.
Animals and the Viruses They Carry
There are countless viruses out there in the world. Some that evolved with humans -- so we're the viruses' primary hosts -- and some that evolved to live in other animals. Sometimes the viruses in other animals are able to jump to humans. Those are called zoonoses. And when a zoonosis makes that jump, scientists call it a spillover.
"Throughout history, human beings have been dealing with those spillover events," Mazet says. "Some of those, we really learn how to control." Rabies and hantavirus, for instance, are zoonoses. So are some strains of E. coli. We've learned to vaccinate our dogs, to be careful about rodent control and to wash our hands and food.
Then there are the viruses like Ebola, MERS, SARS and HIV, all of which originally came from animals. Until we learn how to control those viruses, they seem a lot scarier than a bout of food poisoning.
Searching for the Next Pandemic
Learning about emerging threats is part of what Mazet is doing with Predict.
"We want to be able to better equip ourselves and the countries that we work with to identify what might be out there that could cause an outbreak like this Ebola outbreak," Mazet says. "So in order to do that, we need to understand what the hosts are."
She and the rest of the Predict team, with support from the U.S. Agency for International Development are searching around the world, looking especially at animals that can live easily around humans -- like bats and rodents -- and at animals that are closely related to us, like non-human primates. Also of interest are areas where humans are coming into contact with animals in new ways. "We're more susceptible to an outbreak of disease if our systems are not experienced with that virus or pathogen," she says.
For four years, in 20 different countries, they've been testing animals for viruses. So far, they've found more than 800, the vast majority of them new to science.
Preventing the Next Pandemic
After finding the viruses and assessing the risk of transmission to humans, the Predict team works with communities to warn people about local threats. They also work with labs and hospitals to help doctors diagnose a broader range of diseases.
Instead of testing people for a specific disease, doctors can use the methods Predict has developed to look for a family of diseases. Not just a specific strain of Ebola, for instance, but for the the whole family of viruses that Ebola is in. "And then we can do some genetic sequencing to say, is that an Ebolavirus that we expect to be in the region," Mazet says, "or is that another closely related virus that might be the next cause of the next outbreak or pandemic?"
"We want to give doctors better tools," Mazet says. "And to do that we think we need to not be chasing the last flu that was here last year, or the Ebola that was in the neighboring country, we need to be able to look at whatever might be there with a broader eye."
So the approach is, essentially, two-pronged: Search the world for new viruses, and improve diagnostics.
"The goal is you would know about it ahead of time so you could reduce transmission risk," Mazet says, "but you would also be able to recognize it super quickly. So instead of taking months like in this Ebola outbreak, and potentially allowing the outbreak to get out of control, you'd be able to diagnose it and shut it down very quickly."
The Difference Education Makes
Emerging diseases can travel as fast and as far as people can, since they can hitch a ride with us on airplanes. That's what happened with the SARS outbreak in 2003.
"For Ebola, we're really being vigilant and watching out for it," Mazet says. "In the decade since the SARS outbreak, we've learned a lot." How to track patients and passengers, for instance.
Mazet says the knowledge she and others are amassing could someday prove critical.
"It sounds dramatic to say we found these 800 viruses that might cause a pandemic," Mazet acknowledges. "Likely they're not going to cause a pandemic, but if we don't know about them, we aren't watching for them, we can't learn about them and we can't reduce transmission risk."