When her biology lab started researching Zika in 2008, “nobody was interested in the virus at all,” says Kathryn Hanley ’89. Since its discovery in monkeys in the 1940s, it had crossed over to infect very few human beings, all in Africa and Asia, and the symptoms weren’t life-threatening. “A virus that gives you maybe a fever and a mild rash is just not terrifying, right? Given all the other public health problems in the world, why would you devote time or resources to investigating something that just doesn’t make you very sick?”
Hanley’s lab, however, was already investigating the genetics and ecology of other arthropod-borne viruses—including dengue, chikungunya and yellow fever—so they added Zika to the list. She and her colleagues at New Mexico State University and partner institutions screened mosquitos, monkeys and humans for infection in the jungle of southeastern Senegal.
Meanwhile, Zika went “on the march,” as Hanley puts it. It showed up in more than 100 people on Micronesia’s island of Yap; a few years later, it broke out in even greater numbers on other Pacific islands. While usually spread by mosquito bites, it also proved transmissible through sexual contact, through blood transfusions, and from mothers to infants before or during birth.
By late 2015, the whole world was growing terrified of Zika. It had reached numerous Latin American and Caribbean countries and triggered an official national emergency in Brazil. It was linked to a potentially fatal nerve disorder called Guillain-Barré syndrome, and the fetuses of Zika-infected mothers were found to be at increased risk of congenital microcephaly, a severe malformation of the brain. When the public health community realized the urgent need for Zika vaccines and treatments, they had Hanley’s team to thank for much of the existing preliminary research.
A virus that gives you maybe a fever and a mild rash is just not terrifying, right?
“But you can only test vaccines and drugs in model systems, and we didn’t have any for Zika virus,” says Hanley. So, in partnership with colleagues at the University of Texas medical branch, she began studying it in mice with compromised immune systems, discovering that the virus replicates in their brains and testes, and that “the older the mice, the more likely they were to survive the infection.”
Now they’re treating some of the mice with fluoroquinolones, in the hope that these antibiotics can be effectively repurposed to treat Zika. The team has also been comparing African, Asian and Latin American strains of Zika to see whether the virus is evolving to be more infectious to mosquitos and humans.
Hanley worked earlier in her career at the National Institutes of Health on a dengue vaccine (now in Phase III clinical trials). But she found her calling long before that. “I tell people I met my first great love at Amherst, and that was evolutionary biology,” she says. After her first course in the subject, she “never looked back.”
Indeed, she looks forward. A study she’s leading in Manaus, Brazil, anticipates the possibility that Zika could “spill back” from humans into monkeys. Now that the disease has been confirmed in Mexico, her team hears it “knocking on the door” of New Mexico, so they’ve been monitoring mosquito ecology across the state. And her current sabbatical project at the Cary Institute of Ecosystem Studies in Millbrook, N.Y., focuses on the recent emergence of the tick-borne Powassan virus in New York and New England. Viruses evolve quickly, she knows, and it’s vital to stay one step ahead.