Emory scientists rush to solve the mysteries of Zika
In May, 2015, Uriel Kitron was in Salvador, Brazil, studying dengue when a new virus showed up. At first he brushed it aside like the pesky mosquito that carried it. With his Brazilian collaborators, he published several papers—among the first—on the widespread Zika virus outbreak in northern Brazil, but like others he did not consider it a cause for alarm. The symptoms—a rash, fever, headache, muscle aches—were mild compared with dengue and disappeared within a few days.
“Even though it was spreading so rapidly, we really thought it was no big deal,” says Kitron, professor and chair of the environmental sciences department at Emory and professor of environmental health and epidemiology at Rollins. Dr. Kitron is a faculty member in the PBEE program.
Then came the first surprise—an increase in the cases of Guillain-Barré Syndrome (GBS), an autoimmune disorder that can result in paralysis. A few months later came another, even more disturbing surprise—a spike in the number of babies born with microcephaly, a condition characterized by small heads and underdeveloped brains. This is the first new cause of birth defects identified by the Centers for Disease Control and Prevention in 50 years and the first time ever that the cause has been spread by mosquitoes
“The fact that Zika can pass through a woman’s placenta and affect her unborn child is a game-changer,” says Kitron. “That goes to your deepest fear and is about as unsettling as it gets.”
That fear has leant a sense of urgency to the search for answers about the virus...Only when it made the leap into the Western Hemisphere and spread like wildfire through northern Brazil, leaving unexpected and devastating results, did scientists take notice. The virus has likely infected millions in Latin America, and more than 2,000 cases of microcephaly had been confirmed as of late September.
Zika is transmitted primarily by the Aedes aegypti mosquito—the same mosquito that carries yellow fever, dengue, and chikungunya—but cases of sexual transmission have also been reported. However, much of the biology and epidemiology of Zika remains a mystery. Can asymptomatic people still spread the disease? Are babies of asymptomatic pregnant women at risk for microcephaly? Can it be spread other than by sex or mosquitoes, as a Utah case suggests? And, the million-dollar question, how and why does it cause microcephaly?