The Zika virus just got more dangerous.
U.S. officials recently confirmed that the virus causes birth defects. Brazilian scientists, meanwhile, have discovered that it may also affect the brains of adults. Several patients with Zika are suffering from an illness similar to multiple sclerosis.
"Most of what we've learned is not reassuring," said Anne Schuchat, principal deputy director of the Centers for Disease Control and Prevention."
Fortunately, about 15 biopharmaceutical companies and a number of research universities are working on a vaccine to combat the Zika virus. Research animals—especially primates—will play an essential role in vanquishing it.
The CDC has confirmed that the virus causes microcephaly, whereby babies are born with noticeably smaller heads and underdeveloped brains. Brazil, the epicenter of the outbreak, is investigating nearly 5,000 suspected microcephaly cases associated with Zika virus infection.
Babies aren't the virus's only victims. In March, scientists posited a link between Zika and meningoencephalitis, a deadly type of brain inflammation. Another study found that the virus could cause Guillain-Barré syndrome, a disease that impairs muscle performance and can lead to paralysis.
Scientists discovered the Zika virus in Africa in the 1940s. Until recently, it was not considered a major public health threat. Consequently, little research had been conducted into the virus.
That's about to change, largely through research involving animal models—including primates.
Some of the most promising work is under way at the University of California, Davis and the University of Wisconsin, Madison. Scientists are studying pregnant monkeys to better understand how Zika infects both mother and unborn child.
The two research teams—who are sharing their data with the public in real time—are comparing samples of the Zika virus from Africa, Asia, and South America. Because each strain has a unique set of mutations, researchers are investigating whether they behave differently in animal models. If so, the strains' genetic variance may explain the different symptoms that have surfaced in different parts of the world.
Dr. David O'Connor of the Wisconsin team is currently testing animals infected with the virus to see if they develop immunity against re-infection. Meanwhile, scientists at the University of Texas Medical Branch just announced the discovery of a type of mouse that reacts to Zika just as humans do. That makes it ideal for testing possible treatments.
These animal models are paving the way toward a vaccine or cure for Zika. As California team researcher Koen Van Rompay put it, "When we study how the virus affects monkeys, it's very predictive of how it affects people and that information enables us to develop vaccines to fight it."
In order to understand how a disease progresses, researchers have to use a living system with a genetic makeup similar to that of humans. People share 95 percent of their genes with mice—the most popular model for animal research—and 98 percent with non-human primates, like rhesus macaque monkeys. These models provide crucial information about how humans respond to treatments.
Computer models or cells grown in a dish, by contrast, cannot provide an accurate picture of the progression of an infection in a whole living system. Examining how a disease behaves in animal models can teach us how it acts in humans.
Animal models also ensure human safety. Much of the research necessary to understanding Zika can't be conducted on pregnant women because the process of taking amniotic fluid out of the womb—which determines if the virus is present—can cause miscarriages.
Animal research is behind virtually every medical treatment in existence. And we have all been the beneficiaries. Research in cows helped create the world's first vaccine, which in turn eradicated smallpox. Trials with monkeys, dogs, and mice led to the polio vaccine. Drugs used to combat cancer, HIV/AIDS, Alzheimer's, hepatitis, and malaria would not have been possible without research with non-human primates.
Now, the world needs a Zika vaccine. And while one is likely still some time away, a nimal research will be key to developing it.
Frankie L. Trull is president of the Foundation for Biomedical Research.
