Doctors discuss new information about Zika risks

April 18, 2016
Aedes mosquitoes
When Aedes species mosquitoes bite a person infected with Zika virus, they can pass along the virus to the people they bite after that.

The doctor who diagnosed the first case of AIDS in South Carolina is reminded of that era as Zika virus creeps into the United States. Robert Ball, M.D., now an adjunct professor in the Medical University of South Carolina’s Department of Public Health Sciences and Division of Infectious Diseases, said, like AIDS, Zika is a pandemic.

“By definition, a pandemic is an epidemic that crosses international borders. The number of Zika cases is still low, but like AIDS, it will increase.”

That said, Ball does not anticipate an explosive outbreak in the U.S. “There will be some cases and clusters of cases,” he said - maybe as soon as this summer.

Ball has the experience to make that prediction. The former infectious disease epidemiologist and medical director for the South Carolina Department of Health and Environmental Control now teaches at MUSC and the College of Charleston.

He said most people who have Zika won’t even know it. The virus doesn’t cause any symptoms in the majority of cases. But when it does, it can be very troubling. Last week, the principal deputy director for the Centers for Disease Control and Prevention said the virus is “scarier than we initially thought,” upping the anxiety level among some Americans.

Both Ball and another MUSC infectious disease expert, Professor John Gnann, M.D., pointed out that all of the 358 confirmed cases of Zika in the United States so far are travel-related. There have been no reported cases of Zika in South Carolina.

But the types of mosquitoes that carry Zika, Aedes aegypti and Aedes albopictus, do live in South Carolina. If one bites a person who caught Zika while traveling, the mosquito can transmit it to any other people it bites, Gnann said.

The virus has been linked to a growing number of serious health problems. The latest possibility is acute disseminated encephalomyelitis, or ADEM, which causes swelling of the brain and spinal cord. It’s been showing up in adults in Brazil who also had Zika-like symptoms. But the link between ADEM and Zika is not definitive at this point.

Zika has also been associated with the rare neurological disorder Guillain-Barre syndrome, which causes temporary paralysis.

The virus’ most devastating impact has been on pregnant women, Ball said, although it’s not as widespread as media coverage might lead some people to think. “The current best guesstimate is about 1 in 100 pregnant women with active Zika will have offspring with neurologic disruption.”

The virus can cause microcephaly, which leads to small heads and underdeveloped brains. But Gnann said it may do more than that. “Now, according to the CDC, there appear to be other congenital malformations. They mentioned blindness, premature onset of labor, so there appears to be a number of obstetrical problems other than microcephaly.” 

Recent reports in the New England Journal of Medicine suggest the virus may hide in the fetus, prolonging the mother’s infection and doing serious damage to her unborn baby.  

But Gnann said it’s important to remember that Zika is not nearly as dangerous as another virus that recently made international news. “Maybe some people have Ebola in the back of their minds from the year before last, which was such an international disaster. One thing for people to focus on is that unlike Ebola, Zika is not usually transmissible person to person.” 

That’s an important distinction, he said. “The only way you can get Zika is from a mosquito bite, with the exception of the small number of cases that are sexually transmitted or transmitted in an unusual way such as blood transfusion.”

While about 4 out of 5 people who are infected won’t feel a thing, it can cause flu-like symptoms, Gnann said. “You’ll have fever, you’ll feel bad, you’ll have muscle aches, a headache, a rash, and you’ll be sick for several days but it’s a self-limited illness and you recover. The mortality rate from Zika virus is very low.”

For now, the best protection, according to both Gnann and Ball: mosquito control. “Avoid mosquito bites to a much higher degree than you ever have before,” Ball said. “Regularly use DEET or another CDC-approved mosquito repellent.”

Get rid of standing water around the house that can be a breeding ground for mosquitos, he said. “Call Charleston County mosquito control for large areas of standing water.”

Gnann’s final thought: “The population that needs special care and precautions are pregnant women or women who are thinking about becoming pregnant. If you’ve been exposed to the Zika virus and you’re considering becoming pregnant, consult with your obstetrician.”

Ball said this pandemic is just beginning. “There are so many unknowns because we’re just beginning to ascend the learning curve.”