Charleston a good fit for packed Zika symposium

As a city that’s weathered multiple epidemics over the centuries, Charleston was the perfect place for the Zika symposium held at the Medical University of South Carolina on June 10.

Keynote speaker Carlos Pardo-Villamizar, M.D., brought up historic accounts of how yellow fever ravaged the Lowcountry in colonial days. “This is why we’re here in South Carolina and Charleston – the best setting to study infectious diseases.”

Pardo-Villamizar, director of the Johns Hopkins Transverse Myelitis Center and principal investigator of the Neurovirus Emerging in the Americas Study, said viruses are nothing new. “They have been with us all or our lives and will be with us all our lives. We need to understand this interaction so we have better control.”

A standing-room crowd gathered to learn about Zika, a flavivirus in the same class as dengue and yellow fever. The symposium was hosted by MUSC in collaboration with Johns Hopkins University and the South Carolina Department of Health and Environmental Control.

Laura Munoz, M.D., a fellow in the Johns Hopkins University Division of Neuroimmunology and Neurological Infections who spoke at the event, said this part of the country may be in Zika’s bull's eye. “The Southeast of the U.S. is the most vulnerable region for Zika virus transmission.”

The types of mosquitos that carry the virus, Aedes aegypti and Aedes albopictus, like it here. It’s warm and there’s plenty of water for larvae. While there have been no reports of infected mosquitos biting people in the continental United States at this time, researchers said that could change soon. 

Part of the reason for that prediction is that 755 travel-related cases of Zika had been reported in the U.S. as of June 15, the last day for which statistics were posted at the time of this report. If an infected person is bitten by a mosquito that carries the virus, the insect can infect the next person it bites. 

The virus, which can be sexually transmitted as well, causes no symptoms in about 80 percent of the people it infects. Most people who do have symptoms feel sick for a few days with a fever, chills and body aches and then get over it. 

But a list of conditions Zika may be linked to is growing. It’s not just microcephaly. It’s also Guillain-Barre syndrome and maybe encephalitis and myelitis, speakers said. Zika may cause other neurological problems as well, according to Pardo-Villamizar. 

Another worrying possibility raised at the symposium: Zika may linger in the body longer than initially thought. There’s a chance it could remain dormant like some other viruses do.

And medical histories may play a role in determining how Zika works in different patients, speakers said. People previously diagnosed with other viruses, including HIV, hepatitis C and West Nile, may take a harder hit from Zika. “They may have a hyper-immunological reaction to the Zika infection that may trigger more neurological complications,” Pardo-Villamizar said.

More details about the possible effects of Zika

Microcephaly

Zika has become infamous around the world for the effect it has had on some babies born to women infected with the virus during pregnancy. A new study out of the Centers for Disease Control and Prevention and Harvard University found that infection during the first trimester raises the risk of having a baby with microcephaly to about 13 percent. The birth defect causes babies to have small heads and underdeveloped brains. The association decreases during the second and third trimesters to a “negligible” level, researchers said.

Anna Powell, M.D., a clinical instructor in the Department of Obstetrics and Gynecology and a Reproductive Infectious Disease fellow at MUSC, said worried women are turning up in MUSC doctors’ offices. “At our last check, we tested 11 women – some of them were pregnant, some were not.” None had Zika.

Other conditions

Microcephaly may not be the only Zika-related threat to babies. Pardo-Villamizar said it may be “the tip of the iceberg.”

“It’s very possible that during the later stage of pregnancy, the virus may go to the baby’s brain and not necessarily produce microcephaly but may produce disruption in the laminar organization of the brain.” Laminar refers to the way brain matter is layered. 

“So these children may look normal but there is going to be a chance for epilepsy and other developmental maladies,” Pardo-Villamizar said. “We may see an increase in the number of children with developmental disabilities and even autism.”

Zika poses another threat as well, not just to babies but to anyone who contracts the virus. In a small number of cases, about one in 4,000 people infected, it appears to be causing Guillain-Barre syndrome. David Cornblath, M.D., director of the Neurology EMG Laboratory at Johns Hopkins University, said GBS can cause weakness, numbness, a reduction in or loss of reflexes and paralysis and, in a small number of cases, even death. 

“We’d like to be able to have people and physicians more quickly recognize this disease when they see it.” That way, they can begin treatment immediately.

Containing the virus

Of course, it’s best for people to try to avoid getting the virus in the first place if it makes its way into the U.S., so many symposium speakers focused on prevention.

People who know they have the virus should take precautions to avoid being bitten by mosquitos, they said.

People should also try to prevent sexual transmission. Cassandra Salgado, M.D., director of Infectious Disease at MUSC, said to use condoms for up to six months if someone has symptoms. “If there are no symptoms but the person traveled to an area where Zika is endemic, use condoms for eight weeks,” she said.

Mosquito control

Mosquitos got plenty of buzz at the symposium. A pair of experts from the South Carolina Department of Health and Environmental Control took part in a community roundtable and spelled out the realities facing state government as it prepares for the possibility that Zika could make its way here. 

Members of the audience, which included doctors and researchers, asked about the possibility of trying to kill mosquitos and their larvae statewide. Michael Elieff, director of the DHEC Office of Public Health Preparedness, said widespread spraying would be too expensive. 

“Just to do a one-time spray of a county is about a million and a half dollars,” Elieff said. “So if you’re looking at 46 counties, you’re looking at 60 or 70 million dollars to treat the state one time.”

And money was already too tight for that, he said, even before the state learned it will get less federal funding than expected to prepare for Zika. “We get a public health emergency preparedness grant every year that funds a significant portion of DHEC and epidemiology and preparedness things, and we, South Carolina, took a seven percent cut to that for next year.”

Chris Evans, a DHEC state public health entomologist, said homeowners can take simple steps to reduce breeding grounds for mosquitos. Get rid of standing water, he said.

“Source reduction is very easy in concept but it’s much harder to implement to get people to do this,” Evans said. “Tip and toss. Tip it over, toss it out. Sounds real simple, but when you go to try to teach it to the public, it’s not as simple.”

He also recommended using larvicides in standing water that can’t be emptied. The Environmental Protection Agency lists the available larvicides and their effects on its website. 

Insect repellent

South Carolinians shouldn’t be shy about using bug spray, experts at the symposium said. Powell, the MUSC Reproductive Infectious Disease fellow, said government-approved repellents are safe for pregnant and breastfeeding women to use, even those with DEET. 

Evans recommended repellents with active ingredients registered with the EPA. They include catnip oil, citronella oil, DEET, IR 3535, oil of lemon eucalyptus and methyl nonyl ketone. He said they’re safe on anybody over two months old. 

He also emphasized the importance of using mosquito repellent when traveling to an area where Zika virus has been reported. That includes countries in South and Central America, the Caribbean and the U.S. territory of Puerto Rico.

Tests for Zika and the hunt for a vaccine

Professor and Vice-Chairman for Laboratory Medicine at MUSC Frederick Nolte, Ph.D., said there are a few tests for Zika right now, including nucleic acid amplification and serological tests. 

Nucleic amplification tests can detect Zika gene sequences in blood, urine, amniotic fluid, cerebrospinal fluid and other specimens. One downside is that a negative result doesn’t rule out Zika because the test works only in small window of time after infection, typically 7 to 14 days.

Serological tests detect Zika antibodies. Nolte said they’re imperfect, too. “There is extensive cross-reaction with other related viruses like dengue and West Nile virus. However, the antibodies are detectable for a longer period of time after infection.”  

The Food and Drug Administration has authorized the emergency use of 3 nucleic acid amplification and one serological test for diagnosis, he said. "Currently, patients seen at MUSC have testing for Zika virus performed at the DHEC Bureau of Laboratories. We have no plans to offer local testing unless this becomes an area with active transmission."

The quest for better tests continues. “What really needs to be developed, and this is up to the diagnostic industry and research laboratories, is recombinant antigens to react specifically with antibodies to the Zika virus and get rid of these problems with cross-reactions,” Nolte told the audience.

Pardo-Villamizar said a National Institutes of Health group is actively working on vaccine development. “There are several pharm companies that may have some interest,” he said. “That process is going to be extremely delayed because the development of vaccines is a very complex process. We have vaccines ready for dengue and they haven’t proved very efficient, unfortunately.”

Going forward

The symposium closed with talk of the need for more funding for Zika prevention and the future treatment of children affected by the virus. There was a sense that Zika isn’t just a problem for officials. It’s a potential problem for everyone. One business owner who employs outside workers wanted information he could hand out to his team.

Charleston County Public Works Director Jim Neal said the symposium was worth everyone’s time. “I think any information we can get to the public about Zika or other mosquito-borne diseases is very important. This forum is highlighting the fact that there are things people can do to help protect themselves.”