Q&A with Professor Ernesto Marques on the Zika Virus

About a year ago, when Ernesto Marques first started hearing about strange rashes in Brazilian patients, he didn’t think much of it. Perhaps it was a mild strain of dengue fever, thought Marques, an associate professor of infectious diseases and microbiology in Pitt’s Graduate School of Public Health. But he was surprised when the Brazilian lab tests were returned, revealing it was the Zika virus. The news hit very close to home. Marques is a Brazilian citizen, and his hometown is Recife, the epicenter of the Zika outbreak in that South American nation. 

The World Health Organization (WHO) has declared Zika an international public health emergency, and Marques is collaborating with the WHO and the Pan American Health Organization to fashion an appropriate global response. He is also engaged with studies at Pitt to learn more about how the virus infects and affects people, particularly pregnant women and their unborn babies. A member of Pitt’s Center for Vaccine Research, Marques believes the development of an antibody might be the fastest route of treatment, protecting people by having them contract the disease in childhood or through an antiserum, which is a blood serum from someone who already had the disease. The Pennsylvania Department of Health recently posted a report on Zika infections found in the Commonwealth, www.health.pa.gov.

What is the Zika virus?

The Zika virus is a mosquito-borne and -transmitted infection related to dengue, yellow fever, and West Nile virus. Scientists first became aware of the virus in 1947, when it was traced to a forest in Uganda. It is typically an obscure virus, and there are no previous reports of any severe disease associated with it. Two years ago, it caused alarm in Polynesia and more recently in Brazil as Zika is suspected to have infected women during pregnancy and is linked to rapidly increasing cases of babies born with microcephaly, a congenital smallness of the head associated with incomplete brain development. The virus is spreading, and millions in the tropical regions of the Americas may be infected. 

Is there science that links Zika and microcephaly?

The Zika virus RNA has been found in placental tissue, amniotic fluid, and cerebral tissue from a stillbirth with microcephaly. In addition, Zika antibodies were found in the cerebral spinal fluid of several newborns with microcephaly. So it is clear that Zika virus can be spread from a pregnant woman to her unborn baby. And there have been reports of microcephaly and other poor pregnancy outcomes in babies of mothers who were infected with Zika virus while pregnant. Both the Centers for Disease Control and the WHO are in Brazil working with local health researchers. FIOCRUZ, a public health think tank in Brazil, and the CDC have confirmed the presence of Zika in two newborns with microcephaly who died and in the placentas of two women who miscarried children with microcephaly. In the meantime, Brazil is investigating at least 12 deaths of children born with microcephaly for connection to the virus. In Brazil, more than 4,000 suspected cases of microcephaly have been linked to women who tested positive for Zika virus and had rash and fever during the first and second trimesters.

How is the virus transmitted?

Aedes mosquitoes are considered the main vectors transmitting Zika, but it is possible that other species of mosquitoes can also transmit Zika virus. Not every species of mosquito is a culprit. Zika is spreading faster then other flavivirus transmitted by Aedes mosquitoes and this suggests that other modes of transmission also play a role. And, at this moment, it is critical to determine clearly if there are other modes of transmission. Recent reports have found the Zika virus in saliva and transmitted through sexual contact. 

Do we know if it’s possible to catch the virus more than once? Or once you get it, does a person develop immunity to the virus?

It is not known yet, but most of the other flavivirus are like that. For example, with dengue, if you get infected once, you are immune; or with the yellow fever vaccine, you are basically immune for life. We do not know for Zika, and since this virus has showed up with so many surprises, we should not take anything for granted. We need to investigate this and find a clear answer. 

Are there symptoms? How do we know if someone is infected?

In most cases and until recently, most symptoms were relatively mild. Only one in five who are infected develop symptoms, which can include fever, rash, joint pain, and red eyes. The risk to non-pregnant adults is considered to be typically mild and most recover within about a week from the symptoms.  

What, in your view, should be done to safeguard the blood and organ supply from Zika?

We need to confirm how long the presence of the virus lasts in the blood and exclude any individuals who have had a rash within that range. In addition, we need to implement a routine molecular test to screen blood and organ donors to confirm they are negative for Zika. There are some technologies that can clear some blood products like platelets and plasma from virus.

What should people be doing— primarily, pregnant women in the United States and Canada—to stay safe, aside from abiding the current travel advisory from the CDC?

During this winter, I do not foresee much risk for women within the United States and Canada. However, there is the potential for the risk to increase as we approach late summer. We need to keep up surveillance and inform the population of the risk levels. The Southern states need to be particularly vigilant because some infectious disease experts believe Zika will travel a path beginning in Puerto Rico and Florida and spreading across the Gulf states. Scientists believe the virus could spread northward due to warming weather. 

What can I do to reduce my risk of becoming infected?

The knowledge of the link between Zika and microcephaly is evolving, but until we know more, the CDC recommends special precaution in women who are pregnant (in any trimester) or trying to become pregnant: These women should consider postponing travel to any area where Zika virus transmission is ongoing. 

According to the CDC and the Pan American Health Organization, here are the counties and territories affected, so far: Brazil, Colombia, El Salvador, French Guiana, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Saint Martin, Suriname, and Venezuela, as well as Puerto Rico. Be aware the list is growing. See the CDC website for more information,www.cdc.gov.

Is there a treatment? 

No. There is no particular antiviral medication recommended. Most symptoms are mild, requiring rest and proper nourishment. There is no vaccine.