November 10, 2016

Zika: Do We Still Have To Worry? Yes.

By Clarissa K. Wittenberg

A moment for reflection

The first shock of the Zika virus epidemic has passed, but the danger continues. On September 28, the U.S. Congress voted to pass a $1.1 billion package to respond to the Zika crisis after President Obama had asked for $1.9 billion back in February [1].

This delay occurred despite information from Brazil about Zika’s danger to pregnant women.  The births of babies with microcephaly and other birth defects should have galvanized legislators into action.  Even in July, when the Centers for Disease Control and Prevention (CDC) said that the virus was “silently and rapidly” spreading in Puerto Rico, funds were not forthcoming [2].  The delay caused public health experts to re-program funds to meet urgent needs and then when funding came, to play catch up – a strategy that tends to costs more than if funds had been available in the first place.  While the Southern U.S. has been hardest hit, many states have the people infected with Zika virus.

The paradox of a mild disease with potentially fatal consequences

Because the Zika virus is mild and many people never feel ill, they fail to take precautions. Four out of five infected people experience no symptoms [2]. Even for those who do feel ill, the symptoms are mild and include fever, rash, joint pain, and conjunctivitis (red eyes) and may go unnoticed. Condoms are recommended for all sexual acts if a sexual partner has traveled to an area where Zika is present, as either partner can infect the other. The virus has been found in the semen of infected men for as long as six or seven months [1].

In addition to semen, Zika can also be transmitted by blood, saliva or urine. The Food and Drug Administration (FDA) issued localized advisories to screen for Zika virus in the blood supply back in February, and issued a stronger advisory for universal testing of blood supplies in August [3].

Case counts

According to the CDC’s Zika map, as of October 26, 2016, there were 4,091cases with laboratory evidence of Zika virus infection in the United States, as well as 28,723 in U.S. territories.  In the U.S., there were 953 pregnant women with Zika and 2,027 pregnant women with Zika in U.S. territories.

Cases are divided into locally infected and infected through travel or intimate contact with travelers to areas with Zika outbreaks.  New York City, for instance, has a large Puerto Rican population and inexpensive airfares to the Island and so has many travel-related cases.  As of October 26, 2016, New York City had over 886 people with Zika virus, and a baby with microcephaly was born in New York in July 2016.

Evidence accumulating on a link between Zika and birth defects

At the early on-set of the breakout, it was assumed that Zika virus was linked to birth defects. However, evidence from Brazil and other countries now shows that if a pregnant woman becomes ill with Zika, it may cause severe birth defects in the fetus such as microcephaly, a devastating stunting of brain and skull [4]. Zika has also been linked to eye defects or hearing loss in a developing fetus, and impaired growth in infants [1]. There are disturbing reports that even babies seemingly normal at birth may develop problems as they grow. But the risk for neurological birth defects seems to be linked to a woman’s individual history of other infections.

For years, Zika seemed a rather mild virus without fetal damage.  Even now, when the birth defects are so alarming, The Washington Post  reported that while birth defects are linked to Zika, the fetal deformities predicted by models are fewer than expected except in northeast Brazil. It is suggested that dengue has not been seen in this area since 2003 and maybe women are lacking immunity to that virus, which is a similar virus spread by the same type of mosquito. The article also mentions “anecdotal evidence that more women have been quietly terminating pregnancies over worries that their babies might be deformed.” Research reports in September 2016 indicated that a previous or a co-infection with herpes simplex virus-2 (HSV-2) might enhance the breaching of the placental barrier that allows such birth defects.

There is much research still needed to be done on Zika infection.  Zika is similar to dengue fever, yellow fever and West Nile fever. For example, if an individual has previously had one of these illnesses, does it make the Zika virus more dangerous or provide some immunity?

The importance of continuing antiviral research

At the start of the Zika crisis, the National Institute of Allergy and Infectious Diseases (NIAID) used the antiviral drug screening program already in place for other viruses such as dengue, West Nile, yellow fever, and Japanese encephalitis, to create an urgently needed test that might be valuable for potential antiviral activity against the Zika virus [6]. More than 60 antiviral compounds were examined and 15 had moderate to high activity and are undergoing more study. The already advanced dengue virus research is helping to speed research on Zika.

A new approach to anti-viral drugs may be needed

NIAID points out the various recent viral pandemics and suggests that development of broad-spectrum antiviral drugs might be needed rather than infection-specific drugs or vaccines.  The challenge of research on these drugs is heightened by the fact that every step must be carefully tested to ensure pregnant women aren’t given anything that can cause birth defects.  Concern about safety is not limited to infectious diseases, but is an issue in other conditions such as heart disease and cancer in women as well.  It is to be hoped that the urgency presented by Zika virus will help across the board to shape safer clinical trials and drug development for pregnant women.

A search for answers

In June 2016, NIAID, Eunice Kennedy Shriver National Institute of Child Health and Human  Development, National Institute of Environmental Health Sciences and the Brazilian Fundacao Oswaldo Cruz-Fiocruz launched the multi-country Zika in Infants and Pregnancy (ZIP) Trial.  A prospective observational trial that plans to enroll as many as 10,000 pregnant women at up to 15 sites and follow them throughout their pregnancies to determine if they become infected with Zika virus, and to learn the outcomes for mother and child [5].

Public health falls to the States: Is more Federal help needed in emergencies?

Zika testing and medical care is a state responsibility.  The CDC does provide information, special teams and emergency grants but not a comprehensive national program. And although the CDC was prepared, until funds were allocated, emergency team activities could not begin until a request from the state is received. Public health laboratories have had a surge in demands for the complex high intensity Zika tests so desperately needed by women causing long waits for results. Controversy at the CDC about the efficacy of specific Zika tests also caused delays. Funds for these tests must compete with spraying for mosquitoes, case finding, and help for women without health insurance and maternal and child health programs in Puerto Rico and other territories. The crisis is intensified, as often the most cases are seen in the poorest women in the poorest states.

Environmental issues are health issues.

Aedes aegypti mosquitos also can transmit yellow fever, dengue, and chikungunya viruses.
Today, crowded cities, areas with poor conditions, and international travel contribute to potential pandemics. Aedes aegypti is a difficult mosquito to eradicate, as it can remain dormant during dry spells and then hatch during a rainfall.  Delays in spraying were also caused by debates over safety and efficacy of mosquito eradication compounds this year in both Puerto Rico and Florida. Various strategies for genetic modification of mosquitoes are being tested.  For the best information on safe and effective mosquito control, consult the U.S. Environmental Agency at

Will warmer temperature bring more mosquitoes?

Temperatures have been rising in the contiguous states since 1901.  (Environmental Protection Agency, “Climate Change Indicators: U.S. and Global Temperatures”, Data source, NOAA, 2016.)  Mosquitoes thrive in hot areas, so a very sophisticated approach involving many specialists is needed to predict patterns of infections and disease. Trade and travel are now global.  Surveillance of disease patterns must meet this challenge and each nation will need to monitor signs of impeding pandemics. The World Health Organization now counts 67 nations with Zika virus infections. Our public health depends upon better health across the globe.





About the Author

Clarissa K. Wittenberg served as a senior communications officer at several NIH Institutes, and the Office of Global Health of the Secretary for Health and Human Services. She was a consultant to the Department of Psychiatry and Human Behavior, the University of Mississippi Medical Center on mental and overall health of underserved populations.  She was a member of a select volunteer health issues committee for the first Obama campaign.