In late March of this year, CRECE posted an article describing some of the steps that were being taken in Puerto Rico to prepare for the inevitable spread of the Zika virus on the island. Five months later, Zika transmission in Puerto Rico is no longer an emerging threat, but an ongoing reality. The island is currently the epicenter of Zika transmission on U.S. soil. As of September of 2016, the virus has infected more than 14,334 people–1,244 of whom have been pregnant women. Unfortunately, these high numbers represent only the tip of the Zika iceberg as up to 80% of individuals with active infections show no symptoms but are still able to pass the virus on to others. Surveillance of blood donations in Puerto Rico found in July that 1.8% of donors were infected with the virus but asymptomatic. Thus, nearly 60,000 people in Puerto Rico may unknowingly have an active Zika infection communicable to others via mosquito bites and, though less common, sexual transmission. According to the Centers for Disease Control and Prevention (CDC) about 25% of Puerto Rico’s 3.5 million inhabitants will become infected with the Zika virus by the end of 2016.

To help prevent the spread of Aedes aegypti, the mosquito that carries Zika (as well as dengue, chikungunya, and yellow fever), municipalities in Puerto Rico have been taking several key steps: spraying communities with insecticides, removing old tires and other detritus that can serve as breeding grounds, and covering open-air windows with screens to keep mosquitos out. A major public health communication campaign has been launched, and the development of an independent vector control unit is currently being planned by the Puerto Rico Trust for Science, Technology, and Research with the help of CDC funding.


The Aedes aegypti mosquito is the main vector that transmits the Zika virus.

Babies of women infected with Zika during pregnancy have an increased risk for serious birth defects such as microcephaly, a concerning finding which has led many to target their Zika-prevention efforts on protecting pregnant women. The Puerto Rico Department of Health in collaboration with CDC has established a strategy to reach pregnant women enrolled in the Women, Infants and Children (WIC) program in clinics scattered across the island. These clinics are well situated for preventing Zika in pregnancy as about 90% of pregnant women in Puerto Rico are eligible to receive nutrition services within them. Through this strategy, thousands of Zika Prevention Kits containing items such as bed nets, condoms, and insect repellent have been distributed, and many information sessions about Zika have been hosted.  CRECE and PROTECT have been supplementing these efforts by providing educational materials and mosquito nets for pregnant women and children attending clinics affiliated with the research.

CRECE and PROTECT have also been working with local healthcare providers to ensure they have accurate information to draw on in caring for their patients. In February, both centers hosted two major information sessions for physicians and healthcare professionals from around the island to provide up-to-date information about the virus and to offer the best practices for avoiding exposure. CRECE and PROTECT continued Zika-education efforts by hosting an informational event at a local university in April.

Zika-prevention efforts by CRECE and PROTECT have also taken the form of collaborative ventures. Dr. Gredia Huerta-Montanez (HSCCOTC) met in May with leaders of the Children’s Health Protection Advisory Committee (CHPAC) to discuss approaches to Zika prevention. CHPAC advises the EPA Office of Children’s Health Protection on regulations and research related to children’s health. In this meeting, Dr. Huerta-Montañez discussed the best practices for avoiding exposure to the Aedes aegypti mosquito and analyzed the role of Integrated Pest Management (IPM) strategies for vector control of the mosquito population. Dr. Huerta-Montañez also met with the CDC Director and other CDC leaders in June, where she offered CRECE’s and PROTECT’s expertise, resources, and infrastructure to assist in their Zika epidemic control efforts.

While much has changed in a short time when it comes to battling the progression of Zika in Puerto Rico, much work remains to be done, especially in the realm of research. A recent study in Brazil found that nearly one third of developing babies of women who had been infected with Zika during pregnancy showed signs of severe abnormalities, including, but not limited to, microcephaly. Yet the link between Zika infected mothers and babies born with birth defects has, thus far, been focused on symptomatic cases, and more research is still needed when it comes to understanding the risk asymptomatic Zika infections pose to pregnant women and their developing infant(s) in utero.

Efforts are being made to expand upon the world’s knowledge-base of Zika, and CRECE and PROTECT’s participation in the Zika in Pregnancy Study (ZIP) led by Dr. José Cordero should help to answer some of these key questions. Over the course of the next two years, the CRECE and PROTECT research teams will be recruiting and following approximately 900 pregnant women throughout their pregnancies. Infants born to these participants will be followed for at least two years postnatally. This study is part of a consortium of research sites located in Latin American countries such as Brazil, Colombia, and Puerto Rico. The findings of this research will provide key information on the risk asymptomatic infections pose to pregnant women and their developing infants as well as key information on the length of time the Zika virus can persist in diverse body fluids. The study will also allow researchers to move closer to understanding if exposures to everyday toxins (such as those present in pesticides) can have the unintentional effect of amplifying the risks of Zika during pregnancy.