Saturday, April 30, 2016

MMWR: Ongoing Zika Virus Transmission - Puerto Rico

Credit MMWR


The news late yesterday afternoon of the first Zika death in a United States territory - while garnering a lot of press coverage - is far from unexpected.

Zika, like West Nile Virus and Chikungunya, has often been described as `rarely fatal', but last year West Nile Virus killed 119 Americans, and in 2015 PAHO reported 73 CHKV deaths in the Americas.
Both are likely under counts. And while rare in comparison to the hundreds of thousands of those mildly affected, fatal outcomes do occur.

This same (rare) pattern is expected with the Zika virus, particularly among the elderly, or in those with comordbidities or compromised immune systems.

While the greatest threat from the Zika virus remains to the developing fetus - for an unlucky few serious, and sometimes fatal complications such as Guillain-Barré syndrome (GBS) , Encephalitis, or Myelitis are possible.

This first death - which occurred back in February and was listed as due to severe thrombocytopenia - was announced in an Early Release MMWR published yesterday afternoon  that updates the epidemiology and public health response to the ongoing Zika epidemic in Puerto Rico, from November 1, 2015–April 14, 2016.  

During the first five and a half months, public health authorities screened  6,157 specimens, and validated 683 (11%) as laboratory confirmed Zika infections. The most frequently reported signs and symptoms were rash (74%) and myalgia (68%), with headache, fever, and arthralgia all reported in 63% of cases.

First, the MMWR summary, followed by the link to and some excerpts from the full report.  Follow the link to read the report in its entirety.


What is already known about this topic?
 Zika virus transmission in Puerto Rico has been ongoing, with the first patient reporting symptom onset in November 2015. Zika virus infection is a cause of microcephaly and other severe birth defects. Zika virus infection has also been associated with Guillain-Barré syndrome.

What is added by this report?
 During November 1, 2015–April 14, 2016, a total of 6,157 specimens from suspected Zika virus–infected patients from Puerto Rico were evaluated and 683 (11%) had laboratory evidence of current or recent Zika virus infection. The public health response includes increased capacity to test for Zika virus, preventing infection in pregnant women, monitoring infected pregnant women and their fetus for adverse outcomes, controlling mosquitos, and assuring the safety of blood products.

What are the implications for public health practice?
 Residents of and travelers to Puerto Rico should continue to employ mosquito bite avoidance behaviors, take precautions to reduce the risk for sexual transmission, and seek medical care for any acute illness with rash or fever. Clinicians who suspect Zika virus disease in patients who reside in or have recently returned from areas with ongoing Zika virus transmission should report cases to public health officials.

 Emilio Dirlikov, PhD1,2; Kyle R. Ryff, MPH1; Jomil Torres-Aponte, MS1; Dana L. Thomas, MD1,3; Janice Perez-Padilla, MPH4; Jorge Munoz-Jordan, PhD4; Elba V. Caraballo, PhD4; Myriam Garcia5,6; Marangely Olivero Segarra, MS5,6; Graciela Malave5,6; Regina M. Simeone, MPH7; Carrie K. Shapiro-Mendoza, PhD8; Lourdes Romero Reyes9; Francisco Alvarado-Ramy, MD10; Angela F. Harris, PhD11; Aidsa Rivera, MSN4; Chelsea G. Major, MPH4,12; Marrielle Mayshack1,12; Luisa I. Alvarado, MD13; Audrey Lenhart, PhD14; Miguel Valencia-Prado, MD15; Steve Waterman, MD4; Tyler M. Sharp, PhD4; Brenda Rivera-Garcia, DVM1 (View author affiliations)
View suggested citation

Zika virus is a flavivirus transmitted primarily by Aedes species mosquitoes, and symptoms of infection can include rash, fever, arthralgia, and conjunctivitis (1).* Zika virus infection during pregnancy is a cause of microcephaly and other severe brain defects (2). Infection has also been associated with Guillain-Barré syndrome (3). In December 2015, Puerto Rico became the first U.S. jurisdiction to report local transmission of Zika virus, with the index patient reporting symptom onset on November 23, 2015 (4). 



Zika virus remains a public health challenge in Puerto Rico, and cases are expected to continue to occur throughout 2016. Building upon existing dengue and chikungunya virus surveillance systems, PRDH collaborated with CDC to establish a comprehensive surveillance system to characterize the incidence and epidemiology of Zika virus disease on the island. Expanded laboratory capacity and surveillance provided timely availability of data, allowing for continuous analysis and adapted public health response. Following CDC guidelines, both symptomatic and asymptomatic pregnant women are tested for evidence of Zika virus infection. 

Information from the Zika Active Pregnancy Surveillance System will be used to raise awareness about the complications associated with Zika virus during pregnancy, encourage prevention through use of mosquito repellent and other methods, and inform health care providers of the additional care needed by women infected with Zika virus during pregnancy, as well as congenitally exposed fetuses and children. In addition, the prevalence of adverse fetal outcomes documented through this system can be compared with baseline rates as further evidence of associations between Zika virus infections and adverse outcomes, such as microcephaly (2).

The finding that women constitute the majority of cases might be attributable to targeted outreach and testing. The most common symptoms among Zika virus disease cases were rash, myalgia, headache, fever, and arthralgia, which are similar to the most common signs and symptoms reported elsewhere in the Americas (9). Although Zika virus–associated deaths are rare (10), the first identified death in Puerto Rico highlights the possibility of severe cases, as well as the need for continued outreach to raise health care providers’ awareness of complications that might lead to severe disease or death. To ensure continued blood safety, blood collection resumed with a donor screening program for Zika virus infection, and all units screened positive are removed.

Residents of and travelers to Puerto Rico should continue to employ mosquito bite avoidance behaviors, including using mosquito repellents, wearing long-sleeved shirts and pants, and ensuring homes are properly enclosed (e.g., screening windows and doors, closing windows, and using air conditioning) to avoid bites while indoors.††† To reduce the risk for sexual transmission, especially to pregnant women, precautions should include consistent and proper use of condoms or abstinence (5). Such measures can also help avoid unintended pregnancies and minimize risk for fetal Zika virus infection (6). Clinicians who suspect Zika virus disease in patients who reside in or have recently returned from areas with ongoing Zika virus transmission should report cases to public health officials.

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