By Amanda Feldpausch, MPH; Julie Gabel, DVM, MPH; and Cherie L. Drenzek, DVM, MS
The Zika virus is a mosquito-borne flavivirus primarily transmitted to humans by Aedes aegypti mosquitoes, but it can also be transmitted sexually, intrauterine (resulting in congenital infection), intrapartum, via blood transfusion and by laboratory exposure.
Zika virus outbreaks have occurred in countries in tropical Africa, Southeast Asia, the Pacific Islands, and the Americas since the discovery of the virus in Uganda in 1947. In May 2015, the PanAmerican Health Organization (PAHO) issued an alert detailing the first confirmed Zika virus infections attributed to local vector-borne transmission in Brazil. The outbreak spread rapidly throughout most of South and Central America and the Caribbean and was declared a “Public Health Emergency of International Concern†by the World Health Organization in February 2016. The Centers for Disease Control and Prevention (CDC) reports that the Zika virus is likely to continue to spread to new areas.
Zika virus symptoms, which include maculopapular rash, fever, joint pain and/or conjunctivitis, are manifested in approximately 1 out of 5 persons infected with the virus. Others will not experience symptoms or may only have mild symptoms. For the majority of persons infected, symptoms will resolve within a few days to a week.
In April 2016, evidence confirming the link between Zika infection during pregnancy and severe birth outcomes including microcephaly was confirmed. In the U.S., the greatest concern is for pregnant women and/or their sexual partners who have traveled to areas where Zika virus transmission is ongoing.
To understand more about the effects of the Zika virus infection on the fetus, the CDC established the U.S. Zika Pregnancy Registry through collaboration with state, tribal, local and territorial health departments. The Zika Pregnancy Registry will collect information about pregnancy and infant outcomes following laboratory evidence of Zika virus infection during pregnancy. The data will be used to update recommendations for clinical care, to plan for services for pregnant women and families affected by the Zika virus and to improve prevention of Zika virus infection during pregnancy.
Georgia participates in the U.S. Zika Pregnancy Registry, which is coordinated through the Georgia Department of Public Health’s (DPH) Epidemiology Program. Currently, 671 women are being followed nationally in the registry; there have been 17 live births reported with birth defects and 5 pregnancy losses with birth defects as of Sept. 1, 2016. It is critical that pregnant women, or women who are planning to become pregnant, receive prevention education regarding travel and safe sex practices to avoid the serious outcomes associated with Zika virus infection during pregnancy.
To date, Florida is the only state to report locally acquired mosquito-borne Zika virus infections in the continental United States. However, Zika infections have been reported in almost 3,000 travelers returning to the U.S. from countries where Zika virus transmission is active. The CDC maintains a webpage that includes maps and detailed information regarding affected areas at https://www.cdc.gov/zika/geo/active-countries.html.
Zika virus infections have also been confirmed in 24 individuals who had sexual contact with an infected person who acquired the disease while traveling. Because the species of mosquitoes (Aedes spp.) that transmit Zika virus can be found in many parts of the U.S., including Georgia, there is a risk that th virus imported into the U.S. by travelers will lead to local mosquito-borne transmission. It is imperative that potential infections in humans are identified quickly so that precautions to minimize exposure to local mosquitoes can be taken.
Astute clinicians are critical to recognition of Zika and other emerging diseases and form the cornerstone of all disease prevention and control efforts. Routine collection of recent travel history from every patient is imperative in this recognition.
Keeping up with rapidly changing travel advisories about Zika-affected areas and diagnostic testing information amid clinical demands is challenging. DPH has recently established a new web tool, the Travel Clinical Assistant, which provides clinical information on travel-related diseases in near real-time for 231 countries, including all Zika-affected areas (http://dph.georgia.gov/TravelClinicalAssistant). In addition, to rapidly detect (and subsequently mitigate) local transmission of Zika, clinicians in areas at risk need to consider that some patients without travel to Zika-affected areas, such as patients with fever, rash, joint pain or conjunctivitis, may also warrant Zika testing.
Healthcare providers evaluating symptomatic persons (male or female) and pregnant women (symptomatic or asymptomatic) who have traveled to areas where Zika virus transmission is ongoing, a suspected case of sexual transmission of Zika, or a suspected local mosquito-borne transmission should report the suspect case immediately to the Georgia DPH to determine whether Zika testing is indicated and to facilitate appropriate specimen collection.
All Zika testing requests must be approved by DPH Epidemiology at 404-657-2588 (during business hours) or 1-866-PUB-HLTH. The Georgia Public Health Laboratory (GPHL) performs RT-PCR testing on serum, urine, CSF and amniotic fluid as well as MAC-Elisa IgM testing on serum. Special investigations such as pregnancy loss may require that additional specimens be sent to the CDC for testing. These specimens must also be triaged through DPH Epidemiology to receive the necessary approval for submission.
Since January 2016, the Georgia DPH has triaged about 1,600 inquiries from clinicians seeking approval for testing a patient for Zika infection. While as of Sept. 12, 2016, more than 900 Georgia residents have been tested for Zika, only 80 travel-associated infections have been confirmed. In addition to facilitating testing for the Zika virus, the DPH works with clinicians and other partners to provide education about Zika virus prevention.
Travelers returning from areas where Zika virus transmission is ongoing should avoid mosquitoes for three weeks after their return regardless of whether or not they have symptoms. Additionally, travelers should be educated about potential sexual transmission of Zika virus and prevention. Current recommendations for the prevention of sexual transmission can be found on the CDC website.
The DPH Zika Epidemiology Team is available Monday through Friday 8 a.m. to 5 p.m. at 404-657-2588 for any Zika-related questions and to triage testing requests/facilitate submission of samples to GPHL, or clinicians may call 1-866-PUB-HLTH 24/7.
References
PAHO alert 2015: http://www.paho.org/hq/index.php?option=com_docman&task=doc_view&Itemid=270&gid=30075
Frieden TR, Schuchat A, Petersen LR. Zika Virus 6 Months Later. JAMA. Published online Aug. 08, 2016. doi:10.1001/jama.2016.11941.
CDC Zika website: https://www.cdc.gov/zika/
CDC Pregnancy Registry Case Count: https://www.cdc.gov/zika/geo/pregwomen-uscases.html
Mlakar J, Korva M, Tul N, Popovic M, Poljsak-Prijatelj M, Mraz J, Kolenc M, Rus KR, Vesnaver TV, Vodusek VF, et al. Zika virus associated with microcephaly. N Engl J Med. 2016;374(10):951–8.
