Zika Virus UPDATE #2: Q&A
By Douglas A. Holt, MD
Andor Szentivanyi Professor of Medicine
Director, Division of Infectious Diseases and International Medicine
USF Health Morsani College of Medicine
(Updated June 24, 2016)
What more is known about Zika Virus Disease (ZVD) and birth defects?
- Additional evidence has been published confirming that ZVD causes microcephaly and other serious brain abnormalities.
- The risk of microcephaly is lower when the mother is infected during the third trimester of pregnancy.
- Asymptomatic ZVD can cause microcephaly.
- A study of pregnant women in Colombia over nine months during a ZVD outbreak is providing some preliminary data:
- Nearly 12,000 pregnant women reported having experienced symptoms suggesting ZVD.
- 1,850 of these pregnant women had ZVD that was confirmed by blood testing.
- 616 of these women were infected during the third trimester of pregnancy and there were no cases of microcephaly or brain abnormalities.
- There were also four cases of microcephaly in mothers who tested positive for ZVD but did not recall any illness.
- Further studies are ongoing to define:
- The full spectrum of congenital ZVD.
- Quantity of the risks of fetal microcephaly overall and based upon when during pregnancy the mother is infected.
- Whether current or past infection with another flavivirus like dengue influences the risk of congenital ZVD.
Will there be local transmission of Zika in Tampa Bay? That is, will people become infected with Zika by mosquitoes right here in Tampa Bay?
- Local transmission of Zika virus in Tampa Bay is probable.
- The type of mosquitoes that spread Zika are already here. We are entering “peak mosquito season,” which lasts about six months.
- The risk of mosquitoes spreading Zika in the United States is higher for Florida, especially Miami, Orlando and Tampa Bay, because we have more travelers returning from Zika outbreak areas.
- There will continue to be travelers who become infected outside the continental United States and return with live Zika virus in their bloodstream.
- Eventually sufficient numbers of mosquitoes will become infected and likely spread Zika to people here.
- This cycle continues and, as we have seen in other countries, can result in sustained and widespread transmission of Zika.
- What makes Zika especially concerning is that even after mosquitoes no longer carry Zika, women of child-bearing age or pregnant women can also become infected through sex by their partners. Thus, the public health threat of Zika to our community could continue for months after the Zika outbreak ends.
What is being done to prevent having Zika spread by mosquitoes in Tampa Bay?
- Everyone should take steps to prevent mosquito bites:
- Remove standing water from inside and outside your home or workplace. Check containers like flowerpots, buckets, animal water bowls, and children’s pools. Scrub them clean and turn them over, or cover them so they don’t collect water.
- Use an insect repellent, like bug spray or lotion, registered with the Environmental Protection Agency (EPA). All EPA-registered bug sprays and lotions are checked to make sure they are safe and work well. If you use sunscreen, apply it first before bug spray or lotion.
- Wear a hat, a long-sleeved shirt, long pants, shoes and socks when outdoors. Treat clothes, shoes and other gear with bug spray called permethrin or wear treated clothes if you’re spending time hiking, camping, or engaged in other outdoor activities.
- Use air conditioning and screens on windows and doors to keep mosquitoes out. Make sure screens on doors and windows don’t have holes or tears.
- Travelers returning from a Zika area are advised to report to their health care providers any symptoms of illness that might be ZVD: Fever, rash, itching, muscle or joint aches, headache, conjunctivitis or pink eye.
- Anyone infected with Zika should be monitored for two weeks until the virus is no longer in their bloodstream.
What will happen if people become infected by Zika in Tampa Bay?
- A coordinated community action plan will be implemented.
- The Hillsborough County Emergency Operations Center would be activated.
- Florida Department of Health (FDOH) will notify mosquito control of a confirmed local transmission. Mosquito control will then conduct aggressive mosquito control activities within a minimum of an expanded 200-yard zone around the residence.
- Mosquito control will conduct enhanced mosquito surveillances and control activities around the residence at least weekly for six weeks.
- FDOH will organize outreach activities in neighborhoods within 1/8 mile of confirmed cases using FDOH employees and community volunteers such as the Medical Reserve Corps.
- State blood banks will be notified to screen blood supply and availability of Zika free products, particularly for pregnant women. Individuals from the impacted zip code(s) will be excluded from donating blood until six weeks after the last identified case of local transmission from the zip code.
- Following confirmatory testing at CDC, a medical advisory for the zip code(s) will be issued, with public notification through media, targeted outreach, health care provider notification and guidance targeted to OB/GYNs, midwives, Healthy Start, and others caring for pregnant women.
- Voluntary isolation will be recommended for infected individuals for 7 to 10 days from the onset of symptoms.
- FDOH will implement active case findings to identify additional infections including door-to-door outreach, enhanced syndromic surveillance, medical record review, and testing additional suspect cases.
- FDOH will provide Zika Prevention Kits to pregnant women through distribution at OB/GYN practices, Healthy Start Programs, CHD clinics and the community outreach activities described above.
- Active surveillance and response will continue until no additional cases are identified for at least six weeks.
During a local Zika outbreak, what will be advised for women who are pregnant, planning to become pregnant or might become pregnant?
- Pregnant women should take all precautions to avoid mosquito bites.
- Pregnant women should not have unprotected sex.
- Ideally couples (especially if the women is under age 35) should delay becoming pregnant until the Zika transmission ends.
- Women should practice safe sex and consider methods to avoid pregnancy such as Long Acting Reversible Contraception (LARCs) such as IUD’s and implantable devices.
Where can I get more information?
- CDC Zika Page: http://www.cdc.gov/zika/index.html/
- CDC Travel Notices: http://wwwnc.cdc.gov/travel/notices
- FDOH Zika Page: http://www.floridahealth.gov/diseases-and-conditions/zika-virus/
- CDC Microcephaly: http://www.cdc.gov/ncbddd/birthdefects/microcephaly.html
- CDC: Questions and Answers: Zika virus infection (Zika) and Pregnancy: http://www.cdc.gov/zika/pregnancy/question-answers.html
- March of Dimes Zika Information: http://www.marchofdimes.org/
- Zika Virus Disease in Colombia – Preliminary Report: http://www.nejm.org/doi/full/10.1056/NEJMoa1604037
- Zika and the Risk of Microcephaly: http://www.nejm.org/doi/full/10.1056/NEJMp1605367
- Zika Virus and Birth Defects – Reviewing the Evidence for Casualty: http://www.nejm.org/doi/full/10.1056/NEJMsr1604338
- Zika Virus Infection with Prolonged Maternal Viremia and Fetal Brain Abnormalities: http://www.nejm.org/doi/full/10.1056/NEJMoa1601824