Bracing for Zika Virus Inside the United States

CDC Releases Zika Virus Case Studies

March 02, 2016 02:30 pm Chris Crawford

During the Feb. 24 meeting of the CDC's Advisory Committee on Immunization Practices (ACIP), Toby Merlin, M.D., director of the CDC's division of preparedness and emerging infections, discussed the agency's preparations for Zika virus in the mainland United States.

[Man fogging too eliminate mosquitos]

AAFP liaison to the ACIP Margot Savoy, M.D., M.P.H., told AAFP News that during the presentation, Merlin said Zika virus is a threat to the United States because there are many parts of the country -- particularly the Southeast up through the eastern Midwest -- where the vector mosquitos for Zika virus (Aedes aegypti and Aedes albopictus) easily can live and propagate.

"Because we have yet to start our mosquito season and have a significant number of Americans who travel to Zika-infected areas, we are likely to see an increasing number of cases," Savoy said.

This month, a coordinated effort among government agencies and outside organizations is planned to strategize how best to control these vector mosquito types in the United States this year.

Additional Zika Notes From ACIP Meeting

Merlin also said there are challenges around basic diagnosis of Zika virus infection as the required serum test isn't widely available or easy to conduct. As such, the CDC is working to create a more accessible and useable test.

Story highlights
  • During the Feb. 24 meeting of the CDC's Advisory Committee on Immunization Practices, the CDC's Toby Merlin, M.D., discussed the agency's preparations for Zika virus in the mainland United States.
  • Merlin also said there are challenges around basic diagnosis of Zika virus infection as the required serum test isn't widely available or easy to conduct, which the CDC is trying to fix.
  • On Feb. 26, the CDC released two Morbidity and Mortality Weekly Reports (MMWRs) featuring case studies of Zika virus infection in pregnant U.S. travelers and also of people who acquired Zika virus through sexual transmission.

In regard to the documented health issues in pregnant women and infants related to Zika virus infection, he said that microcephaly and Guillain-Barré syndrome could be just the tip of the iceberg, with more problems possibly presenting later on.

In addition, Merlin said there is a possibility that eventually, people who have traveled to Zika-infected countries might not be allowed to donate blood because it might prove too difficult to run assays on the whole blood supply in order to avoid contamination.

"They have found that even after you've cleared the (Zika virus) infection and aren't symptomatic any longer, you can still transmit the virus through sperm," Savoy said. "And we already know it can cross the placenta from mother to child. So you have to wonder if a person who had the infection could pass it on to someone else who receives their donated blood."

The CDC isn't ready yet to recommend against these travelers donating blood but this could be addressed as the number of cases continues to grow, she said.

Bruce Gellin, M.D., M.P.H., deputy assistant secretary for health and director of the national vaccine program office, also updated the ACIP group on the pipeline for a Zika virus vaccine.

"On Feb. 1, there were six (Zika virus) vaccines being developed; now there are 22 in development but almost all are in the discovery phase with only one in the pre-clinical phase," Savoy said.

CDC Releases Zika Virus Case Studies

On Feb. 26, the CDC released two Morbidity and Mortality Weekly Reports (MMWRs) featuring case studies of Zika virus infection in pregnant U.S. travelers(www.cdc.gov) and of people who acquired Zika virus through sexual transmission.(www.cdc.gov)

In the first MMWR, the CDC reported that as of Feb. 17, it had received reports of nine pregnant travelers with laboratory-confirmed Zika virus disease, with 10 more cases still under investigation.

Travel Advice for 2016 Summer Olympic Games

On Feb. 26, the CDC advised in a media statement(www.cdc.gov) that pregnant women should consider not traveling to Rio de Janeiro, Brazil, for the 2016 Summer Olympic Games.

If a pregnant woman must attend the Olympics, the CDC advises she talk with her physician first and strictly follow steps to prevent mosquito bites(wwwnc.cdc.gov) during the trip.

For women who are trying to become pregnant, the agency advises they speak with a physician about their plans to begin a pregnancy and the risk of Zika virus infection during a trip to the Olympics. The same protocol for preventing mosquito bites is recommended, as well.

From Aug. 1, 2015, to Feb. 10, the CDC received 257 requests for Zika virus testing of pregnant women. Of these requests, almost 60 percent indicated that the woman had a clinical illness consistent with Zika virus disease such as acute onset of fever, rash, conjunctivitis or arthralgia. The other requests didn’t document illness but symptom information might have been incomplete. Of the 257 specimens from pregnant women that the CDC tested, 97 percent were negative for Zika virus infection. In addition, one confirmed case was reported to the CDC by a state health department.

The pregnancy outcomes of the nine confirmed cases included two early pregnancy losses, two elective terminations and three live births (two apparently health infants and one infant with severe microcephaly). The other two pregnancies were continuing without known complications at about 18 weeks and 34 weeks gestation, respectively.

All nine pregnant women with confirmed Zika virus disease reported at least one of the four previously mentioned symptoms; each reported a rash and all but one had at least two symptoms.

Of these women, six reported symptoms of Zika virus infection during the first trimester and their outcomes were two early pregnancy losses, two elective terminations, delivery of a live-born infant with microcephaly and one pregnancy still continuing.

Two women had symptoms during the second trimester of pregnancy, with one delivering an apparently healthy infant and the other pregnancy still continuing.

One woman reported symptoms in the third trimester of pregnancy and later delivered an apparently healthy infant.

In the second MMWR, the CDC reported it had received two confirmed and four probable cases of Zika virus transmitted sexually from Feb. 6-22. The median age of these patients was age 22.5. For the cases that documented the type of sexual contact, all involved condomless vaginal intercourse and all cases happened while the male partner was symptomatic or shortly after his symptoms had resolved.

The CDC pointed out that these cases suggest sexual transmission of Zika virus is more common than previously reported.

The agency suggests health care professionals consider any patient as potentially exposed to Zika virus infection if she or he has had condomless sex with a male partner who has traveled to an area of ongoing Zika virus transmission and had symptoms of the disease during travel or within two weeks after returning.

The CDC also recommends that men who have resided or traveled to an area of ongoing Zika virus transmission and have a pregnant partner should abstain from sexual activity or use condoms during sex with their partner for the duration of the pregnancy.

Related AAFP News Coverage
CDC Issues New Guidance on Zika Virus Testing, Transmission
Research Documents Eye Defects in Affected Infants

(2/12/2016)

WHO Declares Public Health Emergency Likely Tied to Zika Virus
AAFP Creates Educational Resource for Members

(2/3/2016)

CDC Issues Interim Guidance on Pregnant Women, Zika Virus
(1/20/2016)

More From AAFP
Zika Virus Outbreak


please wait Processing