Clinical Review
5 ways to reduce infection risk during pregnancy
Which infections affect women more adversely during pregnancy, and how can risk of exposure to these infections be diminished?
Zika virus infection in the news
- CDC: Zika virus disease cases by US state or territory, updated periodically
- CDC: Q&As for ObGyns on pregnant women and Zika virus, 2/9/16
- CDC: Zika virus infection among US pregnant travelers, 2/26/16
- CDC: Interim guidelines for health care providers caring for infants and children with possible Zika virus infection, 2/19/16
- SMFM statement: Ultrasound screening for fetal microcephaly following Zika virus exposure, 2/16/16
- FDA approves first Zika diagnostic test for commercial use. Newsweek, 2/26/16
- NIH accelerates timeline for human trials of Zika vaccine. The Washington Post, 2/17/16
- Patient resource: Zika virus and pregnancy fact sheet from MotherToBaby.org
- Zika virus article collection from New England Journal of Medicine
- Zika infection diagnosed in 18 pregnant US women who traveled to Zika-affected areas
- FDA grants emergency approval to new 3-in-1 lab test for Zika
- ACOG Practice Advisory: Updated interim guidance for care of women of reproductive age during a Zika virus outbreak, 3/31/16
- MMWR: Patterns in Zika virus testing and infection, 4/22/16
- What insect repellents are safe during pregnancy? 5/19/16
- Zika virus and complications: Q&A from WHO, 5/31/16
- WHO strengthens guidelines to prevent sexual transmission of Zika virus, 5/31/16
- Ultrasound screening for fetal microcephaly following Zika virus exposure (from AJOG), 6/1/16
- CDC: Interim guidance for interpretation of Zika virus antibody test results, 6/3/16
- First Zika vaccine to begin testing in human trials, The Washington Post, 6/20/16
- NIH launches the Zika in Infants and Pregnancy (ZIP) international study, 6/21/16
CASE 1: Pregnant traveler asks: Should I be tested for Zika virus?
A 28-year-old Hispanic woman (G3P2) at 15 weeks’ gestation visits your office for a routine prenatal care appointment. She reports having returned from a 3-week holiday in Brazil 2 days ago, and she is concerned about having experienced fever, malaise, arthralgias, and a disseminated erythematous rash. She has since heard about the Zika virus and asks you if she and her baby are in danger and whether she should be tested for the disease.
What should you tell this patient?
The Zika virus is an RNA Flavivirus, transmitted primarily by the Aedes aegypti mosquito.1 This virus is closely related to the organisms that cause dengue fever, yellow fever, chikungunya infection, and West Nile infection. By feeding on infected prey, mosquitoes can transmit the virus to humans through bites. They breed near pools of stagnant water, can survive both indoors and outdoors, and prefer to be near people. These mosquitoes bite mostly during daylight hours, so it is essential that people use insect repellent throughout the day while in endemic areas.2 These mosquitoes live only in tropical regions; however, the Aedes albopictus mosquito, also known as the Asian tiger mosquito, lives in temperate regions and can transmit the Zika virus as well3 (FIGURE 1).
| FIGURE 1 Aedes aegypti and Aedes albopictus mosquitoes | ||
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Aedes aegypti (left) and Aedes albopictus (right) mosquitoes. Aedes mosquitoes are the main transmission vector for the Zika virus. | ||
The Zika virus was first discovered in 1947 when it was isolated from a rhesus monkey in Uganda. It subsequently spread to Southeast Asia and eventually caused major outbreaks in the Yap Islands of Micronesia (2007)4 and French Polynesia (2013).5 In 2015, local transmission of the Zika virus infection was noted in Brazil, and, most recently, a pandemic of Zika virus infection has occurred throughout South America, Central America, and the Caribbean islands. To date, local mosquito-borne virus transmission has not occurred in the continental United States, although at least 82 cases acquired during travel to infected areas have been reported.6
Additionally, there have been rare cases involving spread of this virus from infected blood transfusions and through sexual contact.7 In February 2016, the first case of locally acquired Zika virus infection was reported in Texas following sexual transmission of the disease.8
Clinical manifestations of Zika virus infection
Eighty percent of patients infected with Zika virus remain asymptomatic. The illness is short-lived, occurring 2 to 12 days following the mosquito bite, and infected individuals usually do not require hospitalization or experience serious morbidity. When symptoms are present, they typically include low-grade fever (37.8° to 38.5°C), maculopapular rash, arthralgias of the hands and feet, and nonpurulent conjunctivitis. Patients also may experience headache, retro-orbital pain, myalgia, and, rarely, abdominal pain, nausea, vomiting, diarrhea, ulcerations of mucous membranes, and pruritus.9 Guillain-Barré syndrome has been reported in association with Zika virus infection10; however, a definitive cause-effect relationship has not been proven.
If a pregnant woman is infected with the Zika virus, perinatal transmission can occur, either through uteroplacental transmission or vertically from mother to child at the time of delivery. Zika virus RNA has been detected in blood, amniotic fluid, semen, saliva, cerebrospinal fluid, urine, and breast milk. Although the virus has been shown to be present in breast milk, there has been no evidence of viral replication in milk or reported transmission in breastfed infants.11 Pregnant women are not known to have increased susceptibility to Zika virus infection when compared with the general population, and there is no evidence to suggest pregnant women will have a more serious illness if infected.
