Serological cross-reactions with closely related flaviviruses such as dengue and West Nile virus as well as vaccines to flaviviruses are possible. As of 2019, the FDA has authorized two tests to detect Zika virus antibodies. Screening in pregnancy
The CDC recommends screening some pregnant women even if they do not have symptoms of infection. Pregnant women who have traveled to affected areas should be tested between two and twelve weeks after their return from travel. Due to the difficulties with ordering and interpreting tests for Zika virus, the CDC also recommends that healthcare providers contact their local health department for assistance. For women living in affected areas, the CDC has recommended testing at the first prenatal visit with a doctor as well as in the mid-second trimester, though this may be adjusted based on local resources and the local burden of Zika virus. Additional testing should be done if there are any signs of Zika virus disease. Women with positive test results for Zika virus infection should have their fetus monitored by ultrasound every three to four weeks to monitor fetal anatomy and growth. Infant testing
For infants with suspected congenital Zika virus disease, the CDC recommends testing with both serologic and molecular assays such as RT-PCR, IgM ELISA and plaque reduction neutralization test (PRNT). RT-PCR of the infants serum and urine should be performed in the first two days of life.
Later, the advice was updated to caution pregnant women to avoid these areas entirely if possible and, if travel is unavoidable, to protect themselves from mosquito bites. Male partners of pregnant women and couples contemplating pregnancy who must travel to areas where Zika is active are advised to use condoms or abstain from sex. The agency also suggested that women thinking about becoming pregnant should consult with their physicians before traveling.In September 2016, the CDC travel advisories included:
Cape Verde
Many parts of the Caribbean: Anguilla, Antigua and Barbuda, Aruba, The Bahamas, Barbados, Bonaire, British Virgin Islands, Cayman Islands, Cuba, Curaçao, Dominica, Dominican Republic, Grenada, Guadeloupe, Haiti, Jamaica, Martinique, Puerto Rico, Saba, Saint Saint Barthélemy, Saint Lucia, Saint Martin, Saint Vincent and the Grenadines, Sint Eustatius, Sint Maarten, Trinidad and Tobago, and the U.S. Virgin Islands
Central America: Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, and Panama
Mexico
Most of South America: Argentina, Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Suriname, and Venezuela
Several Pacific Islands: American Samoa, Fiji, Marshall Islands, Micronesia, New Caledonia, Papua New Guinea, Samoa, and Tonga
In Asia: Singapore, Malaysia, BruneiIn December 2020, no active Zika outbreaks were reported by the CDC. WHO response
Both the regional Pan American Health Organization (PAHO) as well as the WHO have issued statements of concern about the widespread public health impact of the Zika virus and its links to GBS and microcephaly.