Q What precautions are recommended in regard to Zika virus and pregnancy?

— Eric Farnsworth, Madison, Wis.

A Dr. Kathleen Antony, maternal-fetal medicine specialist at the University of Wisconsin-Madison:

Many people travel to areas that have active, ongoing transmission of the mosquito-borne Zika virus disease.

Unless someone’s had symptoms of Zika virus disease within the first two weeks of returning from travel — the incubation period of the virus — the recommendation is not to test the person. If symptoms did appear, those symptoms would clear within a couple weeks.

In terms of pregnancy, recommended waiting times have lengthened because the Zika virus can persist in semen for about six months.

The World Health Organization has recommended that both men and women wait six months from the time of travel before attempting conception.

In adults, Zika virus disease has historically been thought to be pretty innocuous. About 80 percent of people don’t have symptoms, and those who were symptomatic recovered within a few weeks.

Symptoms include fever, a reddish rash, and conjunctivitis or red eyes. People with Zika virus disease can also get swollen lymph nodes, body aches and headaches.

In pregnancy, it’s been discovered that Zika virus can have profound effects when transmitted to the baby. Typically doctors see things like microcephaly, which is an abnormally small head in a baby.

These babies have microcephaly because their brains aren’t developing correctly. Ultrasound views show an increased amount of fluid in the brain and less brain material than expected.

Some brain structures either don’t develop properly or are much smaller than expected, and there can also be problems with the baby’s eyes and hearing.

Blue Sky Science is a collaboration of the Wisconsin State Journal and the Morgridge Institute for Research.