A North Dakota woman who recently traveled to Puerto Rico before giving birth was infected with Zika virus — making it a high-risk case because the mosquito-born infection is known to cause birth defects, public health officials announced Thursday.

The North Dakota Department of Health plans to monitor the woman’s newborn for a year for problems. Most notoriously, Zika can cause microcephaly, an underdevelopment of the brain and head that has been detected among infected infants in South American and Caribbean nations where the virus is prevalent.

So far, the Health Department reported no such problems in the infant, but the case renewed calls for travel precautions. “Pregnant women should not travel to countries with Zika transmission, and if they must travel, be extremely careful to avoid mosquito bites,” said Laura Cronquist, an epidemiologist with the North Dakota agency.

On Friday, U.S. health authorities said researchers have for the first time detected the Zika virus in Aedes albopictus, a mosquito species known as the “Asian tiger,” that ranges farther north than Aedes aegypti, the primary carrier in the southern United States. The expanded range includes southern Minnesota, but not the Dakotas.

The infection is the first known case in North Dakota. Health officials are urging the same precautions in Minnesota, where 14 people have been confirmed with travel-related infections, according to the latest figures from the U.S. Centers for Disease Control and Prevention.

Only four states have reported higher numbers to date, though that is probably a reflection of eager Minnesotans escaping the cold this winter than a particular problem with the virus in the state, said Elizabeth Schiffman, an epidemiologist with the Minnesota Department of Health’s vector-borne disease unit.

In people who aren’t pregnant and are in good health, the infection can cause no symptoms and clear out of their blood in as little as three weeks. But mild symptoms are common, including fevers, headaches, red eyes, and joint and muscle pains. A Zika infection is often characterized by a generic rash of flat, bumpy spots.

Infected men are encouraged to abstain from sexual activity — because that is one way other than mosquitoes by which the virus can spread — or use condoms during sex, for at least six months. Men with no signs of infection who traveled to high-risk areas are asked to take similar protective steps for eight weeks.

Schiffman said these time periods reflect evidence that Zika can remain longer in semen and other bodily fluids compared to blood.