• Infectious Diseases A-Z: Zika virus cases lower, but virus remains a risk

word definition of zika virus with a syringe and pillsThe number of reported Zika virus cases is much lower so far this year than at this point in 2017. However, pregnant women remain advised not to travel to areas where there is a risk of contracting the virus.

"It’s still important that pregnant women avoid travel to Zika-endemic areas. We know that there is a defined risk of birth defects in the children of mothers infected during pregnancy," says Dr. Pritish Tosh, an infectious diseases specialist at Mayo Clinic.

Contracting Zika during pregnancy can cause microcephaly and other birth defects. The virus is primarily transmitted by bite of an infected Aedes species mosquito. Pregnant women also can pass the virus along to their unborn children. The virus also can be spread during sexual contact.

Watch: Dr. Pritish Tosh discusses Zika update.

Journalists: Broadcast-quality sound bites are in the downloads.

So far, there have been 65 cases of local mosquito-borne Zika virus reported in Puerto Rico in 2018compared to 620 cases in 2017.

At this time, no local mosquito-borne Zika virus transmission has been reported in the continental U.S. in 2018, according to the Centers for Disease Control and Prevention (CDC).

Ongoing Zika transmission throughout Central America and South America continues but at much smaller numbers than in 2017.

Dr. Tosh explains that the number of people who are getting Zika this year is lower than in past years. That’s partly because more people have gained immunity to it. When more people are immune, the odds of contracting Zika are lower for everybody — even those without immunity.

Find Zika travel information on the CDC website.