Washington, January 28 (RHC)-- In the U.S. state of Virginia, the Health Department has confirmed its first Zika virus infection in an adult, sparking concern the mosquito-borne infection could soon sweep the United States as it has dozens of other countries.

The Zika virus itself is usually not life-threatening, but it appears to be linked to a condition called microcephaly, a rare and dangerous birth defect that causes babies to be born with abnormally small heads.

The Centers for Disease Control and Prevention says microcephaly also causes a host of other health problems, including seizures, developmental delays, hearing loss and vision problems.

A recent study estimates the Zika virus could reach regions where 60 percent of the U.S. population lives. At least 22 countries and territories in the Americas have recorded confirmed cases of the Zika virus.