In 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. World Health Organization Director-General Margaret Chan says the virus is “spreading explosively.” One of the hardest-hit countries is Brazil, where more than 4,000 babies have been born with microcephaly since October. Brazil has mobilized the military and health workers to combat the virus. Another hard-hit country, El Salvador, has taken the extreme step of recommending women not get pregnant before 2018. Scientists have linked rising temperatures from global warming to the increased incidence of mosquito-borne infections such as Zika. Australia’s Climate and Health Alliance executive director Fiona Armstrong said, “Zika is the latest example of the many mosquito-borne viruses which pose an increasing threat to humans due to warmer and wetter conditions associated with climate change.”