A mosquito-borne virus that is spreading rapidly in the Caribbean and has now shown up in several people in the United States isn't a big deal for most people.

At most, it causes mild flu-like symptoms, including fevers, rashes, conjunctivitis and achy joints that last for about a week.But for pregnant women, the Zika virus could, health experts believe, cause abnormalities in developing babies' brains and skulls. The condition is called microcephaly.Recently the first baby in the United States thought to be afflicted with microcephaly as a result of the virus was born in Hawaii. The baby's mother had contracted Zika while in Brazil.The virus is spread via Aedes albopictus mosquitoes, a species found throughout the United States. It cannot be spread by casual contact.In Pennsylvania, 11 people have been tested for the virus. Of those, one was negative, seven tests are pending, and three were rejected.They were infected while traveling in areas where the virus is spreading, according to Dr. Loren K. Robinson, deputy secretary for Health Promotion and Disease Prevention at the Pennsylvania Department of Health, in a conference call last week by the Pennsylvania Medical Society.Because of federal laws protecting patients' privacy, Robinson could not provide details on where the people are in the state, or whether any are pregnant.She said the state Department of Health is working with the U.S. Centers for Disease Control and Prevention to track the spread of the illness.Robinson urged pregnant women who have recently traveled to areas where Zika is spreading to be tested. The tests are done by submitting blood samples to the state Department of Health, which sends them to the CDC, the only place in the United States where testing is being done. The process takes about two weeks.She also suggested pregnant women not go to areas where the illness is spreading. If they do, they should take precautions to avoid mosquito bites, such as using insect repellent, and wearing light-colored, long pants and long sleeves.Some U.S. airlines and cruise operators are offering refunds or letting pregnant women change travel plans if they booked a trip to places dealing with an outbreak of the virus.About ZikaThere is no vaccine or cure for Zika. Most people infected with the virus have either no symptoms, or mild ones, said infectious disease specialist Dr. Stephen Colodny of Allegheny County.The incubation period is short, and the symptoms last about a week, he said."People don't really get that sick," said Allegheny County infectious disease specialist Dr. Ray Pontzer.Dr. Kurt Barnhart of Philadelphia, chair of the Pennsylvania Section of the American Congress of Obstetricians & Gynecologists, said health experts do not know the rate of infection, and that not every pregnant woman who is exposed to Zika contracts it, nor does every fetus exposed suffer microcephaly. Nor is it known how severe the impact is at each trimester.While chances of contracting Zika within the United States is unlikely, Robinson said the Department of Health will work with the state Department of Environmental Protection to track mosquitoes that could carry the virus.Where is Zika spreading?Before last year, 2015, Zika outbreaks have occurred in areas of Africa, Southeast Asia, and the Pacific islands, according to the World Health Organization. In May 2015, the Pan American Health Organization issued an alert of the first confirmed Zika infections in Brazil.The WHO anticipates that the virus will spread to all but two countries in South, Central and North America. About 1.4 million cases have been found in South America, according to the WHO.Currently, the virus is spreading in Barbados; Dominican Republic; Guadeloupe; Haiti; Martinique; Puerto Rico, a U.S. territory; Saint Martin; U.S. Virgin Islands; El Salvador, Guatemala, Honduras, Panama; Mexico, Samoa, and Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Suriname, and Venezuela.