About half the time there are no symptoms. Symptoms that do occur are usually mild and begin about 2 to 3 weeks after acquiring the virus. Symptoms include slight fever and rash. The rash is not unique and may appear on the face first as flat or slightly raised red spots. It may then spread to the body, arms and legs. Low-grade fever for a day or two, followed by joint pains may occur. Some people have swelling and redness of the joints. Rarely, people may have low counts of cells involved in blood clotting, called platelets. Encephalitis (en-sef-ah-lite-is), an infection involving the brain, may also rarely occur.
Infection in a fetus can cause many serious problems in the infant, including: