MILWAUKEE (AP) -- The city of Milwaukee has issued a health alert after a cab driver was diagnosed with rubella.

Health officials want to get in touch with anyone who took a taxi with American United between 8 p.m. and 8 a.m. from April 13 to 21. Any contact the driver may have had with a pregnant woman could endanger her unborn child.

Milwaukee Health Department director Paul Biedrzycki says birth defects, developmental delays and seizures can result from respiratory contact with a pregnant woman. Rubella, or German measles, can be transmitted through coughing, sneezing or even talking in close proximity.

Health officials tell WTMJ-TV that rubella has a long incubation period, so it could be a week before other cases surface.