Dallas Morning News, Feb. 28, 2007 A nationwide government survey estimates that one in four females between ages 14 and 59 is infected with HPV, thought to be the most common sexually transmitted infection in the U.S. In the survey, 3.4 percent of U.S. females in that age range were infected with the strains of human papillomavirus that lead to most cases of cervical cancer and genital warts. These four strains are the ones covered by Gardasil, the HPV vaccine that Gov. Rick Perry has ordered for Texas schoolgirls.  (This story has run widely in state and national publications.)