Chlamydia trachomatisis a bacterium that causes the most STIs in the U.S.
- More than 1 million cases reported each year in U.S.
- Many more cases unreported; estimated at 2.8-5 million
- Most common reportable infectious disease
- Primary cause of urethritis and cervicitis
- Lymphogranuloma venereum is caused by different serotypes from those causing urethritis and cervicitis
- Asymptomatic in 25% of men and 70% of women
