Many types of infections can cause abnormal cervical cell changes. The most common cause of cervical cell changes is the human papillomavirus (HPV). This viral infection usually is not treated, but the abnormal cell changes can be treated if needed. HPV is also the cause of genital warts. An abnormal Pap test may be the first sign that a woman is infected with HPV.

Other types of infection that can cause abnormal cell changes include:

• Bacterial infections such gonorrhea, chlamydia, or bacterial vaginosis.
• Fungal (yeast) infections such as candidiasis or monilia infection.
• Protozoan infection (Trichomonas).

While these infections can cause changes in cervical cells, they do not cause cervical cell dysplasia or increase the risk of cervical cancer. These types of infections can be specifically treated, and a follow-up Pap test should be done no sooner than 4 months after treatment to allow the cervical cell changes to return to normal.