Numbers of those with genital warts infections reaching epidemic proportions


January 04, 1994|By Dr. Genevieve Matanoski | Dr. Genevieve Matanoski,Contributing Writer

Infection with the human papillomavirus (HPV) is becoming an epidemic. Reports indicate that about 170,000 Americans sought help for genital warts in 1966, and by 1984 this number had climbed to 1.15 million -- an almost seven-fold increase.

Although the rapid increase in this sexually transmitted infection is relatively recent, medical interest in warts is not. The infectious nature of human warts has been known since 1907.

Over the last 50 years, we've learned that papillomaviruses are a family of viruses that cause warts at various sites in the body. We also know that some may be related to cancer. Dr. Keerti Shah, professor of immunology and infectious diseases at the Johns Hopkins School of Hygiene and Public Health, has studied these viruses extensively and discussed some of the current thinking about papillomaviruses in relation to genital warts and cervical cancer.

Q: How can women avoid infection?

A: Women who have partners with warts or who themselves have warts of the external genital region should know they have high risk of having a lesion on the cervix and should seek medical help. Routine Pap tests and gynecological exams will detect unrecognized lesions that can then be carefully followed to avoid any serious long-term consequences.

To avoid this sexually transmitted infection, women and their partners must avoid high-risk behaviors that increase the probability of contact with an infected person.

Q: What are the signs of infection with the human papillomavirus?

A: HPV causes warts on skin and mucous membranes. The virus attacks the dividing cells of the tissue's basal layer, gaining access through trauma sites.

Growths appear on hands or other skin surfaces, the respiratory tract, oral cavity or genital tract. The lesions of the genital tract can be either a raised wart that is found on sites other than the cervix, or flat warts called condylomata, which are common to the cervix.

There are about 60 different types of papillomaviruses and specific types are related to the occurrence of warts at different sites on the body.

Q: How common are HPV infections of the genital tract?

A: Since many HPV infections do not have symptoms, the exact frequency of infection is unknown. However, scientists estimate that 10 percent of young men and women currently have recognized infections, and the rate may be twice this number if those without any symptoms are included.

The number increases if we consider people who have past infections. Pap tests of American women indicate infection rates of 9 to 16 percent, but these rates vary depending on the population tested and how carefully the investigator searches for all virus types.

Q: Do we expect HPV to continue to be such a widespread problem?

A: With 12 to 24 million Americans infected with HPV today, this epidemic of genital warts should continue to increase. HPV infections have a very high transmission rate. Two-thirds of the partners of an infected person will become infected within three months of contact.

HPV infections usually will disappear in about two years. However, the virus leaves a permanent "footprint" in cells, and this is the second concern. Test-tube and human studies indicate that HPV is often associated with the presence of abnormal or precancerous cells from the cervix, suggesting that HPV probably is associated with the development of cervical cancer.

Additional damage to tissue may have to occur in order for cancer to result, but HPV may play a role.

Q: What is the evidence linking cervical cancer and HPV infections?

A: Women with abnormal cells on Pap tests have evidence of HPV infection in 29 to 92 percent of the specimens. In specimens of normal cells, only 9 to 16 percent have evidence of HPV. Women with early cervical cell changes have infections with HPV types that are different from women who have invasive cervical cancers.

Sixty percent or more of the latter group have infections with HPV-16 and HPV-18, which are only two of the 25 types infecting genital mucosa. This may mean that only certain types of HPV increase the risk of invasive cervical cancer.

An HPV infection does not signal the onset of cervical cancer. The period between infection and disease appears to be very long, on the order of 20 to 50 years.

Therefore, most scientists feel that another unknown factor occurs before cervical cancer develops. However, most scientists agree that HPV plays some role in cancer.

Q: How can we treat HPV infection?

A: Most warts disappear, but it takes several years. Treatments are often difficult, since they require repeated use of drugs and results are not always effective.

Treatments vary from use of chemicals to surgery. Recent evidence has shown that interferon injected into the wart will reduce its size and often result in a cure.

The prospect of creating a vaccine to immunize the population against these infections is still a long way off. Women must act to prevent infection or reduce the probability of developing cancer.

Dr. Genevieve Matanoski is a physician and epidemiologist at the Johns Hopkins School of Hygiene and Public Health. She is a founding director of the school's Institute for Women's Health Research and Policy.

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