Risky HPV detected in human breast milk

NEW YORK (Reuters Health) - Human papillomavirus type 16 (HPV-16), which has been linked to cervical cancer, can be detected in human breast milk collected during the early period after a woman delivers her baby, doctors from Finland report.

It is possible that HPV DNA present in breast milk may be transmitted to the infant during breast feeding, study chief Dr. Stina Syrjanen suggested in correspondence with Reuters Health.

In previous research, Syrjanen, a pathologist at the University of Turku, and colleagues found evidence of transmission of HPV from an infected mother to her newborn infant. This led to the Finnish HPV Family Study, the goal of which is to elucidate the transmission modes of HPV between family members.

For their current report, Syrjanen's team looked for HPV in cervical scrapings obtained from 223 mothers, and in oral scrapings from the mothers and 87 fathers prior to delivery and at 2, 6, and 12 months after delivery. They also looked for HPV in breast milk expressed on postpartum day 3.

High-risk HPV DNA was detected in 10 milk samples (4.5 percent), the team reports. DNA sequencing from nine samples confirmed that the virus was high-risk HPV-16.

The detection rate of high-risk HPV was 12 to 15 percent in cervical samples, 20 to 24 percent in oral samples from mothers, and 21 to 26 percent in oral samples from fathers.

The team also observed a significant link between HPV in milk and the presence of high risk-HPV in oral scrapings obtained from the father.

Thus, transmission could have occurred by the spouse, from the mouth to the nipple and then to the breast, or it could have occurred from the mother's hands, Syrjanen said.

She theorized that "if there are viral particles in breast milk, the infant might acquire oral HPV infection via breast milk during (breast feeding).

SOURCE: Pediatric Infectious Disease Journal, June 2008.