INACTIVATION OF PAPILLOMAVIRUS BY LOW CONCENTRATIONS OF POVIDONE-IODINE

Background and Objectives: A recent report by Hermonat et al showed th at nonoxynol 9 is completely inactive against bovine papillomavirus, w hich is very closely related to human papillomavirus. Finding a vagina l microbicide active against human papillomavirus to reduce the risk o f sexual transmission of human papillomavirus would be desirable. Goal of This Study: To determine whether povidone-iodine is active in vitr o against bovine papillomavirus. Methods: A bovine papillomavirus-l st ock prepared by extraction of a fibropapilloma was treated with variou s concentrations of povidone-iodine. The virus/povidone-iodine samples were incubated at 37 degrees C for 15 minutes and then placed on cont act-inhibited cells of mouse fibroblast line C127 in 10-cm tissue cult ure dishes for the transformation assay. At 2 weeks post-infection, on cogenic foci induced by bovine papillomavirus appeared and were counte d after the cells were fixed with 4% formaldehyde and stained with met hylene blue. Results: Approximately 90% inactivation of papilloma viru s was demonstrated with exposure to 0.1% povidone-iodine, and 99.9% in activation was seen at 0.3%. Conclusions: The concentrations of povido ne-iodine that were effective in this study are lower than concentrati ons in available over-the-counter preparations of povidone-iodine. Add itional research is needed to verify whether papillomavirus is suscept ible to other, more acceptable agents. Clinical trials may be warrante d to determine whether povidone-iodine or other agents would reduce th e rate of sexual transmission of the human papillomavirus strains asso ciated with cervical cancer.