Sexually transmitted human Papillomavirus type variations resulting in high grade cervical dysplasia in North-East North Dakota and North-West Minnesota

Background: A review of Pap smear diagnoses from a reference laboratory in Grand Forks, North Dakota over a 3-year period (07/00 to 10/03) revealed a two-fold higher rate of high grade squamous intraepithelial lesion in a community in northwest Minnesota ( Roseau, 0.486%) than in northeast North Dakota ( Grand Forks, 0.249%), in spite of both having similar rates of low-grade squamous intraepithelial lesion ( 1.33% vs. 1.30% respectively) Objectives: To identify the different types of HPV present in patient populations showing high-grade dysplasia in Grand Forks, ND and Roseau, MN. Study design: Formaldehyde-fixed paraffin-embedded cervical tissue samples were analyzed using polymerase chain reaction (PCR) to detect the presence of HPV type 16, 18 and 31. Results: Our studies showed that 41 % of samples from Roseau were triply infected with HPV serotypes 16, 18 and 31 in comparison to 12 % from Grand Forks. Conclusion: Due to the small sample size we were unable to prove the study to be statistically significant. However, our results suggest that the presence of HPV 16, 18 and 31 in triply infected samples may be the cause of the higher percentage of high-grade dysplasia in Roseau, MN when compared to Grand Forks, ND.