HPV prevalence and type distribution in women with normal or abnormal Pap smear in Bulgaria.

Human papillomavirus (HPV) is a well-known pathogen for lower genital tract neoplasias, yet little is known regarding HPV prevalence in Bulgaria. The aim of this study was to investigate the prevalence of HPV DNA and to determine HPV types distribution among women with normal and abnormal cytology. Cervical smears with different cytological diagnoses were collected from 355 Bulgarian patients. The cohort of patients selected is the biggest ever studied in this country. Using the Roche Linear Array HPV Genotyping Test, papillomavirus DNA was found in 217 out of the 355 samples, 164 of which had only one and 53 had more than one HPV type. The distribution of the viruses tested in 355 samples was as follows: (i) the most common type was HPV 16, which was found in 61 samples; (ii) the next most frequent HPV type was HPV 33, found in 14 of the samples. A high prevalence of HPV infection was observed in this study. As HPV infection has a high correlation with cervical cancer, this study emphasizes the need for both primary prevention of cervical cancer with HPV vaccines as well as secondary prevention with screening. Currently, two HPV vaccines are included in the National immunization schedule in Bulgaria. Thus, new clinical studies will benefit from patient stratification by the presence or absence of HPV, and by designing separate clinical trials specifically for HPV associated cancers.