Prevalence and Genotyping of the Human Papillomavirus in the Cervical Specimens among Women of Southern Croatia (Dalmatia County)

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SUMMARY

Aim: The aim of this study was to evaluate the prevalence of HPV types in the female population with either normal or abnormal Pap smears in Southern Croatia (Dalmatia County) and to evaluate the distribution of HPV types and their association with different cytological findings.

Methods: During one year period, we routinely screened 1,160 women for H R H PV at the Educational Public Health Institute of Split and Dalmatia County, by using Hybrid Capture 2 HPV DNA test. Only HR HPV positive specimens determined by HC2 were further genotyped by polymerase chain reaction (PCR) based assay at the Department of Pathology and Forensic Medicine, Split.

Results: Out of the total number of tested women, 406 (35%) of them were positive to HR HPV. The following frequency was observed: HPV 16 in 10.8%, HPV 18 in 7.8%, HPV 31 in 2.3%, HPV 33 in 1.1%, HPV 52 in 0.9%, HPV 45 in 0.6%, and HPV 59 in 0.4% specimens.

Conclusion: The data obtained from our study indicate that HPV 16 is the most common HPV type found in the cervical specimens among women of Southern Croatia, as in most studies worldwide, followed by HPV 18 and HPV 31. The positivity rates in our study slightly differed for HPV types 18 and 31 from those found in the other studies conducted in Northern Croatia. These suggesting geographic and environmental factors are related to the prevalence of HPV types. We consider it very important to gather information on regional variations in the HPV type spectrum.

Key words: HPV, high-risk genotypes, Dalmatia County, Croatia

INTRODUCTION

Cervical cancer is the second most common cancer in women worldwide. There are about 490,000 newly registered cases every year. There are about 270,000 cervical cancer deaths in the world annually, 85% of which take place in developing countries because of absent or poor screening programmes. Infection with Human Papillomavirus (HPV) is the main cause of cervical cancer. HPV is also one of the most frequent causal agents of sexually transmitted diseases. It can cause various clinical conditions, from asymptomatic infections to benign and malignant diseases of the genital region. Luckily most HPV infections are spontaneously cleared by host immune response. At present, there are more than 200 known HPV types. More than 40 types attack the epithelium of the genital tract, and are transmitted mainly through sexual intercourse. The types that are most commonly related to the development of cervical cancer, so called oncogenic or high-risk types (HR HPV), are: 16, 18, 31, 33, 34, 35, 39, 45, 51, 52, 56, 58, 59, 66, 68 and 70 (1-3).

Genital HPV infection is rarely reported (there is no legal obligation). While its worldwide prevalence is assumed to be higher than 20 million, the incidence of HPV infection in the United States ranges from 1 million to 5.5 million per year (2). The prevalence of HPV DNA in cervical cancer cases is 99.7% (3), compared to 5% to 20% of cervical specimens in women without cervical cancer (4-6). HPV 1 6 and HPV 1 8 are associated with 70% of cervical cancer worldwide (1, 7). The prevalence and distribution of the different HPV types in cervical samples with normal cytology and low grade cervical lesions vary around the world (2).

Croatia has a lower cancer incidence than most Central and Eastern European countries. There are about 355 new cases (incidence rate 13.3/100,000), and about 100 deaths each year (mortality rate 5.0/100,000 women) (8).

Very little is known about prevalence and distribution of HPV types in Croatia. There are a few studies from Northern Croatia about HPV prevalence related only to cervical specimens of women with abnormal Pap smear (9-1 1). There is only one small scale study for Southern Croatia (Split and Dalmatia County) conducted by Kaliterna et al. related to cervical samples of women with either normal or abnormal Pap smear (12).

We decided to expand our research on this topic in a larger and more detailed study. …