Human papillomavirus genotypes distribution among Gabonese women with normal cytology and cervical abnormalities

Cervical cancer is one of the most common tumors affecting women with a disproportionate mortality occurring in developing countries. Despite the high prevalence of cervical cancer and cervical neoplasia in Gabon, few studies have been performed to evaluate the prevalence and determinants of HPV infection in this country. The aim of this study was to determine the HPV prevalence and distribution in a population of Gabonese women with normal cytology and cervical abnormalities.

A total of 200 cervical samples collected in the "Departement d'Anatomie et de Cytologie Pathologiques" of the "Faculté de Medecine et des Sciences de la Santé" in Libreville, Gabonwere analyzed. Cytological status was classified according to Bethesda 2001. Nested polymerase chain reaction (PCR) using consensus degenerate PCR primers (MY09/11 and GP5+/6+) was performed for the detection of HPV DNA and HPV typing was done by DNA sequencing.

Cytological analysis showed that 87 % of women had normal cytology (n = 174/200). Among the 26 women with cytological abnormalities, predominance (61.5 %; 16/26) of low grade squamous intraepithelial lesion (LSIL) was found and no cervical cancer case was detected. Overall, HPV DNA was detected in 60 % of women (120/200). With respect to the cytological status, HPV DNA was found in 57.5 % of women with normal cervix and 76.9 % of women with abnormal cytology. HPV genotyping was performed on 114 HPV positive cases and revealed the presence of 11 distinct genotypes: 16, 18, 33, 31, 56, 6, 66, 70, 35, 45 and 81. The high risk type HPV 16 was the most common genotype found in all cytological categories. Six HPV positive samples could not be typed by DNA sequencing, probably due to multiple HPV infection. Evaluation of possible risk factors showed that HPV infection was related positively with number of sexual partners (≥3, OR = 2.3; 95 % CI, 1.3-4.3), history of sexually transmitted infection (Chlamydia, OR = 1.9; 95 % CI, 1.01-3.4) and marital status (single, OR = 2.0; 95 % CI, 1.1-3.5).

The prevalence of HPV infection among Gabonese women is high. Our findings highlight the need to set up a national program to fight cervical cancer, combining Pap smear test and HPV testing, to improve cervical cancer prevention in Gabon.