Co-infection of human papillomavirus and herpes simplex virus-2 with cervical dysplasia among women in Kaduna State, Nigeria

Abstract

Background: The epidemiology of human papillomavirus (HPV) and co-infections with herpes simplex virus type 2 (HSV-2) remains poorly characterized in Africa. High risk HPV (hrHPV) infection is the primary cause of 99.7% all cervical cancer especially in the presence of genital ulcer disease (GUD) which is usually caused by HSV-2. Herpes simplex virus-2 might interact directly with hrHPV to increase the risk of cervical cancer. Co-infection of HPV and HSV-2 in asymptomatic women could provide a clue to early diagnosis of cervical cancer and this could aid in the development of new strategies for effective management and improvement of the quality of life of women who are infected. If the synergy between HPV and HSV-2 can be prevented, there may be significant reduction of the incidence of cervical cancer. Methodology: This was a descriptive cross-sectional study of 515 randomly selected apparently healthy women of reproductive age whose cervical samples were screened for HPV and HSV-2 in Kaduna State, Nigeria. The cervical samples were collected by liquid-based cytology (LBC) for detection of cervical epithelial cell abnormalities (CEA) and molecular detection of HPV and HSV-2 using conventional polymerase chain reaction (PCR) assay. Extracted viral DNAs from the samples were amplified by convectional PCR using specific hrHPV (HPV 16,18, 31 and 45) primer sets and a broad spectrum MY09/11 and GP5+/6+ primers for a wider range of HPV genotypes while HSV-2 DNA was detected by florescence-based PCR assay with HSV-2 gG primers and probes. Results: PCR assay revealed that 14.7% (n=76) of the 515 selected women harbored HPV, HSV-2 or both. The prevalence of HPV, hrHPV, HSV-2 and HPV/HSV-2 co-infection among in the study participants are 11.8% (n=61), 9.3% (n=48), 5.6% 4% (n=29) and 2.3% (n=12) respectively. The frequency of HPV detection in HSV-2 infected participants (41.4%, 12/29) was significantly higher (OR=6.295, p<0.0001) than in HSV-2 negative participants (10.1%, 49/437), but only co-infections of HPV-31 (p=0.004) and HPV-18 (p=0.040) with HSV-2 were significantly associated. Cervical cytology reports on the smears revealed prevalence of cervical epithelial abnormalities (CEA) of 16.7% (n=86), with cervical dysplasia prevalence of 6.4% (n=33), consisting of high grade squamous intraepithelial lesion (HGSIL) of 1.6% (n=8), low grade squamous intraepithelial lesion (LGSIL) of 4.1% (n=21) and atypical squamous cells of uncertain significance (ASCUS) of 0.8% (n=4). The frequency of HPV detection in women with cervical dysplasia (93.9%, 31/33) was significantly higher (OR=14.22, p<0.0001) than in women without cervical dysplasia (6.2%, 30/482), and all HPV genotypes were significantly associated (p<0.05) with cervical dysplasia except HPV 16 (p=0.051). Also, the frequency of HPV/HSV-2 co-infection among women with cervical dysplasia (15.2%, 5/33) was significantly higher than among women without cervical dysplasia (1.5%, 7/482) (OR=12.12, p<0.0001). Comparing women with cervical inflammatory and atrophic changes (n=53), women with cervical dysplasia (HGSIL, LGSIL and ASC-US) had significantly higher frequency of HPV infection (χ2=42.829, p=0.000), HSV-2 infection (χ2=25.140, p=0.001) and HPV/HSV-2 co-infections (χ2=66.602, p=0.000). Conclusion: Co-infection rate of hrHPV and HSV-2 among women in Kaduna State is 2.3%. Demographic factors significantly influencing the rate of co-infections included age and marital status. In spite of the screening method using the traditional Pap smear, GUD and cervical cancer continues to be a major public health problem, thus more sensitive and specific methods such as liquid based cytology technique and polymerase chain reaction for early detection of cervical dysplasia and hrHPV or HSV-2 in asymptomatic women should be adopted for routine use