Human papillomavirus spectrum of HPV-infected women in Nigeria: an analysis by next-generation sequencing and type-specific PCR

Abstract

Background: Human papillomavirus (HPV) infection and cervical cancer are leading health problems and causes of death in many parts of the world. There are ~ 200 HPV types that can infect humans. This study aims to understand the spectrum of HPV infections in Nigerian women with normal or abnormal cytology.

Methods: We screened cervical samples from 90 women with possible HPV infections collected in two regional hospitals in Nigeria. The first screening was done using next-generation DNA sequencing (NGS), identifying multiple HPV types in many samples. Thereafter, type-specific PCR analysis was used to verify the NGS-identified HPV types in each sample.

Results: NGS analysis of the 90 samples from the Nigerian cohort identified 44 HPV types. The type-specific PCR confirmed 25 HPV types out of the 44 HPV types detected by NGS, and ~ 10 of these types were the most prevalent. The top five prevalent types found in the Nigerian cohort were HPV71 (17%), HPV82 (15%), HPV16 (16%), HPV6 (10%), and HPV20 (7%). Among the PCR-confirmed HPV types, we found 40.98% high-risk HPV types, 27.22% low-risk HPV types, and 31.15% undetermined HPV types. Among these 25 HPV types in Nigeria, only six were included in the current nine-valent HPV vaccine. We also observed strikingly high multiple HPV infections in most patients, with as many as nine HPV types in a few single samples.

Conclusions: Our NGS-PCR approach of HPV typing in the Nigerian cohort samples unveiled all possible HPV types currently circulating in Nigerian people. We confirmed 25 HPV types using NGS and PCR, with many samples infected with multiple HPV types. However, only six of these types are part of the nine-valent HPV vaccines indicating the need to develop region-specific selective vaccines.

Keywords: HPV types; Next-generation sequencing; Nigeria; Polymerase chain reaction; Spectrum.

Fig. 1

Prevalent HPV types by next-generation sequencing and type-specific PCR A Frequency of HPV types detected by next-generation sequencing. B Frequency of HPV types detected by type-specific PCR. Bars indicate the percentages of HPV types

Fig. 2

Phylogenetic Analysis of select Papillomavirus found in the cohort. HPV DNA sequences for each papillomavirus were obtained from PAVE and used for MEGA analysis. The resulting multiple alignments were then used to generate a phylogenetic tree to analyze the evolutionary patterns of select papillomavirus. Clades were identified related to the classical Papillomavirus genera indicated on two genera of the PV: alpha-papillomavirus genera and Beta-papillomavirus. Phylogenetic trees were constructed by the Maximum Likelihood method and the Kimura 2-Parameter model by MEGA package

Fig. 3

Pie chart representing the top ten prevalent HPV types in Nigeria. Among the HPV types detected, the mean of the top ten detected with NGS and verified by ts-PCR were used to determine the distribution

Fig. 4

The detection rate of 9v (Gardasil 9) human papillomavirus (HPV). Of the 44 HPV genotypes found in the Nigerian cohort, 63% were covered by the nine-valent Gardasil^® 9 HPV vaccine