Cervical human papillomavirus infection and squamous intraepithelial lesions in rural Gambia, West Africa: viral sequence analysis and epidemiology

Abstract

The development of effective strategies against cervical cancer in Africa requires accurate type specific data on human papillomavirus (HPV) prevalence, including determination of DNA sequences in order to maximise local vaccine efficacy. We have investigated cervical HPV infection and squamous intraepithelial lesions (SIL) in an unselected cohort of 1061 women in a rural Gambian community. Squamous intraepithelial lesions was diagnosed using cytology and histology, HPV was typed by PCR-ELISA of DNA extracts, which were also DNA sequenced. The prevalence of cervical HPV infection was 13% and SIL were observed in 7% of subjects. Human papillomavirus-16 was most prevalent and most strongly associated with SIL. Also common were HPV-18, -33, -58 and, notably, -35. Human papillomavirus DNA sequencing revealed HPV-16 samples to be exclusively African type 1 (Af1). Subjects of the Wolof ethnic group had a lower prevalence of HPV infection while subjects aged 25 -44 years had a higher prevalence of cervical precancer than older or younger subjects. This first report of HPV prevalence in an unselected, unscreened rural population confirms high rates of SIL and HPV infection in West Africa. This study has implications for the vaccination of Gambian and other African populations in the prevention of cervical cancer.

Human papillomavirus genotype distribution and cervical squamous intraepithelial lesions among high-risk women with and without HIV-1 infection in Burkina Faso

“…Human papillomavirus-52, HPV-35, and HPV-58 were the most prevalent types in the present study. A high prevalence of these HPV types has been also observed in other African studies (Gravitt et al, 2000;Castellsague et al, 2001;De Vuyst et al, 2003;Mayaud et al, 2003;Xi et al, 2003;Baay et al, 2004;Thomas et al, 2004;Wall et al, 2005).…”

“…While the epidemiology of genital HPV types has been relatively better studied in Southern and Eastern African countries such as Kenya (Temmerman et al, 1999;De Vuyst et al, 2003), Malawi (Miotti et al, 1996), Mozambique (Castellsague et al, 2001), Tanzania (Mayaud et al, 2003), Uganda (Serwadda et al, 1999), and Zimbabwe (Gravitt et al, 2002;Baay et al, 2004), data from Western Africa have been scarce. The prevalence of HPV infection and associated cervical lesions have been studied in Ivory Coast (La Ruche et al, 1998) and Mali (Bayo et al, 2002), but detailed HPV types were only reported from Senegal (Xi et al, 2003), Nigeria (Thomas et al, 2004), and The Gambia (Wall et al, 2005). Prevalence rates of HPV infection ranging from 13 to 40% have been reported from low-risk or general populations of sub-Saharan African countries (Miotti et al, 1996;Temmerman et al, 1999;Castellsague et al, 2001;De Vuyst et al, 2003;Mayaud et al, 2003;Xi et al, 2003;Baay et al, 2004;Thomas et al, 2004;Wall et al, 2005).…”

“…The prevalence of HPV infection and associated cervical lesions have been studied in Ivory Coast (La Ruche et al, 1998) and Mali (Bayo et al, 2002), but detailed HPV types were only reported from Senegal (Xi et al, 2003), Nigeria (Thomas et al, 2004), and The Gambia (Wall et al, 2005). Prevalence rates of HPV infection ranging from 13 to 40% have been reported from low-risk or general populations of sub-Saharan African countries (Miotti et al, 1996;Temmerman et al, 1999;Castellsague et al, 2001;De Vuyst et al, 2003;Mayaud et al, 2003;Xi et al, 2003;Baay et al, 2004;Thomas et al, 2004;Wall et al, 2005). The 66% prevalence found in the present study, which is still much higher than the 40% prevalence found in similar highrisk populations in Africa (Kreiss et al, 1992;Langley et al, 1996;Piper et al, 1999), might reflect the high sexual exposure of our study population and, as mentioned earlier, may be attributed in part to the exhaustive nature of our HPV detection strategy.…”

“…Available data suggest, however, a higher prevalence and wider spectrum of oncogenic HPV types compared to studies conducted elsewhere (Castellsague et al, 2001;De Vuyst et al, 2003;Mayaud et al, 2003;Clifford et al, 2005;Wall et al, 2005). Furthermore, the high background prevalence of human immunodeficiency virus type 1 (HIV-1) observed in many African settings adds complexity to our understanding of the epidemiology of HPV…”

Human papillomavirus infection: an Anonymous Prevalence Study in South Wales, UK

“…However, comparison of our data with the Scottish cohort identified an overall lower percentage of HPV 16, HPV 18, HPV 31, HPV 51, HPV 52 and HPV 68 and an increase in HPV 35, HPV 66 and LR-HPV types. The high incidence of HPV 35 has been reported in other papers using the PCR-EIA method of Walboomers et al (Wall et al, 2005) and future work will investigate this further. …”