EPIDEMIOLOGIA MOLECOLARE DELLE INFEZIONI DA HUMAN PAPILLOMAVIRUS (HPV) E CHLAMYDIA TRACHOMATIS NELLA POPOLAZIONE GENERALE FEMMINILE
Tesi di Dottorato
Data di Pubblicazione:
2012
Citazione:
EPIDEMIOLOGIA MOLECOLARE DELLE INFEZIONI DA HUMAN PAPILLOMAVIRUS (HPV) E CHLAMYDIA TRACHOMATIS NELLA POPOLAZIONE GENERALE FEMMINILE / E.r. Frati ; tutor: E. Tanzi ; coordinatore: M. Pontello. Universita' degli Studi di Milano, 2012 Feb 02. 24. ciclo, Anno Accademico 2011. [10.13130/frati-elena-rosanna_phd2012-02-02].
Abstract:
Introduction
Sexually transmitted infections (STIs) are a major public health concern: according to WHO estimates, 448 million new cases of curable STIs (syphilis, gonorrhoea, chlamydia and trichomoniasis) occur annually throughout the world in adults aged 15-49 years.
There are more than 30 different sexually transmissible bacteria, viruses, mycetes and protozoa. Human Papillomavirus (HPV) and Chlamydia trachomatis are the causes of two of the most common STIs.
HPVs are double-stranded DNA viruses, grouped into cutaneous and mucosal types according to their infection site, and further subdivided into high-risk (HR) and low-risk (LR) genotypes, depending on their association with disease malignancy. More than 40 HPV genotypes can infect the genital area: HR-HPVs (e.g. HPV types 16 and 18) can cause cervical cancers and LR-HPVs (e.g. HPV types 6 and 11) can cause genital warts. It has been estimated that more than 50% of sexually active persons become infected with HPV at least once in their lifetime. Most of these infections are asymptomatic or subclinical and, fortunately, usually self-limiting. However, persistence of HPV infection can occur in 30% of cases and when these infections are sustained by HR types the risk to develop cancer is increased.
Chlamydia trachomatis is an obligate intracellular bacterium. Currently, 18 different serovars of C. trachomatis have been identified, 10 of these infect the genital area. Silent and asymptomatic infection is common in both women and men. In women, acute infection with C. trachomatis can result in pelvic inflammatory disease, whose long-term consequences include chronic pain, ectopic pregnancy and infertility. C. trachomatis infection has also been demonstrated to be a risk factor for the acquisition of HPV infection.
This work aimed at studying the molecular epidemiology of HPV and C. trachomatis infections; carrying out a microbiological surveillance of these infections by molecular and phylogenetic methods; evaluating the HPV/C. trachomatis co-infection in sexually active young women aged 13-24 years; evaluating the epidemiological aspects in relation to novel preventive strategies (for example the opportunity to set C. trachomatis screening programme).
Materials and methods
1,557 cervical brush samples were collected from 1,557 women between January 2009 and December 2011. In particular:
- 688 were collected from women aged 25-64 years (median age 36 years);
- 563 from sexually active females aged 13-24 years (median age 19 years);
- 306 from sexually active young women (median age 19 years, range: 19-21 years) vaccinated with a tetravalent HPV vaccine. These samples were collected one year after the end of the vaccination schedule.
All samples were analyzed to identify the presence of HPV infection and genotypes using molecular methods. HPV-16 and HPV-18 positive samples were analyzed through phylogenetic methods in their L1 gene coding for the major capsid protein to characterize the potential vaccine escape mutants and in the LCR to investigate the circulation of geographical variants.
Samples collected from adolescents/young women aged 13-24 years were analyzed to determine the presence of C. trachomatis by molecular methods. All C. trachomatis positive samples were phylogenetically analyzed in the ompA gene (coding for the major membrane protein MOMP) to evaluate the circulating serovars.
Results
The prevalence of HPV infection in sexually active women aged 13-64 years was 16.5%. In details, among adolescent/young women aged 13-24 years the prevalence was 22.7%, whereas in women aged 25-64 was 11.3%. According to several epidemiological studies, our data show a decrease in prevalence with increasing age of women (26% in 19-24-year old, 18.5% in 25-34-year
Tipologia IRIS:
Tesi di dottorato
Keywords:
human papillomavirus ; Chlamydia trachomatis ; molecular epidemiology ; microbiological surveillance
Elenco autori:
E.R. Frati
Link alla scheda completa:
Link al Full Text: