Chlamydia trachomatis infection and HPV/Chlamydia trachomatis co-infection among HPV-vaccinated young women at the beginning of their sexual activity.

PURPOSE: This study investigated the prevalence of Chlamydia trachomatis infection, co-infection with Human Papillomavirus (HPV) and associated risk factors in a cohort of sexually active young women enrolled in an ongoing trial on HPV vaccination at the European Institute of Oncology (IEO, Milan, Italy). METHODS: Cervical samples were collected from 591 girls (median age 18.8 years) at the beginning of their sexual activity. At the time of sample collection, 354 women had not yet been vaccinated, and 237 women had been vaccinated for at least 12 months. All samples were analyzed through a molecular assay for the detection of C. trachomatis infection. Demographic, behavioral risk factors and high-risk HPV (HR-HPV) status were investigated. RESULTS: The prevalence of C. trachomatis infection was 4.9 % and HPV/C. trachomatis co-infection rate was 1.5 %. The exact analysis has not underlined statistical significance for the variables considered, except for the infection with HR-HPV (p < 0.001). The prevalence of C. trachomatis infection among women who had not been immunized and those already vaccinated was similar (5.6 vs 3.8 %). However, the rate of HPV/C. trachomatis co-infection was twice as high in unvaccinated women (2 %) compared to vaccinated women (0.8 %). CONCLUSIONS: Over 16 % of young women had at least one of the two STIs investigated. The risk of C. trachomatis infection was higher in HR-HPV infected compared to HR-HPV uninfected young women. The rate of co-infection was halved in HPV-vaccinated compared to unvaccinated women. This study underlines that HPV vaccination can confer benefits also in terms of co-infections prevention, leading to a decreased risk of developing cervical malignancies.

Prevalence of human papillomavirus in young Italian women with normal cytology: how should we adapt the national vaccination policy?

BACKGROUND: Human Papillomavirus (HPV) is the most common sexually transmitted infection. In Italy, HPV vaccination is now offered free of charge to 12-year-old females. However, some regional health authorities have extended free vaccination to other age-groups, especially to girls under 18 years of age. We conducted a multicentre epidemiological study to ascertain the prevalence of different genotypes of HPV in young Italian women with normal cytology, with the aim of evaluating the possibility of extending vaccination to older females. METHODS: The study was performed in 2010. Women aged 16-26 years with normal cytology were studied. Cervical samples were analyzed to identify the presence of HPV by PCR amplification of a segment of ORF L1 (450 bp). All positive HPV-DNA samples underwent viral genotype analysis by means of a restriction fragment length polymorphism assay. RESULTS: Positivity for at least one HPV genotype was found in 18.2% of the 566 women recruited: 48.1% in the 16-17 age-class, 15.4 in the 18-20 age-class, 21.9% in the 21-23 age-class, and 15.5% in the 24-26 age-class; 10.1% of women were infected by at least one high-risk HPV genotype. HPV-16 was the most prevalent genotype. Only 4 (0.7%), 4 (0.7%) and 3 (0.5%) women were infected by HPV-18, HPV-6 and HPV-11, respectively. Of the HPV-DNA-positive women, 64.1% presented only one viral genotype, while 24.3% had multiple infections. The HPV genotypes most often involved in multiple infections were high-risk. A high prevalence was noted in the first years of sexual activity (48.1% of HPV-DNA-positive women aged 16-17 years); HPV prevalence subsequently declined and stabilized.The estimate of cumulative proportions of young women free from any HPV infection at each age was evaluated; 93.3% and 97.1% of 26 year-old women proved free from HPV-16 and/or HPV-18 and from HPV-6 and/or HPV-11, respectively. CONCLUSIONS: Our findings confirm the crucial importance of conducting studies on women without cytological damage, in order to optimise and up-date preventive interventions against HPV infection, and suggest that vaccinating 26-year-old females at the time of their first pap-test is to be recommend, though this issue should be further explored.

Genetic characterization of variants of HPV­16, HPV­18 and HPV­52 circulating in Italy among general and high­risk populations.

Viral factors, such as high­risk human papillomavirus variants, can increase the risk of viral persistence and influence the progression to cancer. In the present study, the long control region (LCR) of human papillomavirus (HPV)­16 and HPV­52, and the L1 region of HPV­16 and HPV­18, identified from subjects belonging to both general and high­risk populations (migrants, HIV+ subjects and adolescent/young people) residing in Italy, were characterized using molecular and phylogenetic techniques. To the best of our knowledge, this is the first Italian study to analyze a large number of sequences (n=458) and report phylogenetic data on the HPV­52 variants. The phylogenetic analysis showed that 90% of the LCR variants of HPV­16 and HPV­52 clustered within lineage A (European lineage) and only sequences identified from subjects belonging to high­risk populations fell into the non­European lineages. Analysis of the LCRs revealed a high genomic diversity with a large number of changes. Several mutations in the binding sites for viral and cellular transcription factors characterized the HPV­16 LCR variants belonging to the African lineages B and C, were observed in subjects with cytological abnormalities (high squamous intraepithelial lesions). The HPV­16 and HPV­18 L1 molecular characterization identified 30% of changes in the immune­dominant epitope loops. These data give a clear picture of the situation in Italy, and a starting point for understanding the molecular pathogenesis and developing molecular diagnostics for HPV, vaccines and other therapeutic approaches in order to control and/or eliminate virus­induced diseases.

Time-scaled phylogeography of complete Zika virus genomes using discrete and continuous space diffusion models.

Zika virus (ZIKV), a vector-borne infectious agent that has recently been associated with neurological diseases and congenital microcephaly, was first reported in the Western hemisphere in early 2015. A number of authors have reconstructed its epidemiological history using advanced phylogenetic approaches, and the majority of Zika phylogeography studies have used discrete diffusion models. Continuous space diffusion models make it possible to infer the possible origin of the virus in real space by reconstructing its ancestral location on the basis of geographical coordinates deduced from the latitude and longitude of the sampling locations. We analysed all the ZIKV complete genome isolates whose sampling times and localities were available in public databases at the time the study began, using a Bayesian approach for discrete and continuous phylogeographic reconstruction. The discrete phylogeographic analysis suggested that ZIKV emerged to become endemic/epidemic in the first decade of the 1900s in the Ugandan rainforests, and then reached Western Africa and Asia between the 1930s and 1950s. After a long period of about 40 years, it spread to the Pacific islands and reached Brazil from French Polynesia. Continuous phylogeography of the American epidemic showed that the virus entered in north-eastern Brazil in late 2012 and started to spread in early 2013 from two high probability regions: one corresponding to the entire north-east Brazil and the second surrounding the city of Rio de Janeiro, in a mainly northwesterly direction to Central America, the north-western countries of south America and the Caribbean islands. Our data suggest its cryptic circulation in both French Polynesia and Brazil, thus raising questions about the mechanisms underlying its undetected persistence in the absence of a known animal reservoir, and underline the importance of continuous diffusion models in making more reliable phylogeographic reconstructions of emerging viruses.

Dating the origin and dispersal of Human Papillomavirus type 16 on the basis of ancestral human migrations.

A major limitation when reconstructing the origin and evolution of HPV-16 is the lack of reliable substitution rate estimates for the viral genes. On the basis of the hypothesis of human HPV-16 co-divergence, we estimated a mean evolutionary rate of 1.47×10(-7) (95% HPD=0.64-2.47×10(-7)) subs/site/year for the viral LCR region. The results of a Bayesian phylogeographical analysis suggest that the currently circulating HPV-16 most probably originated in Africa about 110 thousand years ago (Kya), before giving rise to four known geographical lineages: the Asian/European lineage, which most probably originated in Asia a mean 38 Kya, and the Asian/American and two African lineages, which probably respectively originated about 33 and 27 Kya. These data closely reflect current hypotheses concerning modern human expansion based on studies of mitochondrial DNA phylogeny. The correlation between ancient human migration and the present HPV phylogeny may be explained by the co-existence of modes of transmission other than sexual transmission.

HPV Testing from Dried Urine Spots as a Tool for Cervical Cancer Screening in Low-Income Countries.

Nowadays, several screening strategies are available to prevent cervical cancer, but inadequate resources, sociocultural barriers, and sampling issues impede their success in low-income countries. To overcome these issues, this study aimed to evaluate the performance of human papillomavirus (HPV) testing from dried urine spots (DUS). Eighty-eight urine samples (including 56 HPV DNA positive specimens) were spotted on filter paper, dried, and stored in paper-bags. HPV DNA was detected from the DUS after 1 week and 4 weeks of storage using a polymerase chain reaction (PCR) assay. The sensitivity, specificity, and concordance of the DUS-based HPV test were evaluated by comparing the results with those of HPV testing on fresh urine samples as the gold standard. The sensitivity of the test was 98.21% (95% CI: 90.56-99.68) for DUS stored for 1 week and 96.42% (95% CI: 87.88-99.01) for DUS stored for 4 weeks. The specificity was 100% (95% CI: 89.28-100) at both time points. The concordance between DUS and fresh urine HPV testing was "almost perfect" using the κ statistic. These preliminary data suggest that a DUS-based assay could bypass sociocultural barriers and sampling issues and therefore could be a suitable, effective tool for epidemiological surveillance and screening programs, especially in low-income countries.

Chlamydia trachomatis prevalence and chlamydial/HPV co-infection among HPV-unvaccinated young Italian females with normal cytology.

Infections caused by Chlamydia trachomatis (Ct) and human papillomavirus (HPV) are the two main sexually transmitted infections; however, epidemiological data on Ct prevalence and Ct/HPV co-infection in Italy are scant. This study aimed at estimating the prevalence of Ct infection and Ct/HPV co-infection in young HPV-unvaccinated females with normal cytology, and placed particular attention on the possible association between Ct-DNA positivity and different HPV infecting genotypes. Five hundred 66 healthy females aged 16-26 years without cervical lesions, previously assessed for HPV infection (HPV-DNA prevalence: 18.2%), were tested for Ct-DNA. The overall prevalence of Ct was 5.8% (95% CI: 4.2-8.1), while Ct/HPV co-infection was recorded in 2.7% (95% CI: 1.6-4.3) of subjects. Compared with HPV-DNA-negative females, HPV-DNA positive subjects had significantly (P < 0.001) higher odds of being infected with Ct (odds ratio of 4.20, 95% CI: 2.01-8.71). Both Ct and Ct/HPV infections were much more prevalent in under 18-year-olds than in older women. Subjects positive for single high-risk HPV genotypes and various multiple HPV infections had higher odds of being Ct-DNA positive. Our findings confirm that HPV and Ct infections are very common among asymptomatic young Italian females. This underlines the urgent need for nationwide Ct screening programs and reinforcement of sexual health education, which would be the most important public health strategies, since no Ct vaccines are currently available.

Phylogeny and population dynamics of respiratory syncytial virus (Rsv) A and B.

Respiratory syncytial virus (RSV) is a major cause of lower respiratory tract infections in infants and young children. RSV is characterised by high variability, especially in the G glycoprotein, which may play a significant role in RSV pathogenicity by allowing immune evasion. To reconstruct the origin and phylodynamic history of RSV, we evaluated the genetic diversity and evolutionary dynamics of RSV A and RSV B isolated from children under 3 years old infected in Italy from 2006 to 2012. Phylogenetic analysis revealed that most of the RSV A sequences clustered with the NA1 genotype, and RSV B sequences were included in the Buenos Aires genotype. The mean evolutionary rates for RSV A and RSV B were estimated to be 2.1 × 10(-3) substitutions (subs)/site/year and 3.03 × 10(-3) subs/site/year, respectively. The time of most recent common ancestor for the tree root went back to the 1940s (95% highest posterior density-HPD: 1927-1951) for RSV A and the 1950s (95%HPD: 1951-1960) for RSV B. The RSV A Bayesian skyline plot (BSP) showed a decrease in transmission events ending in about 2005, when a sharp growth restored the original viral population size. RSV B BSP showed a similar trend. Site-specific selection analysis identified 10 codons under positive selection in RSV A sequences and only one site in RSV B sequences. Although RSV remains difficult to control due to its antigenic diversity, it is important to monitor changes in its coding sequences, to permit the identification of future epidemic strains and to implement vaccine and therapy strategies.

Detection and genotyping of human papillomavirus in urine samples from unvaccinated male and female adolescents in Italy.

The introduction of vaccination against Human Papillomavirus (HPV) in adolescent girls in 2006 has focused virological surveillance on this age group. As few studies have evaluated HPV infections in young populations, further data are needed in order to improve and extend prophylactic policy and to monitor epidemiological changes. The present study aimed at evaluating overall and type-specific HPV prevalence in both female and male adolescents in Italy. HPV DNA detection and genotyping was performed on urine samples collected from 870 unvaccinated adolescents (369 females, 501 males, 11-18 years of age) in five cities in Italy. Following DNA extraction by means of a commercial kit (NucliSENS(®)-miniMAG(®), bioMérieux), the L1 gene fragment was PCR amplified and genotyped by restriction fragment length polymorphism analysis. HPV DNA was detected in 1.5% of all samples, and in 3% and 0.4% of samples from females and males, respectively. In approximately 70% of HPV DNA positive adolescents, the infection was due to a single genotype, with 88.9% of genotypes belonging to the HR-clade. The only two HPV-positive boys (14 and 18 years old) had HPV-70 genotype. Only one of the 11 HPV-infected girls was in the 11-14 age-group. HPV prevalence was 4.2% in girls aged 15-18 years and 60% of infections were due to vaccine types HPV-16 or HPV-6/-11. This is one of the few studies, the first conducted in Italy, on HPV infection in adolescents. Urine testing is the easier way of detecting HPV infection in younger populations. Our data revealed a very low HPV prevalence, and no infections were observed in the 12-year-old vaccine target population. The majority of infections were seen in females aged 15-18 years. Overall, more than 50% and 30% of the potentially persistent HPV infections detected in this group could have been prevented by the quadrivalent and the bivalent vaccines, respectively.