Genetic variability of the measles virus hemagglutinin gene in B3 genotype strains circulating in Northern Italy.

Sequencing the whole measles virus hemagglutinin (H) gene, in conjunction with a 450-nucleotide region of the nucleoprotein gene (N-450), is helpful for the identification of new genotypes and as an auxiliary in outbreak characterization. In addition, it is essential to be able to predict the antigenic changes of the H protein to gain a better monitoring of the response to the vaccine. In this study, we obtained the full-length H gene sequences from 19 measles virus (MV) strains belonging to two B3 genotype variants circulating in Lombardy (Northern Italy) between July 2015 and February 2016 and evaluated the variability of the whole MV-H gene. Furthermore, we compared the obtained H amino acid sequences to all MV sequences available in the GenBank database (n = 1152 in total) and analyzed the amino acid substitutions in the H protein within clades where the Italian strains were included. We identified a higher variability in the H gene compared to the N-450 region and our results support previous studies, highlighting that the H gene is more informative for characterizing the MV B3 genotype than the N-450 sequence. Some of the amino acid substitutions were fixed in the viral population and, remarkably, some of the amino acid substitutions were typically present only in the Italian sequences. Accumulating further molecular information about MV-H gene will be necessary to enable in-depth analyses of the variability of this gene in the vaccinated population.

Genetic characterisation of Measles virus variants identified during a large epidemic in Milan, Italy, March-December 2017.

In 2017, Italy experienced a large measles epidemic with 5408 cases and four deaths. As Subnational Reference Laboratory of the Measles and Rubella surveillance NETwork (MoRoNET), the EpiSoMI (Epidemiology and Molecular Surveillance of Infections) Laboratory (University of Milan) set up rapid and active surveillance for the complete characterisation of the Measles virus (Mv) responsible for the large measles outbreak in Milan and surrounding areas (Lombardy, Northern Italy). The aims of this study were to describe the genetic profile of circulating viruses and to track the pathway of measles transmission. Molecular analysis was performed by sequencing the highly variable 450 nucleotides region of the N gene (N-450) of Mv genome. Two-hundred and ninety-nine strains of Mv were analysed. The phylogenetic analysis showed five different variants, two not previously described in the studied area, belonging to D8 and B3 genotypes. Three events of continuous transmission of autochthonous variants (D8-Osaka, D8-London and B3-Milan variants) and two events of continuous transmission of imported variants (B3-Dublin and D8-Hulu Langat) tracked five different transmission pathways. These pathways outlined two epidemic peaks: the first in April and the second in July 2017. The correlation between Mv variant and the epidemiological data may enable us to identify the sources of virus importation and recognise long-lasting virus transmission pathways.

Measles surveillance activities in the Metropolitan Area of Milan during 2017-2018.

INTRODUCTION: In Italy, the transmission of measles is still endemic, and 7,919 cases were reported to the National Surveillance System between January 2017 and December 2018. Aim of this study is to report the results of the measles surveillance activities in the Metropolitan City of Milan from March 2017 to December 2018, and to evaluate the surveillance performance WHO indicators. METHODS: The Local Health Units (LHUs) carried out case investigations and collected specimens to send to the EpiSoMI Lab (Subnational Reference Laboratory, SRL) of the University of Milan for cases/outbreaks confirmation and genotyping performed according to the WHO Guidelines. RESULTS: Overall, 610 suspected measles cases were reported by the surveillance system of the Metropolitan City of Milan. A total of 439 out of 540 cases with adequate specimens were laboratory-confirmed by molecular and/or serological assays. Two-hundred and thirty-six cases were notified as sporadic and 203 as related to 94 outbreaks. The most confirmed cases were aged 15-39 years, almost all not vaccinated. Overall, 282 cases were genotype D8 and 118 genotype B3.The evaluation of a set of indicators to monitor the quality of surveillance activities demonstrated the proficiency of the EpiSoMI Lab. CONCLUSIONS: A well-done investigation of cases and outbreaks by the surveillance local system, in a timely manner, in order to notify and investigate suspected cases and to laboratory confirm or discard cases is fundamental to reduce morbidity, to prevent further virus transmission and to achieve measles elimination.

Cervical Human Papillomavirus genotypes in HIV-infected women: a cross-sectional analysis of the VALHIDATE study.

INTRODUCTION: Primary-prevention by prophylactic vaccination against HPV-related cancers and HPV-based screening programs are based on HPV-type distribution in immunocompetent individuals. HIV-infected women are at high risk of invasive HPV-disease sustained by a broader range of HPV-types and have higher multi-type infection rates than immunocompetent hosts. METHODS: This is a cross-sectional analysis of High Risk HPV (HR HPV) type distribution in 805 HIV+ women (HIW) compared with a control group of 1402 immunocompetent HIV- women (SPW) enrolled in the VALHIDATE study in order to define HPV type-specific distribution according to cytology. RESULTS: HIW had a 3.8, 3.6, and 2.7 times higher risk of atypical squamous cells of undetermined significance (ASCUS), low-grade squamous intraepithelial lesion (LSIL) and high grade squamous intraepithelial lesion (HSIL) than SPW respectively. HPV-DNA prevalence was 28.4% in HIW and 11.81% in SPW (p<0.0001). The prevalence of infection increased from normal cytology to HSIL both in HIW (from 21.45% to 90.91%) and SPW (from 9.54% to 75%). The OR for women with normal cytology of having a positive HPV-DNA test result of was 2.6 times higher in HIW than in SPW. The cumulative prevalence of HPV-16/18 in HSIL is much lower in HIW (36.4±28.4) than SPW (62.5±33.5). CONCLUSIONS: A higher prevalence of infection and broader HPV type distribution were observed in HIV+ women compared to the general population. More than 60% of HSIL lesions of HIW patients are caused by single or multi-type infections from non-HPV16/18 HPVs. The potential 9v-HPV vaccine coverage could be even higher than that expected for the general population given the wide panel of HPV-types observed in the HSIL of HIV+ women.

Molecular epidemiology and genotyping of Chlamydia trachomatis infection in a cohort of young asymptomatic sexually active women (18-25 years) in Milan, Italy.

INTRODUCTION: Chlamydia trachomatis (Ct) is the most common bacterial cause of sexually transmitted infections (STI) and is associated with severe long-term sequelae in female populations. In Italy Ct infections are not submitted to a screening programme, and its epidemiological profile is understudied. Even scarcer information is available about the genetic diversity on ompA gene, whose sequence defines 18 different genovars. This study aims at evaluating the prevalence of Ct infection in young sexually active asymptomatic women aged 18-25, and characterizing the molecular epidemiology of the different circulating genovars in this population. METHODS: Cervical samples collected from 909 sexually-activeyoung women (mean age 21.5 years) were analyzed through molecular assay for the detection of Ct infection. Phylogenetic analysis on the ompA gene was performed on Ct positive samples to identify the circulating genovars. RESULTS: The overall prevalence of Ct-infection was 4.4% (95%CI: 3.2-5.9%): 5.3% among women aged 18-21 years and 3.5% among those aged 22-25 years. Phylogenetic analysis has identified 5 different genovars: D, E, F, G, and H. The most common genovar was the E (46%), followed by genovar F and G (18.9% each), D (13.5%), and H (2.7%). CONCLUSIONS: This study underlines the high prevalence of asymptomatic Ct-infections among young women. Overall, about half of the asymptomatic infections is sustained by genovar E. The introduction in Italy of a systematic screening program should be considered to allow a better understanding of Ct spreading and providing women with an opportunity for early treatment to protect their sexual and reproductive health.

HPV genotypes detected in the oropharyngeal mucosa of HIV-infected men who have sex with men in Northern Italy.

The aim of this study was to investigate the epidemiological profile of HPV oropharyngeal infections in HIV-infected men who have sex with men. A total of 135 subjects were enrolled at the L. Sacco University Hospital (Milan, Italy) to evaluate their HPV oropharyngeal infection status at baseline and at a follow-up visit at least 12 months later. HPV DNA was detected from oropharyngeal swabs using an in-house nested PCR that amplifies a segment of the L1 gene. The PCR products were then sequenced and genotyped. A greater percentage of high-risk genotypes was identified compared to low-risk genotypes (13·7% vs. 6·9%, P < 0·05), and two uncommon alpha-HPV genotypes were detected, i.e. HPV-102 and HPV-114. HPV infection prevalence was 24·4% and the cumulative incidence was 24·1%. During the follow-up period, one case of HPV infection (HPV-33) persisted, while the overall rate of infection clearance was 58·3%. HPV oropharyngeal infection was widespread in the cohort examined, and most of the infections were transient and cleared within 12 months. These results may help to clarify the role of HPV in the oropharynx and may also improve our understanding of the need to implement preventive strategies in at-risk populations.

Molecular characterization and phylogenetic analysis of human influenza A viruses in three consecutive seasons with different epidemiological profiles.

INTRODUCTION: Influenza activity and influenza virus circulation were observed in Lombardy (northern Italy) during three consecutive seasons and the molecular characteristics of circulating viruses analysed to control for introduction of new variants. METHODS: The molecular characterization of 38 isolates, namely 20 A/H3N2 and 18 A/H1N1 influenza strains from the 2005/06, 2006/07 and 2007/08 seasons, was performed by sequence analysis of the globular head region of the HA protein (HA1 subunit), specific for influenza virus A/H3 and A/H1. RESULTS AND DISCUSSION: The last three influenza seasons in the study region were characterized by medium-low activity. A typical co-circulation of several variants was shown for A/H3 viruses for approximately two years and were subsequently almost entirely substituted by new emerging variants. Vice versa, A/H1 viruses had a more homogeneous circulation with a single lineage clearly dominating each season. The HA sequences of the A/H3 and the A/H1 viruses isolated in the last three seasons fell into 4 and 3 principal phylogenetic groups, respectively. No evidence of positive or negative selection in the sequence alignments was observed. CONCLUSIONS: Molecular characterization of the influenza viruses in three consecutive seasons highlighted considerable heterogeneity in their HA sequences. A careful surveillance of genetic changes in the HA1 domain during seasonal influenza epidemics may reveal immune escape and provide early information on newly emerging strains with epidemiologic inference.