Elizabeth Pádua

The seroepidemiology of human T-lymphotropic viruses: Types I and II in Europe: A prospective study of pregnant women

Background: Up to 20 million persons are infected with the human retroviruses human T-lymphotropic virus (HTLV)-I and HTLV-II globally. Most data on the seroprevalence of HTLV-I and HTLV-II in Europe are from studies of low-risk blood donors or high-risk injection drug users (IDUs). Little is known about the general population. Methods: A prospective anonymous study of HTLV-I and HTLV-II seroprevalence among 234,078 pregnant women in Belgium, France, Germany, Italy, Portugal, Spain, and the United Kingdom was conducted. Maternal antibody status was determined by standard methods using sera obtained for routine antenatal infection screens or eluted from infant heel prick dried blood spots obtained for routine neonatal metabolic screens. Results: Anti-HTLV-I/II antibodies were detected and confirmed in 96 pregnant women (4.4 per 10,000, 95% confidence interval [CI]: 3.5-5.2). Of these, 73 were anti-HTLV-I, 17 were anti-HTLV-II, and 6 were specifically anti-HTLV but untyped. The seroprevalence ranged from 0.7 per 10,000 in Germany to 11.5 per 10,000 in France. Conclusions: Pregnant women better reflect the general population than blood donors or IDUs. The seroprevalence of HTLV-I and HTLV-II in Western Europe is 6-fold higher among pregnant women (4.4 per 10,000) than among blood donors (0.07 per 10,000). These data provide a robust baseline against which changes in HTLV-I and HTLV-II seroprevalence in Europe can be measured.

Hepatitis C virus subtyping based on sequencing of the C/E1 and NS5B genomic regions in comparison to a commercially available line probe assay

Hepatitis C virus (HCV) genotype determination is required in clinical practice to establish the dose and duration of antiviral treatment. Although subtype identification does not impact on current therapy this is changing with new specific inhibitors of HCV enzymes and functions which are becoming available worldwide. These new drugs may yield different antiviral responses and resistance profiles. Accurate classification of HCV genotype and subtype is therefore crucial. An “in‐house” method was developed for improving HCV subtyping and the results were compared with a second‐generation line probe assay (LiPA) used extensively in Portugal. Phylogenetic analysis was undertaken of the C/E1 and NS5B genomic regions of HCV isolated from 72 prisoners with chronic HCV infection and from reference samples. Although LiPA is considered to be a good method for genotyping, HCV was subtyped in only 47.2% of cases compared with 95.8% of cases by the “in‐house” method. Molecular data for both C/E1 and NS5B regions were obtained in 88.9% of the samples. Two out of 23 cases of subtype 1a were misclassified as subtype 1b by LiPA. A putative recombinant like RF1_2k/1b, two potential inter‐genotypic recombinants 1b/4a and 3a/4a, and also a potential intra‐genotypic recombinant 2q/2k in C/E1 and 2k/2a in NS5B were also identified. The “in‐house” method enabled HCV to be subtyped accurately with the detection, in some cases, of recombinant viruses or dual HCV infections. Near full‐length genomic analysis to characterize these potential recombinant viruses is planned. J. Med. Virol. 85:815–822, 2013.

Assessment of mother-to-child HIV-1 and HIV-2 transmission: an AIDS reference laboratory collaborative study

A prospective study was carried out to assess HIV‐1 and HIV‐2 mother‐to‐child transmission (MTCT) rates in Portugal between 1999 and 2005 by analysing the proportion of diagnosed infected children born to HIV‐positive mothers.

Molecular characterization of hepatitis C virus for determination of subtypes and detection of resistance mutations to protease inhibitors in a group of intravenous drug users co‐infected with HIV

Modifications in therapeutic regimens for the treatment of hepatitis C virus (HCV) have been observed since the approval of viral protease inhibitors (PI), and the selection of natural drug‐resistant variants has been also reported. Thus, it becomes crucial to be aware of consequences of new therapeutic approaches and make available tools for monitoring the infection. The study aimed to apply an “in‐house” method for amplification and sequencing of the NS3 region which is the target of PI, and allowing simultaneously the classification of viral subtypes and identification of resistance mutations. Forty‐seven samples collected from HIV injecting drug users and drug naive for HCV protease inhibitors were tested for anti‐HCV antibodies, 93.6% of them had a positive result and in 70.5% was determined HCV active infection. High frequency of subtype 1a (46.2%), followed by an equal proportion of subtypes 3a, 4a, and 4d (15.4%) was obtained. Two potential recombinants, RF1_2k/1b (3.8%) and 2q/2k (3.8%) were identified. Substitutions V36L/P, T54A, I72L/N/T/V, Q80K/G, S122R/T, D168Q, and I170L/V were observed in 65.4% of the samples. The T54A and Q80K mutations, and the combination V36L + T54A were also identified. Polymorphisms were observed exclusively associated with specific genotypes, particularly, I72L and D168Q with genotype 3, and S122T with genotype 4. The V36L substitution was identified in 92.8% of sequences of non‐genotype 1 denoting that this amino acid substitution is a natural polymorphism associated with non‐genotype 1 strains. Although no major PI resistance mutations were detected, a more extensive study is needed to evaluate the impact of mutations identified in efficacy of PI treatment. J. Med. Virol. 87:1549–1557, 2015.

Potential impact of viral load and genetic makeup of HIV type 1 on mother-to-child transmission: characterization of env-C2V3C3 and nef sequences.

HIV-1 mother-to-child transmission (MTCT) was evaluated in terms of the molecular characterization of the env and nef genomic regions and quantification of maternal RNA viral loads. Assignment of viral subtype was achieved by direct sequencing of PCR 1172 products amplified from proviral DNA in 45 HIV-1-nontransmitting mothers (NTM), along with 13 pairs of HIV-1-transmitting mothers (TM) and their infected children (C). Analysis of the env C2V3C3 and nef sequences revealed that subtypes G and B, and their genetic combinations (AG, BG), accounted for over 84.5% of all viruses identified. The genetic structure form envA-nefG was the most commonly observed, with a lower frequency in the NTM (13.3%) compared to the TM (23.1%) group. A greater number of genetic forms was observed among NTM, namely the presence of sequences assigned to subtypes D and F, as well as the intergenetic A/J, and C/U, recombinant forms, along with a mosaic provirus with a complex putative envA-nefEGE genetic structure. No significant differences were found when RNA viral loads were evaluated as a function of the viral subtypes. Nevertheless, a relatively high quantification of HIV-1 RNA was obtained in the NTM group, emphasizing the importance of the compliance and effectiveness of therapeutic schemes to control viral replication and reduce the risk of HIV vertical transmission. V3 sequences displaying features associated with the R5 phenotype dominated in both groups. Both C2V3C3 and Nefs functional domains were conserved during HIV-1 vertical transmission.

Hepatitis C in a Mobile Low-Threshold Methadone Program

Introduction Data on the epidemiology of hepatitis C among individuals who use drugs in low-threshold settings are lacking, although crucial to assess the burden of disease and aid in the design of treatment strategies. Objective The aim of this study was to characterize the epidemiology and disease related to hepatitis C in a population attending a low-threshold methadone program. Materials and methods A cross-sectional study in the population attending the Mobile Low-Threshold Methadone Program in Lisbon, Portugal, was carried out. The survey included assessment of risk factors for infection with hepatitis C virus (HCV) and liver disease, HCV serology and RNA detection, HCV genotyping, and liver disease staging. Results A total of 825 participants were enrolled, 81.3% men, mean age 44.5 years. Injecting drug use (IDU) was reported by 58.4% – among these, 28.2% were people who inject drugs. Excessive drinking and HIV coinfection were reported by 33.4 and 15.9%, respectively. Among participants with active infection, 16.9% were followed up in hospital consultation. The overall seroprevalence for HCV was 67.6% (94.2% in IDU, 30.0% in non-IDU, 97.1% in people who inject drugs, and 75.6% in excessive drinkers). Among seropositives for HCV, active infection was present in 68.4%. Among individuals with active infection, the most common genotypes were 1a (45.3%) and 3a (28.7%), whereas 30% had severe liver fibrosis or cirrhosis. Age 45 years or older, HCV genotype 3, and coinfection with HIV were significant predictors of cirrhosis. Conclusion This population has a high burden of hepatitis C and several characteristics that favor dissemination of infection. Healthcare strategies are urgently needed to address hepatitis C in this setting.