Browsing by Author "Thamm, Sven"
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- Antiretroviral Drug Resistance Surveillance among Treatment-Naive Human Immunodeficiency Virus Type 1-Infected Individuals in AngolaPublication . Bartolo, Ines; Rocha, Cheila; Bartolomeu, Jose; Gama, Antonio; Fonseca, Marlene; Mendes, Ana; Cristina, Filipa; Thamm, Sven; Epalanga, Marta; Silva, Patricia Cavaco; Taveira, NunoThe prevalence of transmitted human immunodeficiency virus type 1 drug resistance in Angola in 2001 in 196 untreated patients was investigated. All subtypes were detected, along with unclassifiable and complex recombinant strains. Numerous new polymorphis. - Fundacao GlaxoSmithKline das Ciencias da Saude and Fundacao para a Ciencia e Tecnologia, Portugal [PTDC/SAU-FCF/67673/2006]; Fundacao para a Ciencia e Tecnologia, Portugal. - This work was supported by grants from Fundacao GlaxoSmithKline das Ciencias da Saude and Fundacao para a Ciencia e Tecnologia, Portugal (PTDC/SAU-FCF/67673/2006). Ines Bartolo and Cheila Rocha are supported by Ph. D. grants from Fundacao para a Ciencia e
- Antiretroviral drug resistance surveillance among treatment-naive human immunodeficiency virus type 1-infected individuals in Angola: Evidence for low level of transmitted drug resistancePublication . Bártolo, Inês; Rocha, Cheila; Bartolomeu, José; Gama, António; Fonseca, Marlene; Mendes, Ana; Cristina, Filipa; Thamm, Sven; Epalanga, Marta; Silva, Patrícia Cavaco; Taveira, NunoThe prevalence of transmitted human immunodeficiency virus type 1 drug resistance in Angola in 2001 in 196 untreated patients was investigated. All subtypes were detected, along with unclassifiable and complex recombinant strains. Numerous new polymorphisms were identified in the reverse transcriptase and protease. Two (1.6%) unrelated patients harbored nucleoside reverse transcriptase inhibitor- and nonnucleoside reverse transcriptase inhibitor-resistant viruses (mutations: M41L, D67N, M184V, L210W, T215Y or T215F, and K103N). Continued surveillance of drug resistance is required for maximization of ART efficacy in Angola.
- HIV-1 diversity, transmission dynamics and primary drug resistance in AngolaPublication . Bártolo, Inês; Zakovic, Suzana; Martin, Francisco; Palladino, Claudia; Carvalho, Patrícia; Camacho, Ricardo; Thamm, Sven; Clemente, Sofia; Taveira, NunoObjectives To assess HIV-1 diversity, transmission dynamics and prevalence of transmitted drug resistance (TDR) in Angola, five years after ART scale-up. Methods Population sequencing of the pol gene was performed on 139 plasma samples collected in 2009 from drug-naive HIV-1 infected individuals living in Luanda. HIV-1 subtypes were determined using phylogenetic analysis. Drug resistance mutations were identified using the Calibrated Population Resistance Tool (CPR). Transmission networks were determined using phylogenetic analysis of all Angolan sequences present in the databases. Evolutionary trends were determined by comparison with a similar survey performed in 2001. Results 47.1% of the viruses were pure subtypes (all except B), 47.1% were recombinants and 5.8% were untypable. The prevalence of subtype A decreased significantly from 2001 to 2009 (40.0% to 10.8%, P = 0.0019) while the prevalence of unique recombinant forms (URFs) increased>2-fold (40.0% to 83.1%, P<0.0001). The most frequent URFs comprised untypable sequences with subtypes H (U/H, n = 7, 10.8%), A (U/A, n = 6, 9.2%) and G (G/U, n = 4, 6.2%). Newly identified U/H recombinants formed a highly supported monophyletic cluster suggesting a local and common origin. TDR mutation K103N was found in one (0.7%) patient (1.6% in 2001). Out of the 364 sequences sampled for transmission network analysis, 130 (35.7%) were part of a transmission network. Forty eight transmission clusters were identified; the majority (56.3%) comprised sequences sampled in 2008–2010 in Luanda which is consistent with a locally fuelled epidemic. Very low genetic distance was found in 27 transmission pairs sampled in the same year, suggesting recent transmission events. Conclusions Transmission of drug resistant strains was still negligible in Luanda in 2009, five years after the scale-up of ART. The dominance of small and recent transmission clusters and the emergence of new URFs are consistent with a rising HIV-1 epidemics mainly driven by heterosexual transmission.