Characterization of a large cluster of HIV-1 A1 infections detected in Portugal and connected to several Western European countries

Pedro M.M. Araújo, Alexandre Carvalho, Marta Pingarilho, Domitília Faria, Raquel Pinho, José Ferreira, Paula Proença, Sofia Nunes, Mouro, Margarida, Teófilo, Eugénio Jr, Sofia Pinheiro, Fernando Maltez, Maria José Manata, Isabel Germano, Joana Sobrinho-Simões, Olga Costa, Rita Côrte-Real, António Diniz, Margarida Serrado, Luís CaldeiraNuno Janeiro, Guilhermina Gaião, José Melo-Cristino, Kamal Mansinho, Teresa Baptista, Perpétua Gomes, Isabel Diogo, Serrão, Rosário, Carmela Pinheiro, Carmo Koch, Monteiro, Fátima, Maria J. Gonçalves, Castro, Rui Sarmento E., Helena M. Ramos, Joaquim F. Oliveira, José Saraiva da Cunha, Vanda Mota, Fernando Rodrigues, Raquel Tavares, Ana Rita Silva, Fausto Roxo, Maria Saudade Ivo, J. Poças, Bianca Ascenção, Patricia Pacheco, Micaela Caixeiro, Nuno Marques, Maria João Aleixo, Telo Faria, Elisabete Gomes da Silva, Ricardo Correia de Abreu, Isabel Neves, AB Abecasis, Nuno S. Osório

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HIV-1 subtypes associate with differences in transmission and disease progression. Thus, the existence of geographic hotspots of subtype diversity deepens the complexity of HIV-1/AIDS control. The already high subtype diversity in Portugal seems to be increasing due to infections with sub-subtype A1 virus. We performed phylogenetic analysis of 65 A1 sequences newly obtained from 14 Portuguese hospitals and 425 closely related database sequences. 80% of the A1 Portuguese isolates gathered in a main phylogenetic clade (MA1). Six transmission clusters were identified in MA1, encompassing isolates from Portugal, Spain, France, and United Kingdom. The most common transmission route identified was men who have sex with men. The origin of the MA1 was linked to Greece, with the first introduction to Portugal dating back to 1996 (95% HPD: 1993.6-1999.2). Individuals infected with MA1 virus revealed lower viral loads and higher CD4+ T-cell counts in comparison with those infected by subtype B. The expanding A1 clusters in Portugal are connected to other European countries and share a recent common ancestor with the Greek A1 outbreak. The recent expansion of this HIV-1 subtype might be related to a slower disease progression leading to a population level delay in its diagnostic.
Original languageEnglish
Article number7223
Number of pages10
JournalScientific Reports
Issue number1
Publication statusPublished - 1 Dec 2019


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