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Volume 32, Number 4—April 2026

Dispatch

Guillain-Barré Syndrome and Visual Impairment Associated with Emerging Oropouche Virus Lineage, Brazil, 2024

Carlos Garcia FilhoComments to Author , Fernanda Martins Maia Carvalho, Antonio Silva Lima Neto, Ana Maria Cabral Maia, Matheus Andrighetti Rossi, Milena Sales Pitombeira, Paula Camila Alves de Assis Pereira Matos, Tania Mara Silva Coelho, Lauro Vieira Perdigão Neto, Lívia Mendes de Almeida, Felipe Gomes Naveca, Carla Santos de Oliveira, Fernanda de Bruycker-Nogueira, Ana Maria Bispo de Filippis, Kleber Giovanni Luz, André Ricardo Ribas Freitas, and Luciano Pamplona de Góes Cavalcanti
Author affiliation: Secretaria da Saúde do Estado do Ceará, Fortaleza, Brazil (C. Garcia Filho, A.S. Lima Neto, A.M.C. Maia, T.M.S. Coelho, L.V.P. Neto); Universidade de Fortaleza, Fortaleza (C. Garcia Filho, F.M.M. Carvalho, A.S. Lima Neto); Hospital Geral de Fortaleza, Fortaleza (F.M.M. Carvalho, M.A. Rossi, M.S. Pitombeira, P.C.A. de Assis Pereira Matos); Programa de Pós-graduação em Saúde Pública da Universidade Federal do Ceará, Fortaleza (A.M.C. Maia); Universidade Federal do Ceará, Fortaleza (L.V.P. Neto); Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil (L.V.P. Neto); Centro Universitário Christus, Fortaleza (L.M. de Almeida, L.P. de Góes Cavalcanti); Programa de Pós-graduação em Patologia da Universidade Federal do Ceará, Fortaleza (L.M. de Almeida, L.P. de Góes Cavalcanti); Instituto Oswaldo Cruz, Rio de Janeiro, Brazil (F.G. Naveca, C.S. de Oliveira, F. de Bruycker-Nogueira, A.M.B. de Filippis); Universidade Federal do Rio Grande do Norte, Natal, Brazil (K.G. Luz); São Leopoldo Mandic, Campinas, Brazil (A.R.R. Freitas); Escola de Saúde Pública do Ceará, Fortaleza (L.P. de Góes Cavalcanti)

Main Article

Figure 2

Maximum-likelihood tree of Oropouche virus concatenated segments from study of Guillain-Barré syndrome and visual impairment associated with emerging Oropouche virus lineage, Brazil, 2024. Black arrow indicates sequence from study patient. A reference dataset containing concatenated segments (large, medium, and small) of the recent Oropouche virus outbreak (2022–2024) representing different regions in Brazil and sequences obtained from Peru and Colombia were aligned using MAFFT version 7.490 (https://mafft.cbrc.jp/alignment/software/source.html) embedded in Geneious Prime 2025.0.3 (https://www.geneious.com). Subsequently, we used that alignment for phylogenomic reconstruction by maximum-likelihood using IQ-TREE multicore version 2.1.1 COVIDedition for Mac OS X 64-bit (http://www.iqtree.org). MODEL-FINDER (https://iqtree.github.io/ModelFinder) was used for evolutionary model choice, and 2,000 ultra-fast bootstraps and 2,000 SH-aLRT replicates were run to access the branches’ support (support for the CE clade is shown). The maximum-likelihood tree was edited with FigTree version 1.4.4 (https://tree.bio.ed.ac.uk/software/figtree). Scale bar indicates nucleotide substitutions per site. CE, Ceará state; CE-GBS, Ceará–Guillain-Barré syndrome.

Figure 2. Maximum-likelihood tree of Oropouche virus concatenated segments from study of Guillain-Barré syndrome and visual impairment associated with emerging Oropouche virus lineage, Brazil, 2024. Black arrow indicates sequence from study patient. A reference dataset containing concatenated segments (large, medium, and small) of the recent Oropouche virus outbreak (2022–2024) representing different regions in Brazil and sequences obtained from Peru and Colombia were aligned using MAFFT version 7.490 (https://mafft.cbrc.jp/alignment/software/source.html) embedded in Geneious Prime 2025.0.3 (https://www.geneious.com). Subsequently, we used that alignment for phylogenomic reconstruction by maximum-likelihood using IQ-TREE multicore version 2.1.1 COVIDedition for Mac OS X 64-bit (http://www.iqtree.org). MODEL-FINDER (https://iqtree.github.io/ModelFinder) was used for evolutionary model choice, and 2,000 ultra-fast bootstraps and 2,000 SH-aLRT replicates were run to access the branches’ support (support for the CE clade is shown). The maximum-likelihood tree was edited with FigTree version 1.4.4 (https://tree.bio.ed.ac.uk/software/figtree). Scale bar indicates nucleotide substitutions per site. CE, Ceará state; CE-GBS, Ceará–Guillain-Barré syndrome.

Main Article

Page created: March 12, 2026
Page updated: April 10, 2026
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