TY - JOUR
T1 - Active West Nile virus transmission in Brazil
T2 - an epidemiological study
AU - de Lima, Shirlene T.S.
AU - Claro, Ingra M.
AU - Hua, Xinyi
AU - de Jesus, Ronaldo
AU - Serres, Kyla
AU - Simões Mello, Leda M.
AU - Forato, Julia
AU - Moreira, Filipe R.R.
AU - Kato, Rodrigo B.
AU - Guimarães, Gustavo N.
AU - Scachetti, Gabriel C.
AU - Andrade, Pamela dos Santos
AU - Duarte, Larissa M.F.
AU - de Lima, Maria Eduarda T.
AU - Ferraz, Clarissa P.M.
AU - Vianna, Marisa P.N.
AU - Santiago, Rodrigo M.
AU - Braga, Enock L.R.
AU - Carneiro, Igor S.
AU - Carlos L Firmino, Antonio
AU - Cabral, Milena G.
AU - Souza, Caio
AU - Mello, Liana Perdigão
AU - Li, Sabrina
AU - Sabino, Ester C.
AU - Sallum, Maria Anice M.
AU - Weaver, Scott C.
AU - Faria, Nuno R.
AU - Romano, Camila M.
AU - Dellicour, Simon
AU - Proenca-Modena, José Luiz
AU - de Souza, William M.
N1 - Publisher Copyright:
© 2025 The Author(s)
PY - 2025/11
Y1 - 2025/11
N2 - Background: West Nile virus (WNV) is a mosquito-borne flavivirus that can cause neurological and fatal disease in animals and humans. Since its introduction into the USA in 1999, WNV has become the leading arbovirus in North America. In contrast, no major WNV outbreak has been reported in South America. Our study investigated active WNV circulation in Brazil. Methods: We examined WNV epidemiological, molecular, genomic, and serological data from Brazil from January 2014 to December 2024. We also conducted WNV testing in 561 patients with febrile illness, neuroinvasive disease, or death between January 2019 and January 2024 in Ceará State, Brazil. Next, we conducted time series, mapping, ecological niche modeling, age-sex distribution, phylogenetic analyses, and statistical hypothesis tests. Findings: Between January 2014 and December 2024, 110 West Nile cases were reported from 13 of 27 Brazilian states. In addition, our retrospective study in Ceará State revealed 12.1% (68 of 561 patients) were WNV cases, peaking in 2023, when 42.6% (29 of 68) of cases occurred. Among WNV cases, 7 (10.3%) had detected WNV RNA in serum, cerebrospinal fluid, or both, whereas 62 (89.7%) were IgM-positive, with 29 presenting with neurological complications, 35 with febrile illness, and four fatalities. WNV cases were reported in all months, with the highest numbers between May and August. Most cases were female (female-to-male ratio, 1.1:1), and the median age of patients was 40 years (interquartile range, 20–57). Our phylogenetic analysis showed that WNV lineage 1a circulated in Ceará State and caused a fatal horse case. Our ecological niche models identified several areas, mainly situated in the Northeast region, linked to a potentially higher risk of human exposure to local WNV circulation. Interpretation: These findings comprehensively described consistent WNV circulation in Brazil and may contribute to informing public health policy, focusing on the strategies to determine the WNV burden in South America. Funding: Burroughs Wellcome Fund, Wellcome Trust, National Institutes of Health, São Paulo Research Foundation, Brazilian Ministry of Science, and Brazilian National Council for Scientific and Technological Development.
AB - Background: West Nile virus (WNV) is a mosquito-borne flavivirus that can cause neurological and fatal disease in animals and humans. Since its introduction into the USA in 1999, WNV has become the leading arbovirus in North America. In contrast, no major WNV outbreak has been reported in South America. Our study investigated active WNV circulation in Brazil. Methods: We examined WNV epidemiological, molecular, genomic, and serological data from Brazil from January 2014 to December 2024. We also conducted WNV testing in 561 patients with febrile illness, neuroinvasive disease, or death between January 2019 and January 2024 in Ceará State, Brazil. Next, we conducted time series, mapping, ecological niche modeling, age-sex distribution, phylogenetic analyses, and statistical hypothesis tests. Findings: Between January 2014 and December 2024, 110 West Nile cases were reported from 13 of 27 Brazilian states. In addition, our retrospective study in Ceará State revealed 12.1% (68 of 561 patients) were WNV cases, peaking in 2023, when 42.6% (29 of 68) of cases occurred. Among WNV cases, 7 (10.3%) had detected WNV RNA in serum, cerebrospinal fluid, or both, whereas 62 (89.7%) were IgM-positive, with 29 presenting with neurological complications, 35 with febrile illness, and four fatalities. WNV cases were reported in all months, with the highest numbers between May and August. Most cases were female (female-to-male ratio, 1.1:1), and the median age of patients was 40 years (interquartile range, 20–57). Our phylogenetic analysis showed that WNV lineage 1a circulated in Ceará State and caused a fatal horse case. Our ecological niche models identified several areas, mainly situated in the Northeast region, linked to a potentially higher risk of human exposure to local WNV circulation. Interpretation: These findings comprehensively described consistent WNV circulation in Brazil and may contribute to informing public health policy, focusing on the strategies to determine the WNV burden in South America. Funding: Burroughs Wellcome Fund, Wellcome Trust, National Institutes of Health, São Paulo Research Foundation, Brazilian Ministry of Science, and Brazilian National Council for Scientific and Technological Development.
KW - Arbovirus
KW - Emerging viral diseases
KW - Flavivirus
KW - Mosquito-borne flavivirus
KW - Vector-borne viruses
KW - West Nile virus
UR - https://www.scopus.com/pages/publications/105015077689
UR - https://www.scopus.com/pages/publications/105015077689#tab=citedBy
U2 - 10.1016/j.lana.2025.101229
DO - 10.1016/j.lana.2025.101229
M3 - Article
AN - SCOPUS:105015077689
SN - 2667-193X
VL - 51
JO - The Lancet Regional Health - Americas
JF - The Lancet Regional Health - Americas
M1 - 101229
ER -