Fast surveillance response reveals the introduction of a new yellow fever virus sub-lineage in 2021, in Minas Gerais, Brazil

Abstract

BACKGROUND In Brazil, the yellow fever virus (YFV) is maintained in a sylvatic cycle involving wild mosquitoes and non-human primates (NHPs). The virus is endemic to the Amazon region; however, waves of epidemic expansion reaching other Brazilian states sporadically occur, eventually causing spillovers to humans. OBJECTIVES To report a surveillance effort that led to the first confirmation of YFV in NHPs in the state of Minas Gerais (MG), Southeast region, in 2021. METHODS A surveillance network was created, encompassing the technology of smartphone applications and coordinated actions of several research institutions and health services to monitor and investigate NHP epizootics. FINDINGS When alerts were spread through the network, samples from NHPs were collected and YFV infection confirmed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and genome sequencing at an interval of only 10 days. Near-complete genomes were generated using the Nanopore MinION sequencer. Phylogenetic analysis indicated that viral genomes were related to the South American genotype I, clustering with a genome detected in the Amazon region (state of Pará) in 2017, named YFV PA/MG sub-lineage. Fast YFV confirmation potentialised vaccination campaigns. MAIN CONCLUSIONS A new YFV introduction was detected in MG 6 years after the beginning of the major outbreak reported in the state (2015-2018). The YFV strain was not related to the sub-lineages previously reported in MG. No human cases have been reported, suggesting the importance of coordinated surveillance of NHPs using available technologies and supporting laboratories to ensure a quick response and implementation of contingency measures to avoid YFV spillover to humans.

Yellow Fever Virus Maintained by Sabethes Mosquitoes during the Dry Season in Cerrado, a Semiarid Region of Brazil, in 2021

“…The phylogenetic analysis of the generated YFV genomes reinforces the hypothesis that the investigated epizootic is due to a new wave of viral expansion from the Amazon region [ 27 ], i.e., different from the one that caused the 2014–2021 outbreak, named YFV PA/MG [ 15 ] (A bayesian phylogenetic tree is presented in Supplementary Material S3 [ 73 , 74 , 75 , 76 , 77 ]). Opportunities for sequencing near-complete YFV genomes detected in mosquitoes, especially Sa.…”

“…Phylogenetic analysis revealed that the viral genome could be assigned to the South American 1 genotype, sub-clade 1E, which has been circulating in Brazil in recent years. Furthermore, they clustered along a viral sub-lineage that circulated during 2017 in Pará state, Amazon region, and which was previously named YFV PA/MG [ 27 ] ( Figure 3 ; Supplementary Materials S2 and S3 ). Due to the high Ct value found in the only infected Sa.…”

“…This study encompassed five mosquito sampling sites in riparian forest fragments of “Riacho Grande”, a small river of the São Francisco river watershed located in the rural zone that divides the two municipalities of Ubaí and Icaraí de Minas in northern MG, Brazil ( Figure 1 ), where several YFV epizootics were reported between August and September 2021 [ 27 ]. The study area was inserted in an anthropized matrix, surrounded by pastures, with low tree coverage, and was essentially restricted to a narrow corridor of riparian forest.…”

“…Other signs of viral activity were recorded in the Amazon between 2017 and 2020. A new wave of viral expansion was detected in the Cerrado during the rainy season of 2020 in the state of GO [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. The virus was confirmed in the Cerrado, northern MG, in August 2021.…”

Arbovirus surveillance in mosquitoes: Historical methods, emerging technologies, and challenges ahead

“…Their findings indicated that the geographic range of Aedes mosquitoes is expanding in Brazil and that climate change is likely to increase the risk of dengue transmission in many regions of the country. 31 Increases in temperature at equatorial latitudes have been associated with increased 53 Romano et al, 54 Andrade et al 55 and Artika et al 56 a Shows vector competence for MAYV under laboratory conditions.…”