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

In recent decades, waves of yellow fever virus (YFV) from the Amazon Rainforest have spread and caused outbreaks in other regions of Brazil, including the Cerrado, a savannah-like biome through which YFV usually moves before arriving at the Atlantic Forest. To identify the vectors involved in the maintenance of the virus in semiarid environments, an entomological survey was conducted after confirmation of yellow fever (YF) epizootics at the peak of the dry season in the Cerrado areas of the state of Minas Gerais. In total, 917 mosquitoes from 13 taxa were collected and tested for the presence of YFV. Interestingly, mosquitoes of the Sabethes genus represented 95% of the diurnal captured specimens, displaying a peak of biting activity never previously recorded, between 4:30 and 5:30 p.m. Molecular analysis identified three YFV-positive pools, two from Sabethes chloropterus-from which near-complete genomes were generated-and one from Sa. albiprivus, whose low viral load prevented sequencing. Sa. chloropterus was considered the primary vector due to the high number of copies of YFV RNA and the high relative abundance detected. Its bionomic characteristics allow its survival in dry places and dry time periods. For the first time in Brazil, Sa. albiprivus was found to be naturally infected with YFV and may have played a role as a secondary vector. Despite its high relative abundance, fewer copies of viral RNA were found, as well as a lower Minimum Infection Rate (MIR). Genomic and phylogeographic analysis showed that the virus clustered in the sub-lineage YFVPA-MG, which circulated in Pará in 2017 and then spread into other regions of the country. The results reported here contribute to the understanding of the epidemiology and mechanisms of YFV dispersion and maintenance, especially in adverse weather conditions. The intense viral circulation, even outside the seasonal period, increases the importance of surveillance and YFV vaccination to protect human populations in affected areas.

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

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 YFVPA/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.

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

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 YFVPA/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.

[American tegumentary leishmaniasis: a multivariate analysis of the spatial circuits for production of cases in Minas Gerais State, Brazil, 2007 to 2011]. / Ocorrência de casos de leishmaniose tegumentar americana: uma análise multivariada dos circuitos espaciais de produção, Minas Gerais, Brasil, 2007 a 2011.

The aim of this study was to explain the association between social-environmental factors and major land uses and the occurrence of cases of American tegumentary leishmaniasis (ATL) in the spatial circuits of production in Minas Gerais State, Brazil. This was an analytical-type ecological study based on secondary data on ATL divided by three-year period from 2007 to 2011, in which the analytical units were municipalities belonging to the spatial circuits. Two distinct stages were performed. The first was the elaboration of thematic maps with identification of the circuits. In the second, a new indicator, ATL cases by population density, was associated with social-environmental indicators and major land uses, submitted to multivariate principal components analysis (PCA). During the periods studied, three circuits were identified, distributed in the major regions of Northern Minas Gerais, Rio Doce Valley, and Greater Metropolitan Belo Horizonte. There was a strong association between ATL by population density and temporary crops, natural pasture, natural forest, unusable lands, and rural population, and a weak association with planted pasture. The association of cases with the major land uses variable in different agricultural profiles shows the occupational nature of ATL, associated mainly with rural workers. The association of the disease with environmental variables and deficient basic sanitation also proved relevant in the transmission profile in spatial circuits of production in Minas Gerais.

O objetivo deste estudo foi explicar a associação dos fatores socioambientais e dos grandes usos da terra com a ocorrência de casos de leishmaniose tegumentar americana (LTA) nos circuitos espaciais de produção, no Estado de Minas Gerais, Brasil. Trata-se de um estudo ecológico do tipo analítico, baseado em dados secundários de casos de LTA dividido por triênio, no período entre 2007 a 2011, cujas unidades de análise foram os municípios pertencentes aos circuitos espaciais. Duas etapas distintas foram realizadas, sendo a elaboração de mapas temáticos com a identificação dos circuitos a primeira, e na segunda etapa um novo indicador casos de LTA por densidade demográfica foi associado com indicadores socioambientais e dos grandes usos da terra submetidos à análise multivariada de componentes principais (ACP). Para o período avaliado, identificou-se três circuitos distribuídos nas mesorregiões Norte de Minas Gerais, Vale do Rio Doce e Região Metropolitana de Belo Horizonte. Houve forte associação dos casos de LTA por densidade demográfica com lavoura temporária, pastagem natural, floresta natural, terras inaproveitáveis e população rural, e uma fraca associação com pastagem plantada. A associação de casos com variáveis dos grandes usos da terra em diferentes perfis agropecuários demonstra o caráter ocupacional da LTA, associado principalmente com trabalhadores da zona rural. A associação da doença com as variáveis ambientais e deficiência das condições de saneamento básico também demonstram relevância no perfil de transmissão nos circuitos espaciais de produção em Minas Gerais.

El objetivo de este estudio fue explicar la asociación de los factores socioambientales y explotación a gran escala de la tierra, con la ocurrencia de casos de leishmaniasis tegumentaria americana (LTA) en los circuitos espaciales de producción, en el Estado de Minas Gerais, Brasil. Se trata de un estudio ecológico de tipo analítico, basado en datos secundarios de casos de LTA, dividido por trienios, en el período entre 2007 a 2011, cuyas unidades de análisis fueron los municipios pertenecientes a los circuitos espaciales. Se realizaron dos etapas distintas, consistiendo la primera en la elaboración de mapas temáticos con la identificación de los circuitos, y la segunda etapa en un nuevo indicador de casos de LTA por densidad demográfica, que se asoció con indicadores socioambientales y a dos explotaciones a gran escala de la tierra, sometidos a un análisis multivariado de componentes principales (ACP). Para el período evaluado, se identificaron tres circuitos distribuidos en las mesorregiones del norte de Minas Gerais, Vale do Rio Doce y región metropolitana de Belo Horizonte. Hubo una fuerte asociación de los casos de LTA por densidad demográfica con el trabajo temporal, pasto natural, bosque natural, tierras inaprovechables y población rural, y una escasa asociación con pasto plantado. La asociación de casos con variables de las explotaciones a gran escala de la tierra, con diferentes perfiles agropecuarios, demuestra el carácter ocupacional de la LTA, asociado principalmente a trabajadores de la zona rural. La asociación de la enfermedad con variables ambientales y deficiencia en las condiciones de saneamiento básico, también demuestran relevancia en el perfil de transmisión en los circuitos espaciales de producción en Minas Gerais.

Ocorrência de casos de leishmaniose tegumentar americana: uma análise multivariada dos circuitos espaciais de produção, Minas Gerais, Brasil, 2007 a 2011 / American tegumentary leishmaniasis: a multivariate analysis of the spatial circuits for production of cases in Minas Gerais State, Brazil, 2007 to 2011 / Ocurrencia de casos de leishmaniasis tegumentaria americana: un análisis multivariado de los circuitos espaciales de producción, Minas Gerais, Brasil, 2007 a 2011

O objetivo deste estudo foi explicar a associação dos fatores socioambientais e dos grandes usos da terra com a ocorrência de casos de leishmaniose tegumentar americana (LTA) nos circuitos espaciais de produção, no Estado de Minas Gerais, Brasil. Trata-se de um estudo ecológico do tipo analítico, baseado em dados secundários de casos de LTA dividido por triênio, no período entre 2007 a 2011, cujas unidades de análise foram os municípios pertencentes aos circuitos espaciais. Duas etapas distintas foram realizadas, sendo a elaboração de mapas temáticos com a identificação dos circuitos a primeira, e na segunda etapa um novo indicador casos de LTA por densidade demográfica foi associado com indicadores socioambientais e dos grandes usos da terra submetidos à análise multivariada de componentes principais (ACP). Para o período avaliado, identificou-se três circuitos distribuídos nas mesorregiões Norte de Minas Gerais, Vale do Rio Doce e Região Metropolitana de Belo Horizonte. Houve forte associação dos casos de LTA por densidade demográfica com lavoura temporária, pastagem natural, floresta natural, terras inaproveitáveis e população rural, e uma fraca associação com pastagem plantada. A associação de casos com variáveis dos grandes usos da terra em diferentes perfis agropecuários demonstra o caráter ocupacional da LTA, associado principalmente com trabalhadores da zona rural. A associação da doença com as variáveis ambientais e deficiência das condições de saneamento básico também demonstram relevância no perfil de transmissão nos circuitos espaciais de produção em Minas Gerais.

The aim of this study was to explain the association between social-environmental factors and major land uses and the occurrence of cases of American tegumentary leishmaniasis (ATL) in the spatial circuits of production in Minas Gerais State, Brazil. This was an analytical-type ecological study based on secondary data on ATL divided by three-year period from 2007 to 2011, in which the analytical units were municipalities belonging to the spatial circuits. Two distinct stages were performed. The first was the elaboration of thematic maps with identification of the circuits. In the second, a new indicator, ATL cases by population density, was associated with social-environmental indicators and major land uses, submitted to multivariate principal components analysis (PCA). During the periods studied, three circuits were identified, distributed in the major regions of Northern Minas Gerais, Rio Doce Valley, and Greater Metropolitan Belo Horizonte. There was a strong association between ATL by population density and temporary crops, natural pasture, natural forest, unusable lands, and rural population, and a weak association with planted pasture. The association of cases with the major land uses variable in different agricultural profiles shows the occupational nature of ATL, associated mainly with rural workers. The association of the disease with environmental variables and deficient basic sanitation also proved relevant in the transmission profile in spatial circuits of production in Minas Gerais.

El objetivo de este estudio fue explicar la asociación de los factores socioambientales y explotación a gran escala de la tierra, con la ocurrencia de casos de leishmaniasis tegumentaria americana (LTA) en los circuitos espaciales de producción, en el Estado de Minas Gerais, Brasil. Se trata de un estudio ecológico de tipo analítico, basado en datos secundarios de casos de LTA, dividido por trienios, en el período entre 2007 a 2011, cuyas unidades de análisis fueron los municipios pertenecientes a los circuitos espaciales. Se realizaron dos etapas distintas, consistiendo la primera en la elaboración de mapas temáticos con la identificación de los circuitos, y la segunda etapa en un nuevo indicador de casos de LTA por densidad demográfica, que se asoció con indicadores socioambientales y a dos explotaciones a gran escala de la tierra, sometidos a un análisis multivariado de componentes principales (ACP). Para el período evaluado, se identificaron tres circuitos distribuidos en las mesorregiones del norte de Minas Gerais, Vale do Rio Doce y región metropolitana de Belo Horizonte. Hubo una fuerte asociación de los casos de LTA por densidad demográfica con el trabajo temporal, pasto natural, bosque natural, tierras inaprovechables y población rural, y una escasa asociación con pasto plantado. La asociación de casos con variables de las explotaciones a gran escala de la tierra, con diferentes perfiles agropecuarios, demuestra el carácter ocupacional de la LTA, asociado principalmente a trabajadores de la zona rural. La asociación de la enfermedad con variables ambientales y deficiencia en las condiciones de saneamiento básico, también demuestran relevancia en el perfil de transmisión en los circuitos espaciales de producción en Minas Gerais.