BACKGROUND In Brazil, the Yellow Fever virus (YFV) is endemic in the Amazon, from where it eventually expands into epidemic waves. Coastal south-eastern (SE) Brazil, which has been a YFV-free region for eight decades, has reported a severe sylvatic outbreak since 2016. The virus spread from the north toward the south of the Rio de Janeiro (RJ) state, causing 307 human cases with 105 deaths during the 2016-2017 and 2017-2018 transmission seasons. It is unclear, however, whether the YFV would persist in the coastal Atlantic Forest of RJ during subsequent transmission seasons. OBJECTIVES To conduct a real-time surveillance and assess the potential persistence of YFV in the coastal Atlantic Forest of RJ during the 2018-2019 transmission season. METHODS We combined epizootic surveillance with fast diagnostic and molecular, phylogenetic, and evolutionary analyses. FINDINGS Using this integrative strategy, we detected the first evidence of YFV re-emergence in the third transmission season (2018-2019) in a dying howler monkey from the central region of the RJ state. The YFV detected in 2019 has the molecular signature associated with the current SE YFV outbreak and exhibited a close phylogenetic relationship with the YFV lineage that circulated in the same Atlantic Forest fragment during the past seasons. This lineage circulated along the coastal side of the Serra do Mar mountain chain, and its evolution seems to be mainly driven by genetic drift. The potential bridge vector Aedes albopictus was found probing on the recently dead howler monkey in the forest edge, very close to urban areas. MAIN CONCLUSIONS Collectively, our data revealed that YFV transmission persisted at the same Atlantic Forest area for at least three consecutive transmission seasons without the need of new introductions. Our real-time surveillance strategy permitted health authorities to take preventive actions within 48 h after the detection of the sick non-human primate. The local virus persistence and the proximity of the epizootic forest to urban areas reinforces the concern with regards to the risk of re-urbanisation and seasonal re-emergence of YFV, stressing the need for continuous effective surveillance and high vaccination coverage in the SE region, particularly in RJ, an important tourist location.

The current yellow fever outbreak in Brazil is the most severe one in the country in recent times. It has rapidly spread to areas where YF virus (YFV) activity has not been observed for more than 70 years and vaccine coverage is almost null. Here, we sequenced the whole YFV genome of two naturally infected howler-monkeys (Alouatta clamitans) obtained from the Municipality of Domingos Martins, state of Espírito Santo, Brazil. These two ongoing-outbreak genome sequences are identical. They clustered in the 1E sub-clade (South America genotype I) along with the Brazilian and Venezuelan strains recently characterised from infections in humans and non-human primates that have been described in the last 20 years. However, we detected eight unique amino acid changes in the viral proteins, including the structural capsid protein (one change), and the components of the viral replicase complex, the NS3 (two changes) and NS5 (five changes) proteins, that could impact the capacity of viral infection in vertebrate and/or invertebrate hosts and spreading of the ongoing outbreak.

Zika virus (ZIKV) has caused a major epidemic in Brazil and several other American countries. ZIKV is an arbovirus whose natural vectors during epidemics have been poorly determined. In this study, 1,683 mosquitoes collected in the vicinity of ZIKV suspected cases in Rio de Janeiro, Brazil, from June 2015 to May 2016 were screened for natural infection by using molecular methods. Three pools of Aedes aegypti were found with the ZIKV genome, one of which had only one male. This finding supports the occurrence of vertical and/or venereal transmission of ZIKV in Ae. aegypti in nature. None of the examined Ae. albopictus and Culex quinquefasciatus was positive. This is the first report of natural infection by ZIKV in mosquitoes in Brazil and other South American countries. So far, Ae. aegypti is the only confirmed vector of ZIKV during the ongoing Pan-American epidemics.

O estudo objetivou avaliar a cobertura vacinal e os fatores associados ao esquema vacinal básico incompleto aos 12 meses de idade, em 427 crianças de 12 a 59 meses, em São Luís, Maranhão, Brasil, 2006. Trata-se de inquérito domiciliar transversal, de base populacional, com amostragem complexa por conglomerados. Empregou-se regressão de Poisson com ajuste robusto da variância. A cobertura para o esquema básico completo foi de 71,9% segundo doses aplicadas, 61,8% para doses válidas e 23,6% para doses corretas. As vacinas contra hepatite B e tetravalente apresentaram maiores percentuais de doses aplicadas em datas ou intervalos inferiores aos recomendados. Os percentuais de atraso vacinal foram elevados, exceto para a BCG. Percentuais mais elevados de esquema vacinal básico incompleto foram encontrados em crianças das classes econômicas D e E, do sexo feminino e de chefes de família de cor da pele preta. As desigualdades raciais, de gênero e socioeconômicas representaram barreiras à vacinação completa, indicando necessidade de reforçar as políticas equitativas que eliminem essas desigualdades.

The study aimed to evaluate vaccination coverage and factors associated with incomplete basic vaccination schedule at 12 months of age in 427 children aged 12-59 months in São Luis, Maranhão State, Brazil, 2006. This cross-sectional, population-based household survey used complex cluster sampling. Poisson regression with robust adjustment of variance was applied. Complete basic vaccination coverage was 71.9% for applied doses, 61.8% for valid doses, and 23.6% for correct doses. Hepatitis B and tetravalent vaccines showed higher percentages of doses on dates or at intervals lower than recommended. Percentages of delayed vaccination were high, except for BCG. Incomplete basic vaccination was more frequent in girls and children from low-income and black families. Racial, gender, and socioeconomic factors posed barriers to complete vaccination, thus emphasizing the need for policies to address such inequalities.

El estudio tiene como objetivo evaluar la cobertura de vacunación y los factores asociados al esquema incompleto de vacunación básico a los 12 meses de edad, realizado en 427 niños de 12 a 59 meses, en São Luis, Maranhão, Brasil, 2006. Se trata de una encuesta domiciliaria transversal, de base poblacional, con muestreo complejo por conglomerados. Se empleó la regresión de Poisson con un ajuste robusto de variancia. La cobertura para el esquema básico completo fue de un 71,9% según las dosis aplicadas, un 61,8% para dosis válidas y un 23,6% para dosis correctas. Las vacunas contra la hepatitis B y tetravalente presentaron mayores porcentajes de dosis aplicadas en fechas o intervalos inferiores a los recomendados. Los porcentajes de atraso en la vacunación fueron elevados, excepto para la vacuna BCG. Los porcentajes más elevados de esquema incompleto de vacunación básico se encontraron en niños de clases económicas D y E, de sexo femenino y con jefes de familia afrobrasileños. Las desigualdades raciales, de género y socioeconómicas representaron barreras a la vacunación completa, indicando la necesidad de reforzar las políticas equitativas que eliminen esas desigualdades.

O estudo objetivou avaliar a cobertura vacinal e os fatores associados ao esquema vacinal básico incompleto aos 12 meses de idade, em 427 crianças de 12 a 59 meses, em São Luís, Maranhão, Brasil, 2006. Trata-se de inquérito domiciliar transversal, de base populacional, com amostragem complexa por conglomerados. Empregou-se regressão de Poisson com ajuste robusto da variância. A cobertura para o esquema básico completo foi de 71,9% segundo doses aplicadas, 61,8% para doses válidas e 23,6% para doses corretas. As vacinas contra hepatite B e tetravalente apresentaram maiores percentuais de doses aplicadas em datas ou intervalos inferiores aos recomendados. Os percentuais de atraso vacinal foram elevados, exceto para a BCG. Percentuais mais elevados de esquema vacinal básico incompleto foram encontrados em crianças das classes econômicas D e E, do sexo feminino e de chefes de família de cor da pele preta. As desigualdades raciais, de gênero e socioeconômicas representaram barreiras à vacinação completa, indicando necessidade de reforçar as políticas equitativas que eliminem essas desigualdades.

The study aimed to evaluate vaccination coverage and factors associated with incomplete basic vaccination schedule at 12 months of age in 427 children aged 12-59 months in São Luis, Maranhão State, Brazil, 2006. This cross-sectional, population-based household survey used complex cluster sampling. Poisson regression with robust adjustment of variance was applied. Complete basic vaccination coverage was 71.9% for applied doses, 61.8% for valid doses, and 23.6% for correct doses. Hepatitis B and tetravalent vaccines showed higher percentages of doses on dates or at intervals lower than recommended. Percentages of delayed vaccination were high, except for BCG. Incomplete basic vaccination was more frequent in girls and children from low-income and black families. Racial, gender, and socioeconomic factors posed barriers to complete vaccination, thus emphasizing the need for policies to address such inequalities.

El estudio tiene como objetivo evaluar la cobertura de vacunación y los factores asociados al esquema incompleto de vacunación básico a los 12 meses de edad, realizado en 427 niños de 12 a 59 meses, en São Luis, Maranhão, Brasil, 2006. Se trata de una encuesta domiciliaria transversal, de base poblacional, con muestreo complejo por conglomerados. Se empleó la regresión de Poisson con un ajuste robusto de variancia. La cobertura para el esquema básico completo fue de un 71,9% según las dosis aplicadas, un 61,8% para dosis válidas y un 23,6% para dosis correctas. Las vacunas contra la hepatitis B y tetravalente presentaron mayores porcentajes de dosis aplicadas en fechas o intervalos inferiores a los recomendados. Los porcentajes de atraso en la vacunación fueron elevados, excepto para la vacuna BCG. Los porcentajes más elevados de esquema incompleto de vacunación básico se encontraron en niños de clases económicas D y E, de sexo femenino y con jefes de familia afrobrasileños. Las desigualdades raciales, de género y socioeconómicas representaron barreras a la vacunación completa, indicando la necesidad de reforzar las políticas equitativas que eliminen esas desigualdades.