REAL-TIME SEQUENCING AND MOLECULAR ANALYSIS OF COMPLETE GENOMES OF EMERGING AND RE-EMERGING ARBOVIRUSES IN BRAZIL
ZIKV, CHIKV, YFV, epidemic, genomic surveillance, public health, MinIon
The risk of high incidence of Zika virus (ZIKV), associated with the occurrence of microcephaly in infants and of Chinkungunya virus (CHIKV), associated with Guillain-Barré syndrome, which symptoms are severe and incapacitating for long periods of time pose real issues to the public health sectors. In addition to the scenario caused by the emergence of CHIKV and ZIKV, Brazil has experienced an exceptional outbreak, caused by the yellow fever virus (YFV) between late 2016 and middle 2017. In national wide context, it is known that there is co-circulation of these arboviruses which are mainly transmitted by the same mosquito species in the urbanized regions, widely distributed in tropical and subtropical regions. In regions of the Americas, such as Brazil, where the ZIKV epidemic is competing with those caused by CHIKV, the rapid identification of the virus and knowledge of the genome has become crucial for monitoring viral diversity and for understanding the origin, introduction and viral dispersion events, as well as the identification of strains or genotypes with greater epidemic potential. By combining real-time sequencing techniques with a portable nanopore-based sequencer with bioinformatic analyzes (using epidemiological and filodynamic models), it was possible to generate a substantial number of new genomes of arboviruses ZIKV, YFV and CHIKV. In this work, we demonstrate that the ZIKV epidemic in the Americas originated from a single viral line derived from the Asian genotype and the evidence that the Northeast Brazil played a central role in establishment and dissemination of ZIKV in the Americas. In addition, our findings related to the YFV epidemic show that the majority of human cases (98.5%) were reported in municipalities with YFV vaccination coverage above the threshold, indicating that the infection occurred through individuals who reside or work in forest areas where wild transmission occurs. Here, new complete CHIKV genomes were also isolated from different cell compartments (blood, saliva and urine). The genomes belong to the ECSA genotype, indicating the persistence of circulation within the population of Feira de Santana (FSA). These analyzes support public health authorities on epidemic prevention in areas with high risk of introduction or expected incidence. Corroborating with the need to establish a colaborative network of laboratories and researchers to provide rapid responses to the emergence of epidemics, and for their management. In this work, we also present optimizations of the protocols used for amplification of viral genomes, besides the use of nanopore-based sequencing directly from RNA.