Spread, circulation and predominance of chikungunya virus East/Central/South African genotype in Northeast and Southeast Brazil

Abstract

Two recent researches described the spread of East/Central/South African (ECSA) lineage of chikungunya virus (CHIKV) in the Northeastern and Southeastern Brazil (Charlys da Costa et al. 2017, Cunha et al. 2017) . Initial studies in Northern Brazil, as observed in Caribbean, identified the Asian as the circulating lineage of the chikungunya. However, da Charlys da Costa et al. and Cunha et al. reported the exclusive occurrence of ECSA in two different Brazilian regions: Northeast as well as in Rio de Janeiro State (Charlys da Costa et al. 2017, Cunha et al. 2017) , suggesting that the ECSA is the predominant lineage in highly populated Brazilian areas. Despite the well-described vector competence of Aedes mosquitoes for CHIKV transmission, Aedes(Stegomyia)albopictus seems to have a greater competence for transmission of ECSA lineage compared to the Asian lineage (Vega-Rúa et al. 2015) , particularly when variable temperatures mimicking daily fluctuations of temperate climate (Vega-Rúa et al. 2015) . This statement is consistent with the fact that A albopictus has not been denounced as a vector of large outbreaks of chikungunya caused by the Asian genotype. This invasive species have capability of cold-tolerant diapausing eggs, it is paramount to establishment in temperate areas (Mitchell 1995) and new regions are invaded each year (Kraemer et al. 2015) . The predominance of the ECSA lineage in Brazil represents a potential risk of CHIKV dispersion to areas where Ae. albopictus has a broader distribution, particularly in temperate climates, including United States and Europe (Kraemer et al. 2015) , territories with intense commercial and touristic relationship with Brazil. Furthermore, the predominance of ECSA in Brazil can contributes to a better comprehension of the current distinct epidemiological scenarios between Caribbean - where explosive epidemics occurred with Aedes(Stegomyia) aegypti and Asian lineage predominated - and Brazil - with an apparent slower dispersion of CHIKV, where Ae.aegypti predominate but ECSA was prevalent linage. Both studies highlighted the importance of virological surveillance for analysis of current epidemiological scenarios and prediction of potential patterns of spreading of arboviral diseases, locally and worldwide.