Aedes Aegypti, dengue and re-urbanization of yellow fever in Brazil and other South American Countries - past and present situation and perspectives

Dengue (DEN) and yellow fever (YF) viruses are two important arboviruses causing human disease. Dengue fever and dengue haemorrhagic fever (DF/DHF) reemerged in the Americas after Aedes aegypti had reinfested most tropical and subtropical regions in the hemisphere. The number of DF/DHF cases being reported are increasing each year; and in South America only Chile and Uruguay have not reported any cases. Sylvan YF has increased in the last two decades because of increasing human contact with forest areas, and the risk of its re-urbanization has increased dangerously due to the presence of Aedes aegypti proximally to areas with sylvatic YF, particularly in Bolivia, Brazil, Colombia and Peru, where YF is transmitted by Haemagogus mosquitoes. This paper gives an overview of the main epidemiological findings of YF and DEN viruses in the recent past and discusses the future perspectives of the dissemination of DF/DHF and re-urbanization of YF in South America. Current situation demands the adoption of a massive YF vaccination programme in the region in conjunction with a powerful regional plan of Aedes aegypti control to avoid deaths attributed to these two viruses in South America.