Yellow fever: the risk of re-urbanization of the disease is real

Publicação: 12 de September de 2017

Study shows a possible risk of urban transmission of the yellow fever virus returning in Brazil

The research involved 11 populations of the disease’s transmitting mosquitoes from Brazil and one from Congo, place of origin of the vírus

An article published on the international journal Scientific Reports, this July, alerts for the re-introduction of the yellow fever virus in urban environments. The study entitled “Potential risk of re-emergence of urban transmission of Yellow Fever virus in Brazil facilitated by competent Aedes populations” (linkar o PDF) showed that the existing Aedes aegypti populations in Brazil are able to transmit the virus, currently circulating in wild areas and, this way, there is a possibility of the re-emergence of the virus in urban areas.

The research involved 11 populations of the disease’s transmitting mosquitoes in Brazil: Aedes aegypti, Aedes albopictus, Haemagogus leocucelaenus and Sabethes albiprivus, and one from Congo, Africa, the virus’ place of origin. The insects were infected with three strains of the virus, from which two are currently circulating in Brazil and one in Africa. Rio de Janeiro, Goiânia and Manaus were the surveyed cities, since they combine features as simultaneous infections in several animals of a given geographic area, similar to a human epidemic. The returned results were surprising: Rio de Janeiro had the greatest potential for yellow fever virus dissemination in urban areas. The mosquito populations from Goiânia and Manaus, were also susceptible to transmitting the disease, but in a smaller scale.

Doctor Pedro Vasconcelos, head of the Evandro Chagas Institute, who joined the study, explains that the Aedes were efficient to disseminate and transmit the virus after day 14 after infection. “It was also shown that the Brazilian Aedes aegypti is susceptible to American and African virus’ genotypes. And that the Rio de Janeiro Aedes albopictus was very efficient in supplying virus particles from saliva”, he details. The research also revealed the Hemagogus and Sabethes from Rio de Janeiro were highly competent to transmit Brazilian and African strains of the virus.

The study was performed by the Oswaldo Cruz Institute in partnership with the Pasteur Institute, from France, and counted with collaboration from the Evandro Chagas Institute, in Pará State.…