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11 Mar 2017

#Epidemiological #update: #Yellowfever #outbreak in #Brazil (@ECDC_EU, Mar. 11 ‘17)


Title: #Epidemiological #update: #Yellowfever #outbreak in #Brazil.

Subject: Sylvatic Yellow Fever Outbreak in Brazil, multi-state, current situation.

Source: European Centre for Disease Prevention and Control (ECDC), full page: (LINK).

Code: [     ]


Epidemiological update: Yellow fever outbreak in Brazil


10 Mar 2017

​Yellow fever is a mosquito-borne viral infection present in some tropical areas of Africa and South America.

In South America, there are two transmission cycles of yellow fever:

  • A sylvatic cycle, involving transmission of the virus between Haemagogus or Sabethes mosquitoes and primates.
    • The virus is transmitted by mosquitoes from primates to humans when humans are visiting or working in the forest.
  • An urban cycle, involving transmission of the virus between Aedes aegypti mosquitoes and humans.
    • The virus is usually introduced in an urban area by a viraemic human who was infected in the forest.

Brazil has been experiencing an outbreak of yellow fever since December 2016. The outbreak was notified on 6 January 2017.


Weekly Summary

  • Between 24 February and 6 March 2017, Brazil reported 95 additional cases of yellow fever (50 suspected and 45 confirmed), mostly in Espírito Santo (41) and Minas Gerais (28).
    • No additional state has reported autochthonous transmission.
  • On 6 March, the World Health Organization updated its recommendations on yellow fever vaccination for international travellers related to the current situation in Brazil.


Epidemiological Summary

  • On 6 January 2017, Brazil reported an outbreak of yellow fever.
    • The index case had onset of symptoms on 18 December 2016.
    • The first laboratory confirmation was notified on 19 January 2017.
  • As of 6 March 2017, Brazil has reported 1 337 cases of yellow fever (966 suspected and 371 confirmed), including 233 deaths (106 suspected and 127 confirmed), in seven states.
    • The case-fatality rate is 17.4% among all cases and 34.2% among confirmed cases.
  • States reporting suspected and confirmed autochthonous cases:
    • Minas Gerais has reported 1 057 cases (769 suspected and 288 confirmed), including 188 deaths (83 suspected and 105 confirmed).
    • Espírito Santo has reported 226 cases (147 suspected and 79 confirmed), including 37 deaths (18 suspected and 19 confirmed).
    • São Paulo has reported 15 cases (11 suspected and four confirmed), including five deaths (two suspected and three confirmed).
  • States reporting suspected autochthonous cases:
    • Bahia has reported seven suspected cases, including one fatal.
    • Tocantins has reported six suspected cases, including one fatal.
    • Rio Grande do Norte has reported one suspected case, fatal.
    • Goiás has reported one suspected case, not fatal.
  • In addition, investigations are ongoing to determine the probable infection site of 24 further suspected cases.
  • The Ministry of Health of Brazil has launched mass vaccination campaigns in addition to routine vaccination activities.
    • As of 6 March 2017, 14.85 million extra doses of yellow fever vaccine have been sent to five states: Minas Gerais (6.5 million), São Paulo (3.25 million), Espírito Santo (3.15 million), Rio de Janeiro (1.05 million) and Bahia (900 000).
    • Sources: Brazil MoH


ECDC Assessment

  • The ongoing outbreak should be carefully monitored, as the establishment of an urban cycle of yellow fever would have the potential to quickly affect a large number of people.
  • EU/EEA citizens who travel to, or live in, areas where there is evidence of yellow fever virus transmission should check their vaccination status and get medical advice about getting vaccinated against yellow fever.
  • In Europe, Aedes aegypti, the primary vector of yellow fever in urban settings, is present in Madeira.
    • Recent studies have shown that Aedes albopictus can potentially transmit the yellow fever virus.
  • However, the risk of the virus being introduced into local competent vector populations in the EU through viraemic travellers from Brazil is considered to be very low, as the current weather conditions in Europe are not favourable for vector activity.
  • ECDC closely monitors this event in collaboration with the World Health Organization.
  • ECDC published a rapid risk assessment on 26 January 2017, and is producing epidemiological updates and a map for travel advice.


- See more at:


Keywords: ECDC; Updates; European Region; Yellow Fever; Brazil.