The Pan American Health Organization (PAHO) released its latest epidemiologic update on the current yellow fever outbreak in Brazil, noting that while cases have decreased in Minas Gerais state, there have been increasing reports of the mosquito-borne disease in Espirito Santo.
Cases move toward Atlantic coast
Though Minas Gerais, an interior state in Brazil, has been the epicenter of the country's yellow fever outbreak, there has not been a new patient with a symptom onset later than Mar 6.
That downward trend is not seen in Espirito Santo, where the southern part of the state is reporting a sharp increase in cases. The state of Rio de Janeiro also reported an uptick of cases between Mar 15 and 25. Both Espirito Santo and Rio de Janeiro are in the middle of a massive yellow fever vaccination campaign.
Since the beginning of the outbreak in December of 2016 through Apr 6, there were 2,210 cases of yellow fever reported, including 604 confirmed. Among confirmed cases, the case-fatality rate is 33%. Five states have reported confirmed cases, including Espirito Santo, Minas Gerais, Rio de Janeiro, and Sao Paulo.
High risk for Aedes transmission
PAHO said that the Aedes aegytpti, the mosquito that dwells in urban centers and can spread dengue and Zika virus, is still not thought to be playing an active role in yellow fever transmission. "However, confirmed epizootics in large cities, such as Victoria in Espirito Santo and Salvador in Bahia, represent a risk a high risk for a change in the transmission cycle," PAHO warned.
As of Apr 6, Brazil said 2,871 nonhuman primates (NHP) epizootics were reported, of which 474 were confirmed yellow fever infections, 997 remain under investigation, and 77 were discarded.
PAHO also said epizootic cases have been reported from Federal district and 21 states, including ones that border nine other countries: Argentina, Bolivia, Colombia, Guyana, Paraguay, Peru, Suriname, Uruguay and Venezuela. Epizootic cases can precede human transmission, and PAHO said they represent a risk of spreading the virus to neighboring countries.
Finally, PAHO urged the importance of vaccination, noting that countries must assess vaccine coverage in areas with a strong risk of yellow fever transmission.
Apr 10 PAHO update