Today the Pan American Health Organization (PAHO), in its weekly yellow fever epidemiologic update, noted that a sixth state, Tocantins, has reported a human case of the mosquito-borne disease.
Tocantins joins Para, Rio de Janeiro, Sao Paulo, Espirito Santo, and Minas Gerais as states with confirmed human cases of yellow fever.
The patient was described as an unvaccinated young person who worked in the jungle and died in January, the first yellow fever death in that state in 17 years. The current outbreak began when sylvatic yellow fever in Brazil's jungles leaped to the human population late in 2016.
As of Apr 20, there are 2,900 yellow fever cases in Brazil, with 681 cases confirmed and 786 under investigation, PAHO said. There have been 372 deaths, making the case-fatality rate 34% for confirmed cases.
Minas Gerais, where the current epidemic began, has reported no new human cases in the past 6 weeks, holding steady at 1,130 suspected cases, PAHO said. Esprito Santo is still experiencing a second wave of new cases, with unvaccinated municipalities most at risk for yellow fever. So far, that state has reported 58 deaths from the disease.
PAHO said Aedes aegypti mosquitoes are still not being implicated in the outbreak, but recent epizootic cases in Victoria and Rio de Janeiro hint at a possible change in the transmission cycle. In between last week's update and this week's, an additional 296 epizootic cases were reported, bringing the total to 3,245 suspected cases in nonhuman primates since the outbreak began.
Epizootic cases represent a risk to nations nearby, according to PAHO. "Reports of epizootics currently under investigation in states bordering Argentina, Bolivia, Colombia, Guyana, Paraguay, Peru, Suriname, Uruguay, and Venezuela represent a risk of spread of the virus to the bordering countries, especially in areas with similar ecosystems."
Peru reports 14 cases, 2 deaths
PAHO also noted today that Peru has reported 14 yellow fever cases and 2 deaths, the same number of cases reported at this time in 2016. These numbers reflect increases from the years before 2016.
The weekly report also contained guidance for member states on vaccination, stating that areas at risk for human transmission should try to obtain a 95% coverage rate. The yellow fever vaccine requires just one dose and is 80% effective 10 days after inoculation, and 99% effective after 1 month.
Earlier this week, CIDRAP News reported that Brazil is confident it can produce enough of the yellow fever vaccine to cover the at-risk population.
Apr 27 PAHO report
Apr 24 CIDRAP News story