First human cases of yellow fever confirmed in Brazil since June

The first human cases of yellow fever since June have been confirmed in Brazil, and public health officials continue to monitor an epizootic outbreak among primates in São Paulo, the World Health Organization (WHO) announced on Friday.

Seventy-one human cases of suspected yellow fever were reported from July to October. Two cases were confirmed, and one resulted in death. Meanwhile, 120 cases were confirmed among primates in São Paulo State, with the number of reported cases increasing through September.

“The detection of two confirmed yellow fever human cases and epizootics in the state of São Paulo, as well as confirmed yellow fever epizootics in the urban area of São Paulo City, prompted national authorities to begin vaccination campaigns in areas previously considered not at risk for yellow fever transmission,” a WHO release stated. “In addition, state and municipality health authorities are strengthening health care services and carrying out risk communication activities.”

The confirmed human cases, coupled with epizootic outbreaks in urban areas previously deemed low-risk, represent a public health concern, WHO stated. However, high vaccination coverage in neighboring communities means that the risk of yellow fever spreading at the regional level is low.

“The risk at the global level is considered to be low and limited only to unvaccinated travelers returning from affected areas,” WHO stated. “Travelers who return home while infected with yellow fever virus may increase the risk of establishing local cycles of yellow fever transmission in areas where the competent vector is present.”

WHO advises travelers to high-risk areas to be vaccinated at least 10 days before departing. Monitoring mosquito bites and being aware of symptoms of yellow fever are also suggested.