Researchers warn Oropouche fever may be spreading throughout Brazil

After a Zika virus epidemic in 2015 and an outbreak of yellow fever earlier this year, Brazil runs a serious risk of being affected by Oropouche fever, a tropical viral infection similar to dengue fever, according to a recent study by the São Paulo Research Foundation (FAPESP) in Brazil.

According to Luiz Tadeu Moraes Figueiredo, a professor at the University of São Paulo’s Ribeirão Preto Medical School, about 500,000 cases of the virus have been reported in the country in recent decades but that number of cases will grow because the virus, transmitted by the midge Cullicoides paraensis, is no longer found only in Amazonian villages and is spreading to big cities.

“C. paraensis is distributed throughout the Americas, and Oropouche virus therefore has considerable emergence potential,” Figueiredo said. “The virus may well spread from the Amazon region and central plateau to the most densely populated regions of the country.”

While the virus has been isolated in the Brazilian state Rio Grnade do Sul and Minas Gerais, the incidence of the virus are rising in urban areas throughout Peru and the Caribbean. Additionally, the presence of antibodies has been detected in primates near the city of Goiânia.

Figueiredo said that he recently diagnosed a patient from Ilhéus with Oropouche fever, in partnership with [Eurico Arruda, professor in the University of São Paulo’s Ribeirão Preto Medical School (FMRP)], and that showed that the virus was circulating around Brazil.

The FMRP diagnosed 128 people infected with the virus in Manaus in 2002, each of which demonstrated common symptoms including fever, joint pain, headache, and intra-ocular pain and were initially misdiagnosed with dengue fever.

“The virus was found in these patients’ cerebrospinal fluid,” Figueiredo said.

Due to the misdiagnosis of the patients, the FMRP has begun to warm public health officials that many suspected cases of dengue in Brazil may be cases of Oropouche infection.

Oropouche fever is a tropical viral infection most commonly transmitted by the mite of midges and various mosquito species. Typical symptoms of infection include chills, headache, muscle pain, joint pain and vomiting. Due to symptom similarities, it is commonly misdiagnosed as dengue fever.