Epidemic outbreaks of Oropouche virus in the Maranhão and Goiás States, Brazil

Abstract

The authors describe the occurrence of outbreaks caused by Oropouche virus (ORO) in the states of Maranhão and Goiás, Brazil in 1988. 36 strains of the virus were obtained from the intracerebral inoculation of the blood of 120 patients into 2-3 day-old infant mice. The illness was characterized by headache, fever, pain in the muscles, joints and back, photophobia, retrobulbar pain, nausea and dizziness. 128 of 197 people examined in Porto Franco, MA, had hemagglutination-inhibiting antibodies to the agent, while 106 of them had IgM antibodies by MAC ELISA test. All age groups were infected, although the incidence was higher among who had 10 to 19 years old. There was no difference, in relation to sex infections. Recurrence of symptoms was reported in 56% of sick people. Mice inoculated with 3624 Culicoides paraensis (Ceratopogonidae) and 1970 Culex (Cux.) quinquefasciatus (Culicidae) collected in Porto Franco resulted in one single isolation of ORO virus, from the Culicoides. These are the first confirmed cases of ORO infection in Maranhão and Goiás states.