Oropouche fever is a tropical viral infection transmitted by biting midges and mosquitoes from the blood of sloths to humans. This disease is named after the region where it was first discovered and isolated at the Trinidad Regional Virus Laboratory in 1955 by the Oropouche River in Trinidad and Tobago. Oropouche fever is caused by a specific arbovirus, the Oropouche virus (OROV), of the Bunyaviridae family. Large epidemics are common and very swift, one of the earliest largest having occurred at the city of Belém, in the Brazilian Amazon state of Pará, with 11,000 recorded cases. In the Brazilian Amazon, oropouche is the second most frequent viral disease, after dengue fever. Several epidemics have generated more than 263,000 cases, of which 130,000 alone occurred in the period from 1978 to 1980. Presently, in Brazil alone it is estimated that more than half a million cases have occurred. Nevertheless, clinics in Brazil may not have adequate testing reliability as they rely on symptoms rather than PCR viral sequencing, which is expensive and time consuming, in many cases there may be co-infection with other similar mosquito-borne viruses. Symptoms and signs Oropouche fever is characterized as an acute febrile illness, meaning that it begins with a sudden onset of a fever followed by severe clinical symptoms. It typically takes 4 to 8 days from the incubation period to first start noticing signs of infection, beginning from the bite of the infected mosquito or midge. Fevers are the most common symptom with temperatures as high as 104F. Clinical symptoms include chills, headache, myalgia, arthralgia, dizziness, photophobia, vomiting, joint pains, epigastric pain, and rashes. There also have been some cases where rashes resembles rubella and patients presented systematic symptoms including nausea, vomiting, diarrhea, conjunctive congestion, epigastric pain, and retro-orbitial pain. The initial febrile episode typically passes after a few days, but it is very common to have a reoccurrence of these symptoms with a lesser intensity. Studies have shown this typically happens in about 60% of cases. Cause The oropouche virus is an emerging infectious agent that causes the illness oropouche fever. This virus is an arbovirus and is transmitted among sloths, marsupials, primates, and birds through the mosquitoes Aedes serratus and Culex quinquefaciatus. The oropouche virus has evolved to an urban cycle infecting humans though midges as its main transporting vector. OROV was first described in Trinidad in 1955 when the prototype strain was