How is it spread?
Oropouche is spread primarily by a tiny midge found across the Americas called culicoides paraensis. It can also be spread by the Aedes aegypti mosquito.
Experts believe the virus is spreading further than the Amazon because of climate change and urbanisation.
To date, there is no evidence of human-to-human Oropouche virus transmission, though the Brazilian health authorities are investigating whether it can pass from mother to child.
What are the symptoms?
Most cases of Oropouche are mild, with symptoms similar to Dengue fever, including a headache, body pains, nausea, and rash.
Some people may also experience gastrointestinal symptoms and sensitivity to light.
Patients typically develop a fever three to eight days after infection, and symptoms typically last less than a week but can occasionally reoccur.
How dangerous is it?
The virus can also have more severe effects including meningitis and encephalitis, or inflammation of the brain.
It is estimated that fewer than four per cent of patients will develop neurological symptoms.
Late last month, Brazil reported the world’s first deaths from the virus after two women in their twenties succumbed to the illness in the northeastern state of Bahia.
A major cause for concern among scientists are oropouche’s potential links to stillbirths and birth defects such as microcephaly, and Brazil’s health ministry has urged doctors to closely monitor pregnant mothers who are infected with the virus.
What treatment is there?
Although oropouche has been known about for decades, relatively little is known about the virus.
There are currently no specific antiviral treatments or vaccines available.
Treatment for symptoms can include rest, fluids, and the use of medicines to reduce pain and fever.