Rift Valley Fever (RVF) is an acute viral hemorrhagic fever that causes illness in livestock (such as cattle, buffalo, sheep, goats, and camels) and people.
RVF spreads mainly by direct contact with the blood, body fluids, or organs of infected animals or through bites of infected mosquitos. RVF is not known to spread from person to person.
Most people with RVF have no symptoms or a mild illness with fever, weakness, back pain, and dizziness. Sudden onset of symptoms usually occurs two to six days after exposure to RVF virus. Less than 2% of people infected with RVF will develop severe symptoms, which can include eye disease, hemorrhage (excessive bleeding), and encephalitis (swelling of the brain).
Most people recover within one week, with treatment limited to supportive care. While mortality is higher in severe cases, only about 1% of people who get RVF die.