Rift Valley Fever (RVF)

What is Rift Valley Fever (RVF)?

Rift Valley Fever is a serious infection caused by the Rift Valley fever virus.

How do you get Rift Valley Fever (RVF)?

The virus is transmitted to humans mainly by direct or indirect contact with infected animal body fluids (e.g., blood or unprocessed milk), meat products or organs of infected animals, (e.g., through the handling of animal tissue during slaughtering or butchering, assisting with animal births, conducting veterinary procedures, or from the disposal of carcasses or fetuses). Occasionally, the virus may also be transmitted by several species of mosquitoes that also bite sheep and other animals that are the hosts for this virus.

Susceptibility and Resistance

After having this infection, a person will have life-long immunity. Therefore, in areas where this virus occurs, much of the population may be immune through previous infection.  Unexposed travellers and children may be the most susceptible to this disease.

Incubation Period

The incubation period for Rift Valley Fever (RVF) is 3-12 days.

What are the Symptoms?

The Rift Valley fever virus causes fever, headache, fatigue, muscle and joint aches and occasionally nausea and vomiting.  Most cases are relatively mild. However, severely infected persons may develop inflammation of the retina (the eye form of the disease), inflammation of the brain (the brain form of the disease) or haemorrhages (the haemorrhagic form of the disease).  Inflammation of the liver may be accompanied by haemorrhage that may be fatal.

Preventative Measures

International travellers are at very low risk of acquiring this disease unless they are involved with livestock and the activities described under “How Do You Get It”. In the presence of any outbreak, these activities should be avoided.

Treatment

There is no specific treatment for this illness other than therapy of symptoms and supportive treatment for severe cases.

Where Does It Commonly Occur?

Rift Valley Fever outbreaks occur in sub-Saharan Africa. Large outbreaks have occurred in Egypt, Madagascar, Mauritania, Kenya, Somalia, Tanzania, Saudi Arabia, Yemen, and South Africa.