Rift Valley Fever

Rift Valley Fever is a disease of livestock. It's a problem for farmers - hurting their herds and their finances - but it can also be a problem for anyone who has contact with their animals. It's a disease that can spread from animal to human.

To find out more about how Rift Valley Fever spreads, click here.

What does Rift Valley Fever (RVF) cause?

Rift Valley Fever is a viral illness that causes a sudden fever and can make animals and people sick.

The animals made ill are usually livestock - cattle, buffalo, sheep, goats, and camels - and are the source of human infections.

It's actually a type of fever that can be associated with hemorrhagic symptoms - and so is a Viral Hemorrhagic Fever.

Can people get sick?

When there's contact between people and animals sick with RVF, people can sick. When there's a lot of contact between sick animals and people, there can even be large outbreaks.

For more information on how people can get sick, click here.

Are there ever outbreaks?

Yes. There have been a few. Some have been associated with animal trade; others with environmental changes.

The virus spread in Egypt in 1977 leading to many animal deaths and over 600 human deaths. The affected animal(s) may have come from Sudan.

The virus spread a decade later in west Africa when the Senegal River Project lead to flooding, affecting the ecology of the environment where livestock and those who cared for them lived.

Later it was found that 1 in 4 people in the area may have antibodies from past exposure.

The virus spread in 2000 from Africa to Yemen and Saudi Arabia causing hemorrhagic fever in people.

The virus also was found to cause an outbreak in Kenya, Tanzania, and Somalia in 2006. It was thought to be associated with heavy rains.

In 2010, South Africa saw an outbreak in 7 provinces with 172 human cases, 15 human deaths (with liver disease and bleeding symptoms); most had contact with animals through work. 2010 - Republic of South Africa

There have been cases recently reported in Uganda.

What sort of illness do most people get?

Most people who are infected don't get sick at all or become only mildly ill. This mild illness involves a flu-like fever, muscle pain, joint pain, headache, dizziness, weakness, back pain, and liver problems. Most get better in 2 to 7 days after illness.

Some can become a bit more ill. They may develop neck stiffness, light sensitivity, loss of appetite, vomiting.

Can people get really sick?

Yes, Rift Valley Fever can lead to a serious illness. About 8-10% can become seriously ill.

There are 3 main types of serious illness: ocular (eye) disease (0.5-2% of patients), meningoencephalitis (less than 1%) or haemorrhagic fever (less than 1%).

  • Ocular: Patients may develop blurry vision - about 1-3 weeks after the first symptoms of RVF. This blurry or decreased vision may resolve in 2-3 months. For about half, there is some permanent loss of vision. This can involve lesions on the retina. 
  • Meningoencephalitis: Patients may develop a bad headache, memory loss, confusion, seizures, hallucinations,vertigo, lethargy, and coma. This may occur 1-4 weeks after the first RVF symptoms. Patients may have permanent neurologic complications, which may develop later (over 2 months later). This is usually not deadly.
  • Haemorrhagic: Symptoms of liver disease and bleeding may develop in the first days of illness, about 2-4 days after symptoms of RVF appeared. A patient may have jaundice, vomiting blood, blood in stool, unexplained bruising, bleeding from nose or gums, heavy vaginal bleeding, or unexpected bleeding from IV sites. About half who develop hemorrhagic symptoms die. Death usually occurs quickly - 3-6 days after symptoms. 50%. 

How long after exposure can someone get sick?

It usually takes 2-6 days from exposure to illness.

How is it diagnosed?

The infection is often picked up when there is an outbreak among animals. It can be confirmed by PCR to show the virus. ELISA Antibody testing can show IgM antibodies soon after infection (to show current and early infection) and IgG later on (to confirm past illness, as these can last for years).

Continue Reading