Rwanda has experienced outbreaks of Rift Valley Fever (RVF) since the disease was first confirmed in livestock in 2012. The current outbreak has been reported in Eastern Province. ALSO READ: What to know about Rift Valley fever as Rwanda responds to latest outbreak As a preventive measure, the animals in affected areas are quarantined and no slaughtering and meat sales are allowed. Here is what you need to know about the disease, how it spreads, who is at risk, and how it can be prevented. How it spreads According to Rwanda Biomedical Centre (RBC) guidelines on Rift Valley fever, the disease is a zoonotic viral infection that mainly spreads through contact with infected animals and, less commonly, through bites from infected mosquitoes. Rift Valley fever is caused by a virus that mainly affects ruminants such as cattle, sheep and goats but can also infect humans, according to Dr Emmanuel Nzabamwita, a veterinarian. He explained that in animals, the disease is transmitted primarily through the bites of infected mosquitoes. “People are mainly infected through contact with body fluids of infected animals, mainly blood from animals showing signs of the disease or by consumption of animals that died of the disease,” Nzabamwita said. The disease puts farmers, veterinarians, slaughterhouse workers and butchers at higher risk because of their close contact with livestock and animal tissues. Nzabamwita said outbreaks are often associated with the rainy season because stagnant water provides breeding sites for mosquitoes, increasing their population and the risk of transmission among animals. The virus can cause miscarriages in pregnant livestock and deaths among young animals. The RBC guidelines state that humans can become infected while slaughtering, butchering or skinning animals, assisting with animal births, carrying out veterinary procedures, or disposing of dead animals and aborted foetuses. Infection can occur through cuts on the skin, needle-stick injuries or inhaling droplets produced during slaughter. Consuming raw or unpasteurised milk from infected animals also increases the risk. Although mosquitoes can transmit the virus to humans, this is a less common route of infection. There has never been a documented case of Rift Valley fever spreading from one person to another. Symptoms and complications Most infected people either do not develop symptoms or experience a mild illness. According to RBC, symptoms usually appear two to six days after infection and include fever, headache, muscle pain and joint pain. Some patients may experience neck stiffness, sensitivity to light, pain behind the eyes, vomiting or loss of appetite. Severe cases can lead to complications such as eye inflammation that may cause permanent vision loss, inflammation of the brain and surrounding tissues, liver damage, kidney failure and haemorrhagic fever, which causes severe bleeding and carries a high risk of death. In animals, Nzabamwita said bleeding from the nostrils is a sign that the disease has reached an advanced stage. Diagnosis, prevention A suspected human case is defined as a person with fever and symptoms such as headache, muscle or joint pain, unexplained bleeding, liver disease, neurological symptoms or eye complications, especially after being in an area where Rift Valley fever has been reported. A probable case involves close contact with infected cattle, sheep or goats, including through slaughtering, handling carcasses, assisting with animal births or consuming raw milk or meat from affected animals. Laboratory tests are required to confirm infection. There is no specific treatment for Rift Valley fever in humans. Patients receive supportive care based on their symptoms, while those who develop kidney failure may benefit from early dialysis. There is no vaccine available for the people. Nzabamwita said there is no specific treatment for infected animals once the disease develops because the virus progresses rapidly. “By the time signs of the disease become visible, treatment becomes difficult because the virus has already spread in the animal,” he said. He added that livestock vaccination is an important prevention measure. “Vaccinating cattle, sheep and goats helps protect livestock and reduces the risk of exposure for people who handle them,” he said. Nzabamwita said veterinarians, farmers and others who handle animals need to use personal protective equipment, avoid contact with potentially contaminated animal products, and take precautions against infection because they may not know whether an animal is infected. “Those who handle animals should always follow safety procedures because they cannot know the condition of an animal before it is examined.” Nzabamwita warned communities against consuming animals that die from unknown causes, giving an example of how people could put themselves at risk by removing and eating dead animals that veterinary teams have recommended for burial because of suspected disease. He said veterinary authorities should work with local leaders to educate communities on why animals suspected to have died from disease must be properly disposed of and not consumed. “Livestock owners are encouraged to report unusual animal deaths and signs of illness to veterinary authorities to support early detection and control of outbreaks.”
