Rift Valley fever is a virus that is spread by mosquitoes. The virus has been identified in Africa and the Middle East. It can spread among livestock and other animals and can also spread to people who come in contact with the blood, fluids, or bodies of infected animals. This means that people who work in slaughterhouses, along with veterinarians, are at higher risk.
People can also get the virus from being bitten by a mosquito or biting fly that's carrying the virus, although this is less common.
Epidemics of Rift Valley fever can come on suddenly, especially after heavy rainfall and flooding. Outbreaks can cause great losses in production and impact food supply and trade in animal products.
Symptoms of Rift Valley Fever in Animals
Sheep (especially lambs) and goats are the animals most at risk for Rift Valley fever virus, but it can also infect cattle. Camelids (llamas and alpacas), pigs, horses, dogs, and cats can also get infected but don't get sick from this virus.
Rift Valley Fever in Sheep
Lambs are most at risk for this virus, and as many as 90–100% of infected lambs die within 3 days. They get sick within 12–36 hours after exposure, with weakness, fever, loss of appetite, and sometimes stomach pain.
Adult sheep don’t get infected as easily, and it takes longer for them to get sick (24–72 hours). Only about 10–30% of infected sheep are likely to die from Rift Valley fever. They get fever and a runny nose, and they might have bloody vomit or diarrhea, but more commonly, they get no symptoms at all. In pregnant ewes, abortion might be the only symptom.
Rift Valley Fever in Cattle
Although calves don't have as great a risk as lambs, up to 70% of those that do get infected can die. Calves get most of the same symptoms as lambs but can also show yellowing of the skin, eyes, and gums.
Most adult cows don’t show infection, but those that do can have symptoms similar to those of adult sheep. Only about 5–10% of cows are likely to die of Rift Valley fever.
Diagnosis and Treatment of Rift Valley Fever in Animals
Several tests are used to diagnose Rift Valley fever. They include evaluation of samples from animals that have died, genetic tests for the virus, isolation of the virus from the organs of an infected animal, and blood tests. Rift Valley fever is suspected after heavy rains and flooding in an area, especially if there are lots of abortions and deaths in newborn animals.
There is no treatment for Rift Valley fever in animals.
Prevention
There are multiple important steps in prevention of Rift Valley fever in animals:
Vaccination is the best strategy. Lambs should be vaccinated at 6 months old, and protection will last for their lifetime. There is a separate vaccine for pregnant animals.
Keeping track of the weather is important in trying to predict outbreaks.
Moving animals to higher ground if heavy rain or flooding is expected can help lower the risks.
Important Human Health Points Regarding Rift Valley Fever
People can get Rift Valley fever from mosquitoes, but it spreads much more commonly from contact with infected animals.
People working with animals in affected areas, especially people involved with slaughter or birthing procedures, should always wear full protective equipment, including masks and gloves.
Protection from mosquitoes can also help prevent infection.
For More Information
Also see professional content regarding Rift Valley fever in animals.
