Rift Valley Fever

Rift Valley fever is a viral disease that usually causes illness in cattle, sheep and goats and other animals. It has been found primarily in eastern and sub-Saharan Africa. In the past decade, it also has caused outbreaks on the Arabian Peninsula.

Animals are infected by bites from infected mosquitoes that multiply during conditions such as local flooding or sustained pooling of water. Animal infections can lead to abortion or death. Human infections also occur, following contact with blood, other body fluids or tissues of infected animals or, to a lesser extent, from mosquito bites .

What are the symptoms of Rift Valley fever? +

Most people who are infected with the Rift Valley fever virus have no symptoms. If symptoms do occur, they usually are mild: fever, headache or muscle pain. Recovery typically takes a few days to a week.

Fewer than 8% of persons infected proceed to more severe illness that can include excessive bleeding, blood loss, eye problems, nausea and vomiting, abdominal pain, liver failure and brain infection (encephalitis). Severe illness may be more common in persons with compromised immune systems (for example, HIV disease) and in those persons who were infected directly from sick animals. Death from Rift Valley fever is rare (less than 1%) .


How common is Rift Valley fever and how is it usually caused? +

Until now, Rift Valley fever has never been detected in the United States, Canada, Central America or South America. In Africa and the Arabian Peninsula, the only parts of the world where it causes naturally occurring disease, Rift Valley fever is mostly a disease of grazing, domesticated animals (cattle, sheep and goats). Outbreaks occur after sustained rains lead to flooding, hatching of mosquito eggs that are infected with the Rift Valley fever virus and rapid increases in infected mosquito populations. Disease is found first in animals that have been bitten by mosquitoes. Farmers, veterinarians and others who come into contact with sick animals are the first persons who usually develop Rift Valley fever. If environmental conditions enable continued increase in mosquito populations, more and more human infections can then be caused by mosquito bites .


What is bioterrorism? +

Bioterrorism is the intentional use of biological agents or germs to cause illness. Bioterrorism has occurred in NYC only in 2001, when several media outlets received letters that were intentionally contaminated with anthrax bacteria.


How soon after infection do Rift Valley fever symptoms appear? +

Illness usually occurs two to six days after exposure to the Rift Valley fever virus.


I am concerned that I have or someone who I know has Rift Valley fever symptoms. What should I do? +

Anyone with the symptoms of Rift Valley fever should contact their medical provider immediately. Call 911 if you have symptoms of uncontrollable or excessive bleeding, eye problems, abdominal pain, yellow eyes or skin, confusion, severe headache or other serious illness.


How is Rift Valley fever spread when it occurs naturally? +

The Rift Valley fever virus is found in the body fluids and tissues of infected animals. Human infection can occur if one comes into physical contact with sick animals, including birth products from animal abortions. Farmers, veterinarians and slaughterhouse workers are more likely to come down with Rift Valley fever than those who do not have contact with cattle, sheep or goats. Rift Valley fever also can be spread by mosquito bites.


Is Rift Valley fever contagious? +

No. Rift Valley fever cannot spread from person to person.


How is Rift Valley fever diagnosed? +

Rift Valley fever is diagnosed by blood tests. Patient samples are tested at the U.S. Centers for Disease Control and Prevention (CDC).


What is the treatment for Rift Valley fever? +

Treatment usually is not necessary for Rift Valley fever. In persons who are severely ill, antiviral medications can kill the virus.


Is there a Rift Valley fever vaccine, and how can I get it? +

There is a Rift Valley fever vaccine that has been used to protect animals from infection. However, there currently is no human vaccine approved for use in the U.S.


What has New York City done to address the threat of Rift Valley fever? +

Many federal, state, and city agencies, including the New York Health Department, have been working together for several years to prepare for the detection and response to a bioterrorism event in New York City. In cooperation with other emergency response agencies, the Health Department has established systems to improve detection and response to public health emergencies caused by the intentional release of a biological agent


How Will I Cope? +

A Rift Valley fever outbreak in NYC can be very stressful, especially if it is a result of bioterrorism. It can disrupt your everyday life and make you and those around you feel less safe. You may experience fear and uncertainty. Learning about stress and strategies to manage it can help you cope.

Prepare Today, Cope Better Tomorrow - Stress during Disasters provides basic information and practical advice on dealing with the stress and anxiety caused by disasters. It is available in seven languages.

If there is a Rift Valley outbreak affecting the city and you feel overwhelmed and unable to cope, or if you are concerned about someone else, you can find help by calling (888) NYC-Well (888-692-9355). NYC Well is a free, confidential helpline for New York City residents, available 24/7, with trained staff ready to take your calls and offer advice.


For more information about Rift Valley fever, visit: Centers for Disease Control and Prevention (CDC)