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Cause and Frequency

B virus infections in people are usually caused by macaque monkeys. These kinds of monkeys are commonly infected with B virus, but they usually do not have symptoms, or have just mild disease. Other primates, such as chimpanzees and capuchin monkeys, can become infected with B virus and will frequently die from these infections. There have not been documented cases of such primates spreading B virus except to macaques.

B virus infections in people are rare. Since B virus was identified in 1932, only 50 people have been documented to have infections; 21 of them died. Most of these people got infected after they were bitten or scratched by a monkey, or when tissue or fluids from a monkey got on their broken skin, such as by needle stick or cut. In 1997, a researcher died from B virus infection after bodily fluid from an infected monkey splashed into her eye.

Hundreds of bites and scratches occur every year in monkey facilities in the United States, but people rarely get infected with B virus. A study of more than 300 animal care workers showed that none had B virus infection, including the 166 workers who had possible exposures to monkeys.

Transmission

B virus can spread from infected macaque monkeys to people. Macaque monkeys commonly have this virus, and it can be found in their saliva, feces (poop), urine (pee), or brain or spinal cord tissue. The virus may also be found in cells coming from an infected monkey in a lab. B virus can survive for hours on surfaces, particularly when moist.

Most people will not come in contact with monkeys, so their risk of getting infected with B virus is very low. However, laboratory workers, veterinarians, and others who may be exposed to monkeys or their specimens have a higher risk of getting B virus infection. In recent years, many macaque attacks have been reported by people visiting temple parks in some countries in Asia, where macaques commonly roam freely. About 70 to 80% of these macaques have been found to be B virus positive, but there have not been any documented cases of B virus spreading to humans.


Signs and Symptoms

Symptoms typically start within one month of being exposed to B virus, but could appear in as little as three to seven days.

The first indications of B virus infection are typically flu-like symptoms:

fever and chills
muscle ache
fatigue
headache
Then, you may develop small blisters in the wound or area on your body that had contact with the monkey.

Other symptoms may include:

Shortness of breath
Nausea and vomiting
Abdominal pain
Hiccups
As the disease progresses, the virus spreads to and causes inflammation (swelling) of the brain and spinal cord. This can lead to:

Neurologic and inflammatory symptoms (pain, numbness, itching) near the wound site
Problems with muscle coordination
Brain damage and severe damage to the nervous system
Death
Problems with breathing and death can occur one day to three weeks after symptoms appear. It may be possible for people to have mild B virus infection or no symptoms. However, there are no studies or evidence of this.


Prevention
There are no vaccines that can protect you against B virus infection.

If you are in a place where there are macaque monkeys, you should stay away from them so that you do not get bitten or scratched. You should not touch or feed monkeys.

Laboratory workers, veterinarians, and others who may be exposed to monkeys or their specimens have a higher risk of getting B virus. See the section on People at High Risk for Infection for ways to help protect yourself.



First Aid and Treatment
First Aid
If you are exposed to a macaque monkey, begin first aid immediately.

First, thoroughly wash and gently scrub the wound or area on your body that had contact with the monkey with soap, detergent, or iodine for 15 minutes.
After, run water over the wound or area for 15 to 20 minutes more. Then, immediately seek medical attention. Tell the healthcare provider that you have been exposed to a macaque monkey that may be infected with B virus.
Treatment
If your healthcare provider determines that you need treatment for B virus exposure or infection, you may be treated with antiviral medications. Timely first aid and treatment for high-risk exposures is thought to be crucial to preventing life-threatening disease.