Herpes simiae (B virus)

Other Names

B virus; Monkey B virus, Macacine alphaherpesvirus 1

Summary

• B virus infection is extremely rare, but it can lead to severe brain damage or death if you do not get treatment immediately.
• People typically get infected with B virus if they are bitten or scratched by an infected macaque monkey, or have contact with the monkey’s eyes, nose, or mouth.
• Only one case has been documented of an infected person spreading B virus to another person.

Cause

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.

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. You can get infected with B virus if you:

• are bitten or scratched by an infected monkey
• get an infected monkey’s tissue or fluid on your broken skin or in your eyes, nose, or mouth
• have a needle stick by a contaminated syringe
• scratch or cut yourself on a contaminated cage or other sharp-edged surface
• are exposed to the brain (especially), spinal cord, or skull of an infected monkey
• Only one case has been documented of an infected person spreading B virus to another person.

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.

Diagnosis

Immediately following exposure, and prior to the onset of symptoms, it is important to collect sera approximately 3 weeks apart to determine whether seroconversion to B virus infection has occurred. If symptoms consistent with B virus disease develop, collection of saliva or material from blisters (if present) can be tested by B virus PCR to determine whether the virus is present. sing B virus serology, determine whether a patient who was B virus seronegative has begun making antibodies to B virus. Samples for PCR should not be obtained at the time of exposure due to the possibility of forcing the virus more deeply into the wound. Samples for PCR are also not recommended immediately following cleansing, because the sample is unlikely to contain detectable levels of virus and could lead to false negative results. If symptoms develop, saliva and/or material from local blisters should be collected and tested by PCR for B virus.PCR has the additional advantage of being more rapid, potentially providing results in a matter of hours rather than days. Diagnoses of B virus infections have been hampered because herpes simplex virus (HSV) and B virus are closely related. Direct culture of B virus has been the standard for diagnosis of infection, but requires a biosafety level 4 (BSL-4) containment facility to reduce the risk of exposure for laboratory workers, and the collection of samples must be delayed until symptoms appear.

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 you are diagnosed with herpes simiae, you may need to be treated with antiviral medications. Timely first aid and treatment for high-risk exposures is thought to be crucial to preventing life-threatening disease. Acyclovir has prevented progression of the disease in some patients and may be life saving, though it is thought to only be 10% as effective against B virus as HSV1.