What are the other Names for this Condition? (Also known as/Synonyms)

• Herpes Simiae (B Virus) Infection
• Herpes Virus Simiae Encephalomyelitis Infection
• Monkey B Virus Infection

What is Simian B Virus Infection? (Definition/Background Information)

• Simian B Virus Infection is an extremely rare disease in humans that is caused by the herpes virus Simiae, also known as the B virus. This virus is commonly found among the macaque monkeys (a type of Asiatic monkeys)
• Individuals, who are exposed to infected monkeys or simian tissue cultures, can get infected with the virus. Since infection requires close contact with infected animals or tissue, those who work with the primates in laboratories, animal houses, zoos, and animal hospitals, are more at risk for developing Simian B Virus Infection
• Some common signs and symptoms of Simian B Virus Infection may include fever, malaise, nausea, vomiting, seizures, and muscle paralysis. Since the infection can spread to the brain, potential complications may include swelling in the brain and spinal cord leading to encephalitis and meningitis
• There are no vaccines available to protect against Simian B Virus Infection. An infected individual is typically monitored in a hospital setting, and treated with antiviral medication as necessary. With early diagnosis and prompt treatment, the outcome is generally good
• The use of protective gear such as eyewear, gloves, and masks while handling the primates and their tissue/waste can help prevent Simian B Virus Infections. Posting clear instructions on necessary steps to be taken upon suspicion of infection can provide clarity and avoid long time lapses before diagnosis and treatment

Who gets Simian B Virus Infection? (Age and Sex Distribution)

• Any individual exposed to infected macaque monkeys or simian tissue cultures may contract Simian B Virus Infection
• There is no gender preference reported and both males and females are affected

What are the Risk Factors for Simian B Virus Infection? (Predisposing Factors)

The risk factors for Simian B Virus Infection may include:

• Working in laboratories handling the virus or infected tissues
• Working in close contact with carriers of the virus, such as with the primates (monkeys)
• Coming in contact with infected monkeys at the zoo or at other places
• Treating infected monkeys (veterinarians)

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Simian B Virus Infection? (Etiology)

Simian B Virus Infection is caused by the herpes virus Simiae, also known as the B virus. This virus is commonly found among macaque monkeys, which are certain Asiatic monkeys belonging to the genus “Macaca”.

The infection can be transmitted to humans through:

• Bites
• Exposure of wounds and scratches to an infected monkey’s secretion
• Mucosal contact with an infected monkey’s body fluid, tissues, or infected saliva
• Needle stick injury from a contaminated needle

What are the Signs and Symptoms of Simian B Virus Infection?

The signs and symptoms associated with Simian B Virus Infection include:

• Fatigue, headache, muscle aches, and fever
• Malaise, lethargy
• Nausea and vomiting
• Visual defects
• Paralysis - weakness of arms, legs, or face
• Breathing difficulties
• Seizures
• Inflammation of the lymph nodes (lymphadenitis)
• Inflammation of lymph vessel walls (lymphangitis)
• Abdominal pain, hiccups

The following signs and symptoms may occur after the infection affects the brain:

• Hyperesthesia: Increased sensitivity to stimuli, particularly to touch
• Ataxia: Lack of muscle control during voluntary movements
• Diplopia or double vision
• Agitation
• Muscle paralysis/weakness
• Stiff neck

How is Simian B Virus Infection Diagnosed?

Early diagnosis of Simian B Virus Infection is critical to control spread of human infection. The following diagnostic methods are generally followed:

• Complete evaluation of medical history along with thorough physical examination
• Direct culture of B virus: Cultures of infected site, conjunctiva, and oropharynx, for checking the presence of B virus
• Serologic test to detect the presence of antibodies in human blood against the virus
• PCR (polymerase chain reaction) methods for detection of viral DNA
• Neurological tests such as:
  • Lumbar puncture; examination of spinal fluid (cerebrospinal fluid)
  • Magnetic resonance imaging (MRI) of the brain
  • Electroencephalography (EEG)

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Simian B Virus Infection?

The following are some possible complications that could arise from Simian B Virus Infection:

• Encephalitis or inflammation and swelling of the brain
• Meningitis: Inflammation of the membranes covering the brain and spinal cord, owing to bacterial infection
• Encephalomyelitis that causes severe neurologic impairment

Coma and death can occur from severe cases of infection.

How is Simian B Virus Infection Treated?

The first and immediate step involved in the treatment of Simian B Virus Infection is to quickly and thoroughly clean the wound or the exposed site.

• The wound must be cleansed with soap and water for at least 15 minutes
• The mucosal surfaces should be rinsed with sterile saline or running water for 15 minutes
• This immediate cleaning and rinsing of the wound can inactivate and wash away any virus present in the exposed site
• Following this, the affected individual needs to be treated and evaluated in a hospital setting

Intravenous antiviral therapy may be administered based on the following criteria:

• Type and physical condition of the implicated animals such as identification of herpetic lesions in the skin of the source animal
• Inadequate cleaning of the wound or exposure area
• Deep wounds that penetrate the skin
• Wounds involving the head, neck, or torso
• Exposure to materials that have come into contact with infected monkeys: Needles and syringes that have come into contact with the central nervous system, eyelids, or mucosa of infected monkeys carry a high risk of infection to humans. In such cases, administering antiviral therapy is strongly recommended

How can Simian B Virus Infection be Prevented?

Presently, there is no vaccine available to prevent Simian B Virus Infection. However, when dealing with (infected) animals, tissues, or body fluids, the following measures could help in preventing or reducing the spread of infection:

• Wearing protective eyewear such as goggles or glasses with solid side shields
• Use of lab coats, gloves, and masks
• Occupational healthcare system maintained for primate workers
• Educating workers about potential exposures, treatment after exposure, and follow-up measures
• Keeping animal workers informed about the potential biohazards involved in their occupation
• Training workers on Simian B virus exposure and biohazards prior to starting their work with the primates/monkeys
• Training and demonstration of eye washing and wound cleaning procedures
• First aids, copies of written instruction materials on the treatment methods, protocols for exposure, etc. are to be printed and made available in areas of possible exposure
• Placing or providing an ‘exposure kit’ in field stations where emergency care can be delayed
• Displaying clear, visible instructions in high risk areas, where potential for exposure to the infection is very high

What is the Prognosis of Simian B Virus Infection? (Outcomes/Resolutions)

• The prognosis of Simian B Virus Infection is good with proper diagnosis and immediate treatment 
• However, untreated infections may lead to life-threatening complications, which can also be fatal

Additional and relevant useful information for Simian B Virus Infection:

• In late 1997, a worker at a primate center died from B virus infection that developed after biologic material from a monkey was splashed into the worker's eye. After this incident, CDC formed a working group to reassess the existing recommendations for the prevention, evaluation, and treatment of B virus infection in humans. These recommendations are helpful in handling with the potentially deadly virus
• Since 1975, United States public health regulations prohibit the importation of primates as pets
• Herpes B virus was first identified in 1932 following the death of Dr. William Brebner. He was a young physician who was bitten by a monkey while researching on the virus that causes poliomyelitis