B Virus (Macacine Herpesvirus 1, Herpes B) Treatment & Management

Updated: Jun 20, 2019
  • Author: Sandra G Gompf, MD, FACP, FIDSA; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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Treatment

Approach Considerations

Treatment for B virus infection is not recommended in the case of exposure to non-macaque primates or exposure of intact skin to a source that is not high-risk (see below).

All macaque species must be presumed to be infected with B virus at the time of a human exposure, as previous serologic testing may not reflect a recently acquired infection.

High-risk exposures

Treatment for B virus infection is recommended for high-risk exposures, as follows:

  • Skin or mucosal exposure to a high-risk source (eg, primate is clinically ill, immunosuppressed, actively shedding B virus, or has lesions suggestive of B virus infection)
  • Inadequately cleansed exposure to nonintact skin (with or without injury)
  • Inadequately cleansed mucosal splash
  • Laceration of the head, neck, or upper body
  • Deep puncture bite
  • Puncture or laceration with needle, device, or other object either (1) contaminated with fluid from monkey oral or genital lesions or with nervous system tissues or fluid or suspicious skin lesions or (2) known to contain B virus
  • Culture positive for B virus performed after the wound was cleansed

Medium-risk exposures

Treatment should be considered for medium risk exposures, as follows:

  • Needlestick injury with a needle containing blood from a clinically ill or immunosuppressed macaque
  • Laceration or broken skin or mucosa contaminated with other body fluids or possibly infected cell culture
  • Mucosal splash with adequate cleansing
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Medical Care

Refer to the most recently published guidelines for a detailed discussion. [10] The substance of these guidelines is delineated below. Prompt attention to a potential exposure is vital to minimize the risk of this disease, which carries high morbidity and mortality rates.

Wound decontamination and culture

Cleansing of the exposed area within minutes of the episode is the only means of preventing a contaminated wound from progressing to actual infection. B virus is likely to enter host cells within 5 minutes.

At least 15 minutes of scrubbing and/or irrigating the exposed area is recommended. Sterile saline or rapidly flowing water is used for the eye, and decontaminants (eg, soap solution, povidone-iodine, chlorhexidine) can be used at other sites.

Dakin solution (0.25% hypochlorite) has been suggested for high-risk deep lacerations or needle sticks, as it may inactivate herpesviruses. The solution must be fresh, and standard decontaminants should be used after a 5-minute treatment. Dakin solution should never be used to wash the eyes or mucous membranes.

After cleansing of a high-risk wound, cultures for B virus should be performed.

Antiviral therapy

Antiviral therapy is clearly indicated for suspected clinical cases of human B virus infection; use of prophylactic antiviral therapy is problematic.

The decision regarding postexposure prophylaxis should be individualized and made by a health care provider experienced with the evaluation, treatment, and prevention of B virus infection. Early prophylaxis may prevent either overall or symptomatic infection; on the other hand, infection is quite rare compared with the number of exposures.

The ability of therapy to prevent B virus infection is not documented, and therapy can suppress shedding and seroconversion, further complicating diagnosis. In addition, the length of therapy is undefined. [10]

B Virus Postexposure Prophylaxis

Postexposure prophylaxis is recommended up to 5 days after exposure or longer if a postcleansing wound culture is positive for B virus, given that results may be delayed. The exposed person should be evaluated frequently and monitored with serologic testing for B virus, for example, at 1, 2, and 4 weeks postexposure. Because postexposure prophylaxis may delay seroconversion, patients receiving antivirals should be retested for antibodies 12 weeks postexposure. Positive postcleansing wound culture findings should prompt cultures of conjunctivae, oropharynx, and any unhealed suspicious skin lesions 1-2 weeks after completion of antiviral therapy. A culture positive for B virus at any point warrants intravenous therapy (see Treatment of B Virus Infection, below).

Postexposure prophylaxis regimens include the following:

  • Valacyclovir 1000 mg PO every 8 hours for 14 days
  • Acyclovir 800 mg PO 5 times per day for 14 days

Treatment of B Virus Infection

Advanced encephalitis is often fatal despite antiviral therapy. Duration and discontinuation of treatment is based on expert guidance. B virus is believed to behave similarly to other human herpesviruses and is reported to have reactivated from latent infection in at least one human case.

Treatment regimens for early symptoms without CNS symptoms include the following:

  • Acyclovir 12.5-15 mg/kg IV every 8 hours OR
  • Ganciclovir 5 mg/kg IV every 12 hours

Treatment for CNS symptoms consists of ganciclovir 5 mg/kg IV every 12 hours.

Acyclovir is preferred in pregnant patients. Currently, treatment with intravenous (IV) antivirals is recommended until symptoms resolve and two sets of cultures yield negative results for 14 days. Thereafter, treatment can be deescalated to oral therapy, as for postexposure prophylaxis, for 6-12 months. Thereafter, a lower oral dose may be considered and continued indefinitely for long-term suppression. [10]

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Surgical Care

Incision of wounds directed at diagnosis or treatment is usually of little benefit and can increase the risk of secondary bacterial infection. Therefore, it is not generally recommended. [10]

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Consultations

For prevention protocol and specimen testing, obtain appropriate consultation from occupational health personnel of primate centers. In addition, the National Institute of Health’s National Center for Research Resources funds the National B Virus Resource Center, which is an excellent resource for numerous topics related to herpes B virus, including both diagnostic testing and education. Other resources include the Centers for Disease Control and Prevention Emergency Operations Center (available 24/7 at 770-488-7100) and the National Institute for Occupational Safety and Health.

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Prevention

Developing herpes B virus–free colonies

The endeavor to develop virus-free colonies has found some success, especially in the United States, where the National Center for Research Resources took a leading role in the 1990s by promoting experimental strategies in husbandry and management.

Achieving completely herpes B virus–free colonies has proven difficult because some macaques may show no antibodies but may retain latent herpes B virus particles. Furthermore, the B virus may become reactivated and shed without any visible symptoms.

Because of the relative ease of monkey-to-monkey transmission, even a single animal infected with herpes B virus may compromise the virus-free status of an entire facility.

Current research focuses on the development of techniques (eg, PCR) to reduce false-negative results and the implementation of regular screening protocols that quickly identify infected monkeys.

Accepting moderate to high infection rates in macaques but minimizing human exposure to herpes B virus

Minimizing social, nutritional, pharmacological, and psychological stress (especially overcrowding and shipping) can reduce viral shedding by monkeys. Promoting good veterinary care and immunocompetence also can reduce shedding.

Eliminating transmission pathways can prevent human exposure. Some means of prevention include the use of protective suits, gloves, eye shields, and similar devices. Given the difficulties and costs of achieving herpes B virus–free colonies, these methods may remain the reality at most facilities, at least for the near future.

Nonmacaque species are highly susceptible to herpes B virus infection. The risk of infection in these animals can be easily minimized by housing macaques in separate nonadjacent cages. A failure to follow this precaution has sometimes led to cross-species infection and fatalities.

Immunoprevention

Immunoprevention has been attempted in animal studies using several different vaccines. Most recently, a recombinant vaccinia virus that expresses herpes B glycoprotein D appears promising in preventing infection and/or latency.

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