B Virus and 70% Mortality

While most patients presenting to the Emergency Department live in the immediate region surrounding the hospital, modern day travel allows patients to have recent exposures from the far reaches of the globe. One particular zoonotic infection, B Virus, carries a 70% mortality rate if not treated promptly. This post aims to introduce the B Virus and summarize the "need-to-know" as a practicing Emergency Physician:

B Virus:

  • Also known as herpes B, monkey B virus, herpesvirus B, herpesvirus simiae
  • Natural Host: macaque monkeys
  • B Virus has a seroprevalance of 70% of adult macaques
  • Active infection on macaques presents as skin blisters/lesions.

Patients at Risk:

  • Veternarians
  • Animal lab workers,
  • Anyone with close contact with macaque monkeys or macaque cell cultures


  • Bite or scratch from infected animal
  • Needlestick from contaminated syringe
  • Scratch or cut from contaminated cage
  • Exposure to nerve tissue or skull from infected animal
  • Transmission to humans is rare. In one study, 166 animal care workers in United States reported exposures and none obtained B virus.

Human Clinical Presentation:

  • Symptoms will occur within 1 month of exposure
  • Vesicular skin lesions can be seen at site of exposure
  • Fever, myalgias, headache, weakness is usually first sign of disease
  • Once infection invades CNS, hyperesthesia, agitation, ataxia, flaccid paralysis can be seen.
  • Respiratory failure from paralysis is most likely cause of death.


  • Washing of the wound should occure within 5 minutes of exposure and last for 15-20 minutes
  • Prophylaxis: valacylovir 1g PO q8 hrs for 14 days, acyclovir 800 mg PO five times daily for 14 days
  • Treatment without CNS Symptoms: acyclovir 12.5-15 mg/kg IV q8 hrs or ganciclovir 5 mg/kg q12 hours
  • Treatment with CNS Symptoms: ganciclovir 5 mg/kg q12 hours

1. "B Virus." Center for Disease Control and Prevention. U.S. Deparment of Health and Human Services. 2017.