Macacine alphaherpesvirus 1

Background

• Also known as macacine herpesvirus 1, macacine alphaherpesvirus 1, cercopithecine herpesvirus 1, CHV-1), herpes B virus, monkey B virus, herpesvirus simiae and herpesvirus B

History

• First diagnosed in a researcher in 1933

Microbiology

• Double-stranded DNA virus
• Alphaherpesvirus, in the same family as HSV

Pathophysiology

• Virus replicates locally at the site of inoculation, then spreads from peripheral nerves to spinal cord to brainstem to brain

Clinical Presentation

• Typically via bite or scratch of macaque monkey
  • Asymptomatic or similar presentation to HSV in the monkey
  • Seroprevalence reaches 100% in some populations of macaques
• Incubation period 5 to 21 days (range 2 days to 5 weeks)
• Three clinical forms:
  • Flu-like illness followed by CNS symptoms
  • Local symptoms (itching, tingling, numbness, or pain) at the inoculation site, with or without vesicular rash and regional lymphadenopathy
  • Peripheral or central nervous system symptoms, with meningismus, vomiting, confusion, cranial nerve palsies
• Eventually progresses to global encephalitis, seizures, paralysis, and respiratory failure
• Mortality 70% if untreated

Diagnosis

• Serology, with acute and convalescent (3 to 6 weeks) titres, looking for a 4-fold rise
  • Seroconversion may be delayed if on acyclovir, so should be repeated at 12 weeks
  • Done at NML or sent out to Georgia State University
• Viral culture is possible but not done routinely
• PCR is available for swab, tissue, blood, and CSF
  • Sent out to Georgia State University
  • In autopsy, send right and left trigeminal ganglia or the sacral dorsal root ganglia