Therapy of human rabies: lessons from
experimental studies in a mouse model
Alan C. Jackson, MD
Courtney A. Scott, BSc
James Owen, BSc
Simon C. Weli, PhD
John P. Rossiter, MB, PhD
Departments of Medicine (Neurology)
Microbiology and Immunology
Centre for Neuroscience Studies
Queen’s University, Kingston, ON, Canada
Medical complications of rabies
multisystem organ failure
 respiratory



failure, hyperventilation, aspiration pneumonia
cardiac

failure, arrhythmias
gastrointestinal hemorrhage
 hyperthermia or hypothermia
 endocrine – SIADH, DI

Recovery from rabies

6-yr-old male from Ohio. Hattwick et al.
Ann Intern Med (1972)

45-yr-old female from Argentina. Porras et al.
Ann Intern Med (1976)

32-yr-old male lab worker from New York.
Tillotson et al. MMWR (1977)

9-yr-old male from Mexico. Alvarez et al.
Pediatr Infect Dis (1994)

6-yr-old female from India. Madhusudana et al.
Int J Infect Dis (2002)
Clinical Infectious Diseases 36:60-63, 2003
Specific therapies

rabies vaccine

human rabies immune globulin (or mabs)

ribavirin

interferon-

ketamine

role of combination therapy?
Jackson et al.: Clinical Infectious Diseases 36:60-63, 2003
N Engl J Med 352:2508-14, 2005
Survival Case
healthy 15-year-old in Wisconsin
 bitten by bat – probable bat rabies virus (no
virus isolated, no antigen or RNA identified)
 antibodies on presentation (RFFIT 1:102)

midazolam infusion to produce burst
suppression pattern on EEG with supplemental
phenobarbital
 IV ketamine infusion 2 mg/kg/hr
 antiviral therapy with ribavirin (IV) and
amantadine

N Engl J Med 352:2508-14, 2005
Survival Case

Did specific therapy play important role in
recovery?

therapeutic coma??

ketamine?

antiviral therapy?
Attenuated bat rabies virus strain?
 Early antibody response
 Lack of detection of viral antigen and RNA,
suggests that effective viral clearance was in
progress

Ketamine

dissociative anesthetic agent

ketamine (1-2 mM) inhibits in vitro
replication of rabies virus by inhibiting
genome transcription

with stereotaxic inoculation of fixed rabies
virus into neostriatum of rats, ketamine 60
mg/kg IP q12h reduced infection in multiple
brain regions (hippocampus, cerebral
cortex, and thalamus)
Lockhart et al. – Antiviral Chem Chemother 1991 and 1992
Antimicro Agents Chemother 1991
Journal of Virology 80:10270, 2006
Toluidine blue-stained plastic sections
cerebral cortex – 48 hrs
Mock-infected
CVS-infected
J Virol 80:10270, 2006
Trypan blue exclusion
cerebral cortex – 72 hrs
Mock-infected
CVS-infected
J Virol 80:10270, 2006
Trypan Blue Staining
Cerebral Cortex
Hippocampus
Cerebral Cortex
100
100
80
80
% of viable cells
% of viable cells
Hippocam pus
60
40
60
40
20
20
0
0
1
2
1
3
2
3
Days
Days
Mock-infected
CVS
J Virol 80:10270, 2006
Effects of 125 μM ketamine on viability
of cortical neurons in CVS infection
J Virol 80:10270, 2006
Cumulative mortality
ketamine 60 mg IP q12h or vehicle
intracerebral
log rank test p= 0.50
footpad
log rank test p= 0.53
J Virol 80:10270, 2006
Therapy with Ketamine
Ketamine did not:
•
•
•
•
•
reduce mortality
attenuate the clinical neurologic illness or
prolong survival
reduce viral spread or the number of
infected neurons
reduce the amount of infectious virus
reduce neuronal apoptosis after
intracerebral inoculation
Lancet Neurology 3:744, 2004
multiple sclerosis
spinal cord injury
Parkinson’s disease
Huntington’s disease
amyotrophic lateral sclerosis
viral diseases of CNS – reovirus, SIV, Sindbis v.
Journal of Virology 81:6248, 2007
log rank test p=0.003
J Virol 81:6248, 2007
Summary

Therapy with minocycline (50 mg/kg/d) was
associated with more severe neurologic disease
and higher mortality than with vehicle in rabies
virus – infected mice.

The number of rabies virus-infected neurons was
similar with vehicle and minocycline.

Neuronal apoptosis was more marked in infected
mice that received vehicle than minocycline
(minocycline was anti-apoptotic).

There were smaller numbers of CD3 positive cells
in the brainstem of mice that received minocycline
than vehicle, indicating an anti-inflammatory effect
of the drug.
J Virol 81:6248, 2007
Conclusions

Therapy of rabies with minocycline in an
experimental mouse model did not provide
neuroprotection and aggravated the
neurological disease.

Caution should be taken before using
minocycline for empirical therapy of rabies or
other viral encephalitis in humans before
more experimental data become available.
Therapeutic approach similar to the Willoughby
protocol has been unsuccessful in at least 8 cases:
• United States – 3 (TX, IN, CA)
• Canada (Alberta)
• Germany – 2
• India
• Thailand
Conclusions: Ketamine

Lack of efficacy of ketamine in about 8
human cases since the Milwaukee case

Lack of efficacy of ketamine in primary
neuronal cultures and in vivo in mice at
120mg/kg/d

More experimental evidence is needed that
supports the use of ketamine in rabies
virus infection before recommending its
use for the therapy of human rabies.
Therapeutic coma









useful for therapy of status epilepticus
efficacy in other neurologic disorders is unproven
no experimental evidence of efficacy in rabies or
any other infectious disease
potential serious adverse effects
lack of effective neuroprotective agents even in
common acute neurologic disorders (e.g., stroke),
despite numerous clinical trials
no scientific rationale for use in rabies
does not work
risks outweigh benefits
should not be used for human rabies
Willoughby protocol
•
•
•
•
•
Multiple failures of the protocol in developed and
developing countries.
It is now highly questionable that therapy using
this protocol was directly responsible for the
favorable outcome.
This protocol should not be repeated indefinitely.
Experimental work should be performed in cell
culture and in animal models to identify promising
therapeutic agents.
New approaches should be taken for future rabies
patients.
Acknowledgments
Queen’s University Violet E. Powell Fund