What are the signs and symptoms of Rabies?
The first symptoms of rabies in people may be nonspecific flu-like signs — malaise,
fever, or headache, which may last for days. There may be discomfort or paresthesia at the
site of exposure (bite), progressing within days to symptoms of cerebral dysfunction,
anxiety, confusion, agitation, progressing to delirium, abnormal behavior, hallucinations,
and insomnia. The acute period of disease typically ends after 2 to 10 days (6).
Once clinical signs of rabies appear, the disease is nearly always fatal, and treatment is
typically supportive. Disease prevention is entirely prophylactic and includes passive
antibody (immune globulin) and vaccine. Non-lethal exceptions are extremely rare, with
only six documented cases of human survival from clinical rabies, but each included a
history of either pre- or postexposure prophylaxis.
Pathology
Pathology of rabies infection is typically defined by encephalitis and myelitis.
Perivascular infiltration with lymphocytes, polymorphonuclear leukocytes, and plasma cells
can occur throughout the entire CNS. Common with rabies infection is the presence of
cytoplasmic eosinophilic inclusion bodies (Negri bodies) in neuronal cells, including
pyramidal cells of the hippocampus and Purkinje cells of the cerebellum, and within
neurons of the cortex and other regions of the CNS, including the spinal ganglia. These
inclusions have been identified as areas of active viral replication by the identification
of rabies viral antigen.
Several factors may contribute to the outcome of rabies exposure. These include the virus
variant, dose of virus inoculum, route and severity of exposure, location of exposure,
host species, and individual host factors, such as age and host immune defenses. |
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