Genetic characteristics of field and attenuated rabies viruses ... - Evira

own urine, abnormal liking of water, regurgitation, altered behavior, the biting and eating
of abnormal objects, aggression, biting without provocation, running without no apparent
reason, stiffness upon running or walking, restlessness, biting during quarantine, sleepy
appearance, gait imbalance, and frequent demonstration of the “Dog sitting” position
(Tepsumethanon et al., 2005).
1.3.3. Pathological changes
The pathology of rabies infection is typically characterized by encephalitis and
myelitis. When brain tissue from rabies virus-infected animals is observed with a
histological stain, such as hematoxylin-and-eosin, evidence of encephalomyelitis may be
recognized by light microscopy (Fig. 4 A&B). A perivascular non-suppurative infiltration is
the most frequently noted histological alteration in rabies (Perl, 1975). The cytoplasmic
eosinophilic inclusion bodies (Negri bodies) can often be found in rabies-infected neurons
(Fig. 4 C&D), especially in the pyramidal cells of the hippocampus and the Purkinje cells
of the cerebellum (Negri, 1903). These Negri bodies may vary in size from 0.25 to 27 µm,
and these inclusions have been defined as areas of active viral replication by the
identification of rabies viral antigen (Schneider et al., 1975).
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