Canine Distemper:
Canine distemper is a highly contagious, systemic, viral disease of dogs seen worldwide.
Clinically, canine distemper is characterized by:
a diphasic fever
leukopenia
GI and respiratory catarrh, and
frequently, pneumonic and neurologic complications
Canine distemper virus, or CDV, is a paramyxovirus closely related to the viruses of measles and rinderpest. The fragile, enveloped, single-strand RNA virus is sensitive to lipid solvents, such as ether, and most disinfectants, including phenols and quaternary ammonium compounds. It is relatively unstable outside the host. The main route of infection is via aerosol droplet secretions from infected animals. Some infected dogs may shed virus for several months.
PATHOGENESIS
The virus initially replicates in the lymphatic tissue of the respiratory tract. A cell-associated viremia results in infection of all lymphatic tissues, which is followed by infection of respiratory, GI, and urogenital epithelium, as well as the CNS and optic nerves. Disease follows virus replication in these tissues. The degree of viremia and extent of viral spread to various tissues is moderated by the level of specific humoral immunity in the host during the viremic period.
CLINICAL FINDINGS
Classic neurologic signs include:
localized involuntary muscle twitching (myoclonus, chorea, flexor spasm, hyperkinesia)
convulsions, including salivation and chewing movements of the jaw (chewing-gum fits)
Other neurologic signs include:
circling
head tilt
nystagmus
paresis to paralysis
focal to generalized seizures
Lesions found in the brains of dogs with neurologic complications include:
neuronal degeneration
gliosis
noninflammatory demyelination
perivascular cuffing
nonsuppurative leptomeningitis, and
intranuclear inclusion bodies predominately within glial cells
TREATMENT
Treatments are symptomatic and supportive, aimed at limiting secondary bacterial invasion, supporting fluid balance, and controlling neurolog