The alphaviruses Estern, Western and Venezuelan ecnecphalomyelitis, belong to which Family?
Describe the pathology of E/W/Ven encephalomyelitis, in horses?
Mosquito bite. It replicates in the vesselsan lymph nodes, viraemia develops. Then secondary replication in lymph nodes and muscles. Then brain invasion, where it replicates in h neurons,glial cells and blood vessels.
What are the gross lesions expected with E/W/Ven encephalomyelitis in horses?
Cerebral hyperemia, edema, petechiation and focal necrosis in the gray matter
E/W/Ven encephalomyelitis causes neuronl necrosis, but what else, less commonly?
After primary viraemia, a secondary viraemia occurs with systemic epithelial colonization and viral shedding. Then spreads haemotogenously to the brain and choroid plexus, to infect astrocytes and microgli
How long before a dog recovers from CDV?
Within 14 days if good immunity; if poor or intermediate then may develop severe disease
What would you look for intracytoplasmic inclusion bodies of CDV?
in the respiratory epithelium
When would CNS signs develop?
about 1-3 weeks after systemic signs. Or they may occur after a subclinical infection
What gross lesions would you see in the CNS, with CDV?
White matter vacuolation, due to the direct effect of the virus on oligodendrocytes.
What are the three syndromes (age-related) of CDV?
Distemper encephalomyelitis in mature dogs (progressive, when infects dogs at 4-8yo), Post-vaccinal canine distemper encephalitis (Live vaccines occasionally fatal encephalitis in young dogs and exotic carnivores), "old dog" encephalitis (usually past middle age, due to long-term sublincnial persistent infection)