Canine Distemper Virus Update
(N. America) In early October of 2018, a 12-week old "Sheltie" arrived from Korea. Approximately 12 days later, the dog began with a cough and lethargy with blood work indicating "anemia."
About 10 days later, the dog developed a unilateral myoclonus with relapsing lethargy. In another week the neurological signs had progressed to tonic clonic seizures that continued to worsen to a persistent uncontrolled myoclonus at which time the dog was euthanized.
Samples (serum, ocular swab, urine) obtained at 9 days post onset of clinical signs were forwarded to the AHDC for canine influenza virus serology and canine distemper virus RT-PCR testing. The HI serology test indicated no exposure to H3N2 CIV which is the endemic strain of flu A in Korea. However, the RT-PCR tests on the ocular swab and urine were strong positive for canine distemper virus. Attempts were made to isolate the virus from the samples submitted for PCR, but with no success. Our next effort was to try to obtain sequence for virus directly from the nucleic acid used for the RT-PCR assay. This was successful for the F and H genes of CDV. Phylogenetic analyses of the sequences against various clades of CDV, indicated the imported dog was infected with the Asia-1 strain of CDV. We have no information on the existence of this clade of CDV in North America.
While we have been most concerned with the importation of canine influenza virus from Asia to North America by improper procedures by various "rescue" groups, the importation of CDV may be more significant in that CDV once it enters an ecosystem cannot be eradicated even with effective vaccines. Once again the North American dog population is being put at risk by those who have no regard for the importation of foreign animal diseases.