Canine Distemper Virus (CDV)
Sample: 0, 5 ml EDTA-blood, Conjuctival swab, Oropharyngeal swab
Canine distemper virus (CDV) belongs to the genus Morbillivirus, family Paramyxoviridae. Canine distemper virus is the causative agent of a severe systemic disease in dogs. Canine distemper virus has a broad host range, and evidence for the infection has been obtained in several mammalian species in the families Canidae, Mustelidae, Procyonidae, Ursidae, and Viverridae.
Modes of transmission
Transmission mainly occurs by direct animal-to-animal contact or by exposure to infectious aerosol.
The virus enters the new host by the nasal or oral route and promptly starts replication in the lymphoid tissues, resulting in severe immunosuppression. T cells are more affected than B cells. The decrease lymphocytes is quick and persists for several weeks.
The incubation period may range from 1 to 4 weeks. Transient fever is associated with the initial virus spread in the body. Loss of appetite, slight depression, ocular and nasal discharge, and tonsillitis may be observed. Canine distemper virus spreads by cell-associated viremia to the epithelial cells in most organs. At this stage, the outcome of the infection and the severity of the signs vary markedly on the basis of strain virulence, the age of the animal, and the immune status.
If the dog develops a strong immune response, the virus gets cleared from the tissues and the animal completely recovers from the infection. When dogs develop a weak immune response, the virus is able to reach the epithelial tissues and the central nervous system. The virus persists for extended periods in the uvea, neurons, or urothelium and in some skin areas.
As a result of the epithelial localization, respiratory, intestinal, and dermatologic signs occur by 10 days after infection. The symptoms include purulent nasal discharge, coughing, dyspnea, pneumonia, diarrhea, vomiting, and dermal pustules. Enamel hypoplasia and hyperkeratosis of the foot pads and nose are typical signs of CDV infection.
Starting from 20 days after infection, neurologic signs may be observed, such as circling, head tilt, nystagmus, partial or complete paralysis, convulsions, and dementia. Some dogs may still recover, but compulsive movements tend to persist.
Treatment consists of supportive care and antibiotics and is aimed at preventing the secondary bacterial infections that are frequent in immunosuppressed animals.
Pups should be vaccinated at 7 to 8 weeks of age and again after 2 to 4 weeks. Annual revaccination is usually performed.
Meli, M.L., Cattori, V., Martínez, F., López, G., Vargas, A., Simón, M.A., Zorrilla, I., Muñoz, A., Palomares, F., López-Bao, J.V., et al. (2009). Feline leukemia virus and other pathogens as important threats to the survival of the critically endangered Iberian lynx (Lynx pardinus). PLoS ONE 4.