A fatal viral disease of dogs and other carnivores, with a worldwide distribution. Canine distemper virus has a wide host range; most terrestrial carnivores are susceptible to natural canine distemper virus infection. All animals in the families Canidae (such as dog, dingo, fox, coyote, wolf, jackal), Mustelidae (such as weasel, ferret, mink, skunk, badger, stoat, marten, otter), and Procyonidae (such as kinkajou, coati, bassariscus, raccoon, panda) may succumb to canine distemper virus infection. Members of other Carnivora families, including domestic cats and swine, may become subclinically infected. The virus has also been isolated from large cats (lions, tigers, leopards) that have died in zoological parks in North America, from wild lions in the Serengeti National Park (Tanzania), and from wild javelinas (collared peccaries). Canine distemper virus is classified as a morbillivirus within the Paramyxoviridae family, closely related to measles virus and rinderpest virus of cattle and the phocine (seal) and dolphin distemper virus. The virus is enveloped with a negative-sense ribonucleic acid and consists of six structural proteins: the nucleoprotein and two enzymes in the nucleocapsid, the membrane protein on the inside, and the hemagglutinating and fusion proteins on the outside of the lipoprotein envelope. Animal virus Paramyxovirus Canine distemper is enzootic worldwide. Aerosol transmission in respiratory secretions is the main route of transmission. Virus shedding begins approximately 7 days after the initial infection. Acutely infected dogs and other carnivores shed virus in all body excretions, regardless of whether they show clinical signs or not. Great variations occur in the duration and severity of canine distemper, which may range from no visible signs to severe disease, often with central nervous system involvement, with approximately 50% mortality in dogs. The first fever 3–6 days after infection may pass unnoticed; the second peak (several days later and intermittent thereafter) is usually associated with nasal and ocular discharge, depression, and anorexia. A low lymphocyte count is always present during the early stages of infection. Gastrointestinal and respiratory signs may follow, often enhanced by secondary infection. A specific antiviral drug having an effect on canine distemper virus in dogs is not presently available. Treatment of canine distemper, therefore, is nonspecific and supportive. Antibiotic therapy is recommended because of the common occurrence of secondary bacterial infections of the respiratory and alimentary tracts. Administration of fluids and electrolytes may be the most important therapy for canine distemper because diseased dogs with diarrhea are often dehydrated. |
