Canine distemper is a very serious viral disease affecting animals in the families Canidae, Mustelidae, Mephitidae, Hyaenidae, Ailuridae, Procyonidae, Pinnipedia, some Viverridae and Felidae (though not domestic cats; feline distemper or panleukopenia is a different virus exclusive to cats). It is most commonly associated with domestic animals such as dogs, although ferrets are also vaccinated for it. It is a single-stranded RNA virus of the family paramyxovirus, and thus a close relative of measles and rinderpest. Despite extensive vaccination in many regions, it remains a major disease of dogs.
Although very similar to the measles virus, CDV seems to have appeared more recently, with the first case described in 1905 by French veterinarian Henri Carré. It was first thought to be related to the Plague and Typhus and resulted from several species of bacteria. It now affects all populations of domestic dog and some populations of wildlife. A vaccine was developed in 1950, yet due to limited use the virus remains prevalent in many populations. The domestic dog has largely been responsible for introducing canine distemper to previously unexposed wildlife and now causes a serious conservation threat to many species of carnivores and some species of marsupials. The virus contributed to the near-extinction of the black-footed ferret. It also may have played a considerable role in the extinction of the Tasmanian tiger and recurrently causes mortality among African wild dogs. In 1991, the lion population in Serengeti, Tanzania experienced a 20% decline as a result of the disease. The disease has also mutated to form phocid distemper virus, which affects seals.
Puppies from three to six months old are particularly susceptible. Canine distemper virus (CDV) spreads through the aerosol droplets and through contact with infected bodily fluids including nasal and ocular secretions, feces, and urine 6-22 days after exposure. It can also be spread by food and water contaminated with these fluids. The time between infection and disease is 14 to 18 days, although there can be a fever from three to six days postinfection.
Canine distemper virus tends to orient its infection towards the lymphoid, epithelial, and nervous tissues. The virus initially replicates in the lymphatic tissue of the respiratory tract. The virus then enters the blood stream and infects the lymphatic tissue followed by respiratory, Gastrointestinal, urogenital epithelium, the Central Nervous System, and optic nerves. Therefore, the typical pathologic features of canine distemper include lymphoid depletion (causing immunosuppression and leading to secondary infections), interstitial pneumonia, encephalitis with demyelination, and hyperkeratosis of foot pads.
The mortality rate of the virus largely depends on the immune status of the infected dogs. Puppies experience the highest mortality rate where complications such as pneumonia and encephalitis are more common. In older dogs that do develop distemper encephalomyetilis, vestibular disease may present. Around 15% of canine inflammatory central nervous system diseases are a result of CDV.
There exist a number of vaccines against canine distemper for dogs and domestic ferrets, which in many jurisdictions are mandatory for pets. The type of vaccine should be approved for the type of animal being inoculated, or else the animal could actually contract the disease from the vaccine. A dog who has eaten meat infected with Rinderpest can also sometimes receive temporary immunity. Infected animals should be quarantined from other dogs for several months due to the length of time the animal may shed the virus. The virus is destroyed in the environment by routine cleaning with disinfectants, detergents, or drying. It does not survive in the environment for more than a few hours at room temperature (20-25 °C), but can survive for a few weeks in shady environments at temperatures slightly above freezing. It, along with other labile viruses, can also persist longer in serum and tissue debris.
Dem Advises Dog Owners about Re-Emergence of Canine Distemper Virus after the Recent Diagnosis of a Raccoon on Prudence Island with the Disease
Nov 15, 2012; PROVIDENCE, RI -- The following information was released by the state of Rhode Island: The Department of Environmental Management...