Canine Distemper Virus
Canine Distemper Virus
Canine Distemper is a single strand RNA viral disorder that affects dog breeds at all ages even though puppies aged 3 to 6 months are the most vulnerable to infection. Canine Distemper (or a mutated form) also affects several other animal species including wild dogs, hyenas, the big cats, weasels, skunks, pandas, raccoons and seals. It is spread through direct contact with infected body fluids such as urine, feces and nasal droplets, or through water and food already contaminated with the virus. Infection results in a weakened immune system, impairment of the dog’s motor functions, thickening of the footpads and interstitial pneumonia. In previous years Canine Distemper Virus was sometimes mistaken for Canine Infectious Hepatitis.
On average 14 to 18 days will pass between the time a dog has been infected with the disease to the time that the disease will become evident. Some dogs may have a fever around 3 to 6 days post infection.
Signs and Symptoms
Dogs infected with canine distemper virus (CDV) usually suffer from two bouts of acute fever accompanied by loss of appetite, running nose, anorexia, diarrhea, vomiting, dehydration, coughing, weight loss and an eye discharge. The dogs may also display neurological weakness that is exhibited through seizures, involuntary muscle twitching, inco-ordination and sudden sensitivities to light. The first bout of fever occurs after 96 hours of infection and the second after about one and a half weeks of infection. The second bout of fever takes a longer time to recede and the virus remains in an active state for at least 7 days. Severe cases of CDV may lead to the loss of eye sight, paralysis and even death.
CDV has a propensity to direct its infection towards the epithelial, lymphoid, and nervous tissues. At the start of the infection, the CDV will begin by replicating itself in the lymphatic tissue of a dog’s respiratory tract. Then the virus will enter the blood stream and begin to infect the following: lymphatic tissue, respiratory, Gastrointestinal, urogenital epithelium, the Central Nervous System, and lastly, the optic nerves.
The main characteristics of the distemper virus in dogs is interstitial pneumonia, encephalitis with demyelination, hyperkeratosis of the pads of the dog’s feet, and lymphoid depletion (which causes immunosuppression leading to secondary infections).
The strength of a dog’s immune system will largely determine the mortality rate of the distemper virus. Therefore, puppies experience the highest mortality rate due to their underdeveloped immune system and will usually succumb to complications of the virus, such as pneumonia. Older dogs more commonly develop encephalitis in response to an inadequate clearing of the virus. Hypertrophic osteodystrophy in puppies can occur as a result of the Distemper Virus.
Approximately 15% of all inflammatory central nervous system diseases in dogs are caused by the distemper virus.
The symptoms of CDV are sometimes confused with those of other illnesses that affect dogs. The most effective way to diagnose CDV is by a Brush Border smear test of the inside bladder lining of the dog. Almost 90% of the cells in this area will respond positively to a CDV test. However, this test is only practical within 21 days after infection. After that, the more obvious outward clinical signs of the illness will start to appear.
For many years after the disease was first discovered, CDV treatment was ineffective. The main reason for this was misdiagnosis. However, over time, research revealed a connection between canine distemper and measles. The viruses causing either illness both belong to the paramyxovirus family. An interesting finding was that Vitamin A and Ribavirin, for long known as effective in measles treatment, have proven to be just as effective on CDV.
The most effective preventative measure for Canine Distemper is to ensure vaccination at an early age. Actually, in a number of countries and States in the US, vaccination is mandatory. That said, vaccination must be done very carefully.
This is because CDV affects a number of other domesticated animals such as ferrets, and the vaccine for use for each animal is different. In general, the vaccines for CDV are safe and effective, however hypertrophic osteodystrophy and juvenile cellulitis have been associated with distemper vaccination in young dogs. Signs usually occur approximately 10 days following vaccination and have been seen with all MLV ( modified Live virus) vaccine strains
In the event of infection, the affected dog should be kept away from other dogs for several months. The virus does not survive in the environment for more than several hours and even though it can stay alive for longer in shaded areas. Thus, routine cleaning using liquid soap and disinfectant is advised.