CANINE DISTEMPER DIAGNOSIS
Since many of the symptoms of the Canine Distemper Virus (CDV) are also present in many other health conditions, it may be some time before a positive diagnosis for CDV is confirmed. It's important to tell your veterinarian if your dog may not have received the distemper vaccine, since this is usually a sign that testing for distemper should be an initial diagnostic procedure before other medical conditions.
Also, if your dog has recently been vaccinated against CDV (usually during the puppy stage), it is possible for some of the symptoms of Canine Distemper to develop.
There are several procedures available to allow veterinarians to obtain a positive diagnosis for Canine Distemper.
1. DISTEMPER INCLUSION BODIES
This test involves scanning the blood content of a dog suspected to be infected with CDV under a high-powered microscope. The CDV virus, if present, may be visible in this test as "clumps" of the virus. These clumps are called "Distemper Inclusion Bodies". To figure out if the distemper virus is present, the antibodies against CDV are tagged with microscopic fluorescent markers (this procedure of fluorescent tagging is also called "immunocytology"), and then added to a sample of the possibly infected dog's blood.
If Distemper Inclusion Bodies are present, the tagged antibodies will bind to these clumps of virus, which allows the virus to also be "dyed" with the fluorescence. Presence of these Distemper Inclusion Bodies confirms that the dog is infected with CDV. However, it is also possible for this test to be negative in dogs that are infected with CDV, as the Distemper Inclusion Bodies may already be completely covered in the inherent antibodies present in the dog's bloodstream. If this test is negative, additional diagnostic procedures may be performed.
2. DISTEMPER ANTIBODY LEVELS
In dogs that are infected with the Canine Distemper virus, there are two types of antibodies that may be present. If a dog is in the initial (early) stages of CDV infection, "IgM" type antibodies will be present. In later stages of infection with CDV, "IgG" type antibodies will be present. The only problem with this test, is if a dog has been recently vaccinated against Canine Distemper. If so, there may be residual antibodies from the vaccine that are still present in the dog's bloodstream. This is another reason why it's very important to give your veterinarian the complete medical history for your dog, including any recently performed vaccinations.
3. CEREBROSPINAL FLUID ANTIBODY LEVELS
Once a dog infected with Canine Distemper has reached the stage of neurological infection (which usually includes neurological symptoms such as seizures and loss of coordination), it is possible to perform a test involving the Cerebrospinal fluid. In this diagnostic test, a sample of the Cerebrospinal fluid is extracted, and subsequently tested for the presence of Canine Distemper antibodies. This test is more definitive than simply checking for possible Distemper antibodies in the bloodstream, since residual antibodies from a recent Distemper vaccine will not be present in the Cerebrospinal Fluid.
However, this diagnostic test also requires that a dog is in the more advanced stages of infection with the Canine Distemper Virus.