Why Vaccination Programs are Changing?
Giardiosis kutyákban és macskákban Mikor gondoljunk rá? Elsősorban fiatal egyedeknél vagy legyengült immunrendszerű állatokban, krónikus jelleggel intermittálóan jelentkező nyálkás-véres hasmenés esetében.
Why, when you know from personal experience that life-long immunity exists for many human vaccines, do you have great difficulty believing a canine vaccine can also provide life-long immunity? Immunologic memory varies from disease to disease and among different types of vaccines. Immunologic memory is likely to be giardia vaccine usa same for modified live viral vaccines, as it is from natural immunity, immunity after infection or disease.
Similarly bacterial infections and vaccines or bacterins killed bacterial vaccines can provide immunologic memory. Immunologic memory to bacteria is generally not as long as to viruses and, in general, immunologic memory to killed viral vaccines and to bacterial vaccines or bacterins is not as long lived as it is to MLV vaccines. The duration of immunity or length of immunologic memory varies among the agents causing the diseases.
For example, our immunologic memory for measles virus is generally life-long. How do we know that it is life long? In contrast to the MLV vaccine, the killed measles vaccines that were used for a short period of time about 25 years ago failed to give life-long immunity.
Many individuals receiving killed vaccines were either inadvertently infected or had to be revaccinated with a MLV when they were 15 to 20 years of age. Their exposure to virus or vaccine provided lifelong immunity. How many giardia vaccine usa do you know that were vaccinated with the modified live measles virus product, in use for approximately 40 years, or that had measles as a child, later developed measles during their life?
It is possible, but rarely occurs.
A very similar story to measles can be told for canine distemper virus CDV in the dog. CDV is in the same virus family as measles virus and rinderpest in cattle and the viruses share many similarities. As you may know, MV veterinary vaccines have been and were available until recently for use in dogs to prevent disease not infection caused by CDV.
Like measles immunity in humans, giardia vaccine usa from canine distemper infection confers immunologic memory resulting in lifelong immunity. How do I and my older, wiser and now retired giardia vaccine usa and canine infectious disease experts, Dr.
Max Appel, Dr. Skip Carmichael, and Dr.
Larry Swango know that distemper immunity is life long? We know because we had the opportunity to follow dogs that recovered from infection with CDV or puppies giardia vaccine usa were vaccinated once or twice with MLV CDV and lived for 7 or more years and never developed disease even though they were exposed to CDV via natural outbreaks or experimental challenge with CDV. We also know the vaccinated or recovered dogs had lifelong immunity because we and others performed antibody tests for years on the dogs after they recovered from infection or after puppy vaccination.
These dogs all had antibody, showing that immunologic memory was present.
Most of the dogs had titers that provide sterile immunity protection from infection much like the measles titers after vaccination or natural immunization e.
An antibody titer no matter how low shows the animal has immunologic memory since memory effector B cells long-lived plasma cells must be present to produce that antibody.
Some dogs without antibody are protected from disease because they have T cell memory, that will provide cell mediated immunity CMI. CMI will not protect from reinfection, but it will prevent disease. When an animal is antibody negative it may have T cell immunologic memory, but I generally consider a CDV antibody negative dog not to be protected, therefore, I recommend revaccination!.
Some researchers, including féreghajtó szerek embernek, have had the opportunity to follow the duration of immunity for dogs living in natural or experimental environments that are free of CDV and CPV Why is it important that observations are made on dogs and cats that are not exposed to the virus? Because in those environments it is possible to demonstrate that immunologic memory is independent of natural or giardia vaccine usa stimulation with the wild type virus or the vaccine virus.
If infection does not occur, there is no stimulation of the specific memory T or B cells, thus the antibody titer does not increase. However, none of more than 50 dams with sick and dying puppies had a significant increase in antibody titer, none had virus in their feces and none showed clinical signs of CPV-2 disease, all excellent indicators the dams had sterile immunity did not get infected!
Is immunologic memory and duration of immunity to all giardia vaccine usa viruses life-long? The answer is NO!