New Principles of Immunology-Canine
- Immunity is not controlled entirely by antibody levels as we once thought. Immunity is controlled by memory cells. Memory cells are B and T lymphocytes. These are white blood cells which stand ready in the body to respond with protective antibodies when challenged by a disease agent. Memory cells, once programmed, persist for the lifetime of the animal. Therefore it is possible to have low antibody levels (or titer) and still have protective immunity. Although memory cells cannot be measured, their presence can be demonstrated by challenge studies. (23)
- Dogs’ & cats’ immune systems mature fully at 6 months. If a modified live virus (MLV) vaccine is given after 6 months of age, it produces an immunity which is good for the life of the pet (i.e. canine distemper, parvo, feline distemper)(15- p35, 20, 21, 23) Modified live virus vaccines must replicate to stimulate the immune system. If another MLV vaccine is given, the antibodies from the first vaccine block the replication of the new virus. The actively acquired immunity in effect neutralizes the antigens of second vaccine, and there is little or no effect. (8,15,16,19,23a,23c) The titer (level of immunity) is not “boosted” nor are memory cells expanded.
- Not only are annual boosters for parvo and distemper unnecessary (6), they subject the pet to the potential risk of adverse reactions like allergic reactions, Immune Mediated Hemolytic Anemia (4, 21) (a disease where the dog rejects its’ own blood) and Injection Site Fibrosarcomas for cats.
- The AVMA Council on Biologic and Therapeutic Agents has stated: There is no scientific documentation to back up label claims for annual administration of modified live virus vaccines.
- Puppies receive antibodies through their mother’s milk (colostrum) the very first time they nurse. This natural protection can last up to 8 – 14 weeks. Puppies & kittens should not be vaccinated at less than 8 weeks. Maternal immunity will neutralize the vaccine & only a few (0 -35%) will be protected(6, 7, 11, 13, 20, 21, 23). Unfortunately, taking this unprotected baby out of the house and to a veterinary clinic will expose it to parvovirus without protection. Vaccination at home by a breeder at 6 weeks may provide protection for some puppies (0 -35%) It is the not the vaccination at 6 weeks that is objectionable, but the increased risk of exposure to the Parvovirus you are trying to protect against. Vaccination at 6 weeks will, however, delay the timing of the first highly effective vaccine.
- Vaccination of dogs for Distemper at too young of an age has been shown to cause Hypertropic Osteodystrophy, especially in Weimaraners. Vaccinations given 2 weeks apart suppress rather than stimulate the immune system (6, 27, 23).
- A series of vaccinations is recommended starting at 8 weeks and given 3 – 4 weeks apart up to 16 weeks of age. Another MLV vaccination given sometime after 6 months of age (usually at 1 year & 4 months) will provide lifetime immunity (15, 20, 21, 23)
Current Recommendations for Dogs
Distemper and Parvovirus In 1994, Ft. Dodge marketed a new high titer Parvovirus vaccine (RF11). Testing by Dr. Ron Schultz demonstrated that this vaccine and a new high titer vaccine from Immunovet (Proguard) provided much better protection than all other vaccines against canine parvovirus (19,23). When studies by Dr Schultz demonstrated that the new high titer vaccines by Fort Dodge and Intervet were much more effective, Meriel improved their product to match. Pfizer came out with a high titer vaccine, Vanguard puppy. Pfizer and Biocor still market the old vaccines, Vanguard 5 and Biocor.
The frustrating experiences we had prior to 1995, with vaccine breaks were largely resolved by the new improved vaccines. Attempts to improve the efficacy by more frequent administration of the vaccine are no longer necessary.
According to Dr. Schultz in the Journal of the AVMA Aug. 15. 1995, when a vaccination series given at 2, 3, and 4 months and again at 1 year(>6m0) with a modified live virus, puppies and kittens program memory cells that survive for life, providing lifelong immunity for diseases like Parvo and Distemper.(6, 15, 20, 21,23).
Dr. Leland Carmichael at Cornell University and Dr. Schultz have studies showing immunity against challenge at 7 years for canine distemper and 7 years for parvovirus; and immunity by serology out to 15 years for distemper. (22,23 b). Studies for longer duration are pending (5, 13, 14, 15, 18, 22,23 b, 23c.) *A copy of Dr Schultz’s study is in our pet care library for your convenience.
Adverse events from canine distemper vaccine include vaccine induced distemper, vaccine induced folliculitis, and HOD (hypertropic osteodystrophy). HOD is most common in Wiemaraners.
Virus drift There are no new strains of parvovirus as some would like to suggest. Parvovirus vaccination provides cross immunity for all types.
Dogs will not get Parvo from the vaccine, but when the vaccine is administered at a vet clinic to 6 wk old puppies only 30% will respond to the vaccine with any protection while all will likely be exposed. It is likely some of them will come down with parvo which they caught at the Vet Clinic. For this reason we do not start the initial series of vaccinations until the puppies are 8 wks old and are better able to respond to the vaccine.*** It is not the vaccination at 6 wks that I object to but the increased exposure to the virus at the Vet Clinic at an age when maternal antibodies will interfere with the response to the vaccination. I would encourage breeders who have a problem with Parvovirus to vaccinate puppies at home with Parvo, but not Distemper, and only at 6 weeks and no younger, to aid in cutting losses.
Hepatitis (Adenovirus)- (CAV2) is one of the agents known to be a cause of “kennel cough.” Only vaccines with CAV-2 should be used as CAV-1 vaccines carry the risk of “hepatitis blue-eye” reactions and kidney damage. Hepatitis (CAV1) in dogs is a very rare disease. I see several cases per year of “blue eye” from CAV 1 Vaccine purchased at a feed store. I have never seen a dog with hepatitis.
Bordetella – Parainfluenza Commonly called “kennel cough,” the Parainfluenza vaccine is recommended only for those dogs boarded, groomed, taken to dog shows, or for any reason housed where exposed to a lot of dogs. The intranasal vaccine provides more rapid onset of immunity with less chance of reaction (23). Immunity requires 72 hours and does not protect from every cause of “kennel cough”
The vaccine does not contain the serovar of bordetella that a dog would likely be exposed to. It is the parainfluenza portion that is of benefit. Unfortunately an intranasal vaccine for parainfluenza without bordetella is not available.
Rabies Although there have been no reported cases of rabid dogs or cats in Harris County, Montgomery County, or Ft. Bend County, there have been rabid skunks and bats, so the potential exists.
If a dog or cat bites someone and is not vaccinated, it must be quarantined in a licensed facility. Rabies vaccine is highly recommended for your pets protection. This is a killed vaccine. Killed vaccines provide a shorter duration of immunity than MLV (19). Duration of immunity for rabies vaccine has been shown to be at least 7 years.(23b)
In Texas, rabies vaccination is required to be administered at four months of age, one year later, and then every three years for dogs. To help prevent injection site fibrosarcomas, a one year duration of immunity non- adjuvanted vaccine, Purevac, has been approved for cats. This vaccine must be administered annually. A three year license is pending.
Canine corona virus is only a disease of puppies less than eight weeks of age (15- p20). It is a rare, self-limiting disease (i.e. dogs get well in 3 days without treatment)(3). Corona virus does not cause disease in adult dogs. Cornell University and Texas A&M University have only diagnosed one case each in the last 7 years. For a veterinarian to make a diagnosis of Corona Virus based on clinical signs is highly presumptive. Only electron microscopy of feces can verify the presence of canine corona virus. This is only done at places such as Texas A & M Diagnostic Laboratory, and they report no positive tests. The presence of the virus does not indicate it is the cause of disease. Dogs over 8 wks of age cannot and have not been experimentally induced to exhibit disease from corona virus. This is age related immunity.
Immunologists have reason to believe that the vaccine does not work. Mucosal secretory IgA antibodies would be necessary to protect a dog against this disease & an injectable vaccine will not provide this type of protection.(13, 19- p18, 21) I see no justification for the use of corona virus vaccine.
In 1985 a significant number of dogs (>189) died from encephalitis caused by Corona Virus vaccine, combined with the Rockborn strain distemper. (3, 21) An unfortunate & heartbreaking catastrophe caused by an unnecessary vaccine.
Leptospirosis vaccine is a common cause of adverse reactions in dogs ranging from life threatening anaphylactic reactions to mild facial swelling and urticaria.
Leptospirosis is an infection of the kidneys and liver. Dogs and people get it from contact with urine from rats, raccoons, cows and pigs. The risk of contagion from dogs to humans is very low.
Most of the clinical cases of leptospirosis reported in dogs in the U.S. are caused by serovars (or types) L. grippotyphosa, L. pomona and L. bratislava.(1, 9, 15-p20, 21) The most commonly used vaccines contain different serovars-L. canicola & L.icterohaemmorrhagiae. Cross protection is not provided and protection is short-lived (6 – 7 months)(19) New Vaccines recently introduced by Fort Dodge include L. grippotyphosa., and L. pomona .
Although Leptospirosis in dogs seems to be increasing in Michigan, Wisconsin, Ohio, and New York, this disease is rare in Texas. Records at Texas Veterinary Medical Diagnostic Lab show an average of 12 cases of Leptospirosis in dogs in Texas per year. In 2000 the TVMDL recorded L. Icterohaemorrhagiae -3 cases, L. canicola -2, L. pomona -2, L grippotyphosa -1. Texas A&M University reports 31 cases in 21 years. Although this is a serious and life threatening disease, in a state with an estimated dog population of over 7 million, I do not think the risk justifies routine vaccination, with two vaccines twice per year.
This vaccine should not be given to puppies less than 16 weeks of age as it is very immunosuppressive. It can interfere with immunization against parvo & distemper. Reactions are common. Deaths due to immunosupression can occur.
Lyme Disease is a tick born disease which can cause lameness, kidney failure and heart disease in dogs and people. Ticks transmit the disease to humans. Eighty five percent of Lyme disease cases in dogs in the USA are found in nine New England area states Michigan and Wisconsin.
We do not have Lyme disease in Texas. In the N.E. U. S. Ixodid ticks acquire the Lyme disease organism from the deer mouse. The Ixodid tick in Texas feeds on lizards which do not transmit Lyme disease.
Confusion as to the occurrence of Lyme disease in Texas exists due to three things. #1. In Texas we have a disease that closely resembles Lyme Disease, Southern Tick Associated Rash Illness or STARI cause by Borrelia lonestari and spread by the Lone Star Tick. ( Lyme disease is caused by Borrelia burgdoferi and spread by Ixodes scapularis.) #2.Lyme disease testing with the most commonly used test can give a false positive reaction to normal spirochete organisms in a dogs mouth. #3 Manufacturers of the vaccine and the test exaggerate the incidence of the disease in order to sell their product.
Texas A&M University has never seen a case of Lyme disease in a dog from Texas.
The advent of a new ,more accurate Lyme disease Test (Snap Test by Idexx) in 2000 will hopefully give us better information about the non-existence of this disease in Texas.
The average dog in Houston would be at very no risk of contracting Lyme disease. If you travel to endemic areas with your dog, you may still want to consider the safety & effectiveness of Lyme disease vaccine. Dr. Jacobson, Cornell Diagnostic Lab, reported a temporal relationship of 327 dogs which developed polyarthritis after vaccination with Lyme disease vaccine. These dogs did not show antibody titers suggestive of Lyme disease infection. Other causes of arthritis were ruled out. Lyme vaccine has been demonstrated to cause arthritis in hamsters. There is a class action suit in human medicine for failure to warn people about the possibility of developing polyarthritis from human Lyme disease vaccine.
The main antigen displayed by the Lyme disease organism inside the dogs body is Outer Surface Protein B- OSP B. Newer PCR vaccines by Muriel and Schering only contain OSP A antigens. The importance of OSP B & C antigens were discovered after the new vaccines were developed (2, 11)
Theoretically OSP A antibodies in the blood of an immunized dog are ingested by a tick. This prevents the bacteria from reproducing within the tick and therefore from being injected into the dog, if antibodies are in high enough concentrations.
Most Colleges of Veterinary Medicine do not recommend Lyme Disease vaccine.
Lyme disease prevention should emphasize early removal of ticks. Ticks must be attached to the dog for 24 hours to transmit the disease. Amitraz (Preventick) collars are more effective than Frontline as Amitraz paralyzes the tick’s mouth parts preventing transmission of disease (11). Amitraz tick collars should be used with extreme caution, as they are toxic if chewed on or swallowed by a dog or children. Frontline takes 24 – 48 hours to kill ticks, allowing for the possibility of disease transmission. This is an important aid in tick control, but will not prevent the transmission of tick born diseases like Lyme disease, Ehrlichia, Babesia or Rocky Mountain Spotted Fever. Vaccinating pets against Lyme disease does not provide any protection for the owners.