{{We've heard for a number of years that the severe increase we now see in canine allergies is likely tied to the decades of overvaccination, in part. This article kind of breaks it down and explains the process at a cellular level...rather an interesting read. Mainly, it focuses a lot on food allergies - which aren't as common in dogs as enviro are...but nonetheless, still interesting. What left me hanging, though, at the end was the closing comment about "prevention"...but then it didn't provide us any guidance on what "prevention" should mean to us.}}
Anyway,
here is the article:
Vaccination And Allergies: The Surprising Truth
Does your dog itch and scratch?
Does she suffer from recurrent ear infections, hot spots or hair loss? If so, she’s not alone.
Food allergy is a growing concern. In fact, it’s the third leading cause of allergy symptoms in dogs, after flea bite allergies and atopy.
Food Allergy or Intolerance
It’s important to know the difference between a food allergy and intolerance. Food intolerance is the result of poor digestion and the symptoms normally include diarrhea or other chronic, low-level symptoms.
Food allergies are the result of the over-response of the immune system to a food protein. Nearly all food your dog eats contains protein and these proteins all have the ability to trigger food allergies.
The most common proteins that cause allergy symptoms in dogs are beef, dairy and chicken, although some plant based proteins including corn, wheat and soy, can also be triggers.
While food allergies are an increasingly large problem in dogs, most vets and pet owners are most concerned with treating existing allergies with food elimination diets or immune suppressing drugs. Anybody who has a dog with allergies knows they are notoriously difficult to treat, so focusing on prevention is important for any pet owner.
And the first step toward prevention of allergies is of course being able to identify their cause.
Creating Food Allergies
When dogs eat food protein, it’s first digested in the stomach where stomach acids and enzymes break complex proteins into smaller pieces. This partially digested food then moves into the intestines, where it’s further digested and the proteins are broken down into their smallest parts: amino acids. These amino acids are then absorbed by the body, where they pass through special cells called enterocytes. These cells are capable of rejecting any amino acids they see as a threat or foreign invader.
What Happens When Food Proteins Are Injected?
When food proteins are injected directly into the blood stream, a type 1 hypersensitivity reaction against this new allergen causes a response in a type of immune cell called a TH2 lymphocyte, which belongs to a subset of T cells that produce a cytokine called interleukin-4 (IL-4). These TH2 cells interact with other lymphocytes called B cells, whose role is the production of antibodies. Coupled with signals provided by IL-4, this interaction stimulates the B cell to begin production of a large amount of a type of antibody specific to food proteins, known as IgE.
Secreted IgE circulates in the blood and binds to an IgE-specific receptor on the surface of other kinds of immune cells called mast cells and basophils, which are both involved in the acute inflammatory response. The IgE-coated cells are then sensitized to the allergen (food proteins).
If the vaccinated dog now eats these foods, the food proteins bind to the IgE held on the surface of the mast cells or basophils. Cross-linking of the IgE and Fc receptors occurs when more than one IgE- receptor complex interacts with the same food allergenic molecule, and activates the sensitized cell. Activated mast cells and basophils undergo a process called degranulation, during which they release histamine and other inflammatory chemi- cal mediators (cytokines, interleukins, leukotrienes, and prostaglandins) from their granules into the surrounding tissue, causing several systemic responses, such as vasodilation, mucus secretion, nerve stimulation and smooth muscle contrac- tion. This is what causes food allergy symptoms like itchiness and inflamed ears.
Depending on the individual dog, the food allergen and how it’s introduced, the symptoms can be system-wide (anaphylaxis), or localized to particular body system like the skin.
So to summarize, an allergic reaction occurs to the foods that contain the food proteins that were present in the vaccine.
The Role Of Vaccines
Most viruses (like distemper and parvovirus), need to be first grown and harvested to make the vaccine. This process begins with a small amount of virus, which needs to be grown in cells. Various types of cells can be used, including chicken embryos, calf serum, or other cell lines that reproduce quickly and repeatedly.
Once the antigen is grown, vaccine manufacturers try to isolate it from the cells. But proteins and other food particles can still be present in the vaccine. Then an adjuvant (a material that stimulates an exaggerated immune response) may be added, as well as stabilizers or preservatives. Many vaccine adjuvants are made from vegetable oils, such as soybean, corn and peanut, and these plant-based oils can also cause food allergy. It’s no wonder so many children have recently developed peanut allergies.
Modern Research
The Centers for Disease Control (CDC) published a document called “Recommendations of the Advisory Committee on Immunization Practices (ACIP)”. This paper includes research from Nakayama et al (A clinical analysis of gelatin allergy and deter- mination of its causal relationship to the previous administration of gelatin-containing acellular pertussis vaccine combined with diphtheria and tetanus toxoids. J Allergy Clin Immunol 1999). They found that,
"Most anaphylactic reactions and some urticarial reactions to gelatin-containing measles, mumps, and rubella monovalent vaccines are associated with IgE-mediated gelatin allergy. DTaP immunization histories suggest that the gelatin-containing DTaP vaccine may have a causal relation- ship to the development of this gelatin allergy."
In the same paper, Sakaguchi et al concluded the following:
"We reconfirmed a strong relationship between systemic immediate-type allergic reactions, including anaphylaxis, to vaccines and the presence of specific IgE to gelatin."
Gelatin in Vaccines
Several vaccines contain gelatin (which is derived from collagen, normally from cows or pigs), as well as other food proteins. This is the same conclusion Charles Richet arrived at over 100 years ago, so it seems that although vaccines have changed in the last century, their ability to cause food allergy hasn’t.
And of course, these injected food proteins can cause a myriad of other health concerns. Robert S Mendelsohn MD, pro- fessor of pediatrics at the University of Illinois warns,
“No one knows the long term consequences of injecting foreign proteins into the body. Even more shocking is the fact that no one is making any structured effort to find out.”
Until the day comes when scientists, vets and doctors make an effort to learn more about how these injected foreign proteins cause allergies and many other auto-immune diseases in our dogs (and ourselves), the best approach to food allergies is prevention.
As allergist Warren Vaughan said,
"we find ourselves in somewhat of a dilemma, faced with the necessity for choosing the lesser of two potential evils. But as savvy vets and pet owners are starting to delve more deeply into the safety and even the necessity of vaccines, the next hundred years of what will hopefully be more objective vaccine research, might make a difference in which evil pet owners will choose."