The following is an excerpt from Catherine O’Driscoll’s article “Follow-up to the Purdue Study Analysis”, to be published in the November/December 2011 issue of Dogs Naturally Magazine.

I would also point out that the veterinary vaccine industry is a multi-billion, international, highly profitable, blossoming, business. Is it too much to ask that the products they sell us might be free from contaminants? They can afford it. Would we buy food knowing that it’s full of salmonella, excusing the manufacturer because at least the food was cheap?

In fact, vaccine contamination is a real problem if you want to be able to take your dog to the vet for a jab in the sure knowledge that he isn’t going to die as a result of it. Last year (2010), for example, researchers in Scotland and Japan isolated a feline retrovirus in both dog and cat vaccines. (Isolation of an Infectious Endogenous Retrovirus in a Proportion of Live Attenuated Vaccines for Pets, Journal of Virology, April 2010, p. 3690-3694, Vol. 84, No. 7.)

The authors stated: “the current methods used for screening human vaccines for retroviral contaminants include extremely sensitive PCR-based RT assays (not required for veterinary vaccines) that are much more sensitive than conventional RT assays”.

The authors added:

“In this study, we isolated a feline infectious ERV (RD-114) in a proportion of live attenuated vaccines for pets. Overall, it is possible that our data under-represent the number of vaccines from which RD-114 can be isolated….

“Collectively, our data show unequivocally that RD-114 is present in live attenuated vaccines commonly used in dogs and cats from different continents and produced by three different manufacturers… the large-scale exposure to RD-114, particularly of the dog population, may have effects that are impossible to predict even if successful RD-114 transmission was an extremely rare event.

“Millions of puppies are vaccinated annually worldwide, and they may be more susceptible to RD-114 infection than cats as the dog genome does not harbor RD-114. … it is impossible to rule out chronic effects, especially as we were able to grow RD-114 very efficiently in dog cell lines, confirming older published studies….

The study concluded that:

• Future studies will be necessary to determine whether RD-114 has any negative impact in cats or dogs….

• A recently identified novel human retrovirus (xenotropic murine leukemia virus-related retrovirus [XMRV]) has been found in some forms of prostate cancers and chronic fatigue syndrome in humans

• sensitive PCR-based RT assays (as used in this study) are not required for veterinary vaccines

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Writing in US Dog World, March, 1995, Dr Jean W Dodds offers some clarification on the implication of retrovirus contamination in dog vaccines:

“Immune–suppressant viruses of the retrovirus and parvovirus classes have recently been implicated as causes of bone marrow failure, immune-mediated blood diseases, haematologic malignancies (lymphoma and leukaemia), dysregulation of humoral and cell-mediated immunity, organ failure (liver, kidney) and autoimmune endocrine disorders – especially of the thyroid gland (thyroiditis), adrenal gland (Addison’s disease) and pancreas (diabetes). Viral disease and recent vaccination with single or combination modified live virus vaccines, especially those containing distemper, adenovirus 1 or 2 and parvovirus, are increasingly recognised contributors to immune-mediated blood diseases, bone marrow failure and organ dysfunction.”

So a feline retrovirus in their vaccines could cause serious problems for our dogs – but don’t worry, because it means we get ‘cheap’ vaccines! According to UK Kennel Club research, one in four dogs in the UK can be expected to die of cancer. Retroviruses are implicated in this scenario.