After reading Hemopet’s blog post titled “Parvovirus Variants and Vaccines”, one reader noted that Dr. Dodds did not include the vaccine to protect against infectious canine hepatitis (ICH), a potentially deadly disease caused by canine adenovirus 1 (CAV-1).
ICH – while recognized worldwide – is an uncommon disease in North America. It Is found not only in
dogs but also can be spread to and amongst bears, coyotes, foxes, lynx, seals and wolves. Typically,
infection occurs through ingestion of feces, nasal discharge, saliva or urine of animals shedding the virus.
Signs and symptoms of ICH are:
-occasional abdominal pain
-discharge from the mucous membranes
-leukopenia (reduced white blood cell count)
Vaccine Against ICH
The vaccines that protect against CAV-1 are actually those made against canine adenovirus-2 (CAV-2) as they also provide good cross-protection against ICH.
The original CAV-1 vaccine was discontinued years ago because it could induce antigen-antibody
complex deposition and a cloudy blue discoloration of the cornea of vaccinated dogs (the so-called “blue eye”).
If you are wondering, the CAV-2 virus typically produces mild respiratory symptoms and is a member of the kennel cough complex.
Reputable veterinary groups, such as the American Animal Hospital Association, include the injectable CAV-2 vaccine to protect against CAV-1 and CAV-2 in their core vaccination protocols.
Why does Dr. Dodds not include it in her current vaccination protocol?
The Reasoning of Dr. Dodds
1. The last known documented case of ICH in North America was over fifteen years ago. Clearly,
effective vaccination and other mitigation techniques have limited the prevalence of the virus.
2. However, when the CAV-2 injectable vaccine to protect against CAV-1 and CAV-2 infection is added to the canine distemper vaccine (a vaccine Dr. Dodds strongly recommends), interactions between the two are responsible for a multi-vaccine induced suppression of lymphocyte responsiveness in puppies for at least 10-14 days. Fortunately, this immune suppression does not occur in vaccinated adult dogs.
Dr. Dodds’ Recommendation
If people think their companion dogs need the CAV-2 vaccine to protect against CAV-2 virus, Dr. Dodds prefers to give the oral version after the initial set of puppy shots. The second option is to give the intranasal Bordetella combination.
By the way, the intranasal and oral CAV-2 vaccines are intended to help provide cross-protection against ICH as well. Cross-protection also works with the injectable CAV-2 vaccine contained in the combination vaccine products. Regardless, giving injectable combination vaccines to adult dogs should help protect against ICH.
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Manual, Merck, June 2013, https://www.merckvetmanual.com/generalized-conditions/infectious-canine-hepatitis/overview-of-infectious-canine-hepatitis.
Dodds, Jean. “Kennel Cough Complex: A Complicated Phrase for the Canine Common Cold.” Dr. Jean
Dodds' Pet Health Resource Blog, Tumblr, 25 Oct. 2015,
Dodds, Jean. “Know Your Bordetella Vaccine.” Dr. Jean Dodds' Pet Health Resource Blog, Tumblr, 31 July
Hornsey, Samuel J., et al. “Canine Adenovirus Type 1 Causing Neurological Signs in a 5-Week-Old
Puppy.” BMC Veterinary Research, vol. 15, no. 1, 21 Nov. 2019, doi:10.1186/s12917-019-2173-5,
Phillips, T R et al. “Effects of vaccines on the canine immune system.” Canadian journal of veterinary
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Sykes, Jane E. “Infectious Canine Hepatitis.” Canine and Feline Infectious Diseases (2014): 182–186.