Page 830 - Veterinary Immunology, 10th Edition

example, some modified live parvovirus vaccines may cause a
VetBooks.ir transient decrease in lymphocyte responses to mitogens or even a

lymphopenia in some puppies, although not all strains of canine
parvovirus 2 are immunosuppressive. Some polyvalent canine viral

vaccines can cause a transient drop in absolute lymphocyte
numbers and their responses to mitogens (see Fig. 40.1). This occurs
even though the individual components of these vaccines may not
have this effect. Several vaccine combinations may result in

transient immunosuppression between 5 and 11 days after
vaccination. For example, a combination of canine adenovirus type
1 or type 2 with canine distemper virus suppresses lymphocyte
responses to mitogens. This T cell suppression may be accompanied

by simultaneous enhancement of B cell responses and raised
immunoglobulin levels. Rather than being a pure
immunosuppressive effect, it may simply reflect a transient change
in the Th1/Th2 balance.

Live bluetongue vaccine has been reported to cause
malformations in the offspring of ewes vaccinated while pregnant.
The stress from this type of vaccination may also be sufficient to
reactivate latent infections; for example, activation of equine

herpesvirus has been demonstrated following vaccination against
African horse sickness. Mucosal disease may develop in calves
vaccinated against bovine virus diarrhea.

Vaccine-Associated Autoimmune Disease

It is widely believed that the prevalence of autoimmune disease in
domestic pets, especially dogs, has risen in recent years. Some
investigators have attributed this rise to excessive use of potent
vaccines. This link is by no means proven; nevertheless, there is

limited evidence that supports an association between vaccination
and autoimmunity. A retrospective analysis of the history of dogs
presenting with immune-mediated hemolytic anemia (IMHA)

(Chapter 37) showed that 15 of 70 dogs with IMHA had been
vaccinated within the previous month, compared with a randomly
selected control group in which none had been vaccinated. Dogs
with IMHA that developed within a month of vaccination differed
in some clinical features from dogs with IMHA unassociated with

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