Since in the last 5 years, our research activity has involved
veterinary Universities, Hospitals and Institutions and private
animal clinics, together with human clinicians in comparative
studies between human mankind and domestic or wild
animals; the aim is to clarify some common physiopathology
pathways, and to share diagnostics and therapeutic steps with
animal cohorts having a shorter overall survival perspective
compared with the human beings; in this way it is possible to
accelerate the recognition of investigational drugs outcome.
In the paper, we perform a retrospective study about vaccination
toxicity in some animal species, mainly cats and dogs.
Although there is no government obligation for veterinarians
to report vaccine reactions, cumulative incidence of vaccination
adverse events data between dogs and cats are reported
to the vaccine manufacturer and/or to the Canadian Centre
for Veterinary Biologics (CCVB) by the veterinarian or pet
owner in Canada between 2010 and 2014 (Table 1).
Table 1: Suspected adverse reactions for small animals (dogs, cats) vaccines
reported to the Canadian Centre for Veterinary Biologics between
2010 and 2014.
The most common registered adverse reactions are allergic:
2663 cases per 10.000 vaccinated domestic animals. Indeed,
Type III allergic reactions, including cutaneous vasculopathy
and Arthus reactions (36 cases) occurred mainly at the rabies
vaccination, could be correlated to a genetic predisposition. Transient symptoms, such as fever (570 cases), lethargy
(3.396 cases), injection site swelling/tenderness (1833 cases),
pain (200 cases), or anorexia (24 cases), prolonged up to 48 h,
were observed in several cats and dogs [6-8].
Feline injection site sarcomas are rare (1 to 10 per 10.000
cats), but serious, since involve prolonged or repeated inflammatory
processes in genetically predisposed individuals and
can occur also in response to injected therapeutics including
steroids, non-steroidal anti-inflammatory drugs (NSAIDS),
non-absorbable sutures, and a microchip device.
Neurological symptoms (e.g. head tremor/bobbing, encephalitis,
head pressing, convulsion/seizure, rigidity, weakness,
altered reflexes) have been reported in animals (1186 cases
per 10.000 doses) that are showed an allergic reaction or pronounced
inflammatory reaction (Cooper C and Naczynski Z,
CFIA CCVB, 2015, personal communication).
Type II immunemediated
disorders such as immune-mediated thrombocytopenia
and immune-mediated hemolytic anemia are very rare
in small animals (62 cases per 10000 doses), but case control
studies did not demonstrate a causal relationship between
vaccine administration and autoimmune disorders.
Protective and susceptible gene haplotypes have been identified
in dogs, demonstrating genetic predisposition to type II
hypersensitivities. As vaccines are designed to stimulate
an immune response, it is not surprising that a predisposed
individual may react to vaccination due to the production
of inflammatory mediators. A retrospective study in nine veterinary hospitals in Sydney
recorded, in 705 rabbits, 17 (1.8%) adverse reactions: 13
(76.5%) were local injection site reactions involving alopecia,
abrasions and scabbing. Other reactions, including systemic
signs of gastrointestinal tract stasis, lethargy and forelimb
lameness, were also documented. A significant association
between increasing age and decreased incidence of adverse
events was demonstrated (p value: 0.038).
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