Page 811 - Veterinary Immunology, 10th Edition

laryngotracheitis, and avian encephalomyelitis in poultry.
VetBooks.ir Alternative routes of vaccine administration that are in

development or employed in humans include cutaneous
vaccination using liquid-jet injectors, microinjection, or topical skin

application through patches or nanoparticles. Plague vaccine-
coated M&Ms have been delivered to prairie dogs and black-footed
ferrets in the western United States by means of drones that can
shoot the candies in three directions simultaneously in order to

ensure even coverage.

Multiple-Antigen Vaccines

For convenience, it is common to employ mixtures of organisms
within single vaccines. In cattle, for example, vaccines are available

that contain infectious bovine rhinotracheitis (BHV-1), bovine virus
diarrhea (BVDV), parainfluenza 3 (P13), and even Mannheimia
hemolytica. Dogs may be given vaccines containing all of the

following organisms: canine distemper virus, canine adenovirus 1,
canine adenovirus 2, canine parvovirus 2, canine parainfluenza
virus, leptospira bacterin, and rabies vaccine. These mixtures may
be used when exact diagnosis is not possible and may protect
animals against several diseases with economy of effort. However,

it can also be wasteful to use vaccines against organisms that may
not be causing problems. When different antigens in a mixture are
inoculated simultaneously, competition occurs between antigens.

Manufacturers of multiple-antigen vaccines take this into account
and adjust their components accordingly. Vaccines should never be
mixed indiscriminately since one component may dominate the
mixture or interfere with the response to the other components.
Some veterinarians have questioned whether the use of complex

vaccine mixtures leads to less than satisfactory protection or
increases the risk for adverse side effects. They are concerned that
the use of 5- or 7-component vaccines in their pets will somehow

overwhelm the immune system, forgetting that our animals
encounter hundreds of different antigens in daily life. The
suggestion that these multiple-antigen vaccines can overload the
immune system is unfounded, nor is there any evidence to support
the contention that the risk for adverse effects increases

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