Mucosal Veterinary Vaccines: Comparative Vaccinology

Infections of mucosal surfaces are major causes of morbidity, mortality, and economic loss in species of veterinary interest, and a concern for animal welfare. Vaccines are used extensively in veterinary medicine, and innovative vaccine technologies such as recombinant DNA-vectored and distinguishing infected from vaccinated animals (DIVA) vaccines and automated in ovo vaccination (of embryonated chicken eggs) have been rapidly adopted commercially. Immunological research using outbred, nonrodent animal models has contributed to a broader understanding of mucosal defenses, and has provided the initial impetus for investigation of the common mucosal immune system. Studies of the potential of novel adjuvants to improve vaccine efficacy against genetically unstable, immune-subverting RNA viruses, such as porcine reproductive and respiratory syndrome virus in pigs, should assist in the control of pathogens with similar characteristics in other species. Successful development of vaccines to prevent and treat ascending infections of the reproductive tract of cattle set a precedent for applications in other species including humans. Studies of mucosal adjuvants and delivery systems continue at the interface between passive and active immunity, with the goal of inducing the earliest possible protection against enteric and respiratory pathogens of neonates.