2016 ACVIM Forum Research Abstract Program

All four of the dogs were diagnosed with Canine Influenza H3N2 through PCR, three through the New York State Veterinary Diagnostic Laboratory and one through Idexx Diagnostic Laboratory. In patients with characteristic clinical features, Canine Influenza H3N2 virus infection should still be considered as differential diagnosis. A study was conducted in dogs to evaluate the efficacy of an inactivated Canine Influenza Virus (CIV) H3N2 vaccine following experimental challenge with a virulent heterologous strain of CIV H3N2, isolated from the recent CIV H3N2 outbreak in the United States. Eleven dogs, 7-8 weeks of age, were vaccinated with 2 doses of an inactivated CIV H3N2 vaccine, 3 weeks apart, and 19 dogs were vaccinated with a placebo. Two weeks after the second vaccination, all dogs were challenged intranasally with virulent CIV H3N2 and then monitored daily for 10 days for clinical signs including fever, nasal discharge, sneezing, coughing, depression, and dyspnea. Nasal swabs were collected to evaluate viral shedding, and serum samples were collected at various time points to determine antibody titers. At necropsy, lungs were scored for consolidation. Following the booster vaccination, the placebo-vaccinated control dogs remained seronegative (<10) to CIV H3N2, while 10 of the 11 vaccinated dogs developed an antibody titer to CIV H3N2 (GMT = <80; Range = <10 -320). Antibody titers in dogs from both treatment groups increased following challenge, but the increase was greater in the vaccinated dogs (GMT = >1452; Range = 40 ->10,240). Following challenge, 8 (42%) of the 19 placebo-vaccinated control dogs were euthanized prior to the 10-day post-challenge observation period due to severe clinical signs, including difficulty breathing, depression, fever, and severe coughing with retching; whereas, none (0%) of the vaccinates had to be euthanized (P = 0.014). Clinical signs were evaluated based on a weighted scoring system. The mean clinical score for the placebo-vaccinated control group was 24.9, compared to only 8.7 for the vaccinated group (P = 0.036). The placebovaccinated control group shed CIV H3N2 virus for a mean of 1.9 days, compared to 1.4 days for the vaccinated group (P = 0.507). The median lung consolidation score for the placebovaccinated control group was 7.4, compared to 0.0 for the vaccinated group (P = 0.026). Results of this study demonstrate that this inactivated CIV H3N2 vaccine significantly protects dogs against severe clinical disease and lung consolidation associated with a virulent CIV H3N2 infection. Canine infectious respiratory disease complex (CIRDC) is caused by many different viruses and bacteria. In June 2015, veterinarians around Atlanta, Georgia and also western areas of North Carolina began to notice an unusual increase in dogs presenting to their clinics with signs of infectious respiratory disease. Nasal and pharyngeal swabs from dogs exhibiting clinical signs were submitted to the Animal Health Diagnostic Center (AHDC) at Cornell University. A canine respiratory polymerase chain reaction (PCR) screening panel was utilized which allows identification of the following CIRDC pathogens: Bordetella bronchiseptica, Mycoplasma cynos, canine adenovirus 1 and 2, canine distemper, canine influenza A, H3N8 and H3N2, parainfluenza virus 5, pneumovirus and respiratory coronavirus.