RESUMEN
Canine influenza virus (CIV) is an emerging pathogen that causes acute respiratory disease in dogs. As with any communicable disease, dog-to-dog transmission of CIV occurs when infected dogs come in contact with other susceptible dogs. We demonstrate that CIV transmission occurs readily from CIV-infected dogs to susceptible dogs following co-mingling. Four experimentally infected dogs were co-mingled with a group of eight CIV-negative dogs at 1 day post-infection and both groups were observed for CIV-associated respiratory disease. The onset of clinical signs, virus shedding, seroconversion, and appearance of lung lesions were observed earlier in experimentally infected dogs; however, the severity of the clinical signs and lung lesions were very similar in both groups. One hundred percent of the experimentally infected dogs and 75% of the contact-exposed dogs excreted virus in their nasal secretions. Additionally, 100% of experimentally infected dogs and 75% of the contact-exposed dogs exhibited varying degrees of pneumonia. Our study results demonstrate that CIV spreads readily from infected dogs to other susceptible dogs through direct contact.
Asunto(s)
Enfermedades de los Perros/transmisión , Subtipo H3N8 del Virus de la Influenza A , Infecciones por Orthomyxoviridae/veterinaria , Animales , Enfermedades de los Perros/patología , Enfermedades de los Perros/virología , Perros , Pulmón/patología , Pulmón/virología , Nariz/virología , Infecciones por Orthomyxoviridae/patología , Infecciones por Orthomyxoviridae/transmisión , Infecciones por Orthomyxoviridae/virología , Factores de Tiempo , Tráquea/virología , Esparcimiento de VirusRESUMEN
Canine influenza virus (CIV) subtype H3N8 is an emerging pathogen with sustained horizontal transmission in the dog population in the United States. This study evaluated the efficacy of an inactivated CIV vaccine in 6- to 8-week-old beagle pups challenged with virulent CIV. One group of CIV-seronegative pups was vaccinated with two doses of a CIV vaccine 3 weeks apart; a second group of pups received adjuvanted placebo as a control. Blood samples were collected at various times to determine antibody titers. All pups were challenged with a virulent CIV isolate 13 days after the second vaccination and monitored for clinical signs of respiratory disease, virus shedding, and lung consolidation. Vaccinated pups developed hemagglutination inhibition antibody titers after vaccination. The severity of clinical signs (P < .001) and the magnitude and duration of virus shedding (P < .0001) were significantly lower in vaccinated pups compared with control pups. These results demonstrate that the CIV vaccine used in this study provides protection against virulent CIV challenge in dogs.
Asunto(s)
Enfermedades de los Perros/prevención & control , Subtipo H3N8 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/normas , Infecciones por Orthomyxoviridae/veterinaria , Animales , Anticuerpos Antivirales/sangre , Antígenos Virales/análisis , Perros , Femenino , Pruebas de Inhibición de Hemaglutinación/veterinaria , Inmunohistoquímica/veterinaria , Subtipo H3N8 del Virus de la Influenza A/aislamiento & purificación , Vacunas contra la Influenza/inmunología , Pulmón/patología , Pulmón/virología , Masculino , Infecciones por Orthomyxoviridae/patología , Infecciones por Orthomyxoviridae/prevención & control , Infecciones por Orthomyxoviridae/virología , Vacunas de Productos Inactivados/inmunología , Vacunas de Productos Inactivados/normas , Esparcimiento de VirusRESUMEN
Canine influenza virus (CIV) subtype H3N8 has emerged as a new pathogen with sustained transmission in the dog population in the United States. In this study, we report the experimental induction of respiratory disease in dogs using three CIV field isolates. Young (14 to 15 weeks of age) CIV-seronegative pups were challenged with one of three CIV isolates and monitored for clinical signs of respiratory disease, nasal virus shedding, seroconversion, lung lesions, and virus isolation from the lower respiratory tract. The challenged pups developed clinical signs and lung lesions typical of influenza virus infection, shed virus in their nasal secretions for 7 to 8 days after challenge, and exhibited serum antibodies at 7 and 14 days after challenge. Lung tissues and tracheal swabs collected at 3 and 6 days after challenge exhibited active virus replication. These results demonstrate that CIV causes respiratory disease in dogs.
Asunto(s)
Enfermedades de los Perros/virología , Subtipo H3N8 del Virus de la Influenza A , Infecciones por Orthomyxoviridae/veterinaria , Animales , Anticuerpos Antivirales/sangre , Enfermedades de los Perros/patología , Perros , Femenino , Pulmón/patología , Masculino , Infecciones por Orthomyxoviridae/patología , Infecciones por Orthomyxoviridae/virología , Replicación ViralRESUMEN
The results of this study confirmed that dogs vaccinated subcutaneously with a commercially available multivalent vaccine containing modified-live canine distemper virus, canine adenovirus type 2, canine parvovirus type 2b, and canine parainfluenza virus antigens were protected against sequential experimental challenge 55 to 57 months after initial vaccination given at 7 to 8 weeks of age. All 10 vaccinates were protected against clinical diseases and mortality following parvovirus and infectious canine hepatitis experimental infections. All vaccinates were protected against mortality and 90% against clinical disease following distemper challenge. These data support at least a 4-year duration of immunity for these three "core" fractions in the combination vaccine.