Newcastle disease in white Pekin ducks: response to experimental vaccination and challenge

A total of 120 Pekin ducks were distributed at random into four experimental groups, vaccinated or not against Newcastle disease (ND): G1 (Ulster 2C strain), G2 (B1 strain), G3 (LaSota strain), and G4 (nonvaccinated group). At 60 days of age, all groups were challenged with a pathogenic ND virus (NDV) suspension, and a group of specific pathogen free (SPF) chicks (G5) was also inoculated. Cloacal and tracheal swabs from all birds were collected after six, 14, 20, and 30 days post-challenge for virus isolation. NDV was isolated in 100% of SPF chicks. Pekin ducks from all groups, vaccinated or not, did not show any ND clinical signs, demonstrating that these birds are not susceptible to ND clinical disease. In the control group (G4), the virus was isolated 20 to 30 days after challenge, suggesting their possible NDV carrier state. In the vaccinated groups, no virus was isolated. This demonstrates that vaccination of white Pekin ducks against NDV is important to reduce NDV shedding in the field.

Newcastle disease in white Pekin ducks: response to experimental vaccination and challenge

A total of 120 Pekin ducks were distributed at random into four experimental groups, vaccinated or not against Newcastle disease (ND): G1 (Ulster 2C strain), G2 (B1 strain), G3 (LaSota strain), and G4 (nonvaccinated group). At 60 days of age, all groups were challenged with a pathogenic ND virus (NDV) suspension, and a group of specific pathogen free (SPF) chicks (G5) was also inoculated. Cloacal and tracheal swabs from all birds were collected after six, 14, 20, and 30 days post-challenge for virus isolation. NDV was isolated in 100% of SPF chicks. Pekin ducks from all groups, vaccinated or not, did not show any ND clinical signs, demonstrating that these birds are not susceptible to ND clinical disease. In the control group (G4), the virus was isolated 20 to 30 days after challenge, suggesting their possible NDV carrier state. In the vaccinated groups, no virus was isolated. This demonstrates that vaccination of white Pekin ducks against NDV is important to reduce NDV shedding in the field.

Evaluation of experimental vaccination of white pekin ducks (anas platyrhynchos) against newcastle disease

ABSTRACT This study aimed the characterization of the importance of vaccination against Newcastle disease of white Pekin duck (Anas platyrhynchos). There were used 120 Pekin ducks, distributed at random into 4 groups, vaccinated or not. At 60 days of age, all groups were challenged with a pathogenic virus (NDV) suspension, EID50 = 108.15/0.1 mL and a group of Specific Pathogen Free (SPF) chicks were used as control of the virus. Cloacal and tracheal swabs from each bird were collected after 6, 14, 20 and 30 days post-challenge for viral isolation in SPF embryonated eggs. White Pekin ducks of all groups did not demonstrate symptoms of the Newcastle Disease (ND). They were refractory to the ND clinical disease. In Pekin ducks from control group, the viral isolation was obtained from 20 up to 30 days after challenge. The NDV isolation was possible in 100% of SPF chicks that died after challenge with ND clinical signs, suggesting the possible state of carrier of NDV by Pekin ducks. In vaccinated groups, the viral isolation was null. It was also demonstrated therefore the relevance of the vaccination to control the virus dissemination by white Pekin ducks infected with NDV.

RESUMO O objetivo do trabalho foi estudar a importância da vacinação de marrecos de Pequim (Anas platyrhynchos) contra a Doença de Newcastle (DN). Foram utilizados 120 marrecos, distribuídos aleatoriamente em 4 grupos, vacinados ou não. Aos 60 dias de idade, todos os grupos foram desafiados com uma suspensão de vírus patogênico (VDN), EID50 = 108,15/0,1 mL e um grupo de aves livres de patógenos específicos (SPF) foi utilizado como controle do vírus . Suabes cloacais e traqueais foram colhidos após 6, 14, 20 e 30 dias após o desafio para isolamento viral, realizado em ovos embrionados SPF. Os marrecos de Pequim de nenhum dos grupos demonstraram sinais clínicos da DN, mostrando-se refratários à doença clínica. Nos marrecos do grupo controle, o isolamento viral foi positivo de 20 até 30 dias após o desafio, sugerindo o possível estado de portador do VDN pelos marrecos de Pequim. Foi realizado o isolamento viral em 100% das aves SPF, que apresentaram sinais clínicos e vieram a óbito após o desafio com o VDN. Nos grupos vacinados, o isolamento do VDN foi nulo. Tais dados demonstraram a importância da vacinação para o controle da disseminação do vírus pelos marrecos de Pequim infectados pelo VDN.