The inactivated infectious bronchitis virus (IBV) vaccine used as booster in layer hens influences the breadth of protection against challenge with IBV variants.

To achieve long term protection of laying and breeding hens against aberrant egg production caused by infectious bronchitis virus (IBV), a vaccination programme incorporating both live-attenuated and inactivated IBV vaccines is required. High quality IBV vaccines of both types are widely available, but the number of IBV variants of global importance continues to increase and it is not possible to develop vaccines against each one of them. Therefore, it is desirable to perform studies under controlled conditions to determine which IBV vaccine(s) provide the best protection for laying hens against different IBV challenges. Previous vaccination and challenge studies have shown that it is possible to obtain relevant data in a small number of laying hens housed under conditions of strict isolation. The present work extends this finding by investigating the efficacy, against challenge with five IBV strains of global importance, of an IBV vaccination programme including two live-attenuated IBV vaccines (Massachusetts and 793B types) and three different commercially available inactivated vaccines each containing antigen against at least one IBV strain. The results reported here confirm the importance of IBV vaccination for laying hens, show that efficient live priming makes a beneficial contribution to this protection and confirm that inactivated IBV vaccines contribute significantly to effective protection against at least the five IBV challenge strains used here. Furthermore, we provide data to support the "protectotype concept", long-established using different live-attenuated IBV vaccines in young chickens, is valid in broadening protection against IBV challenges in laying birds.RESEARCH HIGHLIGHTSIBV vaccination is essential as an aid in protecting laying hens against IBV infection.Live priming is a beneficial part of the IBV vaccination programme.IBV inactivated vaccine improves IBV protection.Heterologous IBV protection is confirmed in laying hens.

Diagnostic Accuracy of Ultrasonography to Detect False Layers in a Commercial Laying Flock Infected by an Infectious Bronchitis Virus Delmarva Genotype Causing Cystic Oviducts.

Infection of the oviduct by an infectious bronchitis virus (IBV) in laying hens has been associated with the false layer syndrome. Because the diagnostic procedure for the detection of cystic oviducts by postmortem examinations in IBV-positive replacement pullet flocks could involve the unnecessary sacrifice of numerous healthy pullets without reproductive tract anomalies, the development of a noninvasive and nonlethal diagnostic procedure would be desirable. The first objective of the study was to evaluate the diagnostic accuracy of a transcutaneous ultrasonography method to predict the presence of cystic oviducts compared to postmortem examinations in a commercial pullet flock positive for an IBV genotype Delmarva (DMV) variant. The second objective was to evaluate the performance of the same ultrasonography method to later detect false layers in the same flock in sexually mature hens by identifying the presence of an egg in the oviduct due to the presence of atretic oviducts undetectable by ultrasonography and the absence of cystic oviducts at that age. In replacement pullets, the sensitivity (Se) and specificity (Sp) of the ultrasonography (index test) compared to the postmortem examination (reference standard test) were 73% and 91%, respectively. The positive predictive value (PPV) and negative predictive value (NPV) were 67% and 93%. The ultrasonography technique showed a positive likelihood ratio (LR+) of 7.82 and a negative likelihood ratio (LR-) of 0.30. In sexually mature hens, the Se, Sp, PPV, and NPV of the ultrasonography compared to the laying status were 98%. The LR+ was 49.00 and the LR- was 0.02 when compared to the laying status. In conclusion, the ultrasonography could replace postmortem examinations to detect cystic oviducts in commercial flocks of replacement pullets previously infected with an IBV-DMV 1639 variant. Although the test accuracy of ultrasonography was excellent for the hens at production peak to identify laying and nonlaying hens based on the presence of an egg in the reproductive tract, its practicality was limited due to atretic oviducts being not detectable.

Precisión diagnóstica de la ultrasonografía para detectar gallinas falsas ponedoras en una parvada comercial infectada por un virus de la bronquitis infecciosa genotipo Delmarva que causa oviductos quísticos. La infección del oviducto por el virus de bronquitis infecciosa (IBV) en gallinas de postura se ha asociado con el síndrome de la falsa ponedora. Debido a que el procedimiento de diagnóstico para la detección de oviductos quísticos mediante exámenes post mortem en parvadas de pollitas de reemplazo positivas para bronquitis infecciosa podría involucrar el sacrificio innecesario de numerosas pollitas sanas sin anomalías del tracto reproductivo, por lo tanto es deseable el desarrollo de un procedimiento de diagnóstico no invasivo y no letal. El primer objetivo del estudio fue evaluar la precisión diagnóstica de un método de ultrasonografía transcutánea para predecir la presencia de oviductos quísticos en comparación con los exámenes post mortem en un lote comercial de pollitas que resultó positivo para una variante del genotipo Delmarva (DMV) del virus de la bronquitos infecciosa. El segundo objetivo fue evaluar el desempeño del mismo método de ultrasonografía para detectar posteriormente gallinas falsas en la misma parvada en las gallinas sexualmente maduras mediante la identificación de la presencia de un huevo en el oviducto debido a la presencia de oviductos atrésicos indetectables por ultrasonografía y la ausencia de oviductos quísticos a esa edad. En las pollitas de reemplazo, la sensibilidad (Se) y la especificidad (Sp) de la ultrasonografía (prueba de índice) en comparación con el examen post mortem (prueba estándar de referencia) fueron de 73% y 91%, respectivamente. El valor predictivo positivo (VPP) y el valor predictivo negativo (VPN) fueron 67% y 93%. La técnica de ultrasonografía mostró una razón de probabilidad positiva (LR+) de 7.82 y una razón de probabilidad negativa (LR­) de 0.30. En las gallinas sexualmente maduras, la Se, Sp, PPV y NPV de la ultrasonografía en comparación con el estado de postura fueron del 98%. El LR + fue 49.00 y el LR­fue 0.02 en comparación con el estado de la postura. En conclusión, la ultrasonografía podría reemplazar los exámenes post mortem para detectar oviductos quísticos en parvadas comerciales de pollitas de reemplazo previamente infectadas con una variante DMV-1639 del virus de la bronquitis infecciosa. Aunque la precisión de la prueba de la ecografía fue excelente para las gallinas en el pico de producción para identificar gallinas ponedoras y no ponedoras en función de la presencia de un huevo en el tracto reproductivo, su funcionalidad fue limitada debido a que los oviductos atrésicos no fueron detectables.