Newcastle disease virus infection in 38 weeks old layer brown chicken, mild respiratory signs, normal daily mortality rate, drop of egg production, change color egg, abnormal shape.
Velogenic Newcastle disease virus is the deadliest virus for poultry. So many people assume, if this virus infects a chicken flock, then they will get a very significant chicken mortality rate. But the reality is not always like that.
Clinical symptoms of Newcastle disease vary widely, depending on the level of immunity from chickens. Death can occur in chickens with very low immunity or even no immunity at all. But that does not mean the virus velogenic Newcastle disease will not be able to cause symptoms of disease in chickens with moderate immunity or perhaps with higher antibodies.
Drop egg production with or without respiratory symptoms can occur by infection of this virus in chickens with moderate immunity. This often happens on commercial layers that have been vaccinated against Newcastle disease repeatedly.
Adult commercial layer chickens have been vaccinated repeatedly at a time when they were young. So we rarely get adult layer chicken with low immunity or very low levels of antibodies. So that viral velogenic virus infection Newcastle disease rarely results in high mortality in adult layer chicken flock or during laying. Respiratory symptoms, few nerve symptoms may still be encountered. However, the most dominant clinical symptoms are decreased egg production and changes in the color and shape of the eggshell.
see also: Newcastle disease symptoms video
In a large poultry farm, Often, a young chicken flock is located close to adult layer chicken flock. Then the spread of disease often occurs between the two flocks, then the high mortality will occur in the young chicken flock.
So in adult layer chickens this disease often does not cause high mortality, even there are no severe pathological lesions, then the clinical symptoms of decreased egg production followed by few respiratory symptoms by Newcastle disease virus often misdiagnose with infectious bronchitis.
see also: Infectious Bronchitis Pictures
Neurological symptoms can be a specific symptom, but on a farm with a cage battery system getting a chicken with these symptoms is more difficult. Except for a severe viral infection with a high mortality rate. The nerve symptoms will look very dominant after several weeks of infection.
Velogenic Newcastle Disease is a deadly disease for chickens. What do you think, when compared to H5N1? follow us. Hopefully, this becomes a discussion material for veterinary students.