Virulent Newcastle Disease
What is it?
A highly contagious viral disease impacting all birds; chickens are the most susceptible to the disease. There are few areas of the world that have not been affected by this disease. There are three very different forms of Newcastle Disease: mild (lentogenic), moderate (mesogenic) and virulent (velogenic). Mild and moderate forms of Newcastle Disease may not cause birds to become sick, or can be controlled with different vaccination strategies. However, if combined with other disease agents or poor environmental conditions, it can become a significant disease problem. Exotic Newcastle Disease is the virulent form, which is a great concern to poultry producers because of the potential to cause illness and death, sometimes without any warning. It can also lead to possible trade restrictions. Strains of this virus are endemic in Asia, Africa and some North and South American countries. The U.S. and Canada have import restrictions, testing, and depopulation standards to reduce the risk of those strains. There have been cases of the disease in Arizona, California, Nevada and Texas; each was eradicated.
Transmission
Infection can occur when healthy birds come in direct contact with infected birds or their bodily fluids (feces or respiratory). Once in the environment of domestic poultry, the disease can move rapidly and infect entire flocks. Some wild birds, like cormorants, are highly susceptible and are known to carry and may spread the disease to domestic poultry if preventative measures are not in place.
Signs and Symptoms
Respiratory issues, like coughing, gasping, sneezing and rales; nervousness, tremors or paralysis; a drop in egg production; and varying degrees of depression. These signs can vary between birds and the different forms of the virus. This is why it’s important to be vigilant for any changes in a flock and to investigate those changes immediately.
Diagnosis
Tracheal or cloacal swab samples or other tissues need to be collected from the birds and submitted to a certified laboratory for testing to identify and isolate the virus. Labs like the Minnesota Poultry Testing Laboratory and the University of Minnesota Veterinary Diagnostic Laboratory can test for the disease.
Treatment
There is no standard treatment available for Newcastle Disease. However, vaccination is the best way to reduce the symptoms of the disease and reduce the risk of it spreading between animals.
Prevention
Many different types of vaccines are available for poultry and help reduce the risk of Newcastle Disease infection. Biosecurity is also an excellent deterrent to this disease and many other diseases. Because this disease can travel in infected feces, barn boots, wild birds and other ways; biosecurity measures are important to keep it out of healthy flocks. Flock surveillance and quick identification of sick birds also reduce the risk of disease spread.
Human Risk
While this virus can infect people, this usually only occurs after close handling of live birds who are infected. There is not a risk of Newcastle virus from handling or consuming poultry products, such as meat or eggs. If those working with infected poultry become ill with this virus, symptoms are most often a mild eye infection.
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