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 very 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 very 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.
How is it
transmitted? 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.
What are the
clinical signs? 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.
How is it
diagnosed? 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.
Is there a risk to
people? It is zoonotic and people may become infected with Exotic
Newcastle Disease. It can cause conjunctivitis in humans, often in people who
work closely with poultry, and is considered a mild risk to overall health.
Poultry products like meat and eggs are still safe to eat, and should always be
cooked to safe temperatures.
How can it be
prevented? Many different types of vaccines are available for
poultry and help reduce the risk of Exotic 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
reduces the risk of disease spread.
|