In September, a lethal virus was detected in Californian birds. A
paramyxovirus type-1 virus, it has not been found in Canada to date.
Called Newcastle disease, it infects both wild birds and domestic
poultry. It has devastating consequences once it gets into a flock,
with up to 90 percent of infected birds dying from respiratory and
nervous symptoms.
So far, Newcastle disease has not invaded commercial poultry farms.
This outbreak is potentially dangerous because the source of the
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infection is fighting cocks. Animal cruelty laws that ban cock fighting
in most states encourage cock owners to keep their birds hidden.
Tracing the movement of infected birds and their contacts is extremely
difficult under these circumstances.
Valuable fighting cocks are worth a lot of money so it is not unusual
for them to travel great distances to fight other cocks of merit.
This may allow Newcastle disease to spread to other states, and
conceivably, Canada.
Eradication of the virus is also difficult.
There is a vaccine available that will protect poultry from Newcastle
disease, but very few cock owners use it in their fighting birds.
Commercial producers don’t routinely use the vaccine because Newcastle
disease is so rare.
The Newcastle virus does not infect people, but it is airborne and
extremely contagious between birds. If the virus gets into a flock,
symptoms occur simultaneously in almost all birds two to 15 days after
exposure. Young birds are particularly susceptible, so broiler flocks
suffer high death rates. Egg production is halted in laying flocks
afflicted with Newcastle disease.
As of Nov. 14, more than 11,000 birds – chickens, ducks, turkeys, and a
few pet birds – had been destroyed in the immediate vicinity of Los
Angeles. These birds were members of backyard flocks or were kept in
private homes.
The last outbreak of Newcastle disease in California in the 1970s cost
the industry $56 million to eradicate.
More than 12 million chickens had to be destroyed.
The current outbreak has already had an impact on trade. Some export
markets have dried up, including the European Union, Japan, Taiwan,
Poland, Argentina and the Philippines. Canada has placed a ban on the
import of hatching eggs and live poultry from California.
As a precaution, many producers have implemented biosecurity measures.
Workers must disinfect their boots before entering the premises and the
tires of all vehicles that enter the farm must be cleaned. Visitor
access is strictly limited and bird transport is discouraged.
Jeff Grognet is a veterinarian and writer practising in Qualicum Beach,
B.C.
