Infectious Coryza

Infectious Coryza

Cause
The bacterium causing this disease is Hemophilus paragallinarum.

Transmission
The disease spreads from bird to bird and flock to flock by
contact and airborne infected dust particles and via the
drinking water.
Spread by equipment and personnel has also been reported.
The incubation period varies from 1 to 3 days.

Species affected
Chickens appear to be the only natural hosts of
H. paragallinarum.

Clinical signs
The main signs of the disease are inflammation of eyes and
nose with foul-smelling discharges, conjunctivitis, sneezing
and facial swellings. Feed and water intake is reduced,
leading to loss of weight. Egg production in laying birds will
drop.
Mortality will vary with the virulence of the infection but is
generally low.

Diagnosis
A field infection produces similar symptoms to chronic
respiratory disease, a diagnosis is difficult to establish.
The most certain diagnosis may be obtained by the isolation
of the organism from the sinus or airsac exudate from
affected birds. This procedure must be carried out in the
laboratory.

Treatment and control
Treatment with antibiotics can be given to subdue clinical
infection, but eradication and prevention are the most
desirable means of control of coryza. Vaccines have been
developed, but are only used in areas where the disease is
endemic and cannot be eradicated.