Blackhead disease or more correctly,
Hisomoniasis, is primarily a deadly
disease of young turkeys. It is caused by
microscopic protozoans called
Histomonas Melegridis that usually
have entered the eggs of another
parasite; the cecal worm, that is
Chickens are more resistant to the
effects of blackhead and many times
are the carriers of the disease-causing
organism.
Other sources for the disease comes
from various wild birds such as
pheasants and grouse, earthworms that
have ingested the organism and then
are eaten by the birds, and contaminated
grounds.
The protozoan can remain infectious
for up to 3yrs. while inside a host
parasite. If found directly in the droppings
of an infected bird, they rapidly die,
especially in warm dry weather.
Signs of the disease are a decrease in
food and water consumption with resulting
weight loss. Birds will appear dull and
depressed often off to themselves with
drooping tails and ruffled feathers and
an overall sleepy appearance.
Sulphur-colored droppings may be seen
as well. The heads of turkeys do not
become black as the name suggests. If
they are not treated or there is a delay
in beginning treatment, the death count
could reach high levels.
Birds that are dying, upon examination,
will have enlarged livers with circular
depressed areas and an enlarged ceca
containing a rather dry cheesy material.
Recovered birds may have swollen, hard
and scarred livers at the time of slaughter.
Treatment is usually accomplished by
adding one of several drugs to the water
or feed to control an outbreak. I also have
come across some information stating that
adding cayenne pepper to feed and water
supplies can be effective. Sick birds should
be isolated from the flock and treated
separately.
Dead birds should be burned, ideally, or
buried very deeply to avoid other birds
coming in contact with the organisms.
All equipment should be thoroughly cleaned
and disinfected after exposure is suspected.
Prevention is key to controlling outbreaks
and losses in flocks.
Due to the length of time the protozoan
can remain infective, each new flock of
turkeys should be reared on new grounds.
Young turkeys should not be raised
with older birds or with chickens. Periodic
moving of feeders, waterers and roosts
will help in controlling the build-up of
infected organisms.
Good sanitation and litter management
is a must in the controlling the transmission
of the blackhead protozoans as well as
cecal worms.
Credits:
Sources used in this article are :
Miller Hatcheries page on Blackhead
from Alberta Agriculture.
This article written by; Jeaninne
For use on The Gander Gab Sites.
All rights reserved
copyright 2002, June 13th,2002
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