Enteric Flagellated
Protozoa in Turkeys
Steven Clark
Alpharma Animal Health, Inc., Fort Lee, New Jersey,
USA steven.clark@alpharma.com
Koen De Gussem
Alpharma Animal Health, Inc. Antwerp, Belgium koen.de-gussem@alpharma.com
John Barnes
North Carolina State University, College of Veterinary
Medicine, Raleigh, North Carolina, USA John_Barnes@ncsu.edu
Several types of protozoa
are associated with enteric disease of turkeys. Protozoal
enteritis can present with general signs, including
dehydration, loss of appetite (off-feed), loose droppings
and watery intestinal contents. Flagellated protozoa
include Cochlosoma, Tetratrichomonas, Histomonas and
Hexamita. Coccidia Cryptosporidia and Eimeria are
non-flagellated protozoa of turkeys. Cochlosoma and
Hexamita have recently been associated with enteritis,
primarily in young turkeys, especially in the summer
months. There are field reports of co-infections with
Cochlosoma and Tetratrichomonas, or Cochlosoma and
Hexamita, or flagellated protozoa and Eimeria.
Cochlosoma anatis
is an enteric flagellate protozoan. It is about the
same size as the turkey’s red blood cell. Microscopically,
it is will have a rapid, spiral movement. Cochlosoma
organisms are found in the villi of the jejunum (upper
small intestine), and attaches to the mucosa by means
of a sucker-apparatus. C. anatis is associated with
significant production losses in turkeys.
Hexamita meleagridis,
now called Spironucleus meleagridis, is another enteric
protozoa. Hexamita is smaller than a red blood cell.
It has a characteristic torpedo, fast, straight movement
and has a narrow, elongate appearance on the microscope
slide. Hexamita is found in the crypts or lumen of
the upper small intestine (duodenum, jejunum, and
ileum).
Tetratrichomonas
gallinarum, another common flagellate protozoa of
turkeys, is larger than a red blood cell. Microscopically,
Tetratrichomonas has a jerky motion and is found in
the ceca. Trichomonads have an undulating membrane
and are plump, pyriform in shape. Unless found in
high numbers, Tetratrichomonas, commonly referred
to as “Trich”, probably does not cause
clinical disease.
Blackhead
(Histomonas) is caused by Histomonas meleagridis,
a flagellated protozoan. The bird ingests embryonated
ova of cecal worms (Heterakis gallinarum) that contain
Histomonas.
Protozoan infections can be diagnosed in the laboratory
from fresh intestinal mucosa scrapings; each organism
has a distinctive microscopic appearance. Recent research
has reported the negative effects Cochlosoma has on
bird performance. Biosecurity and sanitation are essential
steps in controlling and preventing flagellated protozoan
infections. Chlortetracycline, oxytetracycline and
tetracycline have FDA-approved label claims for the
control of hexamitiasis. In the USA, both nitarsone
and roxarsone have been used successfully in the field
and research settings to control enteritis caused
by flagellated protozoan.