Garlic flakes versus "Cutebra" in wild birds

To: Birding-Aus <>
Subject: Garlic flakes versus "Cutebra" in wild birds
From: John Gamblin <>
Date: Sun, 6 Jul 2003 17:54:28 -0700 (PDT)
If added to the food then ....?
Taenia serialis
The cysts are the larval form of the tapeworm Taenia serialis. Lagomorphs such 
as jack rabbits and rabbits are intermediate hosts for the cestode Taenia 
serialis. The definitive hosts are dogs and foxes, which ingest the larvae by 
eating infected lagomorphs. Adult tapeworms are found in the small intestine of 
dogs and foxes, which pass gravid proglottides or tapeworm segments containing 
eggs in the feces. Jack rabbits ingest the eggs by eating vegetation on which 
the infected carnivore h as defecated.

Once the eggs reach the intestinal tract of the lagomorph, the embryos hatch 
and migrate to intermuscular connective tissue. In this tissue, the larva 
transforms into a bladder-shaped structure with one or more inverted scolices 
(a specialized anterio r segment of the tapeworm or "head") in an invaginated 
portion of the wall. If the bladder wall has a germinal layer capable of 
producing multiple scolices, it is referred to as a coenurus or multiceps. 
Another example of this type of cestode is Coenur us cerebralis, the larval 
stage of the dog tapeworm Multiceps multiceps. It is the causative agent of an 
uncommon disease of the central nervous system of sheep known as "gid," in 
which a larval bladder is localized in the brain or spinal cord.

If the larva has a solid caudal portion and a bladder-like proximal portion, it 
is called a cysticercus. An example is Cysticercus pisiformis which occurs on 
the peritoneum and liver capsule of rabbits, squirrels, and other small 
rodents. The a dult stage of this parasite is Taenia pisiformis and is found in 
the small intestine of the dog, cat, fox, wolf, and other carnivores. 
Generally, because the coenurus is a single bladder with multiple scolices, it 
grows to 4-5 cm in diameter, and occurs s ingly or occasionally as two or three 
bladder-like cysts. In contrast, because cysticercus contains only one scolex, 
it grows into a fluid-filled sphere 15-18 mm in diameter, and often occurs as 
multiple cysts resembling a bunch of grapes. Other modificat ions of the 
bladder include the strobilicercus, with an invaginated scolex attached to a 
small bladder by a segmented portion; and the echinococcus or hydatid cyst, 
with a germinal layer that produces brood capsules within which scol

The scolices in all the larval stages possess suckers and hooklets identical to 
the adult stage. When ingested by the definitive host, the scolex evaginates 
and attaches itself to the intestinal mucosa. Growth of the tapeworm then 
proceeds by prolifer ation of segments at the posterior extremity.

Lagomorphs of many species are infected with Taenia serialis1. The distribution 
of T. serialis is more restricted, and the rate of infection is less than for 
T. pisiformis 2. The coenurus generally occurs on the side of lagomorphs, in 
the intermuscular connective tissue between the ribs and hips, and over the 
ribs. In these locations, the coenuri are generally non-pathogenic and finding 
them is incident al. Those coenuri that develop in areas other than 
intermuscular connective tissue, for example in the abdomen or brain, can 
compromise the host. Coenurus serialis has occurred in laboratory rabbits3, but 
is more likely to be seen now in pet rabbits, in which T. serialis is enzootic4.

The Plum Island researchers first suspected that the cysts were 
sialoceles--cysts that form in an obstructed salivary duct due to the dilating 
effect of the contained salivary gland secretion--because of their location 
along the path of the parotid sa livary duct. However, this did not seem likely 
when they saw a cyst on the chest wall of another jack rabbit. 

An alternate consideration was that the cysts might be the subcutaneous larvae 
of botflies (Cutebra spp.). Several species of Cutebra frequently infect wild 
lagomorphs. However, the subcutaneous swellings containing the larvae are 
characterized by a fistula or air-hole for the larva to breathe. The 
researchers did not find holes in any of the cysts. When the researchers 
dissected the cysts, they found numerous scolices, which identified the cyst as 
a coenurus.

The researchers? VHD susceptibility studies indicated that wild North American 
leporids were clinically unaffected by experimental exposure to the VHD virus5 

Dr. Gregg is a veterinary pathologist at the Plum Island Foreign Animal Disease 
Diagnostic Laboratory, Greenport, NY. The opinions and assertions contained in 
this article are the author?s own, and are not to be construed as official or 
as reflecting t he views of the USDA. The research described was conducted 
according to the regulations of the Animal Welfare Act, and the principles set 
forth in the NIH Guide for the Care and Use of Laboratory Animals.


   Hofing, G.L., and Kraus, A.L. Arthropod and Helminth Parasites. In: Manning, 
P.J., Ringler, D.H., and Newcomer, C.E., eds. The Biology of the Laboratory 
Rabbit (2nd ed). Academic Press Inc., San Diego, CA, pp. 231-257, 1994. 
   Pfaffenberger, G.S. and Valencia, V.B. Helminths of sympatric black-tailed 
jackrabbits (Lepus californicus) and desert cottontails (Sylvilagus audubonii) 
from the high plains of eastern New Mexico. J. Wildl. Dis.; 2 4: 375-377, 1988. 
   Hamilton, A.G. The occurrence and morphology of Coenurus serialis in 
rabbits. Parasitology; 40: 46-49, 1950. 
   Goudswaard, M.F. and Thomas, J.A. Coenurus serialis infection of a white 
rabbit. Vet. Rec.; 129: 295, 1991.
   Gregg, D.A., House, C., Meyer, R. et al. Viral hemorrhagic disease of 
rabbits in Mexico: epidemiology and viral characterization. Revue Scientifique 
et Technique, Office International des Epizooties; 10:435-451, 1991.

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