TapeWorm In Goats
Written by Administrator-GL   
Friday, 26 June 2009

TapeWorm and Echinococcosis (hydatid disease)

 
Hydatidosis in domestic ruminants inflicts enormous economic damage due to the condemnation of affected organs and lowering of the meat, milk and wool production.
Life cycle: The infective eggs containing the oncosphere passed in the faeces are accidentally ingested by cattle, sheep, pigs, other animals or humans which act as a intermediate hosts. After the infective eggs are ingested by these intermediate hosts, the oncospheres in the eggs penetrate the intestine and reach the liver, lungs and other organs including the brain and muscles to develop into hydatid cysts at the end of about five months. These cysts measure commonly 5 - 10 cm and contain fluid. Some may reach up to 50 cm in diameter. Others may produce daughters cysts. The diagnostic features of a hydatid cysts are a concentrically laminated thick outer layer within which is a germinal layer. In fertile hydatids the germinal layer is granular and has brood capsules each containing protoscoleces. When brood capsules become detached and float free in the cysts fluid they are referred to as hydatid sand. In some animals a fair proportion of hydatid may be sterile. The life cycle is completed when a fertile hydatid cyst is eaten by a definitive host, the dog or the appropriate carnivore. Cattle and majority of intermediate hosts show no clinical evidence of infection. However, in humans hydatid cysts can cause serious disease.
Antemortem findings: None of significance
Postmortem findings:
Hydatid cysts as described are found in :
Liver (Fig. 92) , lungs (Fig. 93) , heart, spleen, kidneys ,
Muscle and brain
Any tissue including bone



Hydatid disease occurs in sheep, cattle, swine, horses and humans. Echinococcosis is a disease which occurs when the larval stage of Echinococcus granulosus and Echinococcus multilocularis are ingested by an intermediate host (sheep,goats, cattle). These larvae then develop into hydatid cysts in various tissues. The adult tape worms are found in dogs, cats and other carnivores and sometimes in livestock. They may ingest the hydatid cysts by eating infected organs of the intermediate hosts. The scolex attaches to the intestinal wall. Adult tapeworms develop in approximately seven weeks and eggs are shed in the feces and are ingested by sheep, goats and cattle. The ova hatch to liberate the onchospheres which penetrate the intestinal wall and through the portal venous supply to the liver where they become arrested. In older sheep or goats  and cattle the larvae may reach the lungs and various other organs through the systemic circulation.

The most common sites of cysts are the liver and lungs. The cysts are different sizes and shapes and they contain a clear fluid. Due to the growth of the cyst, pressure atrophy is noted in the surrounding tissue.

Daughter cysts are found outside the mother cyst and are formed due to trauma or external pressure on the mother cyst. They may or may not be attached to the mother cyst. Daughter-cyst formation may have neoplastic characteristics when there is penetration to the blood and lymph vessels and metastases to various distant organs.
Humans gets infected with hydatid disease via the ingestion of ova from Echinococcus tapeworm in the dog. This usually occurs by touching dog hair that has been contaminated by ova from feces and then  touching food or cigarettes.  It also may occur by the dog transferring ova from the anus to its mouth and then by licking humans.

Postmortem findings : Multiple Echinococcus granulosus cysts in the liver, lungs and other organs.
Judgement : The animal carcass affected with echinococcosis is approved if edema and emaciation are not found. Otherwise the carcass is condemned. The affected organs are also condemned and must be destroyed. The lungs are most commonly affected and these should be carefully checked because lesions are often missed on routine inspection.


TAPEWORM-Cysticercus tenuicollis infestation                            
Cysticercus tenuicollis is the cystic stage of tape worm Taenia hydatigena which is found in dogs and cats. Ova pass with dog feces on the pasture and may get ingested by intermediate hosts sheep and pigs. Larvae which develop from ova penetrate the intestine and pass by portal vein to various tissues especially the omentum, mesentery, peritoneum and liver. Migration through the liver leaves greyish-white tortuous tracts. If larvae reach the liver surface they develop into thin-walled fluid filled bladders and if they fail they degenerate and become calcified.
Heavy infestation with Cysticercus tenuicollis in young animals causing liver damage and haemorrhages or peritonitis, rarely results in the death of the animal.
Antemortem findings :
Moderate to heavy infections produce:-
Loss of appetite
Depression
Weakness
Postmortem findings :
Cysts of different diameters on the liver, diaphragm and peritoneum
Subserosal cysts on the liver 
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Cysticercus ovis infestation (sheep measles, sheep bladder worm)
Cysticercus ovis is the larval stage of Taenia ovis, a tapeworm found in the intestines of dogs and wild carnivores. Its development is similar to that of Taenia saginata. However, in the case of Taenia ovis, the definitive hosts are sheep. The cysts are found in the heart, diaphragm, masseters and the skeletal musculature of sheep. They are fully developed from 7 to 10 weeks after the ingestion of the ova. The rapid degeneration of cysts commence almost immediately after the cysts reach maximum development. When degenerated, the cysts appears as a caseous nodule in the musculature.
Antemortem findings : Usually no clinical signs are recognized.
Postmortem findings :
The cysts are oval, measure 9 mm 5 mm when fully developed and are most common in the heart , the masseters, the diaphragm and the skeletal musculature
 
In older animals the cysts degenerate and calcify
The degenerated cysts appears as greenish yellow caseous nodules with calcification often present.
Judgement : In moderate or light infestation consisting of a small number of dead or degenerated cysticerci, the carcass can be boned out under supervision, the cysts removed and the meat passed after being held for 10 days at -10C. If the freezing treatment is not possible, the heating of the carcass at 56C is suggested.
In heavy infestations the carcass is condemned. It is commonly considered that an animal is heavily infested if lesions are discovered in two of the usual inspection sites including the masseter muscle, tongue, oesophagus, heart, diaphragm or exposed musculature and in two sites during incision into the shoulder and the rounds. Carcasses with C. ovis infestations may not be acceptable for export.
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Stilesia hepatica
This is a tape worm which occurs in the bile duct of sheep, goats and wild ruminants. The life cycle is not completely known but oribatid mites are suspected of transmitting the parasites. The parasite affects animals of all ages and is considered non pathogenic. Heavy infections are frequently seen in apparently healthy sheep. With almost complete occlusion of the bile ducts, icterus and the other clinical signs are not observed. There are areas where approximately 80 % of sheep and goat livers are affected.
 
 
 
 
 Tapewrom expelled 5 hours After using Valbazen Dewormer
 
 
 More Tapeworm Photos follow:
 
Photos of Goat Tapeworm
 
 
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Tapeworm in the mucosa of the intestine


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Tapeworm can be up to 3 feet in length

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Last Updated ( Saturday, 07 November 2009 )