PARAGONIMIASIS 241 



MORPHOLOGY. 



A greyish leaf-like parasite quarter of an inch long. 



The oesophagus is short, the two lateral caeca are wavy but not 

 branched. 



The testes are simple, one at either side of the mid-line arranged 

 diagonally. 



The yolk glands are situated in the full length laterally. 



There is no cirrus or cirrus pouch. 



Their life history is not known. 



They infect man, cats, dogs and pigs. 



The true host is the tiger cat. 



Man may be infected through food or drink, and hence the worms 

 are distributed to other parts through the lymphatics. This is, how- 

 ever, not yet proved. 



The eggs are yellowish with a thick shell. 



PATHOLOGY. 



The lesions have been classified thus (Musgrave) : — 

 (i) The suppurating lesion. 



(2) The tubercle-like lesion. 



(3) The ulcerating lesion. 



These may occur in the skin, bronchial or intestinal musosa, or in 

 the bile duct. 



At first the connective tissue seems to be infiltrated with eggs, 

 forming a cirrhosis or a round-celled infiltration with eosinophiles. 



An abscess may form containing caseous matter, or an ulcer 

 develops. 



If this occurs in the liver cirrhotic changes take place. 



If it occurs in the serous membrane there is an adhesive inflam- 

 mation with brown patches of eggs. 



If it occurs in a solid organ, a small focal cyst forms surrounded 

 by fibrous tissue. 



The abscess, cyst or ulcer contains degenerated cells, blood, eggs 

 and parasites. 



The fibrous lesion spreads in a star-shaped manner with small cysts 

 in their centre. These reach the cutaneous or muscular layer and so 

 open intO' the skin, bronchus, intestine, or the bile duct, causing there 

 an ulcer. These ulcers may become secondarily infected. The ulcers 

 sometimes heal by scarring. 



Post mortem, these typical lesions may be found in muscle, lungs, 

 serous membrane, spleen, pancreas, intestine, bladder, epididymis, 

 prostate, and the choroid plexus of the brain. 



The body is often emaciated and anaemic. 



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