512 



THE ANIMAL PARASITES OF MAN 



the liver. In the nine cases observed by WinogradofE, death was not due to 

 the parasites. Yet the changes produced by it are quite considerable, viz., 

 dilatation and inflammation of the bile-ducts, and foci of cirrhosis. In one 

 case there were small pus foci; jaundice and contraction of the liver existed 

 in five cases, ascites in three; the liver was twice found to be enlarged. 



Braun's assumption that, owing to the great dissemination of distomum 

 felineum among cats, it must also be present in man, was soon confirmed. 

 Askanazy reported such a case from East Prussia, in 1900. It occurred in 

 a man who had died of colloid carcinoma, which originated in the epithelium 

 of the bile-ducts. The microscopical examination revealed ova and about 

 100 specimens of distomum felineum in the regions not affected by the tumor. 

 The same author reported a second case, also from East Prussia. 



Askanazy supposes the infection in man to be due, as in the cat, to the 

 consumption of raw, or only partially cooked, fish. 



Of great interest is another trematode, distomum haematobium, Bilharz, 

 1852, or the Bilharzia hsematobia, Bilharz, 1852. The parasites live sexually 



apart. The male is thicker (up to 1 mm.) and 

 shorter (12-14 mm.) than the more slender (up 

 to 0.13 mm.) and longer female (16-18 mm.). 

 The anterior part of the body which contains the • 

 suctorial discs is fiattened. The posterior part of 

 the body of the male, by a turning up of the 

 lateral borders, forms a tube (eanalis gynaecopho- 

 rus) which serves for the reception of the female. 

 The surface of the male is covered with small 

 spiny warts, that of the female is smooth. The 

 ova, which are often found in large numbers ia 

 the vagina, are slender and quite long, about 0.12 

 mm. long and 0.04 mm. broad. They are pointed 

 at one end, or, more rarely, supplied with a 

 pointed side tooth. The shell of the ova is thin, 

 and there is no lid. The full grown parasites are found in man in the portal, 

 splenic and renal veins, also in the venous plexus of the urinary bladder, and 

 in the rectum. The ova lie in small, white masses in the various organs, espe- 

 cially in the urinary passages, in the vesicula seminalis, and in the mucosa 

 and submucosa of the large intestine. The primary seat of the ova is probably 

 the vascular system. The ova, deposited in the veins which are distended to 

 small diverticuli, enter the tissues only after rupture of the vessels. 



The history of the development of the parasite which occurs mostly and 

 quite frequently in Africa, and especially in Egypt, is not yet clear. We Imow 

 only the following : The ova are discharged with the urine. Sometimes empty 

 sacs of ova are found in the urine synchronously with free embryos. Evidently 

 a miracidium, completely ciliated, escapes from the ovum in urine that is 

 greatly diluted with water and floats for some time in the water. It appears 

 likely that there is an intermediate host; but all attempts to infect mollusca, 

 Crustacea, and fish have been fruitless. Loos doubts the transmission' by an 

 intermediate host. The embryo, in the opinion of this author, enters directly 



Fig. 35. — Ova of Distomum 

 h^matobium. 



