108 



The ultimate result is severe anaemia of various forms 

 (e.g., Egyptian chlorosis and Miner's cachexia). The marked 

 inertness so characteristic of tropical communities is now 

 associated with life-long infection of these intestinal " hook- 

 worms," which, when numerous, cause a profound grade 

 of anaemia frequently ending in premature death. 



How could you distinguish Necator americanus from Ancy- 

 lostoma ? State its Geographical Distribution. 



The head of Necator is strongly bent upwards ; and* 

 instead of cutting teeth, it has two chitinous plates. In 

 America it is found in association with Ancylostoma* 

 Their distribution is similar. 



Where is Trichocephalus dispar found ? Describe its general 

 Appearance. 



The Whip- worm ( Trichocephalus dispar, syn. Trichuris 

 trichiura) is a common parasite of Man and monkeys. 

 Its distribution is world- wide. It lives attached to the 

 lining of the caecum and colon. It is seldom dangerous. 



The anterior portion of the body is ve*ry long and thin r 

 whip-like. The female is about 45 mm. in length ; the 

 male is shorter, and has only one copulatory spicule. 



Give an Account of Trichina (syn. Trichinella) spiralis* 

 its Life - History, and its effect on Man. 



Trichina spiralis is a very small Nematode ; the male 

 is little more than a millimetre in length, the female is 

 about three times as long. The natural host is the rat ; 

 but Trichina also infests other animals, notably the pig ; 

 and it is a most dangerous parasite in Man, producing 

 trichinosis, a frequently fatal disease prevalent in many 

 parts of the world, especially North Germany. 



The adult worms live in the duodenum and jejunum. 

 After copulation the males die ; the viviparous females 

 bore through the mucous membrane and enter the lymph 

 spaces where they bring forth their young, each female 

 giving birth to about 1500 larvae. The larvae are carried 

 by the lymph and blood stream to the heart, and are then= 



