TRICHURIASIS 



1759 



directly the cause of appendicitis, for several times we have found it 

 in the inflamed appendix removed by operation. 



Geographical Distribution. — Trichuris trichiura is cosmopolitan 

 in its distribution. 



-ffitiology. — Trichuriasis is caused by Trichuris trichiura Linnaeus, 

 1771, which, as far as is known, is really a parasite of man and 

 monkeys, while alhed forms exist in other animals. The eggs 

 escape with the faeces, and require three to six months for the 

 development of the embryo, which can then remain alive for years 

 inside the shell if kept on moist earth. Usually the eggs gain access 

 to man by means of contaminated food, especially uncooked vege- 

 tables, and to a less extent fruits. This is especially likely to occur 



Fig. 753. — Trichuris trichiura. 

 (Microphotograph by J. J. Bell.) 



in the tropics, where human faecal matter is often allowed to be 

 deposited in vegetable gardens. Musgrave, Clegg, and Polk 

 report finding the ova in washings from fresh vegetables. Domestic 

 animals, insects, flies, dust, etc., are also considered to be possible 

 means of infection. When taken into the ahmentary canal, it 

 hatches and reaches sexual maturity in sixteen days. 



It occurs more commonly among children than adults, women 

 than men, and native races than European. But all these factors 

 appear simply to depend upon good or bad sanitation, for the latter 

 is the principal factor in producing infection. 



Pathology. — It is believed that the worms attached themselves 

 to the mucosa of the bowel by the head penetrating deeply into its 

 tissue either via a gland or directly. In this position the worm is 

 firmly fixed, and is more or less protected against the action of 



