CONTROLLABLE DISEASE AGENTS 337 



Prevention 



Protect soil from contamination 

 Install suitable toilets 



Use privies in which discharges can be steriHzed 

 Prevent contact of skin with contaminated soil 

 Wear shoes ; provide suitable playgrounds for children 

 Extermination 



Prevent spread and reinfection ; cure all infected persons 



4. Arthropod parasites 



The tick ; the itch mite 



5. Ringworm (a fungus) 



QUESTIONS 



1. What is the use of knowing the life histories of parasites upon the 

 human organism ? How can such life histories be discovered ? 



2. How does the tapeworm injure its host ? 



3. Why is hookworm more common in the country than in the city? 



4. What connection is there between the habits and customs of peo- 

 ple and their likelihood of becoming infected with hookworm ? with 

 trichina ? 



5. What can the indi\ddual do to protect himself from tapeworm ? 

 from hookworm ? from ringworm ? from trichina ? 



6. What is the objection to scratching the skin when it itches ? What 

 is the advantage of scratching ? How can one control the desire to scratch ? 



REFERENCE READINGS 



United States Department of Agriculture. Bulletin 880, Effects of Pork- 

 Curing Processes on Trichinae. 



United States Department of Agriculture. Bulletifi 260, The Dog as a 

 Carrier of Parasites and Diseases. 



Public Health Reprint 596, The More Common Helminthic Infestations. 



Farmers' Bulletin 56g, Texas, or Tick, Fever. 



Farmers' Bulletin 1057, Cattle Fever Ticks and Methods of Eradication. 



Farmers' Bulletin ygS, The Sheep Tick and its Eradication by Dipping. 



Bureau of Animal Industry. Bulletins 130, 152, Studies on Biology 

 of Texas-Fever Tick. 



United States Department of Agriculture. Bulletin 147, Effect of Cattle 

 Tick on Milk Production of Dairy Cows. 



United States Department of Agriculture. Bulletifi 553, Chicken Mite. 



