342 Microbes and You 



Gastro-intestinal symptoms are practically non-existent with this 

 poison. Weakness, double vision, difficult)^ in swallowing, and 

 finally death from respiratory failure can be expected for about 

 60 LO 70% of the victims. Several immunological types of the 

 poison are recognized, and specific antitoxins must be given to 

 patients at the earliest possible moment after the condition has 

 been diagnosed. Polyvalent antitoxins are available for administra- 

 tion to. save time in treating afflicted persons. A prophylactic dose 

 is 5,000 units of antitoxin, and a therapeutic dose is 50,000 units. 

 Persons engaged in handling these organisms or their products 

 should be actively immunized with toxoid. 



The toxin is thermolabile, and ten minutes boiling will in- 

 activate it. Steam under pressure, however, is the only safe 

 method of processing high protein, neutral foods (peas, beans, 

 com) for canning if the spores of Clostridium hotulinum (found in 

 the soil in varying concentrations) are to be destroyed, and if the 

 processed food is to be made safe for consumption without fear of 

 botulinus poisoning. 



GRAM NEGATIVE RODS 



SALMONELLA TYPHOSA 



Rods 0.6-0.7 by 2.0-3.0 microns, occurring singly, in pairs, 

 occasionally in short chains. Motile. Optimum temperature 

 37° C. Gram negative. Facultative. Source is feces of in- 

 fected human beings. Cause of typhoid fever. 



The genus Salmonella includes more than 150 species, all of 

 which are believed to be pathogenic. Salmonella typhosa is the 

 etiological agent of typhoid fever, and these bacteria may be spread 

 through the agency of feces, flies, fomites, food, and fingers. Water 

 and milk are particularly important in the dissemination of typhoid 

 fever. 



Once ingested, the typhoid organisms localize in the small 

 intestine, and they eventually invade the blood stream. The 

 bacteria may then set up new foci of infection in the spleen, bone 

 marrow, gall bladder, and other organs. Slightly less than 5% 

 of infected persons remain as typhoid carriers for indefinite periods, 



