INFLUENCE OF DISEASE UPON MILK 121 



TYPHOID FEVER 



Typhoid fever is more frequently spread by milk than 

 any of the other infectious diseases of man except tuber- 

 culosis. As a carrier of typhoid infection, milk is second 

 only to water, although the cases caused by infected water 

 greatly outnumber those resulting from infected milk. 

 Milk may be infected with the Bacillus typhosus in sev- 

 eral ways. The organisms may be introduced into milk 

 when infected water is used to wash the milk vessels and 

 utensils. Infected water may contaminate the milk when 

 there is a leak in the milk cooler or when a can of milk 

 is submerged in such water to cool. Water in open or 

 thin- walled springs, surface wells, and in streams receiv- 

 ing surface drainage may be readily infected by excre- 

 tions from typhoid fever patients, convalescents, and 

 chronic bacilli carriers. Milk bottles from houses where 

 the disease exists may be a source of infection; one or 

 two infected bottles may contaminate the water in which 

 they are washed or rinsed, and this water will infect other 

 bottles washed in it. A few bacilli introduced into a 

 vessel or bottle by infected water will multiply rapidly 

 when milk is placed in it, for the Bacillus typhosus grows 

 abundantly in milk. Milk may be infected directly when 

 the cows are milked or the milk or milk vessels are handled 

 by persons affected with the disease, by convalescents, 

 by chronic bacilli carriers, and by those attending typhoid 

 fever patients. The greatest danger of direct infection 

 is from those cases in which the disease is of such a mild 

 type that it is not recognized, the so-called walking 

 typhoid, and from chronic bacilli carriers, i.e., individuals 

 who continue to excrete typhoid bacilli in the faeces and 

 urine after they have recovered from the disease. It is 

 estimated that 2 to 4 per cent, of typhoid fever patients 



