MILK-BORNE INFECTIONS 439 



By cases of typhoid at the farm or milk shop 70 per cent. 



By cases of typhoid at the farm 40 " " 



By cases of typhoid at the milk shop 30 " " 



By using polluted water for dairy purposes, method of pollution unknown 20 " " 



By insanitation at the farm or milk shop and miscellaneous 10 " " 



Detailed histories of typhoid fever epidemics are given by 

 Swithinbank and Newman, the Bacteriology of Milk; in Hygienic 

 Laboratory Bulletin 56, and in Jordan's article, the Case for 

 Pasteurization. 



Dysentery and parat3rphoid fever may be communicated 

 through milk, although milk-borne epidemics of these diseases are 

 less frequent than those of typhoid fever. The method of trans- 

 mission is similar to that of typhoid fever, and what has been said 

 in this respect applies to dysentery and paratyphoid fever. An 

 epidemic of paratyphoid fever due to improper handling and 

 bottling has been reported by Levine and Emerson. 



Diphtheria. — The transmission of diphtheria through milk is 

 a grave possibility, and a considerable number of epidemics have 

 been definitely traced to milk. The diphtheria bacillus grows 

 well in mUk and produces changes which are not ordinarily notice- 

 able. It gains access to milk chiefly from carriers, who emit 

 bacilli through coughing, sneezing, loud talking, or direct contact. 

 The filthy habit of expectorating into the hands before milking in 

 order to lubricate the teats is probably obsolete at present, but 

 undoubtedly has been the cause of transmission of diphtheria and 

 other throat diseases through milk. 



Milk bottles from a home in which there is a case of diphtheria 

 are subject to infection and should not be removed before the 

 patient has recovered and before the throat of the patient has 

 been shown to be free from bacilli. Such bottles should be steril- 

 ized with special care before using. 



Since domestic animals have been known to carry diph- 

 theria bacilli from one house to another, it is clear that milk 

 and cream bottles should be protected from contact with these 

 animals. 



Diphtheria may be derived from the cow, although she is not 

 susceptible to the disease in the sense that human beings are. 

 Several investigators, notably Dean and Todd, have observed 

 crusts and ulcers on the teats of udders of cows. These lesions 

 were caused by diphtheria bacilli and were undoubtedly of human 

 origin. 



The methods of dissemination of diphtheria through milk 

 is well illustrated in an outbreak at Dorchester, Milton, and 

 Hyde Park in 1907. In Bulletin 56 of the Hygienic Labora- 

 tory the chart which is shown on page 440 explains the routes of 

 infection. 



