4 MASS. EXPERIMENT STATION BULLETIN ?>7Z 



so only milk-borne typhoid will be considered here. Many epidemics are 

 on record ranging all the way from a few cases with few or no deaths, 

 to hundreds of cases with many deaths. 



An instance was reported in California (4) in which milk from a dairy 

 farm was sold raw in one town, and pasteurized milk from the same farm 

 was sold in another town close by. In the first town a number of cases 

 of typhoid fever occurred among about five hundred persons using the 

 milk, while in the second town no cases occurred among about six thou- 

 sand consumers. Investigation of the dairy farm showed that the head 

 milker had been taken ill with typhoid fever shortly before the epidemc 

 occurred. 



Two milk-borne epidemics of typhoid fever in New Jersey (4), which 

 occurred about a year apart, were traced to one carrier. The first epi- 

 demic included seventy-two cases, and a carrier was detected among the 

 workers in the dairy which supplied the suspected milk. A year later 

 an epidemic of thirty cases was reported from another community, and 

 when the farm which supplied the suspected milk was investigated, the 

 same carrier was found to be working as a milker and under an assumed 

 name. 



An extensive epidemic of typhoid fever occurred in Montreal in 1927 

 (2), which lasted from March 1 into July. Evidence collected at the time 

 (5) indicated that milk was the source of infection, but later study of 

 the evidence (6) seems to indicate that water may have been the source. 

 This epidemic, of 5,014 cases with 488 deaths, was one of the most exten- 

 sive on record. 



In Massachusetts (7), from 1921 to 1925, there were 3,390 cases of 

 typhoid fever reported, of which 228 (6.7 percent) were from milk; and 

 from 1926 to 1929, there were 1,635 cases reported, of which 135 (8.3 

 percent) were milk-borne. Dairy products other than milk can spread 

 typhoid fever. Epidemics have been reported from butter, cream, ice 

 cream, and cheese (4). 



Typhoid fever germs get into milk and milk products from human 

 sources, and not from cows. One of the epidemics just described was 

 traced to a worker coming down with the disease, and the other to a 

 carrier. All persons who have typhoid fever continue to excrete typhoid 

 bacteria for several weeks, or even months, after recovery, and thus 

 become "carriers". It happens occasionally that the bacteria invade the 

 human gall bladder, where they thrive on the bile. In such instances, 

 the persons concerned become permanent carriers, and eliminate the 

 bacteria more or less constantly from the intestines. Carriers are a con- 

 stant menace to the public as sources of typhoid fever, and are especially 

 dangerous if they have anything to do with food supplies. Surgical re- 

 moval of the gall bladder is the most effective treatment for chronic 

 carriers. 



Perhaps the most notorious carrier in medical history was Mary Mallon, 

 a cook, who was known as Typhoid Mary because of the typhoid fever 

 that she spread wherever she went. She was a cook in and around New 

 York City, and was known to have infected more than fifty people in 

 families she worked for, over a period of several years. She was sus- 

 pected also of being the source of a water-borne epidemic of over 1,300 

 cases of typhoid fever in Ithaca, N. Y., in 1903. She died in November, 

 1938, after having been virtually a prisoner of the New York City health 



