DISEASES CAUSED BY INFECTED MILK 119 



to person in very much the same way as diphtheria is com- 

 municated. The virus is contained in the discharges from 

 the nose and mouth. The virus is also contained in the dis- 

 charges from the ear, and other comphcations which fre- 

 quently are a result of an attack of scarlet fever. Scarlet 

 fever is sometimes so mild that it is exceedingly difficult to 

 recognize. It is these " missed " cases which are partic- 

 ularly dangerous. Milk is a rather frequent vehicle for 

 scarlet fever infection. 



The milk is practically always contaminated from hu- 

 man sources. There is, however, some suspicion that strep- 

 tococcal diseases of the cow may, in some instances, be 

 identical with scarlet fever: this is doubtful. It appears, 

 however, that there may be some association between 

 streptococcal diseases of the udder and outbreaks of 

 sore throat. 



Trask collected fifty-one scarlet fever epidemics reported 

 as spread by milk. Twenty-five of these occurred in the 

 United States, twenty-six in Great Britain. In thirty-five 

 of the epidemics a case of scarlet fever was found at the 

 producing farm, the distributing dairy, or the milkshop, at 

 such a time as to have been a possible source of infection. 

 In three of the outbreaks bottles returned from infected 

 households and refilled without previous sterilization were 

 given as the source of infection. In three of the outbreaks 

 scarlet fever persons handled the milk or milk utensils. 

 In twelve of the outbreaks the cows were milked by 

 persons having scarlet fever. One epidemic was caused by 

 the same person nursing the sick and handling the milk. 

 Two of the outbreaks were attributed to disease of the 

 cow. 



Milk-borne outbreaks of scarlet fever are sometimes 

 unusually extensive. A good illustration is the epidemic 

 which occurred in Boston in the spring of 1910 as the result 

 of infected milk. 



The Boston epidemic occurred during April and May, A 



