75 



An Epidemic of Diarrhcea, Presumably Milk Borne. 



p. A. Tetrault. 



MILK-BORNE EPIDEMICS IN GENERAL. 



Mllk-borue epidemics, as a rule, show certain characteristics wliich dis- 

 tinguish them from all other epidemics. 



1. A very sudden outbreak and a gradual decline. 



2. The first cases appear among milk users. 



3. The severity of the outbreak depends on the distribution of the 



infected milk and the amount of infection ]n-esent in the milk. 



4. The length of the epidemic varies with the period of incubation of 



the disease, the length of time the milk is infected, and con- 

 tagiousness of the disease. 



5. Secondary cases vei'y often occur. 



THE DUBLIN EPIDEMIC. 



On August 5, 1913, there broke out in Dublin, N. H., an epidemic of 

 diarrhcea exhibiting all of these above-named characteristics. At first the 

 outbreak vv^as localized along one milk route, but soon became general and 

 spread throughout the entire community. During the first few days of the 

 epidemic there was a sudden rise in the number of cases reported and the 

 total jumped from a few cases to thirty-one, all of which were in house- 

 holds takmg milk from this one milkman. 



The Dublin Chemical and Bacteriological Laboratory had been mak- 

 ing routine bacteriological tests of all the milk sold in Dublin. On August 

 4th the milk from this particular barn was found to be infected with B. 

 coll. Up to this time the total count had been very low, with absence of 

 coli and streptococci. Immediately a surve.v of the liarn ;iiid sui'ronnd- 

 ings was made and the following data collected: 



Two members of the family had had diarrhoea on the evening of 

 August 3d. One of these persons handled the milk in the milk room. 



