VACCINATION 



469 



Vaccination. Immunity to typhoid may be gained artificially 

 through vaccination. In the case of smallpox vaccine, the germ 

 material was weakened through cultivating it in animals. In 

 preparing typhoid vaccine, the bacilli are first grown on agar, 

 then killed by heat, and a little carbolic acid is added to the vac- 

 cine for a preservative. When this material is used as a vaccine, 

 the presence of the dead bacilli stimulates the body to make bac- 

 teriolysins and agglutinins. Thus a vaccinated person is pro- 

 tected against the invasion of living germs. Usually three 

 inoculations of vaccine are given, each being seven days apart. 



Very few people are made ill by typhoid vaccination. If the 

 person is likely to come in contact with paratyphoid, which is a 

 disease somewhat similar to typhoid, 

 he is given a combination vaccine of 

 typhoid and paratyphoid. For most 

 people living in the United States 

 or visiting here, the typhoid vaccine 

 is sufficient, because there are few 

 cases of paratyphoid in the United 

 States. 



The investigation of a typical epi- 

 demic. During November, 1924, there 

 was a noticeable rise in the number 

 of typhoid fever cases in New York 

 city. This continued through January, 

 1925. Of the 914 cases recorded in 

 this outbreak, 116 of the residents, and 

 59 nonresidents who were included 

 in the 914 cases, gave a history of 

 having been out-of-town during the 

 period immediately before their illness. 

 The majority of these had eaten oysters while out-of-town. About 

 18 per cent of the cases probably acquired their infections in 



Bacterium coli 



These organisms are commonly 

 present in the intestine of man. 

 Their presence in swimming pools 

 indicates the possibility of contami- 

 nation by human excreta. This 

 might also indicate the possible 

 presence of typhoid bacilli. Bac- 

 teriological examinations of water 

 in swimming pools are frequently 

 made to determine the presence of 

 bacterium coli. Their presence 

 would make the closing of the pool 

 imperative until proper prophylactic 

 measures were taken. 



