METHOD OF SPREAD 



467 



One method of diagnosis is the examination of cultures, made 

 from the feces (excreta) of the patient, for the presence of typhoid 

 germs. Doctors take samples of fecal material from the patient 

 and send it to the Board of Health laboratories. There the ma- 

 terial is mixed with media and the developing bacterial colonies 

 are examined for typhoid bacilli. 



Another method of diagnosis is the Widal test. This con- 

 sists of separating serum from the patient's blood and mixing 

 it with a culture of known typhoid germs. If the patient has 

 typhoid, the blood serum will cause the germs to become ag- 

 glutinated. Agglutinins for typhoid are present in the blood 

 only when typhoid bacilli are in the body or if a person has 

 recently recovered from typhoid. The Widal test is a means of 

 differentiating typhoid fever from other diseases that produce 

 fever. 



Method of Spread. Typhoid germs are spread largely through 

 materials contaminated by the excreta of typhoid patients. This 

 may be, and most frequently is, water which has been polluted by 

 sewage and milk which has 

 become infected probably 

 by being kept in containers 

 which have been washed in 

 polluted water. Raw foods 

 such as oysters, if they 

 are grown where they come 

 in contact with sewage, 

 may cause typhoid fever. 

 Raw foods such as celery 

 and lettuce, which may 

 have been watered or 

 washed with contaminat- 

 ing water, are frequently carriers of the disease. Insects, princi- 

 pally the house flies, which travel readily from filth to exposed 



Agglutinins of various types may be present in the 

 blood. The picture on the left shows agglutinated 

 typhoid bacilli, on the right agglutinated pneumonia 

 cocci. 



