﻿WIDAL REACTIONS AMONG HEALTHY ADULT FILIPINOS 



By David G. Willets 

 {From the Biological Laboratory, Bureau of Science, Manila, P. I.) 



This work was undertaken for the purpose of determining 

 (1) the percentage of healthy adult Filipinos indicating previous 

 or present infection with Bacillus typhosus by the presence of 

 a positive Widal reaction and (2) the percentage of typhoid 

 carriers among this class of individuals. The second phase of 

 the investigation was to have been conducted by Dr. J. A. Johns- 

 ton of this laboratory, but this work was unfortunately inter- 

 rupted.^ The results of the Widal tests alone, however, indicate 

 the advisability of placing them on record. These tests were 

 made on the blood of 300 apparently healthy, young, adult Fili- 

 pino employees (nurses, etc.) of the Philippine General Hospital. 

 In making the tests, serum only was used. The dilutions and 

 time limits are given in the following table. The microscopic 

 method was used, because it was desired to apply to these cases 

 the same routine test as to suspected typhoid cases. In the midst 

 of the investigation, the typhoid culture was examined morpho- 

 logically and culturally and found to be quite pure. It may also 

 be stated that from 15 to 30 tests were made at a time and that 

 these were checked against reactions on the blood of known cases 

 of clinical typhoid fever. It will be noted that control reactions 

 were performed in a number of instances. These were made 

 about ten days after the original tests. 



After cleaning a portion of a finger or of an ear with 95 per 

 cent alcohol and drying with sterile cotton, a small quantity 

 of blood was collected in a capillary pipette. The smaller end 

 of the pipette was closed in a Bunsen flame, and the larger end 

 with sterile cotton. The specimen was then centrifuged until 

 the supernatant serum was quite free from blood corpuscles, 

 whereupon it was placed in a refrigerator for a period of from 

 a few hours to one day. The serum was drawn off by means 

 of a fine capillary pipette and placed in a watch glass. It 

 was diluted 1 to 20 by use of a pipette for counting leucocytes. 



* In the few cases in which cultures of the faeces and urine were made, 

 B. typhosus was isolated in one instance; this case had given a definitely 

 positive Widal reaction. 



253 



