﻿IX. B, 3 Willets: Intestinal Helminthiasis 235 



or prior thereto and that these conditions were favorable to 

 the propagation of hookworms and Trichuris and unfavorable 

 to that of Ascaris. The differences in the Trichuris and Ascaris 

 percentages, however, may be explained in part by the fact 

 that Ascaris infections are treated at the prison hospital as a 

 routine procedure, whereas Trichuris infections are not treated 

 unless they are heavy. Such a state of affairs would naturally 

 lead to carelessness in observing light Trichuris infections in 

 making examinations to detect cases for treatment, such as 

 those here recorded. Garrison examined some admission cases 

 but chiefly those which were already in the institution, and his 

 findings represent an endemic condition.* Improved sanitary 

 conditions in the institution have been efficacious in markedly 

 lowering the incidence of intestinal helminthiasis as shown by 

 the results obtained in the examinations of 930 prisoners in 

 1910 (Table VI). As indicated in the table, these individuals 

 had been prisoners for periods varying from a few months to 

 four years. The only species of helminthic parasites which gave 

 an increased percentage upon length of residence was the seat- 

 worm (Oxyuris). 



A map showing the distribution of infections with the several 

 species of parasites found in the examinations of the Filipinos 

 of the series was prepared. It showed that the distribution 

 of the various parasites is extremely irregular. Adjacent north- 

 em and adjacent southern provinces gave in some instances 

 very different results. Former investigations predicted this 

 result. Indeed, it is on record that Garrison, Leynes, and 

 Llamas * and Rissler and Gomez * found quite different percent- 

 ages of infection with Trichuris in Rizal Province. 



The low percentage of Chinese infected in general and with 

 each common species of parasite, as shown in Tables II and 

 III, is remarkable. The explanation of the differences in infec- 



* It is well known that the sanitary conditions at the prison were deplor- 

 able prior to their being placed in the hands of the Bureau of Health, 

 shortly before Garrison's investigation was begun. It is further known 

 that these conditions were changed, so that within a period of a few months 

 sound sanitary regulations were in force. Since that time, routine examina- 

 tion of stools for evidences of intestinal parasitism has been regularly made 

 by the Bureau of Science, and infected cases have been treated. Prisoners, 

 new ones or those who have been detailed for outside worK, are held in 

 quarantine for five days upon admission. If an individual is found to 

 harbor intestinal parasites other than Trichuris or monads, he is treated in 

 the prison hospital until apparently cured. 



'Ibid. (1909), 4, 257. 



'Ibid. (1910), 5, 267. 



