INTESTINAL PARASITES. 269 



Las Pinas, 53.40 per cent of all the cases examined were infected, and 

 25.90 per cent in Tuguegarao. However, the number of cases infected 

 with Trichuris in Santa Isabel fell much below the average, being only 

 6.23 per cent. 



INFECTIONS WITH HOOKWORMS. 



Hookworm infection was found to be third in frequency in the ex- 

 amination for intestinal parasites. In Las Pinas 11.14 per cent of all 

 the cases examined were infected ; in Tuguegarao, 8.01 per cent. In Santa 

 Isabel we found the highest percentage of infection in all our work, 45.38 

 per cent. 



The adult males show the highest rate; 20.91 per cent in Las Pinas, 13.52 in 

 Tuguegarao, and 60.58 per cent in Santa Isabel. Adult females are less infected; 

 9.45 per cent in Las Pinas, 8.05 per cent in Tuguegarao, and 51.26 per cent in 

 Santa Isabel. Children are infected to a much lesser degree: 2.63 per cent in 

 Las Pinas, 3.66 per cent in Tuguegarao, and 26.42 per cent in Santa Isabel. 



The strikingly high percentage of infection in Santa Isabel may be 

 due to the occupation of the people, which requires almost constant 

 exposure of their bare feet to the soil in the fields while caring for the 

 tobacco plants. Again, the population is concentrated in a single spot 

 on the hacienda. The soil, being clayey, is not particularly favorable 

 to this infection. 



We noticed fissures on the plantar surface of the feet in many individuals 

 found harboring the hookworm, but these did not appear to cause any discomfort 

 except an occasional itching sensation. Upon examination we were not able to 

 demonstrate any embryonic form of the hookworm in these lesions. However, 

 on account of the discovery of these fissures on the feet and the greater prevalence 

 of the hookworm in adult males, although we have found no evidence of Uncinarial 

 dermatitis," we are inclined to think the skin transmission is an important means 

 of infection with this parasite. 



Clinical symptoms. — Cases exhibiting typical symptoms of uncinariasis 

 are rare. A few persons have complained of discomfort in the abdominal 

 region which has been relieved entirely by treatment which resulted in 

 the expulsion of the hookworms. Several cases in the Santa Isabel 

 hacienda were picked out by the manager as being typically lazy, but upon 

 examination they were not found to harbor this parasite. One of these 

 cases showed emaciation together with great pallor of the conjunctiva?, 

 without any history of malaria or tuberculosis. The examination of the 

 blood in general demonstrated an increase of the eosinophile leucocytes. 

 The absence of clinical symptoms was probably due to the paucity of the 

 infecting worms. In most cases only five or ten were expelled after treat- 

 ment, in others only two or three. 



7 Stelwagon, Henry W. • Philadelphia and London, 5th ed. (1907), 1109. 



