ANIMAL PARASITES OF MAN. 199 



the information that although hookworm infections are common, they 

 are usually first diagnosed in routine examinations of the faeces and if 

 severe anaemia is present, a concurrent infection of malaria, tuberculosis 

 or of some other disease which would account for the condition exists. 

 Furthermore, after careful and general inquiry among numerous medical 

 officers of the Army, Navy, and the Bureau of Health who had served or 

 were serving in the provinces, we have failed to obtain any knowledge 

 of any general or marked prevalence of hookworm disease among the 

 natives. 9 Accordingly, while further investigation may discover a greater 

 frequency of uncinariasis in its severer forms than now appears to be 

 the case, it would seem to be reasonably certain that there is no such 

 prevalence of this disease with severe manifestations among the natives 

 of the Philippines as we might expect in view of the apparent fact that 

 over one-half of the population harbors this parasite. 



Whether or not the explanation of this apparent rarity of clinical 

 symptoms in hookworm infections among the Filipinos is a racial im- 

 munity on the part of the people to the toxins secreted by the worms, 

 as has been suggested in regard to the similar condition found by Stiles 

 in negroes in the Southern States, by the Anaemia Commission in Porto 

 Eico and by Zinn and Jacoby in Africa, the fact that severe clinical 

 manifestations of uncinariasis are rare in' the Philippines materially 

 alters the problem which is presented. Instead of producing an acute 

 condition such as was presented in Porto Eico, St. Gothard Tunnel, 

 the Westphalian coal mines, and in other places where uncinariasis 

 prevailed in its severer forms, it would appear that in the Philippines 

 hookworm infections play a part more nearly resembling that of the other 

 common intestinal worms to which no definite pathology or severe 

 symptomatology is usually attributed. 



INFECTIONS WITH ASCAEIS. 

 (20 per cent.) 



Bates of infection with "round worms" have been reported ranging 

 from 0.49 per cent (Stiles and Garrison, United States, 1906) to 50.97 

 per cent (Wellman, west Africa, 1904). 



A compilation of statistics obtained from nearly 3,000 persons ex- 

 amined and reported upon by various authors, shows Ascaris to have 

 been found almost twice as frequently in females as in males, as follows : 

 Males examined, 1,732; infected with Ascaris, 138, or 7.97 per cent; 

 females examined, 1,103 ; infected, 159, or 14.42 per cent. 10 



9 The most severe ease of hookworm disease seen by the author in Manila and 

 the only one showing in a marked degree the cardinal symptoms of extreme 

 anaemia, with cardiac murmurs, oedema, dyspnoea, and great weakness, was a 

 Japanese male infected with the "Old World" hookworm {Agchylostoma duo- 

 denale ) . 



10 Bull. Hyg., V. 8. Pal. Health & Mar.-Eosp. Serv. Wash. (1906), 28, 70-72. 



