﻿THE MORPHOLOGY OF THE ADULTS OF THE FILARIA FOUND 

 IN THE PHILIPPINE ISLANDS 



By Ernest Linwood Walker 

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



One plate 



Ashburn and Craig (1906) described the larval filarise found 

 in the blood of a native of the Philippine Islands as a new species, 

 Filaria philippinensis. The diagnosis of the new species was 

 based on the study of the larvae from a single case of infection. 

 In 1907 these authors made a study of four additional cases of 

 filariasis in the Philippines, which they decided were infected 

 with the same species, and they performed some experiments on 

 the development and transmission of this species by the mosquito, 

 Culex fatigans. Ashburn and Craig distinguish Filaria philip- 

 pinensis from the hitherto described species by certain peculiar- 

 ities in the morphology and the lack of periodicity of the larvae. 

 Furthermore, they believe it to be the only indigenous species, 

 because the previous descriptions of filarial larvae observed in 

 natives of these Islands contain nothing which would exclude 

 the possibility that the observers were dealing with Filaria 

 philippinensis. 



Phalen and Nichols (1908 and 1909) made somewhat extended 

 observations on the occurrence and distribution of filariasis and 

 elephantiasis in the Philippine Islands. They found both to be 

 more prevalent and widespread than the observations of Ashburn 

 and Craig would indicate. Moreover, they found a distinct noc- 

 turnal periodicity in the appearance of the larval filariae in the 

 peripheral circulation in all of their cases, and they concluded 

 that the larvae in all of the cases studied by them corresponded 

 to the larvae of Filaria bancrofti Cobbold. 



Recently Dr. J. W. Smith (1914), chief sanitary officer of 

 Bilibid Prison, has had an extensive series of blood examinations 

 made of the prisoners in that institution. These prisoners come 

 from all parts of the Philippine Islands. The examinations were 

 made of blood taken both during the day and at night. Filaria 

 infection was found in about 6 per cent of the prisoners. The 

 larval filariae have been found to exhibit a distinct nocturnal 



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