196 GARRISON. 



Nine hundred and thirty, or slightly less than one-fourth of the persons 

 examined, showed a double infection, of which hookworms and Trichuris gave 

 518, or about one-half, Ascaris and Trichuris nearly one-fourth, and various 

 combinations the remainder. 



Seven hundred and twenty-three, or about 18 per cent, had triple infections, 

 of which the most common was with Ascaris, hookworms and Trichuris ; although 

 combined infections with Amoeba, hookworms and Trichuris and with hookworms, 

 Trichuris and flagellates were present with almost equal frequency. 



Three hundred and sixty-six prisoners, or 9 per cent, were infected with four 

 different parasites, the most common combination being Amoeba, flagellates, 

 hookworms and Trichuris. 



One hundred and thirty-one prisoners (3 per cent) gave a combined infection 

 with 5 parasites, 80 of which were with Amoeba, flagellates, Ascaris, hookworms 

 and Trichuris. 



A combination of six different infections in one patient occurred fifteen times; 

 in five of these cases the parasites were Amoeba, flagellates, Ascaris, hookworms, 

 Strongyloides and Trichuris. 



Two prisoners had seven separate infections, and one man was infected with 

 nine different parasites, the combination in the last case being Amoeba, flagellates, 

 Balantidium, Ascaris, hookworms, Strongyloides, Trichuris, Opisthorchis and 

 Schistosoma. 



GEOGRAPHIC DISTRIBUTION. 



A rather elaborate attempt was made to determine whether the indi- 

 viduals coming from any particular part of the Islands gave an excess of 

 infection over those from other sections. To this end, a record of the 

 previous residence of prisoners was taken and the infections found were 

 tabulated by separate provinces, separate islands and various groups of 

 provinces and of islands. ISTo significant difference in the total per- 

 centage of infection could be detected. Prisoners from the extreme 

 northerly provinces presented about the same percentage (with all 

 parasites) as did those from the Visayas or from central or southern 

 Luzon. 



The same even geographic distribution seemed to prevail for each 

 separate species of parasite, with the exception of infections with the 

 three trematode genera, Paragonimus, Schistosoma and Opisthorchis, 

 especially the two former, which appeared to originate almost exclusively 

 in certain of the southern islands. 



The distribution of the infections with the three trematodes mentioned 

 will be considered more in detail under each genus. 



While practically all parts of the Islands are fairly well represented 

 at Bilibid, an investigation conducted at such long range would be able 

 to discover none but very marked inequalities in the distribution of the 

 parasites and it is by no means excluded that further work, done in the 

 various provinces themselves, would indicate an excess of infection in 

 certain parts of the Islands, which did not appear among the prisoners 

 examined at Bilibid. 



