﻿IX. B, 2 Sanitary Survey in Mindoro 169 



malaria. The conditions in the Panama Canal Zone are, perhaps, 

 the most nearly comparable with those in the San Jose Estate. 

 In both places the population consists largely of imported 

 laborers who are more or less nonimmune, and in both places 

 prophylactic measures against malaria are practiced. Darling 

 reported in 1910 (3) that he found malarial parasites in the 

 blood of 13 per cent of 276 persons who were up and performing 

 their regular duties. Our findings at San Jose show a much 

 higher percentage of infection. 



Considering them by groups, the individuals sick with fever 

 naturally show the largest percentage of infected persons, it 

 being 51.61 per cent. Well children, as is to be expected, come 

 next with a percentage of 43.48 of infection. The well men 

 follow with 34.05 per cent of infections. Lastly come the well 

 women who were found infected to the extent of 22.22 per cent. 

 Of the total 428 infections with malarial parasites, 157 or 

 36.68 per cent were tertian, 216 or 50.46 per cent were sub- 

 tertian, and 9 or 2.1 per cent were quartan. Double infections, 

 chiefly with tertian and subtertian parasites, were found in 50 

 persons, and triple infections, consisting of double tertian and 

 single subtertian infections, are recorded in 1 man and in 1 child. 

 No spirochsetes or Leishmania were found in any of the blood 

 smears, although a few of the persons examined were East 

 Indians. Spirochsetes have been found previously in the blood 

 of an East Indian employee suffering from black-water fever 

 on this estate.' In a blood smear from one malarial case, a 

 single filarial larva was found. 



Gametes of the malarial parasite were found in only 98 or 

 26.27 per cent of the 373 infected persons. With few exceptions 

 the gametes, when found, were few. Darling (4) has estimated 

 that persons whose blood contains more than 12 gametes per 

 cubic millimeter, or 1 gamete to 500 leucocytes, are capable of 

 infecting mosquitoes, and consequently must be regarded as 

 "malaria carriers." The blood of these 98 persons, and probably 

 others, contained more than 12 gametes per cubic millimeter, and 

 was, therefore, dangerous to other persons in the presence of the 

 proper mosquito host. 



With reference to the red blood corpuscles, the low haemoglobin 

 value and the absence of well-marked regenerative changes are 

 noteworthy. 



In 266 of the cases of malarial infection in which the haemo- 

 globin value was determined, it was as follows: 



'Ashburn, Vedder, and Gentry, Bull. Manila Med. Soc. (1912), 4, 198. 



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