Investigation of Parasitic Infections in the Central Area of Philadelphia

Abstract

Summary In order to obtain data on the parasitological situation in Philadelphia resulting from an increase in Puerto Rican residents an intestinal parasite survey of school children and a housing quality survey were conducted in the fall of 1957. The children were from similar socio-economic environments and were attending the 4th, 5th, and 6th grades of 2 parochial and 2 public schools. Of 395 stool specimens examined 42.3% were from Puerto Rican children and 58.7% were from non-Puerto Rican children (white, Negro, or Mongolian). The examinations revealed 83.2% of the Puerto Rican, 51.0% of the Negro and 30.2% of the white children infected with parasites. A single stool specimen was examined from each child. Fifteen different parasites were identified. The highest prevalence of any single species was for Trichuris trichiura (67.7% in the Puerto Rican children). Excluding Enterobius vermicularis for which specific examinations were not performed, the prevalence rates for all of the helminths were higher in the Puerto Rican children. Although generally true for the protozoa, several of the species had the highest prevalence in the non-Puerto Rican Negro group (e.g. 8.2% for Entamoeba histolytica). The prevalence of Dientamoeba fragilis (24.5%) for the Negro children was four to five times higher than for the other groups. A significant reduction was observed in the helminth prevalence among the Puerto Rican children after six years of residence in the United States. However, there was not a similar reduction in amebic prevalence rate with length of residence. Furthermore, the protozoan infections were relatively high in the non-Puerto Rican children. These observations may demonstrate that although helminth infections (excluding E. vermicularis) are not being transmitted to any significant degree in Philadelphia, protozoan infections probably are. The housing quality survey revealed that the dwellings in the central area of Philadelphia are over-crowded and deficient in toilet and bathing facilities which in all likelihood must facilitate transmission by direct contact.