Parasitologic Surveys in Cali, Departamento Del Valle, Colombia

Summary Study of the intestinal parasites of residents of Ward Siloe, Cali, Colombia, constituted an integral part of the preventive health services in the Family Care Program, Department of Preventive Medicine and Public Health, University of Valle. Altogether 233 families were included in the parasitologic survey. Eighty-eight percent (1227 persons) of families 1–106 provided an average of three stools per person, while 1052 persons of families 107–233 contributed about 2 stools per person during a somewhat shorter time. Stool specimens were examined six days a week by standard direct and zinc sulfate concentration technics for all parasite objects. Record cards were kept of the stage and number of each species diagnosed, and were filed by patient's name, age, sex, family number and relationship of patient to the head of the family. Special study was made of the six common potentially pathogenic parasites (Entamoeba histolytica, Giardia lamblia, Ascaris lumbricoides, Trichuris trichiura, Necator americanus and Strongyloides stercoralis). Rates of infection were calculated for each of these parasites by Areas (I–IV), by age groups, on the basis of persons found infected and of positive stools, and by consecutive trimesters over a four-year period. Less frequent pathogens diagnosed included: Balantidium coli, Isospora belli and I. hominis, Taenia saginata, Hymenolepis nana and H. diminuta. Examination of the feces of dogs, mice, rats and cockroaches showed that, although there were indications that parasite objects of human origin had often been ingested by these animals, there was no suggestive evidence that they had contributed to the prevalence of human intestinal parasitoses. Exposure within the home environments in Siloe favors repeated infection, beginning during the first months of life and continuing until old age. Lack of a clean domestic water supply, filthy latrines and no facilities for garbage disposal provide unusually favorable opportunity for continued reexposure to infection in Ward Siloe, Cali.