Magnitude and distribution of canine fecal contamination and helminth eggs in two areas of different urban structure, Greater Buenos Aires, Argentina.

The canine fecal contamination and the potential transmission of parasites to human and canine populations represent a public health problem of cosmopolitan importance. The objectives of this work were to evaluate the magnitude of fecal and parasite contamination in two suburban areas of different characteristics, and to investigate their distribution in various urban microenvironments such as yards, green spaces and sidewalks. The areas were referred to as middle-income neighbourhood (MIN) and low-income neighbourhood (LIN). To evaluate fecal contamination and its distribution, feces were counted and areas surveyed were calculated. The parasite contamination was evaluated from the prevalence of helminthosis found in a randomly selected fecal sample of the canine population in each of the study areas. The respective median fecal densities in MIN and LIN were 0.11 and 0.12 feces/m2 for green spaces, 0.10 and 0.19 feces/m2 for sidewalks (Mann-Whitney test, p<0.05), and 0.04 and 0.07 feces/m2 for households. In all the surveyed environments, dogs were free-ranging animals and preferred to defecate on grass surfaces rather than on bare soil, tile or sand. In MIN and LIN the respective prevalences were 40% and 70% for helminths in general (Chi square=15.17, p<0.01), 14 and 53% for Ancylostoma (Chi square=23.99, p<0.01), 9 and 17% for Toxocara (p>0.05), and 26 and 38% for Trichuris (p>0.05). Sidewalks were the most contaminated environments in LIN. The level of infected feces in sidewalks and yards was higher in LIN than in MIN (Mann-Whitney test, p<0.05). This study includes a discussion of the influence of variables such as canine population density, sidewalk structure and amount of available green spaces on the distribution of fecal contamination, and results obtained are compared with those previously recorded for Buenos Aires City. An increasing gradient of contamination by canine feces and parasites was observed as socioeconomic status decreased, the canine population increased and the sanitation condition decrease.