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.

Epidemiology of Toxocara canis in the dog population from two areas of different socioeconomic status, Greater Buenos Aires, Argentina.

Toxocara canis infection in dogs is a public health problem in most countries, although it has been poorly documented in many of them. The main objective of the present work was to investigate the epidemiology of infection in the canine populations from two areas of Buenos Aires of different socioeconomic status and urban conditions: a middle-income neighbourhood (MIN) and a low-income neighbourhood (LIN). This study evaluated the prevalence of infection in dogs by parasitological and serological techniques in both areas, and described the relationship between the infection and different epidemiological variables for each neighbourhood. A cross-sectional study was carried out after a house-to-house census was completed. During August 1999, a sample of households was selected at random (nMIN=53 and nPA=52). In each house, one dog was randomly chosen for the collection of fresh faeces and blood. The dog owners were interviewed utilising a questionnaire about dogs on sex, recent anthelmintic treatment, degree of confinement, control by the dog's owner (whether the dog goes out of the house accompanied or not, leashed or unleashed), defecation site, defecation substratum and number of dogs in the house. The diagnostic techniques were concentration-sedimentation formalin/ether method and ELISA test. The parasitological prevalences in dogs were 9% (5/53) in MIN and 19% (10/52) in LIN, and serological prevalences were 22% (2/9) in MIN and 40% (15/37) in LIN. In MIN, the patent infection of males was significantly higher than that of females. In LIN, puppies less than 1 year old were the most prevalent age class. Our serological results showed that the positivity of adult dogs was more frequent in LIN than in MIN. The density of puppies with patent infection was seven times higher in LIN than in MIN, when combining coprological analysis and the estimated age structure obtained by the census.