Table 1.

Conceptual model for hierarchical analysis of factors associated with a positive serology for Toxocara spp.

DISTAL	Block 1: Socio-economic variables
	Wealth status
	Receipt of benefits
	Possession of household
	Years of parental schooling
	Block 2: Domestic and peridomestic environment
	Type of household
	House floor
	Presence of electric power
	Source of domestic water supply
	Piped water supply in house
	Source of drinking water
	Treatment of drinking water
	Intermittence of water supply
	Type of toilet
	Domestic waste disposal
	Public waste collection
	Presence of dogs and cats
	Susceptibility to flooding during rain
	Presence of open sewage near house
INTERMEDIATE	Block 3: Access to health services and child care
	Number of siblings that died before the age of 5 years
	Living with one or both biological parents
	Attending nursery or school
PROXIMAL	Block 4: Characteristics of the birth and breastfeeding
	Low birth weight
	Duration of exclusive breastfeeding
	Block 5: Morbidity and other child factors
	Age
	Gender
	Skin color
	Time living in the house
	Respiratory symptoms or diseases
	Other recent morbidities
	Previous or present diagnosis of intestinal parasites

Adapted from Prado and others, 2003.³⁰