Interviews were conducted in person from October 1 through December 13, 2006. All persons who had lived in the house for at least six of the preceding 12 months were considered members of the household and eligible for inclusion, including persons deceased at the time of the survey if they had been resident during the reference period. Infants <6 months of age were included if they had lived in the household since birth. Households were excluded if a head of household or consenting adult was unavailable after visiting the house on three separate occasions over at least two days, or if the household head declined to participate. Excluded households were not replaced. If a house was abandoned or no longer existed, another house was randomly chosen for inclusion.