that specimens must not be contaminated with urine or water. They were also told that the preferred time for specimen collection was early in the morning. Caregivers were instructed to scoop enough stool to fill approximately one-third of the container (about 5 grams for solid stool and 10 ml for liquid stool, which was about two full scoops), screw the cap on tightly, and shake well. The sample was then transferred to a lab. Following Katz (1972), reported infection intensity was proxied by worm eggs per gram of stool.

Table 8b reports the results from the parasitology analysis. Worm infection was relatively low in our sample, with only 4 percent of the surveyed children testing positive for at least one of the following: worms ( _Ascaris lumbricoides, Trichuris trichuria_ ) and hookworms ( _Ancylostoma duodenale_ and _Necator americanus_ ). We found no significant difference in the probability of having any eggs between the children in the treatment and control groups. Children in the treatment groups appear to have lower infection intensity than those in control groups. However, the difference is not statistically significant. Table 8b also provides information on the prevalence and intensity of infection by organism. Prevalence is highest for _Ascaris_ (3 percent). Hookworm prevalence is 0.5 percent, and _trichuris_ prevalence is 0.1 percent _._ We compare infection prevalence categorized by low, moderate, and high infection intensity using the WHO (2002) thresholds for fecal egg count per gram (epg).<sup>17</sup> As before, we find no significant difference in infection intensity for each organism in the treatment and control groups.

Acute respiratory infections (ARI) are among the leading causes of death in children under five years old. Following the WHO definition, a child is identified as having ARI when he or she presents with a persistent cough or difficulty breathing. A meta-study conducted by Roth et al. (2008) found that throughout the world, 1.9 million children died from ARI in 2000; 70 percent of these deaths were in Africa and Southeast Asia. Acute lower respiratory infection (ALRI) is a more serious condition and is diagnosed when a child has a constant cough or difficulty breathing (ARI) and a raised respiratory rate. A number of factors affect ARI and ALRI rates in young children, including malnutrition, lack of breastfeeding, and the incidence of other diseases that affect susceptibility. The child’s environment (such as crowding and air pollution) can also affect the risk of getting ALRI. Better sanitation in the form of frequent handwashing can reduce the spread of the infection from person to person.

As Table 8b shows, using either a seven- or two-day recall period, ARI and ALRI prevalence are slightly higher for children in the treatment group than for children in the control group, although the differences are small and not statistically significant. ALRI prevalence in the sample is low (around 2 percent of children were found to have had ALRI in the past seven days).

> 17 The infection thresholds for _Ascaris lumbricoides_ are low: 1–4,999 eggs per gram (epg); moderate: 5,000–49,999 epg; and heavy: >50,000 epg. For _trichuris trichuria_ , infection thresholds are low: 1–999 epg; moderate: 1,000– 9,999 epg; and heavy: >10,000 epg. For hookworm, thresholds are low: 1–1,999; moderate: 2,000–3,999; and heavy: >4,000 epg (WHO, 2002).

23