regarding treatment'. We add to these issues the type of diarrhea. Severe diarrhea episodes may have a higher use rate of ORS than milder ones. Thus in Egypt, data collected for younger children during the summer season are likely to show higher rates. To obtain more valid and consistent information on use rates, an attempt is made to reduce methodological biases by standardizing for reference period and age of children. Also, newer evidence is presented20 21' **_22n_ 23,** 24. A summary of information is presented in Table 4. It is obvious that, even after standardization, a wide range of estimates of ORS use in last episodes is provided by different sources of data. In what follows, an attempt is made to reach a single plausible estimate.

The use rate provided by the Menoufia KAP survey is identical to the September/October use rate of the 1990/91 Menoufia Child Survival in Rural Egypt survey. Menoufia use rates are much higher than the national rates, though the difference is reduced by comparing Menoufia to Lower Egypt. The higher use rates for Menoufia may be explained by one or more of the following: the two week reference period may favor recollection of severe cases with higher than average utilization of ORS; and the special history of Menoufiae may have resulted in ORS<sup>2</sup> utilization rates above the national average.

The expectation that the conduct of the Egypt Demographic and Health Survey (EDHS) in winter would underestimate the ORS use rate is not supported by data from Menoufia classified by survey dates, since these data show little variation in use rate per episode by season (see Table 4). The EDHS national estimate of utilization of around 30% seems the most reasonable, but to avoid any underestimate of utilization of ORS an average (using both EDHS and Menoufia Child Survival Survey) level of ORS utilization is around 42%, 44% and 37% for ages less than 1 year, 2 years and 5 years respectively.

The NCDDP encouraged use of ORS at the onset of diarrheal attacks. Nevertheless, the available evidence (unfortunately EDHS estimates are not available yet) strongly suggests differential treatments by type of episode, as is shown in Table 5. Allowing a ratio of 3:1 (a higher ratio than implied by actual data) for use of ORS in severe to non severe cases, and a distribution of diarrhea by mild and stvere of 2:1, would provide an estimate of ORS utilization in severe cases of around 75%. This is of course a very rough estimate but it is as good as the available information permits.

We can now put an upper bound on impact. Assuming proper utilization and that half of all diarrheal deaths are due to dehydration (both quite generous assumptions), the maximum expected reduction in diarrhea associated mortality is 37.5% (.5 X .75) and in infant mortality 19% (.5 X .5 X .75).

# _b) Quali t Use_

The anticipated reductions in diarrheal and overall infant mortality assume 100% efficacy of ORS. Efficacy of ORS is well established in clinical settings. In community settings, the social constraints that resulted in high incidence rates of diarrhea are the same constraints that are likely to impede the proper utilization of ORS.

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