A variation of the housing unit method for estimating the population of small, rural areas: a case study of the local expert procedure.

PIP: Sociologists designed a random sampling study based on an adaptation of the Housing Unit Method and the local expert method to determine the socioeconomic features of a 3 unincorporated rural communities near Yucca Mountain, Nevada which scientists will use to conduct a comprehensive impact analysis of the proposed geologic nuclear waste repository at Yucca Mountain, about 90 miles northwest of Las Vegas. Electrical company representatives indicated the location and type of housing with all up to date electrical connections in southern Nye county. This information was included in the housing unit file made from utility records from each community. After determining the sample size needed, households were randomly chosen from each file (326 Amargosa Valley, 672 Beatty, and 3224 Pahrump). Meter readers from the local utility companies were the local experts. 2 local experts worked together to authenticate the accuracy of recorded data which included number of person in the household as of July 15, 1990 and age and gender of each member. Data accuracy was tested and it was found that the 1990 US Census counts were within the relatively narrow 95% confidence intervals. The mean width was 7.2% of the estimated population, thus the estimates were meaningful. The estimates were too low for Pahrump (7190 vs. 7425) and Amargosa Valley (841 vs. 853), however. This may have been due to recent in-migration from the Las Vegas Valley. Age and gender accuracy could not be tested since the 1990 census data were not yet ready. Nevertheless, it is believed that this procedure can obtain very accurate estimates.^ieng

Controlled trial of Giardia lamblia: control strategies in day care centers.

BACKGROUND: Strategies for control of Giardia lamblia in day care differ in numbers of children treated and in costs to parents and day care operators. The effectiveness of these strategies has not been systematically evaluated. METHODS: We conducted a prospective randomized controlled trial comparing three strategies for control of Giardia in infant-toddler day care centers: Group 1, exclusion and treatment of symptomatic and asymptomatic infected children; Group 2, exclusion and treatment of symptomatic infection only; Group 3, exclusion and treatment of symptomatic infection, treatment of asymptomatic infection in the center. The study included 31 day care centers with 4180 child-months of observation. Giardia prevalence was determined before intervention and 1, 2, 4, and 6 months later; new infants and toddlers were tested on admission. RESULTS: Initial Giardia prevalences were 18% to 22% in the three groups. Giardia was identified in 10.5% of 676 new infants and toddlers entering study day care centers during the 6-month follow-up. Giardia prevalences by intervention group were 8%, 12%, and 7% at 1 month, and 7%, 8%, and 8% at 6 months. CONCLUSIONS: The stricter intervention resulted in greater cost in terms of child day care and parents' work days lost, but did not result in significantly better control of Giardia infections in this day care environment.

An outbreak of non-A, non-B hepatitis associated with the infusion of a commercial factor IX complex during cardiovascular surgery.

An outbreak of non-A, non-B hepatitis was recognized among cardiovascular surgical patients from one hospital in June 1985. Illness was found to be significantly associated with a commercial brand of factor IX complex given to patients because of intraoperative bleeding. A change in the commercial brand of factor IX stocked by the hospital pharmacy had occurred in October 1984 and coincided with the onset of the outbreak. A retrospective study of cardiovascular surgery patients identified 23 cases and 7 probable cases of non-A, non-B hepatitis among patients who had received infusions of brands A and B factor IX complex. Three cases were in brand A recipients and 27 were in brand B recipients. Respective brand-specific attack rates were 5 and 42% (relative risk = 7.7; p less than 2 x 10(-5); chi 2 test). Nineteen of 30 case patients (63%) were jaundiced, including 2 brand A recipients and 17 brand B recipients. Median peak serum aminotransferase was 690.5 IU (range 27-2,824). The incubation period for cases in brand B recipients was a median of 7 weeks (range 2-17 weeks). Prevention of non-A, non-B hepatitis in this population requires adhering to strict indications for the use of clotting factor preparations and avoiding these products when at all possible. Heat treatment of clotting factor products may reduce the risk of viral disease transmission, but certain methods may not inactivate the causative agents of non-A, non-B hepatitis.