Appropriate selection of donors, use of sensitive screening tests, and the application of a mandatory quality assurance system are essential to maintain the safety of the blood supply. Laws, decrees, norms, and/or regulations covering most of these aspects of blood transfusion exist in 16 of the 17 countries in Latin America that are the subject of this review. In 17 countries, there is an information system that, although still incomplete (there are no official reports on adverse events and incidents), allows us to establish progress made on the status of the blood supply since 1993. Most advances originated in increased screening coverage for infectious diseases and better quality assurance. However, in 2001 to 2002, tainted blood may have caused infections in 12 of the 17 countries; no country reached the number of donors considered adequate, i.e., 5% of the population, to avoid blood shortages, or decreased significantly the number of blood banks, although larger blood banks are more efficient and take advantage of economies of scale. In those years, paid donors still existed in four countries and replacement donors made up >75% of the blood donors in another eight countries. In addition, countries did not report the number of voluntary donors who were repeat donors, i.e., the healthiest category. In spite of progress made, more improvements are needed

Intestinal helminths are among the most common infections in school-age children. Of 246 children, aged 7-12 years, attending school in rural Guatemala, 91% carried Ascaris lumbricoides and 82% carried Trichuris trichiura. These children were randomly assigned to receive either albendazole or placebo at 0 and 12 weeks in a 'double-blind' study of the effects of deworming on indicators of school performance. Albendazole successfully rid the children of Ascaris but it was less effective against Trichuris. The children's performance in tests of reading and vocabulary were measured at 0 and 24 weeks, the Peabody picture vocabulary test was given at 24 weeks, and attendance was measured throughout the school year. Comparison of the treated and placebo groups showed no positive effect of deworming. The treated children were largely free of Ascaris for at least 6 months, but during that period we could not detect any improvement in reading, vocabulary, or attendance. The effects of being Trichuris-free were not examined because of the limited effectiveness of albendazole against this worm at the dosage used.

The potential risk of acquiring a transfusion-transmitted infection by the human immunodeficiency virus (HIV), hepatitis B (HBV) virus, hepatitis C (HCV) virus, or Trypanosoma cruzi was estimated for seven South American and five Central American countries during the period 1994-1997. The estimates were based on official national reports of the number of donors, blood screening coverage, and prevalence of serologic markers for infectious diseases. Coverage of screening in 1997 was 100% in 12 and 11 countries for HIV and HBV respectively. Complete screening for HCV was reported by only one country in 1994 and by six in 1997. For T. cruzi, the number of countries with 100% screening coverage increased from two in 1994 to four in 1997. In 1994, three countries showed risk of transfusion-transmitted infections for HIV, seven for HBV, eight for HCV, and seven for T. cruzi. The risk of receiving an infected blood unit and acquiring a transfusion-transmitted infection has been reduced with time in 10 of the 12 countries due to improvements in screening coverage. In Uruguay, the risk was theoretically nil from 1994-1997 because at the beginning of the study period they already had 100% blood donor screening for all infectious diseases transmitted by blood. In 1994, Colombia and Venezuela had the highest health risk associated with blood transfusion (spreading index of 101 and 62, respectively); during the period 1996-1997, Costa Rica presented the highest figures (spreading index of 53 and 83, respectively). The analysis of the potential risk associated with transfusion of tainted blood highlights the need for continuous monitoring of the safety of blood supply.

proportion of paid donors for Brazil (BRA) should be zero (blank) and not 75; the proportion of replacement (Rep) donors should be 75 and not zero (blank). In 1999, the proportion of voluntary (Vol) donors for Ecuador (ECU) should be 19 instead of 20. In 2001/2002, the proportion of Replacement (Rep) donors for Nicaragua (NIC) should be 44 and not 41, and the proportion of voluntary (Vol) donors for Bolivia (BOL) should be 11 and not 10.

Fecal excretion of astroviruses was monitored in 321 children, 0 to 3 years old, living in the rural highlands of Guatemala. During the longitudinal study, from February 1987 to February 1989, we examined 5,000 stool specimens, including 1,805 collected during 1,369 episodes of diarrhea, 830 collected during the convalescent week, and 216 and 244 collected 2 weeks and 1 week, respectively, before the onset of diarrhea. Routine specimens were taken once a month from every child who had been free from diarrhea for at least three consecutive weeks. Of the children, 124 (38.6%) excreted astroviruses during the study. In total, we identified 184 infections by astroviruses. Of the samples collected 2 weeks and 1 week before the initiation of symptoms, 0.9 and 4.9%o, respectively, were positive, while 7.3% of the diarrhea episodes were associated with