No abstract

Despite the long-standing observation that tuberculosis (TB) case rates are higher among racial and ethnic minorities than whites in the United States (U.S.), the proportion of this increased risk attributable to socioeconomic status (SES) has not been determined. Values for six SES indicators (crowding, income, poverty, public assistance, unemployment, and education) were assigned to U.S. TB cases reported from 1987-1993 by ZIP code- and demographic-specific matching to 1990 U.S. Census data. TB risk between racial/ethnic groups was then evaluated by quartile for each SES indicator utilizing univariate and Poisson multivariate analyses. Relative risk (RR) of TB increased with lower SES quartile for all six SES indicators on univariate analysis (RRs 2.6-5.6 in the lowest versus highest quartiles). The same trend was observed in multivariate models containing individual SES indicators (RRs 1.8-2.5) and for three SES indicators (crowding, poverty, and education) in the model containing all six indicators. Tuberculosis risk increased uniformly between SES quartile for each indicator except crowding, where risk was concentrated in the lowest quartile. Adjusting for SES accounted for approximately half of the increased risk of TB associated with race/ethnicity among U.S.-born blacks, Hispanics, and Native Americans. Even more of this increased risk was accounted for in the final model, which also adjusted for interaction between crowding and race/ethnicity. SES impacts TB incidence via both a strong direct effect of crowding, manifested predominantly in overcrowded settings, and a TB-SES health gradient, manifested at all SES levels. SES accounts for much of the increased risk of TB previously associated with race/ethnicity.

Multiple factors contributed to the recent increases in the number of TB cases. The effectiveness of TB screening in immigrants needs further evaluation. Intensified efforts to determine the human immunodeficiency virus status of persons with TB are needed. Screening of subpopulations at increased risk for tuberculous infection or TB should be expanded.

Symptomatic and asymptomatic astrovirus infection was prospectively determined in a 3-year birth cohort of Mayan infants. Stool samples from 271 infants and 268 older siblings were tested for astrovirus, adenovirus 40/41, rotavirus and Salmonella, Shigella and Campylobacter species. Concurrent diarrhea, vomiting, fever, or anorexia were noted. Astrovirus was detected in 164 infants (61%) and 20 siblings (7%). Rotavirus (4%) and adenovirus 40/41 (13%) were isolated less frequently. Of all diarrheal episodes reported at a visit, 26% (78/305) were associated with astrovirus; 17% (78/452) of astrovirus infections were associated with diarrhea and 9% with other symptoms. Only diarrhea was associated with astrovirus infection (odds ratio, 1.4; 95% confidence interval [CI], 1.07 -1.92; P Å .01). Of infants with astrovirus, 70% shed at multiple visits over a period of 2 -17 weeks (median, 5). The point prevalence of astrovirus infection was significantly higher among infants than siblings (relative risk, 6.18; 95% CI, 3.93 -9.72; P õ .0001, x 2 ). Astrovirus was identified throughout the year, peaked in March and May, and decreased in September. In this population, astrovirus was the most common enteric pathogen isolated; symptomatic infection was prevalent among infants.Astroviruses are second only to rotaviruses as a common the incidence of asymptomatic astrovirus infection have been described in US day care center studies [2,3]; no longitudinal cause of viral gastroenteritis in infants and young children worldwide [1]. Acute astrovirus gastroenteritis induces a mild, data have been published regarding children living outside of developed countries. In addition, astroviruses may be isolated watery diarrhea that lasts for 2 -3 days and may be associated with vomiting, fever, anorexia, abdominal pain, and constitufrom stool specimens from children with gastroenteritis that contain other enteric pathogens, making determination of the tional symptoms that last up to 4 days. Protracted diarrhea and viral shedding are uncommon. Most astrovirus infections are causative pathogen difficult. As part of an oral poliovirus vaccine (OPV) immunogenicity detected in the winter months in temperate regions and in the rainy season in tropical climates, a pattern similar to that seen study [4], we collected sequential stool samples from a 3-year population-based birth cohort of rural Mayan infants and their with rotavirus infections. Symptomatic infections are primarily found in infants and young children, particularly in developing older siblings living in Chiapas, Mexico. We studied the prevalence of astrovirus, rotavirus, adenovirus 40/41, and Salmocountries, or in elderly, institutionalized populations.Most data regarding astrovirus infection have been obtained nella, Shigella, and Campylobacter species in this population and obtained information regarding the presence of common from cross-sectional rather than longitudinal studies of children with gastrointestinal symptoms. Longitudinal data regarding gastrointestinal symptoms arou...

Factors affecting immunogenicity of the first 2 doses of oral poliovirus vaccine (OPV) among unimmunized Mayan infants were prospectively evaluated. The relative impact of multiple variables, including mass or routine vaccination, concurrent enteric bacterial (salmonella, shigella, and campylobacter) and viral (adenovirus 40/41, astrovirus, nonpolio enteroviruses, and rotavirus) infections, interference among Sabin vaccine viruses, and preexisting poliovirus antibodies were studied. Sera were available from 181 infants after 2 OPV doses. Seroresponses were 86% to Sabin type 1, 97% to Sabin type 2, and 61% to Sabin type 3 vaccines. Mass versus routine vaccination and preexisting poliovirus antibodies did not affect immunogenicity. By multiple logistic regression analysis, fecal shedding of homologous Sabin strains was associated with increased seroresponses to all Sabin types, especially to Sabin type 3. Decreased OPV immunogenicity was primarily attributable to interference of Sabin type 3 by Sabin type 2. OPV formulations with higher doses of Sabin type 3 could improve immunogenicity among infants in developing countries.