How deceptive are microstructures in granitic rocks? Answers from integrated physical theory, phase equilibrium, and direct observations.

In this contribution, we address the vexed question of the extent to which microstructures in granitic rocks reflect their igneous histories or have been masked by later events. The previous works have tended to address the problem either using theoretical or modelling considerations, or by interpretation of observed microstructures. Here, we use an approach that integrates the theory of microstructural development and the results of experimental phase-equilibrium studies with direct observation of natural examples on a variety of scales. We show that the predictions of the theoretical and experimental approaches agree perfectly with the mesoscopic and microscopic evidence from granitic rocks themselves. Our conclusion is that although, in many cases, granitic rock microstructures have been modified by near-solidus reactions and crystallisation, in the absence of tectonic deformation the fundamental elements of their igneous heritage remain intact. This means that it is perfectly in order to infer aspects of crystallisation sequences, magmatic reactions, and magma flow through careful microstructural observations. Thus, our answer to the question of how deceptive granitic textures are is, in most instances, 'not very'. However, some undeformed plutons have undergone fluid-driven alteration, and others have been affected by contact metamorphism. Thus, each case should be examined on its own merits.

Risk factors associated with typhoid fever in children aged 2-16 years in Karachi, Pakistan.

We analysed the data from the control group in a typhoid vaccine trial in Karachi to assess the differences in individual-, household- and cluster-level characteristics for developing typhoid fever. The annual incidence of typhoid in children aged 2-16 years in the control arm of the vaccine trial was 151/100 000 population. After adjustment, the risk of typhoid was lower with increasing age [risk ratio (RR) 0·89, 95% confidence interval (CI) 0·83-0·95], was higher with an increase in population density (RR 1·13, 95% CI 1·05-1·21) and was lower in the households using a safe drinking-water source (RR 0·63, 95% CI 0·41-0·99). Typhoid fever affects younger children living in areas of high population density and lack of access to safe water in Pakistan. A combination of environmental and biological interventions is required to prevent the continued epidemiological and economic impact of typhoid fever in high-risk areas of Pakistan.

Cholera in India: an analysis of reports, 1997-2006.

OBJECTIVE: To more accurately define the annual incidence of cholera in India, believed to be higher than reported to the World Health Organization (WHO). METHODS: We searched the biomedical literature to extract data on the cases of cholera reported in India from 1997 to 2006 and compared the numbers found to those reported annually to WHO over the same period. The latter were obtained from WHO's annual summaries of reported cholera cases and National health profile 2006, published by India's Central Bureau of Health Intelligence. FINDINGS: Of India's 35 states or union territories, 21 reported cholera cases during at least one year between 1997 and 2006. The state of West Bengal reported cases during all 10 years, while the state of Maharashtra and the union territory of Delhi reported cases during nine, and Orissa during seven. There were 68 outbreaks in 18 states, and 222 038 cases were detected overall. This figure is about six times higher than the number reported to WHO (37 783) over the same period. The states of Orissa, West Bengal, Andaman and Nicobar Islands, Assam and Chhattisgarh accounted for 91% of all outbreak-related cases. CONCLUSION: The reporting of cholera cases in India is incomplete and the methods used to keep statistics on cholera incidence are inadequate. Although the data are sparse and heterogeneous, cholera notification in India is highly deficient.

Non-typhoidal Salmonella rates in febrile children at sites in five Asian countries.

There is increased recognition of non-typhoidal Salmonella (NTS) as a major cause of severe febrile illness in sub-Saharan Africa. However, little is known about community-based incidence of NTS in Asia. In a multicentre, community-based prospective Salmonella surveillance study, we identified a total of six NTS cases: three in Karachi, Pakistan, one in Kolkata, India, and two in North Jakarta, Indonesia. No NTS cases were identified in Hechi, People's Republic of China, and Hue, Viet Nam. Three cases were in children under 3 years, and one case was in a child aged 10 years and one in a child aged 15 years. Only one case was an adult (29 years). The highest incidence of NTS infection was in Karachi (7.2 culture-proven NTS cases per 100,000 person years in age group of 2-15 years). However, in comparison with sub-Saharan Africa, the NTS burden in Asia appears rather limited.

Risk factors for Japanese encephalitis: a case-control study.

Japanese encephalitis (JE) has been found to be endemic in Bali, Indonesia. A case-control study was conducted to identify factors associated with JE infection. All 94 serologically confirmed JE cases (cases) and 163 cases of encephalitis or aseptic meningitis without JE (controls) identified in Bali during 2001-2004 were included in the study. Potential risk factors were surveyed at hospital admission. Univariate analyses revealed the following factors to be associated with JE: older age, referral from sub-district health centre or private hospital, playing outdoors after dinner, use of mosquito repellent or spraying, proximity of the residence to rice fields, and pig ownership by the family or next-door neighbours. Multivariate analysis identified proximity to rice fields (OR 2.93, 95% CI 1.57-5.45), pig ownership (OR 2.24, 95% CI 1.17-4.26), and older age (OR 1.21, 95% CI 1.09-1.33) as being independently associated with the risk of JE. Because rice cultivation and pig rearing are essential to the economy of Bali, JE immunization is the best intervention for prevention of JE in Bali.

Environmental reservoirs of Vibrio cholerae.

The environmental reservoir of Vibrio cholerae, the causative agent of cholera, has been a topic of scientific investigation ever since the discovery of the bacterium itself. While the bacteria can be isolated from both clinical and environmental sources during epidemics, it evades isolation by conventional culture techniques during the period between successive epidemics. The problem is identifying the location and mode of survival and multiplication of V. cholerae during this inter-epidemic period. This information is crucial not only for epidemiological reasons, but also because the seasonality of cholera epidemics is plausibly mediated by the climate-regulated activity of the reservoir. This article focuses on the epidemiological importance of the environmental reservoir of V. cholerae, considering several investigations made on different types of aquatic fauna (zooplanktons, crustaceans, etc.) and flora (macrophytes and microphytes). After evaluating different lines of evidence, we make the case that certain species of cyanobacteria (Anabaena variabilis, Microcystis aeruginosa) can act as inter-epidemic reservoirs of V. cholerae. Physiological and functional aspects of this association are also discussed. We then present a hypothesis, expanding upon a previously published conceptual model, of how the climate-regulated seasonality of cholera epidemics is mediated by the effect of climatic factors on algal bloom and other local abiotic variables in the water, using Bangladesh as a model. Finally, another aspect of the climate-dependence of disease patterns is briefly explored: large-scale environmental signatures associated with cholera, and recent modelling efforts to predict cholera outbreaks based on coastal phytoplankton. The review, therefore, serves not only as a study of the identity of the inter-epidemic reservoir of V. cholerae, but also explores different ways in which the reservoir and the pathogen behaviour is affected by the climate, and the possible consequences it may have on disease pattern.

The public health significance of latrines discharging to groundwater used for drinking.

Faecal contamination of groundwater from pit latrines is widely perceived as a major threat to the safety of drinking water for several billion people in rural and peri-urban areas worldwide. On the floodplains of the Ganges-Brahmaputra-Meghna delta in Bangladesh, we constructed latrines and monitored piezometer nests monthly for two years. We detected faecal coliforms (FC) in 3.3-23.3% of samples at four sites. We differentiate a near-field, characterised by high concentrations and frequent, persistent and contiguous contamination in all directions, and a far-field characterised by rare, impersistent, discontinuous low-level detections in variable directions. Far-field FC concentrations at four sites exceeded 0 and 10 cfu/100 ml in 2.4-9.6% and 0.2-2.3% of sampling events respectively. The lesser contamination of in-situ groundwater compared to water at the point-of-collection from domestic wells, which itself is less contaminated than at the point-of-consumption, demonstrates the importance of recontamination in the well-pump system. We present a conceptual model comprising four sub-pathways: the latrine-aquifer interface (near-field); groundwater flowing from latrine to well (far-field); the well-pump system; and post-collection handling and storage. Applying a hypothetical dose-response model suggests that 1-2% of the diarrhoeal disease burden from drinking water is derived from the aquifer, 29% from the well-pump system, and 70% from post-collection handling. The important implications are (i) that leakage from pit latrines is a minor contributor to faecal contamination of drinking water in alluvial-deltaic terrains; (ii) fears of increased groundwater pollution should not constrain expanding latrine coverage, and (iii) that more attention should be given to reducing contamination around the well-head.

Pretherapeutic morbidity in the prognostic staging of acute leukemia.

To classify the clinical severity of acute leukemia, we have used the degrees of pretherapeutic infection and hemorrhage to construct a taxonomy containing three "stages". The stages are associated with survival gradients that are clinically and statistically distinctive in both acute lymphoblastic leukemia and acute nonlymphoblastic leukemia. Median survival ranged from 64.0 months for stage 1 to 10.5 months for stage 3 in acute lymphoblastic leukemia, and from 7.1 months for stage 1 to 1.2 months for stage 3 in acute nonlymphoblastic leukemia. The gradients, which persist when other prognostic factors and secular therapeutic changes are taken into account, are more distinctive than those found with other forms of stratification.

Peru-15 (Choleragarde(®)), a live attenuated oral cholera vaccine, is safe and immunogenic in human immunodeficiency virus (HIV)-seropositive adults in Thailand.

BACKGROUND: Many areas with endemic and epidemic cholera report significant levels of HIV transmission. According to the World Health Organization (WHO), over 95% of reported cholera cases occur in Africa, which also accounts for nearly 70% of people living with HIV/AIDS globally. Peru-15, a promising single dose live attenuated oral cholera vaccine (LA-OCV), was previously found to be safe and immunogenic in cholera endemic areas. However, no data on the vaccine's safety among HIV-seropositive adults had been collected. METHODS: This study was a double-blinded, individually randomized, placebo-controlled trial enrolling HIV-seropositive adults, 18-45 years of age, conducted in Bangkok, Thailand, to assess the safety of Peru-15 in a HIV-seropositive cohort. RESULTS: 32 HIV infected subjects were randomized to receive either a single oral dose of the Peru-15 vaccine with a buffer or a placebo (buffer only). No serious adverse events were reported during the follow-up period in either group. The geometric mean fold (GMF) rise in V. cholerae O1 El Tor specific antibody titers between baseline and 7 days after dosing was 32.0 (p<0.001) in the vaccine group compared to 1.6 (p<0.14) in the placebo group. Among the 16 vaccinees,14 vaccinees (87.5%) had seroconversion compared to 1 of 16 placebo recipients (6.3%). V. cholerae was isolated from the stool of one vaccinee, and found to be genetically identical to the Peru-15 vaccine strain. There were no significant changes in HIV viral load or CD4 T-cell counts between vaccine and placebo groups. CONCLUSION: Peru-15 was shown to be safe and immunogenic in HIV-seropositive Thai adults.

Educational intervention for altering water-sanitation behavior to reduce childhood diarrhea in urban Bangladesh: impact on nutritional status.

We evaluated whether an educational intervention that was effective in reducing childhood diarrhea also improved childhood nutritional status. Fifty-one communities of 38 families each were randomized to receive the intervention or no intervention. During 1 y of follow-up the rate of diarrhea (per 100 wk) in children less than 6 y in the intervention group was 5.89 episodes whereas that in the nonintervention group was 7.55 episodes (protective efficacy 22%; p less than 0.0001). During the same follow-up period children in both groups exhibited comparable patterns of weight gain; 1 y after the intervention the mean weight for age of children in both groups was 76% of the NCHS standard. No significant differences were observed in the proportion of each group that experienced a major deterioration or improvement of nutritional status. We conclude that an intervention that reduces rates of childhood diarrhea may not necessarily also improve nutritional status.

Bone mineral density and serum levels of aminoterminal propeptides and cross-linked N-telopeptides of type I collagen in elderly men.

Serum levels of aminoterminal extension propeptides (PINP), the carboxyterminal telopeptide (ICTP), and the cross-linked N-telopeptides (NTx) of type I collagen were determined in 78 healthy, elderly men aged 76 +/- 5 years in 1993 and 1996 and compared with bone mineral density (BMD) measurements of their lumbar spine, femoral neck, and total body regions made using dual X-ray absorptiometry. Compared with 11 men who had normal lumbar spine (SBMD) and femoral neck BMD (NBMD), 13 of the subjects with SBMD and NBMD classified as osteopenic by t-score criterion had higher mean serum levels of PINP and alkaline phosphatase activity, but these increases were not statistically significant at the 95% confidence interval. In osteopenic men, a correlation between SBMD and NTx was detected (r = -0.66, p = 0.01). Within the entire population, the serum NTx level correlated with NBMD (r = -0.26, p < 0.05) and PINP (r = +0.63, p < 0.0001), and the change in the circulating concentration of PINP over the 3 year interval correlated with the magnitude of change in total body BMD (r = -0.28, p = 0.02), NBMD (r = -0.24, p = 0.05), and SBMD (r = -0.36, p = 0. 03) as well as with the change in serum NTx levels (r = 0.43, p < 0. 001). The change in the circulating ICTP level was also related to the change in NBMD (r = -0.24, p = 0.01). Together, weight and the serum PINP level accounted for 25% of total body BMD variance in elderly men. These results indicate that larger populations of men and women should be screened over longer time intervals to explore the value of serial measurement of serum collagen metabolites in predicting bone loss in the spine and hip.

Serum levels of cross-linked N-telopeptides and aminoterminal propeptides of type I collagen indicate low bone mineral density in elderly women.

Levels of aminoterminal propeptide (PINP) and the cross-linked carboxyterminal (ICTP) and aminoterminal (NTx) telopeptides of type I collagen were determined in the sera of 202 healthy women, 60-90 years of age, and correlated with densitometric measurements of their lumbar spine, femoral neck, and total body regions. Total skeleton bone mineral density (BMD) was associated most strongly with serum NTx levels (r = -0.51, p < 0.0001). Serum NTx and PINP levels correlated with BMD at all regions measured and were significantly increased in osteopenic women (16.0 vs. 13.3 nmol bone collagen equivalents/L for NTx, p = 0.0006 and 46.5 vs. 40.9 micrograms/L for PINP, p = 0.02). Elevations of NTx and PINP over a 3 year interval correlated with decreases in BMD measured at the femoral neck and to increases in serum concentration of alkaline phosphatase activity and ICTP. Serum levels of ICTP, NTx, PINP, ICTP, estrone, and alkaline phosphatase activity were correlated and serum NTx values were related to circulating thyroxine and intact parathyroid hormone levels. NTx and PINP levels were significantly decreased in the sera of women receiving estrogen replacement therapy (12.0 vs. 14.8 nmol bone collagen equivalents/L for NTx, and 35.5 vs. 45.2 micrograms/L for PINP, p < 0.001). Multiple regression analysis indicated that 42% of the variability observed in total skeletal BMD could be explained by age, weight, and serum levels of NTx and estrone. Within this model of covariance, the serum NTx level alone accounted for 10.1% of total body BMD variability.

Developing improved observational methods for evaluating therapeutic effectiveness.

Therapeutic efficacy is often studied with observational surveys of patients whose treatments were selected nonexperimentally. The results of these surveys are distrusted because of the fear that biased results occur in the absence of experimental principles, particularly randomization. The purpose of the current study was to develop and validate improved observational study designs by incorporating many of the design principles and patient assembly procedures of the randomized trial. The specific topic investigated was the prophylactic effectiveness of beta-blocker therapy after an acute myocardial infarction. To accomplish the research objective, three sets of data were compared. First, we developed a restricted cohort based on the eligibility criteria of the randomized clinical trial; second, we assembled an expanded cohort using the same design principles except for not restricting patient eligibility; and third, we used the data from the Beta Blocker Heart Attack Trial (BHAT), whose results served as the gold standard for comparison. In this research, the treatment difference in death rates for the restricted cohort and the BHAT trial was nearly identical. In contrast, the expanded cohort had a larger treatment difference than was observed in the BHAT trial. We also noted the important and largely neglected role that eligibility criteria may play in ensuring the validity of treatment comparisons and study outcomes. The new methodologic strategies we developed may improve the quality of observational studies and may be useful in assessing the efficacy of the many medical/surgical therapies that cannot be tested with randomized clinical trials.

Community-based evaluation of the effect of breast-feeding on the risk of microbiologically confirmed or clinically presumptive shigellosis in Bangladeshi children.

To assess the association between breast-feeding and the risk of microbiologically confirmed or clinically presumptive shigellosis, the authors performed a case-control analysis of Bangladeshi children younger than 3 years of age who were followed up for 1 month after exposure to Shigella in their residential neighborhoods. Two hundred sixty-nine cases with culture-confirmed shigellosis (n = 119) or clinically presumptive shigellosis (culture-negative dysentery, n = 150) were compared with 819 controls without Shigella diarrhea or other invasive diarrheal illnesses. The odds ratio relating breast-feeding to confirmed or presumptive shigellosis, adjusted for potentially confounding variables, was 0.48 (95% confidence interval = 0.32 to 0.72; P less than .001), suggesting a substantial protective effect. The protective association decreased with age but was still significant during the third year of life; appeared to be directly related to the degree of stunting; and was equivalent for confirmed and presumptive shigellosis. Notably, the protective association remained substantial against episodes due to Shigella which were resistant to at least one of the antibiotics customarily used for treatment of Shigella diarrhea (age-adjusted odds ratio = 0.40; 95% confidence interval = 0.22 to 0.74; P less than .01). These data suggest that breast-feeding confers a high level of protection against shigellosis throughout the first 3 years of life, especially among nutritionally compromised children, and thereby underscore the importance of promotion of breast-feeding as a central component of Shigella control programs in less developed settings.

Serum caffeine and paraxanthine as markers for reported caffeine intake in pregnancy.

PURPOSE: Previous studies of maternal caffeine use and pregnancy outcome have relied on self-reported use. Even if these were perfectly accurate, inter-individual differences in caffeine metabolism result in a relatively weak correlation between caffeine intake and serum concentration. The purpose of this study was to determine whether the serum concentration of caffeine or its primary metabolite, paraxanthine, obtained at an unknown time during working hours, is useful to distinguish between pregnant women who report consuming small and large amounts of caffeine. METHODS: We selected from the Birmingham fetal growth study 60 women with normal pregnancy outcomes who reported consuming < or = 0.8 mg/kg/day of caffeine in a 24-hour dietary recall, 60 who consumed 0.81-2.5 mg/kg/day, 60 who consumed 2.51-5.0 mg/kg/day and 59 who consumed > or = 5.01 mg/kg/day. These women had serum drawn for storage during regular clinic hours on the same day as the recall interview. Caffeine and paraxanthine were measured in the stored serum using high performance liquid chromatography. RESULTS: The weighted kappa coefficient between strata of caffeine intake and quartiles of serum paraxanthine was 0.58 among smokers and 0.53 among nonsmokers, versus 0.44 and 0.51, respectively, for quartiles of serum caffeine. The Pearson correlation coefficient between intake and paraxanthine was 0.50 for smokers and 0.53 for nonsmokers, and 0.37 and 0.51, respectively, for serum caffeine. These values are comparable to the correlation between reported smoking and serum cotinine in pregnancy. CONCLUSIONS: The serum concentrations of paraxanthine, and to a lesser degree, caffeine are useful to distinguish between women with varying levels of caffeine intake.

Low gastric acid as a risk factor for cholera transmission: application of a new non-invasive gastric acid field test.

Although gastric acid is thought to be an important host defense against certain enteric infections, field studies of the role of gastric acid in preventing enteric infections have been hampered by the lack of a suitable non-invasive test. Because low gastric acid output (GAO) is an established risk factor for cholera, we assessed after validation, whether a new non-invasive test which estimates GAO by measuring breath hydrogen excess after ingestion of magnesium and a stimulant of gastric acid secretion, could discriminate between persons at high and at low risk of developing cholera. Fifteen age-matched pairs, participants in the field trial of two oral cholera vaccines in rural Bangladesh, were tested. In each pair the "case" was a person who had recovered from severe cholera at least 6 months before testing and the "control" was a person who resided in the home of a cholera patient but remained uninfected. The stimulated breath hydrogen was higher in controls (median hydrogen excess = 369 mumol/80 min) than in cases (median hydrogen excess = 150 mumol/80 min) (p less than 0.05) and was higher in controls in 12 out of 15 pairs. The results, which are consistent with past invasive assessments of the association between hypochlorhydria and cholera, suggest that this non-invasive test may be useful in evaluating GAO in epidemiological field studies.

Epidemiology of postshigellosis persistent diarrhea in young children.

BACKGROUND: Dysentery accounts for 20% of the 4.6 million diarrhea-associated deaths among children in developing countries, with the risk from death in dysenteric persistent diarrhea 10-fold higher than that in acute dysentery. Although Shigella accounts for the majority of dysenteric episodes, very little is known about the epidemiology of postshigellosis persistent diarrhea. METHODS: Rural Bangladeshi children younger than 5 years of age (n = 1,756) were followed for 1 month after exposure to sentinel cases of Shigella dysentery. The likelihood of an acute diarrheal episode becoming persistent was assessed. RESULTS: Diarrhea caused by Shigella was significantly associated with an increased risk of persistent diarrhea (age-adjusted relative risk, 1.83; 95% confidence interval, 1.19 to 2.81). Despite the use of nalidixic acid in dysenteric episodes, persistent diarrhea occurred in 23% of children with shigellosis. Infection by multiply antibiotic-resistant Shigella isolates (age-adjusted relative risk, 3.76; 95% confidence interval, 1.51 to 9.36) and occurrence of shigellosis during infancy were observed to be risk factors for initiation of Shigella diarrhea persistence. However, 88% of the persistent shigellosis episodes occurred in older children, 50% were associated with nondysenteric shigellosis and 79% were caused by Shigella species other than Shigella dysenteriae 1. CONCLUSIONS: These data demonstrate the importance of Shigella as a cause of persistent diarrhea and indicate that strategies to prevent postshigellosis persistent diarrhea must be broad-based, with a focus on older children as well as infants, management of nondysenteric as well as dysenteric disease and prevention of diarrhea caused by multiple Shigella species.

Respiratory syncytial virus illnesses in human immunodeficiency virus- and noninfected children.

Respiratory syncytial virus (RSV) lower respiratory tract and febrile upper respiratory tract illnesses were prospectively assessed in cohorts of 83 infants born to human immunodeficiency virus (HIV)- and of 48 infants born to non-HIV-infected mothers. Of the infants born to HIV-infected mothers, 18 were themselves infected with HIV, 26 were indeterminant and 39 were free from HIV. Ten RSV illnesses occurred in 8 HIV-infected, 2 illnesses in 2 indeterminant and 17 illnesses occurred in 17 non-HIV-infected children. RSV shedding was prolonged in HIV class P2- vs. non-HIV-infected children, at medians of 30 days (range, 1 to 199 days) and 6 days (range, 1 to 21 days), respectively (P = 0.02). Ribavirin and intravenous immunoglobulin failed to eradicate RSV from one child who shed virus for 199 days. Wheezing occurred in 1 of 4 vs. 9 of 10 episodes of lower respiratory tract illness in HIV-infected and non-HIV-infected children, respectively (P = 0.04). No differences were noted in duration of illness, temperature, respiratory rate or oxygen saturation between HIV- and non-HIV-infected children. Infection control and public health concerns regarding prolonged shedding of RSV in HIV-infected children must be recognized.

The immunogenicity of Haemophilus influenzae type b conjugate vaccines in children born to human immunodeficiency virus-infected women. Women and Infants Transmission Study Group.

BACKGROUND: Immunocompromise caused by HIV-1 infection increases the importance of receipt of routine childhood vaccines to prevent infections such as invasive Haemophilus influenzae type B (Hib) disease. The objectives of the study were to evaluate the immunogenicity of Hib conjugate vaccines among HIV-infected children according to clinical and immunologic disease progression as well as viral load. METHODS: The concentration of antibody to polyribosylribitol phosphate (PRP) was measured at approximately 9 and 24 months of age in plasma specimens from children of HIV-infected women enrolled in the Women and Infants Transmission Study. RESULTS: Among 227 children (35 HIV-infected, 192 uninfected) at the 9-month study visit who were known to have received age-appropriate immunization with CRM197 mutant Corynebacterium diphtheriae protein-conjugated Hib vaccine, geometric mean antibody concentrations were lower among HIV-infected children (1.64 microg/ml) than among uninfected children (2.70 microg/ml), although the difference was not statistically significant. Anti-PRP antibody concentrations did not vary significantly among these HIV-infected children with predominantly mild-moderate disease progression according to clinical category, immunologic stage or viral load (P > or = 0.48). The proportion of children with antibody concentrations > or = 1.0 microg/ml did not vary significantly according to HIV infection status (73% uninfected, 74% infected) or, if infected, clinical or immunologic disease progression or viral load. Similar results were obtained among 127 children (17 HIV-infected, 110 uninfected) eligible for analysis at the 24-month study visit. Changes in antibody concentrations over time (between 9 and 24 months of age) did not differ significantly among 10 HIV-infected as compared with 72 uninfected children (P=0.81). CONCLUSIONS: These results suggest that HIV-infected children with predominantly mild-moderate disease progression respond reasonably well in terms of a quantitative antibody response to Hib conjugate vaccines during the first 2 years of life. Research to further characterize the immune response to Hib conjugate vaccines and to further delineate the "durability" of anti-PRP antibody concentrations beyond 2 years of life should be pursued.

The influence of gender on determinants of urban childhood mortality in Bangladesh.

To assess sociodemographic characteristics predicting childhood mortality in urban Bangladesh, we conducted a case-control study of subjects selected from 51 low and middle class areas of urban Dhaka between 14 October 1984 and 13 October 1985. Cases were the 38 children who died aged under six years during the study interval; six surviving controls aged under six years were selected for each case. Factors associated with childhood deaths included being under one year of age (OR (odds ratio) = 11.80; p less than 0.0001), and several direct and indirect indicators of poor economic status: ie head of household earning a daily wage rather than a salary (OR = 2.63; p less than 0.01); residence in a single-room dwelling (OR = 2.63; p less than 0.05); or residence in a structure of inferior construction (OR = 2.58; p less than 0.05). There were important gender-specific differences in the risk factors. Having one or more male siblings was associated with an increased risk of death for male children (OR = 2.78; p less than 0.05), while having at least one female sibling was suggestively associated with the risk of death for female children (OR = 2.47; p less than 0.10). Family dependence on daily wages rather than on a salary was associated with male deaths (OR = 6.24; p less than 0.001) but not with female deaths (OR = 1.38). Other indices of poverty (poor construction of house and single-room dwellings) were also associated with an increased risk of male but not female deaths.(ABSTRACT TRUNCATED AT 250 WORDS)