Rural drinking water at supply and household levels: quality and management

Access to safe drinking water has been an important national goal in Bangladesh and other developing countries. While Bangladesh has almost achieved accepted bacteriological drinking water standards for water supply, high rates of diarrheal disease morbidity indicate that pathogen transmission continues through water supply chain (and other modes). This paper investigates the association between water quality and selected management practices by users at both the supply and household levels in rural Bangladesh. Two hundred and seventy tube-well water samples and 300 water samples from household storage containers were tested for fecal coliform (FC) concentrations over three surveys (during different seasons). The tube-well water samples were tested for arsenic concentration during the first survey. Overall, the FC was low (the median value ranged from 0 to 4 cfu/100ml) in water at the supply point (tube-well water samples) but significantly higher in water samples stored in households. At the supply point, 61% of tube-well water samples met the Bangladesh and WHO standards of FC; however, only 37% of stored water samples met the standards during the first survey. When arsenic contamination was also taken into account, only 52% of the samples met both the minimum microbiological and arsenic content standards of safety. The contamination rate for water samples from covered household storage containers was significantly lower than that of uncovered containers. The rate of water contamination in storage containers was highest during the February-May period. It is shown that safe drinking water was achieved by a combination of a protected and high quality source at the initial point and maintaining quality from the initial supply (source) point through to final consumption. It is recommended that the government and other relevant actors in Bangladesh establish a comprehensive drinking water system that integrates water supply, quality, handling and related educational programs in order to ensure the safety of drinking water supplies.     

A synthetic dengue virus antigen elicits enhanced antibody titers when linked to, but not mixed with, Mycobacterium tuberculosis HSP70 domain II

Domain II of Mycobacterium tuberculosis (Mtb) heat shock protein 70 (HSP70), spanning amino acid residues 161-370, was covalently linked to a recently described synthetic dengue virus antigen to study the influence of the former on the immunogenicity of the latter. Using an enzyme-linked immunosorbent assay, dengue antigen-specific antibody titers elicited by the fusion protein in Balb/c mice were an order of magnitude higher than those elicited by either the synthetic dengue antigen alone or a physical mixture of the dengue antigen plus Mtb HSP70 domain II protein. Our data demonstrate that (i) Mtb HSP70 domain II is capable of potentiating B-cell response and (ii) it should be covalently linked to the target antigen to do so.     

Alterations of the rat mesentery vasculature in experimental diabetes

The alteration induced by diabetes on vascular permeability to serum albumin was investigated in the mesentery of streptozotocin-induced hyperglycemic rats. Double-tagged ((125)I and dinitrophenol-haptenated) heterologous albumin was intravenously administered in normal and hyperglycemic animals, and the extravasation of the tracer was evaluated by radioactivity measurements and by morphometry at the ultrastructural level using quantitative protein A-colloidal gold immunocytochemistry. The results demonstrate that diabetes induces a significant increase in the permeability of the mesentery vessels to albumin. This increase is due to a more efficient transport of macromolecules by endothelial plasmalemmal vesicles and not to leakier interendothelial junctions. Passage across the endothelial basement membranes did not appear to be restricted in either the control or diabetic condition. However, in diabetes, the mesothelial basement membrane appeared to become modified and to restrain the passage of albumin toward the peritoneal cavity. After 3 months of diabetes, the rats presented a net increase in the average diameter of the blood vessels localized in the mesentery arcada (macrovascular hyperplasy) and a notable angiogenesis, manifested at the level of the microvasculature in the mesenteric windows.     

Clinical and immunological features of 65 Iranian patients with common variable immunodeficiency

Common variable immunodeficiency (CVID) is a primary immunodeficiency disease characterized by hypogammaglobulinemia and recurrent bacterial infections. The records of 65 patients with CVID (37 males and 28 females) in the age range of 24 to 537 months were reviewed. By the year 2003, 11 patients had died and seven patients could not be located. The total follow-up period was 221 patient-years. The median diagnostic delay (time between onset and diagnosis) in our patient group was 60 months. At the time of diagnosis, the baseline serum immunoglobulin G (IgG), IgM, and IgA levels were below the level normal for the patients' age; the medians for this group were 120, 10, and 0 mg/dl, respectively. All of the patients presented with infectious diseases at the time of onset, the most common of which were otitis media, diarrhea, pneumonia, and sinusitis. Acute and recurrent infections were also found in almost all of the patients, particularly involving respiratory and gastrointestinal systems. The most common infections, before diagnosis and during follow-up, were pneumonia, acute diarrhea, acute sinusitis, and otitis media. CVID should be considered in any patient with a history of recurrent infections and decreased levels of all serum immunoglobulin isotypes.     

Mortality in primary immunodeficient patients, registered in Iranian primary immunodeficiency registry

Primary immunodeficiencies (PID) are a group of disorders, characterized by an unusual susceptibility to infections. Delay in diagnosis results in increased morbidity and mortality in affected patients. The purpose of this study was to determine the mortality rate of Iranian immunodeficient patients referred to Children Medical Center Hospital affiliated to Tehran University of Medical Sciences over a period of 20 years.In this study, records of 235 (146 males, 89 females) patients with immunodeficiency who were diagnosed and followed in our center, during 22 years period (1979-2001) were reviewed. The diagnosis of immunodeficiency was based on the standard criteria. The cause of death was determined by review of death certificates.Antibody deficiency was the most common diagnosis made in our patients. The overall five-year survival rate was 22.7% in our studied patient group; this was greatest in antibody deficiency. During the 22 year period of study, 32 patients died. As some of the patients could not be located, the true mortality rate ranged between 13.6% and 17.5%. The main leading cause of death were lower respiratory tract involvement in 14 cases (44%). The most common pathogenic microorganisms causing fatal infections were psudomonas and staphylococcus in 9 cases (28.1%) followed by E. coli in 7 (21.9%), tuberculosis in 13 (40.6%) and salmonella in 1 (3.1%).Based on our study, delay in diagnosis in patients with PID results in tissue and organ damage and several complications. Mortality and morbidity are increased in undiagnosed patients.     

Gastrointestinal manifestations of patients with chronic granulomatous disease

Chronic Granulomatous Disease (CGD) represents a group of inherited disorders of phagocytic system, manifesting recurrent infections at different sites. The present study was accomplished in order to determine the gastrointestinal manifestations of CGD patients. Fifty-seven patients (38 males and 19 females) with CGD, who had been referred to three immunodeficiency referral centers in Iran, were studied during a 24-year period (1980-2004). The median age at the time of study was 14.5 years old (1-56 years). The median onset age of symptoms was 5 months (1 month- 13.75 years), and that of diagnostic age was 5 years (2 months- 54.1 years), with a diagnostic delay of 33 months, on average. Seven patients were presented with acute diarrhea, 3 with oral candidiasis, and 2 with liver abscesses as the first chief complaints. Twenty-four cases (42.1%) had been complicated by gastrointestinal manifestations during their course of the disease. Of those, 12 cases (21.1%) had diarrhea, 7 (12.3%) oral candidiasis, 5 (8.8%) hepatitis, 4 (7.0%) hepatic abscess, and 2 cases (3.5%) gastric outlet obstruction. Also, failure to thrive was detected in 6 patients (10.5%). Four patients died (7%). CGD should be excluded in any patient with gastrointestinal manifestations especially chronic diarrhea, hepatic abscess, and gastric outlet obstruction.     

Environmental isolates of Citrobacter braakii that agglutinate with Escherichia coli O157 antiserum but do not possess the genes responsible for the biosynthesis of O157 somatic antigen

While searching for Escherichia coli O157 in the aquatic environment of Calcutta using an immunodetection procedure, we fortuitously detected five strains of Citrobacter braakii, which cross-reacted with the commercially available O157 polyvalent antiserum. The five C. braakii isolates gave positive results when a sensitive dot-ELISA was performed with E. coli O157 monoclonal antibody. Further, the O157 monoclonal antibody recognized the bands of proteinase K treated whole cells of lipopolysaccharide of all the C. braakii isolates. Apart from weak reactions with two or three of the DNA probes, all the C. braakii strains did not hybridize with the other probes spanning the minimum region required for O157 O-antigen biosynthesis. These strains did not possess any of the virulence genes that are commonly found in the Shiga toxin-producing E. coli (STEC) specially the serotype O157: H7. Therefore, it appears that the serological cross-reaction between C. braakii and E. coli O157 antiserum is based on structural mimicry between the O-polysaccharide of C. braakii and E. coli O157.