International Centre for Diarrhoeal Disease Research, Bangladesh

About: International Centre for Diarrhoeal Disease Research, Bangladesh is a facility organization based out in Dhaka, Bangladesh. It is known for research contribution in the topics: Population & Vibrio cholerae. The organization has 3103 authors who have published 5238 publications receiving 226880 citations. The organization is also known as: SEATO Cholera Research Laboratory & Bangladesh International Centre for Diarrhoeal Disease Research.

Optimization of Quantitative PCR Methods for Enteropathogen Detection.

Abstract: Detection and quantification of enteropathogens in stool specimens is useful for diagnosing the cause of diarrhea but is technically challenging. Here we evaluate several important determinants of quantification: specimen collection, nucleic acid extraction, and extraction and amplification efficiency. First, we evaluate the molecular detection and quantification of pathogens in rectal swabs versus stool, using paired flocked rectal swabs and whole stool collected from 129 children hospitalized with diarrhea in Tanzania. Swabs generally yielded a higher quantification cycle (Cq) (average 29.7, standard deviation 3.5 vs. 25.3 ± 2.9 from stool, P<0.001) but were still able to detect 80% of pathogens with a Cq < 30 in stool. Second, a simplified total nucleic acid (TNA) extraction procedure was compared to separate DNA and RNA extractions and showed 92% (318/344) sensitivity and 98% (951/968) specificity, with no difference in Cq value for the positive results (ΔCq(DNA+RNA-TNA) = -0.01 ± 1.17, P = 0.972, N = 318). Third, we devised a quantification scheme that adjusts pathogen quantity to the specimen’s extraction and amplification efficiency, and show that this better estimates the quantity of spiked specimens than the raw target Cq. In sum, these methods for enteropathogen quantification, stool sample collection, and nucleic acid extraction will be useful for laboratories studying enteric disease.

The epidemiology of visceral leishmaniasis and asymptomatic leishmanial infection in a highly endemic bangladeshi village

Abstract: We examined the epidemiology of kala-azar and asymptomatic leishmanial infection measured by serologic and leishmanin skin test results in a Bangladeshi community. In a subset, we measured serum retinol, zinc and C-reactive protein (CRP). Kala-azar and seroconversion incidence were 15.6 and 63.1 per 1,000 person-years, respectively. Proximity to a previous kala-azar case increased the likelihood of both kala-azar and asymptomatic infection. Bed net use protected against kala-azar (rate ratio = 0.35, P < 0.01), but not subclinical infection (rate ratio = 1.1, P = 0.82). Kala-azar patients were younger (P < 0.001) and reported lower red meat consumption (P < 0.01) than asymptomatic seropositive individuals. Retinol and zinc levels were lower in current kala-azar patients and those who later developed kala-azar compared with uninfected and asymptomatically infected subjects. The CRP levels were higher in kala-azar patients compared with the other two groups. Low red meat intake and poor zinc and retinol status may characterize a group at higher risk of symptomatic disease.

Distribution and Spread of Colonic Lesions in Shigellosis: A Colonoscopic Study

Abstract: In a study of the distribution and severity of colonic lesions in patients with shigellosis, colonoscopy was performed for 33 men with this disease. All 33 patients had inflammatory lesions in the rectosigmoid area; in 18 (55%) the lesions extended to the splenic flexure, in 14 (42%) the disease extended to the distal transverse colon, in nine (27%) the area of involvement included the proximal transverse colon, and in five (15%) pancolitis was evident. In most patients lesions were continuous and diffuse, with the intensity of inflammation decreasing in a proximal direction. Biopsied samples from proximal lesions usually showed less severe inflammation than did those from more distal lesions. Aphthoid erosions, which have not previously been described in shigellosis, were observed in five patients. Proximal colitis was associated with diarrhea of four or more days' duration (P < .01, Fisher's exact test). These findings indicate that the rectosigmoid is the most frequently and most severely affected area of the colon in shigellosis and suggest that during the course of shigella infection, colonic lesions extend in a proximal direction.

Epidemiological methods in diarrhoea studies—an update

Abstract: Background Diarrhoea remains a leading cause of morbidity and mortality but is difficult to measure in epidemiological studies. Challenges include the diagnosis based on self-reported symptoms, the logistical burden of intensive surveillance and the variability of diarrhoea in space, time and person. Methods We review current practices in sampling procedures to measure diarrhoea, and provide guidance for diarrhoea measurement across a range of study goals. Using 14 available data sets, we estimated typical design effects for clustering at household and village/neighbourhood level, and measured the impact of adjusting for baseline variables on the precision of intervention effect estimates. Results Incidence is the preferred outcome measure in aetiological studies, health services research and vaccine trials. Repeated prevalence measurements (longitudinal prevalence) are appropriate in high-mortality settings where malnutrition is common, although many repeat measures are rarely useful. Period prevalence is an inadequate outcome if an intervention affects illness duration. Adjusting point estimates for age or diarrhoea at baseline in randomized trials has little effect on the precision of estimates. Design effects in trials randomized at household level are usually <2 (range 1.0–3.2). Design effects for larger clusters (e.g. villages or neighbourhoods) vary greatly among different settings and study designs (range 0.1–25.8). Conclusions Using appropriate sampling strategies and outcome measures can improve the efficiency, validity and comparability of diarrhoea studies. Allocating large clusters in cluster randomized trials is compromized by unpredictable design effects and should be carried out only if the research question requires it.

Determinants and Impact of Giardia Infection in the First 2 Years of Life in the MAL-ED Birth Cohort.

Abstract: Background. Giardia are among the most common enteropathogens detected in children in low-resource settings. We describe here the epidemiology of infection with Giardia in the first 2 years of life in the Etiology, Risk Factors, and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development Project (MAL-ED), a multisite birth-cohort study. Methods. From 2089 children, 34916 stool samples collected during monthly surveillance and episodes of diarrhea were tested for Giardia using an enzyme immunoassay. We quantified the risk of Giardia detection, identified risk factors, and assessed the associations with micronutrients, markers of gut inflammation and permeability, diarrhea, and growth using multivariable linear regression. Results. The incidence of at least 1 Giardia detection varied according to site (range, 37.7%-96.4%) and was higher in the second year of life. Exclusive breastfeeding (HR for first Giardia detection in a monthly surveillance stool sample, 0.46 [95% confidence interval (CI), 0.28-0.75]), higher socioeconomic status (HR, 0.74 [95% CI, 0.56-0.97]), and recent metronidazole treatment (risk ratio for any surveillance stool detection, 0.69 [95% CI, 0.56-0.84]) were protective. Persistence of Giardia (consecutive detections) in the first 6 months of life was associated with reduced subsequent diarrheal rates in Naushahro Feroze, Pakistan but not at any other site. Giardia detection was also associated with an increased lactulose/mannitol ratio. Persistence of Giardia before 6 months of age was associated with a -0.29 (95% CI, -0.53 to -0.05) deficit in weight-for-age z score and -0.29 (95% CI, -0.64 to 0.07) deficit in length-for-age z score at 2 years. Conclusions. Infection with Giardia occurred across epidemiological contexts, and repeated detections in 40% of the children suggest that persistent infections were common. Early persistent infection with Giardia, independent of diarrhea, might contribute to intestinal permeability and stunted growth.