Showing papers by "International Centre for Diarrhoeal Disease Research, Bangladesh published in 1994"

Extended serotyping scheme for Vibrio cholerae

Abstract: Fifty-seven new O serogroups have been added to the existing serotyping scheme ofVibrio cholerae to extend the scheme from O84 to O140. Prominent new additions were serogroups O139 and O140. The reference strain of O139 was isolated from a patient from an epidemic of cholera-like diarrhea in Madras, Southern India. Serogroup O140 was assigned to a group ofV. cholerae strains which were tentatively named as the “Hakata” serogroup and which possessed the C (Inaba) factor but not the B (Ogawa) nor the A (major specific antigen of O1 serogroup ofV. cholerae). As all antisera against reference strains ofV. cholerae contained some amount of antibody to the rough (R) antigen, all diagnostic O antisera must be absorbed with the reference rough strain, CA385.

The aquatic flora and fauna as reservoirs of Vibrio cholerae: a review.

Abstract: reduce the particulate load, the viability of the organism Aquatic animals and plants may be reservoirs of may be related to the presence of particulates. They y cholerae in the environment. We first consider the suggested that V. cholerae prefer an epibiotic form of possibilities of aquatic fauna as possible reservoirs, habitat. As the organisms can be recovered from filtered Various kinds of aquatic fauna including oysters, estuarine and sea water as well as particulate-free water, zooplankton, crabs, etc. have been considered as potential they also suggested that V. cholerae can survive as a habitats of V. cholerae in the aquatic environment from planktonic form for a certain period of life. time to time. Dastidar and Narayanaswami (13) studied Lee et al. (10) in a 3-year survey from 1979 to 1981 the chitinase activity of 7 strains of V. cholerae classical of the incidence of V. cholerae in water, animals and biotype, 15 strains of El Tor biotype and 4 NAG (non birds in Kent, England, observed that about 6% of all the agglutinating) vibrios. Detectable amounts of chitinase gulls sampled contained V. cholerae non-01. They also activity were observed in most of the strains studied, collected the water samples from the same ditches where Nalin (14) suggested that V. cholerae can survive during y6 h / WCre CaU could not isolate any the interepidemic period attached to copepods in the

Vibrio cholerae O139 Bengal.

Abstract: There have been seven pandemics of cholera in recorded history. Even though the etiological agents of the first four pandemics are not known since they occurred in the time before such agents could be recognized, the last three pandemics are known to be due to Vibrio cholerae serogroup 01. The seventh pandemic of cholera caused by the El Tor vibrio originated in Celebes, Indonesia, in 1961 and has spread far and wide over the last 30 years, reaching the South American continent in 1991 (9, 12). V cholerae non-O1 serogroups were not known to cause epidemics of diarrhea; they were known, however, to cause sporadic cases and small outbreaks of diarrheas and extraintestinal infections (34). A departure from this pattern occurred in October 1992, when an epidemic of cholera-like disease due to a V cholerae non-O1 serogroup broke out in the southern Indian port city of Madras. Over the next few months, it spread to other southern Indian cities and reached the northeastern Indian city of Calcutta (50). In December of that year, there was an outbreak of cholera-like illness in southern coastal Bangladesh, which over the subsequent several months spread to the entire country (1, 6, 8). The strain also caused epidemics of diarrhea in other parts of India at the same time (23). The disease affected thousands of individuals, mainly adults, and caused many deaths in the Indian subcontinent, indicating that the population was virgin to the organism (6). Nomenclature. The epidemic strain was not related to the 138 known serogroups of V cholerae (serogroup 01 and 137 non-O1 serogroups); therefore, a new serogroup, 0139 was assigned to the strain with the synonym Bengal to indicate its first isolation from the coastal areas of the Bay of Bengal (57). At last count, V cholerae 0139 infection had been reported from India, Bangladesh, Nepal, Burma, Thailand, Malaysia, Saudi Arabia, China, and Pakistan (1, 15, 22). There were also imported cases in the United Kingdom (14) and the United States (13). Therefore, it is believed that V cholerae 0139 might be the agent of eighth pandemic of cholera (38, 58). Since the strain causes a disease which is virtually indistinguishable from cholera due to V cholerae 01, it should be considered the second etiological agent of cholera (10, 62). It also shares several properties with V cholerae 01 biotype El Tor: morphology, culture, fimbrial antigens, cholera toxin (CT), genes for zonula occludens toxin (zot), and accessory cholera enterotoxin (ace), in vitro invasiveness for HEp-2 cells, possession and location of CTX element in the core region of the chromosome, possession of toxin coregulated pilus structural gene (tcpA) and iron-regulated genes (IrgA, ViuA, and fur) and their locations on similar sites in the chromosomes,

Isolation of enterotoxigenic Bacteroides fragilis from Bangladeshi children with diarrhea: a controlled study.

Abstract: We undertook a controlled study of children younger than 5 years in Bangladesh to determine whether enterotoxigenic Bacteroides fragilis (ETBF) was associated with diarrhea in this population. ETBF was isolated from 22 (6.1%) of 358 patients and 5 (1.2%) of 425 controls (P = 0.0001). In children younger than 1 year, however, low isolation rates (2 to 3%) were found in both patients and controls. In children older than 1 year, the rates were significantly higher in children with diarrhea (16 [9%] of 177) than in controls (2 [1%] of 264; P = 0.00001). When children with mixed infections with other known diarrheal pathogens were removed, the differences in children older than 1 year were still significant (7 [4%] of 177 versus 2 [1%] of 264; P = 0.033). The syndrome associated with ETBF was secretory in nature, with watery diarrhea, and of mild severity. These epidemiological and clinical findings are similar to those from a previous study of White Mountain Apaches in the United States and are the first to suggest that ETBF may also be an important diarrheal pathogen in other geographic areas and in the developing world where diarrhea is highly endemic.

Maternal and socioeconomic factors and the risk of severe malnutrition in a child: a case-control study.

Abstract: Objective To examine the relation of maternal and socioeconomic factors with the development of severe malnutrition in young children. Design A case-control study. Setting A large diarrhoea treatment centre in a metropolitan city. Subjects Cases were 125 severely malnourished children, aged 60% of NCHS median values. Intervention Mothers of the children were interviewed to record personal history and various socioeconomic variables and examined for height and weight. Results Maternal factors such as illiteracy, mothers' employment outside, lack of breastfeeding and maternal malnutrition (as indicated by low body mass index, weight or height); and selected socioeconomic indicators such as poor family income, use of unprotected surface water or unhygienic latrine were found to be significantly associated with severe malnutrition in their children. In multivariate analysis, maternal illiteracy and lack of breastfeeding were associated with approximately fourfold increased risk of severe malnutrition in their children. A strong positive association of employment of mothers outside homes with fivefold increased risk was surprising and may reflect a complex social problem of poor urban mothers; malnourished mothers were 2.5 times more likely to have severely malnourished children. Conclusion The findings confirm the well-known association of lack of maternal education and breastfeeding with severe malnutrition of their children. Maternal malnutrition may be a useful indicator to identify at-risk families with severely malnourished children. However, its causal association, though plausible, cannot be inferred from the study.

Enteric protein loss and intestinal permeability changes in children during acute shigellosis and after recovery: effect of zinc supplementation.

Abstract: The effect of zinc supplementation on intestinal permeability changes and protein loss was studied in 32 children aged between 1 and 12 years during bouts of acute shigellosis and after recovery. An intestinal permeability test and then a 48 hour balance study were performed on all patients. They were then blindly assigned to receive vitamin B syrup either with or without zinc acetate (15 mg/kg per day) for a month. All patients received a five day course of nalidixic acid. The balance study was repeated during convalescence and follow up, but a permeability test was done only at follow up after one month. Intestinal permeability, expressed as a urinary lactulose:mannitol excretion ratio, improved significantly (p = 0.001) along with a significant increase (p = 0.005) in mannitol excretion in the zinc supplemented children, suggesting a resolution of small bowel mucosal damage. The latter was associated with a higher coefficient of nitrogen absorption (p = 0.03), suggesting a possible role of zinc in the treatment of shigellosis. Enteric protein loss, as assessed by faecal alpha 1 antitrypsin clearance, was not influenced by zinc supplementation.

Probable role of blue-green algae in maintaining endemicity and seasonality of cholera in Bangladesh: a hypothesis.

Abstract: INTRODUCTION A good example of how reservoirs have gone undetected in Australia is shown by Rogers et al. (4). If Vibrio cholerae 01 has been isolated from aquatic there had not been an unusual drought, which resulted in environments in various parts of the world (1-14). the need for a supplementary water supply from a nearby However, little is known about its ecology, notably its river, the presence of V. cholerae 01 in Queensland rivers interaction with the resident flora in an aquatic ecosystem. would have gone unnoticed. It was by accident that the This gap in our knowledge is due to the fact that in the rivers were found to be reservoirs of V. cholerae 01. The past, investigations of the biology of V. cholerae have salinity of water in the rivers is low, in which V. cholerae been mainly based on the assumption that organisms 01 cannot survive long. Therefore, some sort of aquatic causing cholera occurred only clinically in man. flora in this water system must have been supporting the However, Colwell etal. (15) hypothesized that survival of V. cholerae 01. V. cholerae are autochthonous members of the bacterial Islam etal. (19) demonstrated the long-term survival flora of brackish water and estuarine systems. This and multiplication of V. cholerae 01 inside the hypothesis offered a new perspective on the ecology of mucilaginous sheath of a blue-green alga Anabaena this organism. variabilis. We are not aware of any other studies which , ,, j , , , , • , r have shown such a long survival of V. cholerae 01 in Marshall (16) suggested that the enhanced survival oi r, ,, .. . . . ° . . , fresh water m the laboratory. However, studies have microorganisms in aquatic environments is due to , , , , ,, , T/ ■ , . ? ., ^ r demonstrated that V. cholerae Ol survive better with association with some non-living and living surfaces ^ ,, , OA 6 ® aquatic flora (14,20-30). where they find the microenvironment favourable. Our study, the first attempt to examine algae as In the endemic areas of Bangladesh cholera epidemics posslble reservoirs of cholera) cleariy indicates that occur twice a year. During epidemics, V. cholerae Ol are blue-green algae could act as a reservoir of V. cholerae isolated from patients as well as from the surface water of 01 in the environment. Before this study, phycologists pond, lake, river, etc. but disappears from the had observed the association of other Gram-negative environment during the interepidemic seasons (17). The bacilli and blue-green algae in the environment, and had reservoirs or sites of survival and multiplication of V. tried to explain the various interdependent mechanisms of cholerae during the interepidemic period are not known. this co-existence (31). Although little information was

Isolation of Vibrio cholerae O139 synonym Bengal from the aquatic environment in Bangladesh: implications for disease transmission.

Abstract: Currently, Bangladesh is experiencing an epidemic of acute watery diarrhea caused by Vibrio cholerae O139 Surface waters were collected and cultured for vibrious following enrichment Twelve percent (11 of 92) of samples yielded V cholerae O139, and all of them were positive for cholera toxin The data suggest that V cholerae O139 is easily culturable from surface water samples Images

Pathology of shigellosis and its complications

Abstract: One hundred and thirty-three colonic biopsies of proven cases of Shigella colitis were examined and post-mortem examinations were carried out on 29 fatal cases at the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR, B) hospital between 1988 and 1992 The distribution of pathological lesions and the spectrum of histopathological changes in the intestinal tract of these patients, and the features of intestinal and extra-intestinal complications of shigellosis are presented Septicaemia, hyponatraemia, hypokalaemia and hypoglycaemia were present in a high percentage of these cases All but two patients were malnorished at the time of autopsy Shigellosis patients rapidly became hypoproteinaemic and were susceptible to other infections including opportunistic infections Mortality amongst shigellosis patients admitted to our hospital continues to be high in spite of adequate antibiotic and supportive therapy

Production, characterization, and application of monoclonal antibodies to Vibrio cholerae O139 synonym Bengal.

Abstract: Mouse monoclonal antibodies (MAbs) were derived against acetone-treated whole cells of the newly recognized Vibrio cholerae O139 serogroup which is causing epidemics of cholera-like disease in India and Bangladesh. Four MAbs specifically recognized the lipopolysaccharide antigens of V. cholerae O139. MAbs ICL9 and ICL13 were of the immunoglobulin M (IgM) isotype, ICL11 was of the IgG3 isotype, and ICL12 was of the Ig2b isotype. A fifth MAb, ICL10, of the IgG2b isotype cross-reacted with V. cholerae O91. All five MAbs recognized V. cholerae O139 in an enzyme-linked immunosorbent assay, slide agglutination test, motility inhibition test, and indirect immunofluorescence test. During a 1-month evaluation of these MAbs in our clinical laboratory, all 86 cases diagnosed as V. cholerae O139 by a rabbit polyclonal antiserum were also detected by these MAbs, establishing their utility as highly sensitive and specific diagnostic reagents. With these MAbs, it should now be possible to screen for the V. cholerae O139 serogroup in epidemic and endemic diarrhea cases and in environmental and food samples.

Molecular analysis of rRNA and cholera toxin genes carried by the new epidemic strain of toxigenic Vibrio cholerae O139 synonym Bengal.

Abstract: Vibrio cholerae O139 synonym Bengal recently caused large epidemics of cholera-like disease in Bangladesh and India. We compared the restriction fragment length polymorphisms of ctxA and rRNA genes (ribotypes) in 27 isolates of V. cholerae O139 from patients in Bangladesh and India with those of 48 isolates of V. cholerae O1 from patients and 21 V. cholerae isolates from surface waters in Bangladesh, which included 2 O139 and 19 other non-O1 isolates. Ribotyping of the isolates with BglI revealed that all 29 isolates of O139 vibrios belonged to a single ribotype, suggesting a clonal nature of the infection. However, the O139 vibrios comprised two ctxA genotypes and carried three or more copies of the ctxA gene, and the chromosomal locations of these copies were unlike those of the El Tor or classical vibrios. Analysis of the restriction fragment length polymorphisms of the rRNA genes suggested that V. cholerae O139 isolates are more closely related to El Tor strains of V. cholerae O1 than were 19 other non-O1 vibrios and 33 classical V. cholerae O1 isolates that were studied. However, further studies are needed to determine whether V. cholerae O139 originated from mutations and genetic changes in a V. cholerae O1 strain or was due to the acquisition of virulence genes by a previously unknown V. cholerae non-O1 strain.

Detection of 4-quinolone resistance mutation in gyrA gene of Shigella dysenteriae type 1 by PCR.

Abstract: To study 4-quinolone resistance, the N-terminal coding region of gyrA from nalidixic acid-susceptible and -resistant isolates of Shigella dysenteriae type 1 was amplified by PCR, cloned, and sequenced. DNA sequence analysis of gyrA from nalidixic acid-resistant isolates revealed a C-to-T transition at nucleotide position 248 leading to a Ser-83-to-Leu substitution which was absent in susceptible clinical isolates. Direct HinfI digestion of PCR-amplified DNA detected similar mutations. Thus, DNA gyrase A subunit mutation Ser-83 to Leu is implicated in 4-quinolone resistance in S. dysenteriae type 1.

Albendazole and infections with Ascaris lumbricoides and Trichuris trichiura in children in Bangladesh.

Abstract: Two hundred and forty-five children infected with Trichuris trichiura, 143 of whom were also infected with Ascaris lumbricoides, were treated with albendazole as follows: single doses of either 600 mg or 800 mg, or daily doses of 400 mg for either 3 d or 5 d. Three stools were examined over a period of 10 d after treatment and again after nearly 40 d, using a quantitative microscopical technique. Albendazole appeared to act slowly against A. lumbricoides but within 10 d all dosages had cured about 92% of infections. In contrast, albendazole appeared initially to inhibit egg production by T. trichiura, which was then resumed. The single doses gave poor cure and egg reduction rates for T. trichiura of less than 30% each, and 400 mg of albendazole for 3 d was required to achieve a cure rate of 80%. The implications of these results are briefly discussed.

Strongyloides stercoralis in an urban slum community in Bangladesh: factors independently associated with infection

Abstract: Stool samples from 880 residents in an urban slum in Dhaka, Bangladesh, were collected on 3 occasions over one year, and examined for intestinal parasites. Information on many potential risk factors for infection was obtained by questionnaire from a respondent in each household studied. In a crude univariate analysis of the data, several of the factors were found to be significantly associated with Strongyloides stercoralis infection. Most of these factors were co-variate with one another, and with poverty generally. Using Mantel-Haenszel χ 2 tests to control for confounding effects of each variable individually, the following 4 factors remained independently associated with S. stercoralis infection: respondent's use of a community latrine rather than a private latrine, living in a house with an earth floor rather than a cement floor, being of Bihari ethnicity, and being 7–10 years of age. Implications of these results for the epidemiology and control of strongyloidiasis are briefly discussed.

Levels and correlates of maternal nutritional status in urban Bangladesh.

Abstract: Researchers analyzed anthropometric data from 2417 nonpregnant mothers socioeconomic data from 2048 mothers reproductive history data from 1314 mothers and socioeconomic and reproductive history data from 1185 mothers to determine the levels and correlates of maternal nutritional status of nonpregnant mothers in the slums of Dhaka Bangladesh. Mean weight height middle-upper-arm-circumference (MUAC) and body mass index (BMI) of the 2417 mothers stood at 41.8 kg 148.8 cm 232.5 mm and 18.8 respectively. Multivariate regression analyses revealed that mothers schooling and household economic status had a significant positive effect on weight MUAC and BMI (p < .05 and .01 respectively). Schooling had a significant positive association with mothers height (p < .05) but household economic status did not. Maternal height and weight had a significant negative association with child death (p < .001 and < .05 respectively). Mothers equal to or less than 155 cm had an increased risk of child death (odds ratio [OR] = 1.4-2.64) with those less than 140 cm in height having the greatest risk of child death (OR = 2.64). Short stature linked to child loss indicates a possible intergenerational influence of poor childhood nutrition suggesting that improvement of nutritional status for girls would improve child health in the next generation. Sophisticated and long-term planning is needed however to achieve improved nutritional status of girls due to various obstacles (e.g. son preference poverty food scarcity and high prevalence of infectious diseases). In the meantime maternal and child health workers should target shorter mothers (i.e. < 145 cm) for appropriate prenatal and obstetric care since they face the greatest risk of child death.

Socioeconomic and Anthropometric Status, and Mortality of Young Children in Rural Bangladesh

Abstract: This article investigates the interrelationship of socioeconemic status, anthropometric status and mortality of young children in rural Bangladesh. Data for this study come from Matlab, the vital registration area of the International Centre for Diarrhoeal Disease Research, Bangladesh, where anthropometric and socioeconomic data concerning 1976 children aged 12-23 months were collected in November-December 1975. From these data, anthropometric indices are created, and the relationships of socioeconomic status measured by dwelling space and anthropometric indices with mortality during the 2 years following measurement of these children are investigated. It is found that both socioeconomic status and anthropometric indices are related to mortality. However, the relationship of anthropometric indices is much stronger. Among the anthropometric indices considered, weight-for-age, height-for-age and arm circumference reflect socioeconomic status better than weight-for-height does; and, the first three indices are equally good, and individually better than weight-for-height, as predictors of mortality. The degree of the effect of socioeconomic status (dwelling space) on mortality explained by the best performing anthropometric index, weight-for-age, was not more than 25%. It is concluded that an anthropometric index that can classify socioeconomic status more efficiently is a better predictor of 2-year mortality than any other anthropometric index.

Short Report: Detection of Entamoeba histolytica and E. dispar Directly in Stool

Abstract: Current diagnosis of Entamoeba histolytica infection requires the direct microscopic identification of the parasite, a technique that is insensitive and cannot distinguish pathogenic E. histolytica from noninvasive E. dispar. Enzyme-linked immunosorbent assay (ELISA) antigen detection tests were developed to distinguish E. histolytica from E. dispar infection in stool specimens. The ELISA result for E. histolytica antigen was positive in 26 of 27 E. histolytica-positive stool specimens, three of 25 E. dispar-positive stools, and one of 30 stools with other or no intestinal parasites, giving a specificity and sensitivity for the detection of E. histolytica infection of 93% and 96%, respectively. The assay result used to detect both E. dispar and E. histolytica was positive in 26 of 27 E. histolytica-positive stools, 19 of 25 E. dispar-positive stools, and one of 30 stools negative by microscopy and culture for Entamoeba, giving a specificity and sensitivity of 97% and 87%, respectively. Because these ELISAs can be completed in several hours, they offer promise as rapid and sensitive means of detecting amebic infection.

Development and evaluation of rapid monoclonal antibody-based coagglutination test for direct detection of Vibrio cholerae O139 synonym Bengal in stool samples.

Abstract: A monoclonal antibody-based coagglutination test directly detected Vibrio cholerae O139 synonym Bengal in 83 of 120 watery diarrheal stool specimens; on culture, 90 samples were positive. Thus, with 92% sensitivity, 100% specificity, and 100% positive and 95% negative predictive values, the coagglutination test is a useful rapid test for V. cholerae O139.

Hemagglutinating properties of enteroaggregative Escherichia coli.

Abstract: Many intestinal bacterial pathogens possess hemagglutinating properties, which are indicative of their adhesive properties to the intestinal mucosal surface. To understand the bacteria-mucosa interaction, 41 strains of enteroaggregative Escherichia coli (EAggEC), a recently described category of diarrheagenic E. coli, isolated mostly from children with diarrhea in Bangladesh, India, Thailand, Central America, and South America were screened for mannose-sensitive hemagglutination and mannose-resistant hemagglutination of erythrocytes from humans, rats, mice, sheep, cattle, and rabbits. Some strains demonstrated mannose-sensitive hemagglutination of erythrocytes. Most isolates showed mannose-resistant hemagglutination of erythrocytes from all species except rabbits. The hemagglutination patterns could be classified into 18 groups. Studies with three selected isolates suggested that hemagglutinins are cell bound and are protein in nature. On the basis of the pattern of inhibition of hemagglutination by various chemicals, 39 isolates were classified into 19 groups. Hemagglutinations of many isolates were inhibited by sialic acid-containing compounds, suggesting that these compounds may be the receptors for these organisms on erythrocytes and possibly on the intestinal mucosa. These data indicate that strains of EAggEC are a heterogeneous group of organisms with different types of hemagglutinins or adhesins for the intestinal mucosal surface. Also, the adhesion characteristics of EAggEC strains may be too complex to be assessed by simple hemagglutination tests.

Intake from an energy-dense porridge liquefied by amylase of germinated wheat: a controlled trial in severely malnourished children during convalescence from diarrhoea.

Abstract: OBJECTIVE To evaluate the role of an energy-dense diet liquefied with amylase-rich flour from germinated wheat (ARF) in increasing the energy intake in severely malnourished infants and young children and its acceptability to mothers. DESIGN A randomized controlled clinical trial with two sets of controls. SETTING Nutrition rehabilitation unit of a large diarrhoea treatment centre where mothers stay with their very severely malnourished children. SUBJECTS 78 severely malnourished children aged 5-18 months just recovered from diarrhoea. INTERVENTION Children were randomly assigned to receive either an energy-dense porridge made liquid by adding ARF (test diet) or an unaltered thick porridge of similar energy density (control 1 diet), or the porridge made liquid with addition of water to have the same viscosity as the test diet but of lower energy (control 2 diet), in four major meals a day for 5 days and intake was measured; breast-milk was measured by test weighing. Children also received an additional three milk-cereal meals a day. RESULTS The mean energy intake (95% CI, P value for difference between test and control) was 385 (339-431), 289 (251-327, P < 0.005), and 255 (222-289, P < 0.001) kJ/kg.d respectively. Feeding test diet was not associated with significant adverse effects e.g. on diarrhoea, vomiting, breast-milk intake, and was well accepted by mothers. CONCLUSION The results suggest that use of an energy-dense ARF-treated liquefied porridge increases calorie intake by very severely malnourished children during convalescence from diarrhoea, and that it does not produce any adverse effect.

Emergence of a new epidemic strain of Vibrio cholerae in Bangladesh. An epidemiological study

Abstract: For decades, epidemic cholera in Bangladesh has produced contrasting Pictures of appearance and disappearanceof Vibrio cholerae, which until recently, remained confined to the biotypes and to serotypes of V. cholerae a 1. The classical biotype continued to survive and coexisted with El Tor biotype in southern Bangladesh desPite its disappearance from the rest of the world during the present pandemic. For the first time in history, during the cholera epidemic in 1993, both biotypes (classical and El Tor) of V. cholerae a 1 have disappeared and have been replaced by a new strain of V. cholerae non-O 1 (designated as 0139 Bengal). Environmental changes occurring in the Bay of Bengal may have resulted in the emergence of the new epidemic strain of V. cholerae in Bangladesh.

An epidemic of cholera due to Vibrio cholerae O139 in Dhaka, Bangladesh: clinical and epidemiological features.

Abstract: We describe the disease spectrum and socio-demographic and epidemiological features of an epidemic of cholera due to a new pathogen, Vibrio cholerae O139, in patients attending a very large hospital in the metropolitan city of Dhaka, Bangladesh. This hospital treats 70,000-90,000 patients a year with diarrhoeal diseases. A 4% systematic sample of 1854 patients attending from January to April 1993 were studied. Five hundred and two (27%) of the 1854 patients were culture positive for V. cholerae O139 and 63 (3%) were culture positive for V. cholerae O1 biotype El Tor. Patients with V. cholerae O139 were mainly adults with a short history of watery diarrhoea. Eight-three percent of patients had moderate to severe dehydration. All recovered except one 80-year-old man with compromised renal function who died. Seventy-eight percent of patients required initial intravenous rehydration followed by oral rehydration therapy with rice ORS; they also received tetracycline to reduce diarrhoea severity. Most patients were from urban slums with inadequate sanitation facilities and hygiene practices. The newly recognized V. cholerae O139 infection produced an epidemic of severe dehydrating diarrhoea indistinguishable from clinical cholera in a population which experiences two epidemic peaks of cholera in a year due to V. cholerae O1. Infection with the latter does not appear to confer any cross-protection from V. cholerae O139. The new pathogen suppressed, albeit temporarily, V. cholerae O1. Unlike other non-O1 serogroups of V. cholerae this new serogroup appears to have epidemic potential.

Shigella carriers among non-diarrhoeal children in an endemic area of shigellosis in Bangladesh.

Abstract: Shigellosis is endemic in Bangladesh and other developing countries. Asymptomatic carriers have been incriminated in the maintenance and spread of the disease in the community. To study the incidence of the asymptomatic carrier state of Shigella, we conducted surveys in two groups of children under 5 years of age. The first group consisted of 249 ill children who did not have diarrhoea, and the second group consisted of 699 apparently healthy children. The Shigella carrier rate in the first group was 6.4% and that in the second group 2.1%. These carriers may be important in maintaining the transmission of Shigella organisms in the community.

Infectious agents causing acute watery diarrhoea in infants and young children in Bangladesh and their public health implications.

Abstract: We studied the age specific distribution of enteropathogens in young children presenting at a large diarrhoeal diseases hospital in urban Bangladesh. A 5 per cent systematic sample was used to examine 1207 rectal swab specimens of children aged 1-35 months with acute watery diarrhoea. Variation in isolation rates of enteropathogens was observed in different age groups. Overall rotavirus (26 per cent) and Campylobacter (26 per cent) were the most common pathogens followed by enterotoxigenic Escherichia coli (15 per cent), Vibrio cholerae 01 (7 per cent), other Vibrios (9 per cent), Shigella (4 per cent), and Salmonella (< 1 per cent). In early infancy (1-5 months) more rectal swab specimens did not yield any enteropathogen compared to older children of 24-35 months old (44 v. 30 per cent). Rotavirus was most frequently detected (35 per cent) in children between 6 and 11 months old. Attendance of cholera cases at the hospital was alarmingly high in the third year of life (29 per cent). The study provided useful information that, in general, children under 2 years are predominantly infected with agents [rotavirus, Campylobacter, and enterotoxigenic Escherichia coli (ETEC)] for which antibiotic therapy is not usually indicated. These patients can be managed effectively with oral rehydration therapy and proper feeding. Knowledge of pathogens associated with more severe forms of diarrhoea may help in optimizing strategies for vaccination when suitable vaccines are available against enteric infections.