Oct 23, 1982 - hospital in Bangladesh. BARBARA J STOLL, ROGER I GLASS, M IMDADUL HUQ, M U KHAN, JAMES E HOLT,. HASINA BANU. Abstract.
BRITISH MEDICAL JOURNAL
VOLUME 285
1185
23 OCTOBER 1982
Outside Europe
Surveillance of patients attending a diarrhoeal disease hospital in Bangladesh BARBARA J STOLL, ROGER I GLASS, M IMDADUL HUQ, M U KHAN, JAMES E HOLT, HASINA BANU
Abstract In October 1979 a surveillance system was set up at the International Centre for Diarrhoeal Disease Research, Bangladesh, Hospital at Dacca to study a 4% systematic sample of the 100 000 patients with diarrhoea who come to the hospital for care each year. From December 1979 to November 1980 inclusive, 3550 patients were studied. A recognised pathogenic organism was identified for 66% of patients screened for all pathogens, one-third of whom had a mixed infection with two or more agents. Enterotoxigenic Escherichia coli was the most common enteropathogen detected in all age groups (detection rate 20%), followed by rotavirus (19%), Campylobacter jejuni (14%), and Shigella (12%). Infants and young children (up to 5 years) were most often infected with rotavirus, enterotoxigenic E coli, and C jejuni and older children (5-14 years) had more infections with enterotoxigenic E coli, Shigella, and E histolytica. Surveillance has helped to define the range of disease among patients attending the Dacca Hospital. Sixty-five per cent of patients complained of watery diarrhoea, a presentation that was significantly more common in patients with Vibrio cholerae 0:1 (91%), enterotoxigenic E coli (78%), rotavirus (77%), and C jejuni (71%) than in all patients studied. Dysentery, defined as a history of diarrhoea with blood, was the presenting complaint of 20% of all patients but 55% of those with Shigella. Only patients with V cholerae 0:1 and enterotoxigenic E coli were at increased risk for severe dehydration. In addition surveillance has been used to identify areas where patient care can be improved and to generate new ideas for research.
Introduction Since 1962 the International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), formerly the Cholera Research Laboratory, has operated a diarrhoeal disease hospital
International Centre for Diarrhoeal Disease Research, Bangladesh, GPO Box 128, Dacca 2, Bangladesh BARBARA J STOLL, MD, associate scientist ROGER I GLASS, MD, MPH, epidemiologist (on assignment from the Centres for Disease Control, Atlanta, Georgia, USA) M IMDADUL HUQ, MSC, PHD, scientist M U KHAN, MB, DPH, scientist JAMES E HOLT, MA, research associate (Department of Biostatistics, Mount Sinai School of Medicine, New York, USA) HASINA BANU, MA, senior field research officer
in Dacca (Dacca Hospital), the capital and largest city of Bangladesh, that provides care free of charge to all patients. Between 1970 and 1980, the number of patients seen at the hospital increased 10-fold from about 10 000 to about 100 000 patients a year, and it became difficult to collect useful information on all patients. Therefore, in October 1979 a surveillance system was set up to study the epidemiological, clinical, and laboratory characteristics of a sample of the patients who come to the hospital for care each year. We were interested in identifying the relative importance of various enteropathogens in urban Dacca and in determining the seasonality and range of disease associated with these agents. We outline the methods used for surveillance and review the data on patients seen from 1 December 1979 to 30 November 1980.
Materials and methods SURVEILLANCE METHODS
A systematic sample of patients was chosen for surveillance based on the number they were assigned at registration. From October 1979 to February 1980 inclusive, every fiftieth patient was selected but in March 1980 the sample size was increased to 4% for statistical reasons. Surveillance patients were seen by the regular hospital staff with emergency cases treated on a priority basis. All patients were first treated in an outpatient area; those requiring further care were admitted to an intravenous treatment centre or a hospital ward. After initial examination and care by a nurse or doctor, the surveillance patient or an adult guardian was interviewed by a special health assistant who collected uniform information on demographic background, recent medical history, presenting symptoms, previous treatment, and treatment prescribed at ICDDR,B. A doctor performed a physical examination, including assessment of the state of dehydration. Dehydration was graded as none, mild ( < 5%), moderate (5-10%), and severe (>10%) according to clinical signs.' To assess nutritional state, each child 10 years or younger was weighed and measured at discharge and the weight-for-height was compared with the Harvard standard.2 A rectal swab for culture was obtained from all patients, and a stool sample for microscopical examination was requested. Additional information was collected on patients admitted to the intravenous centre or hospital ward.
LABORATORY METHODS
Rectal swabs or stool samples were plated directly on SalmonellaShigella (SS), taurocholate-tellurite-gelatin, and MacConkey's agars. Specimens were also enriched in alkaline peptone water for vibrios and then plated on taurocholate-tellurite-gelatin. The plates were examined for salmonellae, shigellae, and vibrios by standard methods.3 Vibrio-like colonies identified on taurocholate-tellurite-gelatin plates were further characterised and classified as V cholerae 0 group 1 or non-O group 1 (NAG).4 Non-lactose fermenting colonies from MacConkey's and SS agars were screened on Kligler's iron agar slants
1186 and motility indole urea medium. Isolates of Shigella were biochemically identified and serologically grouped with a slide agglutination test using commercially available antisera (Burroughs Wellcome). From March 1980, all specimens were cultured for Campylobacter jejuni using Campy-BAP agar (BBL Microbiology Systems).5 A pool of five colonies of Escherichia coli from each patient was tested for the production of heat labile toxin by the Chinese hamster ovary cell assay and of heat stable toxin by the infant mouse assay.6 Rotavirus antigen was identified by enzyme-linked immunosorbent assay without blocking,7 a method which may result in 10-20% false-positive results (Michael Merson, WHO, personal communication). Fresh stool specimens were tested for an acid or alkaline pH with litmus paper, and examined for red blood cells, white blood cells, qualitative stool fat (recorded as 0 to 4+), and parasites by direct smear without concentration techniques. 8 In this study Giardia lamblia and Entamoeba histolytica were considered possible diarrhoeal pathogens only when trophozoites were found. Although helminths were reported, their relation to diarrhoea was not considered. Results were computerised and analysed monthly. The distribution of diseases in the full patient population was extrapolated from these data. The differences between groups were analysed using X2 statistics.
BRITISH MEDICAL JOURNAL
G lamblia (2%), and Shigella (6%) (table III). Rotavirus (22%) and enterotoxigenic E coli (22%) remained the most common pathogens in toddlers (1-4 years) followed by Cjejuni (17%) and Shigella (14%). Rotavirus and C jejuni were rarely identified in children over 5 years. Neither the detection rates of enterotoxigenic E coli, the most common agent, nor the distribution of toxin types changed with increasing age. Between ages 5 and 14, enterotoxigenic E coli (22%), Shigella (13%), E histolytica (13%), and V cholerae 0:1 (11%) were most frequently identified. Adults (15 years and over) were most often infected with enterotoxigenic E coli (17%), Shigella (13%), and E histolytica (10%) TABLE I-Rate of detection of enteric pathogens, ICDDR,B hospital surveillance, Dacca, Bangladesh, December 1979 to November 1980 Percentage Pathogen detection* Enterotoxigenic E coli 20 Heat stable toxin 10 Heat labile toxin 3 Heat stable and labile toxin 7 Rotavirus 19 Campylobacter jejuni 14 Shigella 12 S flexneri 7 S dysenteriae 1 2 S sonnei 1 S dysenteriae 2 1 S boydii 1 Vibrio 7 V cholerae 0:1 6 V cholerae non 0:1 1 Entamoeba histolytica 6 Giardia lamblia 6 1 Salmonella S typhi
