OBJECTIVE : Distribution of enteropathogens in diarrheal children suffering from severe malnutrition has received little attention. The present study aimed to determine the etiology of diarrhea among severely malnourished <5 children in urban and rural Bangladesh. 
METHOD : nformation of 29,144 children <5 years attending Dhaka Hospital (urban) and 14,563 children attending Matlab Hospital (rural) from 1996-2017 was extracted from the diarrheal disease surveillance system of icddr,b categorized as severe malnourished (SM), moderate malnourished (MM) and normally nourished (NN) defined by any category of malnutrition based on z-score.
RESULTS : Of the children, 21% from urban and 18% from rural were found to be SM (z-score <-3). In urban and rural, MM was 37% and 39%, and NN was 49% and 51% respectively. SM children from urban area were more likely to be infected with Vibrio cholerae than NN (13% vs. 5%, p<0.001). E. coli in SM children was more compared to NN (10% vs. 7%, p=0.027). Conversely, children with SM less likely experienced rota viral diarrhea compared to NN (31% vs. 47%, p<0.001) and MM (31% vs. 38%, p<0.001). Isolation rates of Campylobacter, Salmonella and Shigella were identical in all the groups. In rural area, isolation rates of diarrhoeal pathogens were comparable across the groups accept for rota viral diarrhea, which was low in SM compared to NN (30% vs. 37%, p=0.001). The isolation rates of Vibrio cholerae (13% vs. 6%, p=0.013), and Campylobacter (7.5% vs. 2%, p<0.001) were higher among urban SM children compared to rural; however, isolation rate of Shigella (11% vs. 5%, p=0.007) was higher in rural area. 
CONCLUSION : Urban SM children were more likely to be infected with Vibrio cholerae and Campylobacter; and rural children were more likely to be infected with Shigella. However in both the areas, SM children were less likely to be infected with rotavirus.