Etiology and epidemiology of diarrhea in children in Hanoi, Vietnam.

OBJECTIVES: This paper provides a preliminary picture of diarrhea with regards to etiology, clinical symptoms, and some related epidemiologic factors in children less than five years of age living in Hanoi, Vietnam. METHODS: The study population included 587 children with diarrhea and 249 age-matched healthy controls. The identification of pathogens was carried out by the conventional methods in combination with ELISA, immunoseparation, and PCR. The antibiotic susceptibility was determined by MIC following the NCCLS recommendations. RESULTS: Of those with diarrhea, 40.9% were less than one year old and 71.0% were less than two years old. A potential pathogen was identified in 67.3% of children with diarrhea. They were group A rotavirus, diarrheagenic Escherichia coli, Shigella spp, and enterotoxigenic Bacteroides fragilis, with prevalences of 46.7%, 22.5%, 4.7%, and 7.3%, respectively. No Salmonella spp or Vibrio cholerae were isolated. Rotavirus and diarrheagenic E. coli were predominant in children less than two years of age, while Shigella spp, and enterotoxigenic B. fragilis were mostly seen in the older children. Diarrheagenic E. coli and Shigella spp showed high prevalence of resistance to ampicillin, chloramphenicol, and to trimethoprim/sulfamethoxazole. Children attending the hospitals had fever (43.6%), vomiting (53.8%), and dehydration (82.6%). Watery stool was predominant with a prevalence of 66.4%, followed by mucous stool (21.0%). The mean episodes of stools per day was seven, ranging from two to 23 episodes. Before attending hospitals, 162/587 (27.6%) children had been given antibiotics. Overall, more children got diarrhea in (i) poor families; (ii) families where piped water and a latrine were lacking; (iii) families where mothers washed their hands less often before feeding the children; (iv) families where mothers had a low level of education; (v) families where information on health and sanitation less often reached their households. CONCLUSIONS: Group A rotavirus, diarrheagenic Escherichia coli, Shigella spp, and enterotoxigenic Bacteroides fragilis play an important role in causing diarrhea in children in Hanoi, Vietnam. Epidemiological factors such as lack of fresh water supply, unhygienic septic tank, low family income, lack of health information, and low educational level of parents could contribute to the morbidity of diarrhea in children.

Detection and characterization of diarrheagenic Escherichia coli from young children in Hanoi, Vietnam.

Diarrhea continues to be one of the most common causes of morbidity and mortality among infants and children in developing countries. Escherichia coli is an emerging agent among pathogens that cause diarrhea. The development of a highly applicable technique for the detection of different categories of diarrheagenic E. coli is important. We have used multiplex PCR by combining eight primer pairs specific for enteroaggregative E. coli (EAEC), enteroinvasive E. coli (EIEC), enterohemorrhagic E. coli, enteropathogenic E. coli (EPEC), and enterotoxigenic E. coli (ETEC). This facilitates the identification of five different categories of diarrheagenic E. coli from stool samples in a single reaction simultaneously. The prevalences of diarrheagenic E. coli were 22.5 and 12% in the diarrhea group and the control group, respectively. Among 587 fecal samples from Vietnamese children under 5 years of age with diarrhea, this technique identified 132 diarrheagenic E. coli strains. This included 68 samples (11.6%) with EAEC, 12 samples (2.0%) with EIEC, 39 samples (6.6%) with EPEC, and 13 samples (2.2%) with ETEC. Among the 249 age-matched controls, 30 samples were positive for diarrheagenic E. coli. The distribution was 18 samples (7.2%) with EAEC, 11 samples (4.4%) with EPEC, and 1 sample (0.4%) with ETEC.

Diarrhea caused by enterotoxigenic Bacteroides fragilis in children less than 5 years of age in Hanoi, Vietnam.

Enterotoxigenic Bacteroides fragilis (ETBF) are considered as an emerging enteropathogen causing diarrhea in children. Eight hundred and thirty-six (836) children less than 5 years of age including 587 children with diarrhea and 249 age-matched controls were involved in the study. Within the group of children with diarrhea, 7.3% (43/587) ETBF was detected by immunoseparation in combination with polymerase chain reaction. The corresponding figure for the controls was 2.4% (6/249) (P<0.01). Within the diarrhea group, the prevalence was significantly higher in children older than 1 year of age. Three subtypes of ETBF isolates have been identified with the prevalence of 67.4%, 18.6%, and 16% for bft-1, bft-2, and a new bft, respectively. In the controls, two of the subtypes were identified, 5 bft-1 and 1 bft-2. More than half (55.8%) of the samples harboring ETBF also had other identified pathogens. The clinical symptoms of the single ETBF infection were not different from those of co-infections. This is the first study of the role of ETBF in children's diarrhea in Vietnam and it is concluded that this pathogen is an important causative agent of diarrhea in children in Hanoi, Vietnam.

Diarrhea caused by rotavirus in children less than 5 years of age in Hanoi, Vietnam.

Group A rotaviruses are the major cause of diarrhea in young children worldwide. From March 2001 to April 2002, 836 children less than 5 years of age were investigated in Hanoi, Vietnam. This included 587 children with diarrhea and 249 age-matched controls. Group A rotavirus was identified in 46.7% of the children with diarrhea and 3.6% of the controls, which was a significant difference. Within the diarrhea group, the highest prevalence was seen in children from 13 to 24 months of age, and the prevalence was higher in males than in females. The symptoms of acute diarrhea caused by rotavirus were watery diarrhea, vomiting, fever, and dehydration. A higher prevalence of rotavirus detection was obtained for children who had all of these symptoms, followed by those who had diarrhea with vomiting-dehydration, fever-dehydration, and dehydration. The high rates occurred from September to December, although the infection was encountered all year round. In 58 patients (21.2% of the rotavirus-infected children), rotavirus infection was detected in association with either diarrheagenic Escherichia coli or Shigella spp. The most frequent combinations were rotavirus-enteroaggregative E. coli and rotavirus-enteropathogenic E. coli. At least one enteropathogen was identified from about 64% percent of the samples. The bacterial infection may not have given rise to clinical symptoms of such severity. The present study demonstrates the burden of rotavirus diarrhea in Hanoi, Vietnam. Continuous surveillance of diarrhea caused by rotavirus in young children would play an important role in diagnosis, treatment, and prophylaxis in order to improve the health of children in Vietnam.