Retracted: Risks of avian influenza (H5) in duck farms in the Ayeyarwaddy Delta region, Myanmar.

The Ayeyarwaddy delta region in the south-west of Myanmar is the main agricultural and rice-growing area. The region has a high density of duck and backyard chicken populations with low biosecurity. The objective of this study was to analyse risk factors for avian influenza (H5) in the Ayeyarwaddy delta region, Myanmar. A case­control risk factor study was conducted from April to June 2010 by individual interviews including risk factor questionnaires given to duck farmers (n = 50) in five townships in the Ayeyarwaddy delta region, Myanmar. Risk factor analyses were conducted using univariate analysis and multivariate logistic regression model with backward stepwise (wald) method. The results showed significant risk factors for AI (H5) sero-positivity in ducks were wooden egg box containers (OR = 52.7, 95% CI = 2.34-1188, P = 0.013) and water sourced from wetlands (OR = 30.7, 95% CI = 1.96-481.6, P = 0.015). Conversely, the cleaning of reusable egg containers was determined as a protective factor (OR = 0.03, 95% CI = 0.00-0.42, P = 0.01). In conclusion, this study identified risk factors for AI (H5) in duck farms and the importance of avian influenza prevention and control.

Relationship of breast-feeding and hand-washing with dehydration in infants with diarrhoea due to Escherichia coli.

This prospective cohort study was carried out in the neonatal unit of the Yangon Children Hospital, Myanmar, to gather more information on the types of feedings and hand-washing practices of mothers as the determinant of severe dehydration in infants with acute diarrhoea due to Escherichia coli. The study subjects included 100 infants with diarrhoea, aged less than 4 months, admitted to the hospital from June 1997 to May 1998. Data on isolation of E. coli from rectal swab samples, types of feedings, hand-washing practices, and dehydration status were collected. Of the 100 cases, E. coli was isolated from rectal swab samples of 48 infants. Of these 48 cases, 28 had some dehydration and 20 had severe dehydration. Exclusive breast-feeding was observed only in the age group < 1 and > 1-2 month(s). The association of the severity of dehydration with other types of feedings compared to exclusive breast-feeding was not statistically significant. In this study, most mothers washed their hands with water only after cleansing their children's defaecation, and before and after feeding their children. The severity of dehydration was statistically significant in hand-washing practices when compared to washing with water only and washing with soap and water. This study has shown the association between types of feedings and hand-washing practices with dehydration in infants with acute diarrhoea due to E. coli. The results of the study suggest that there is a need for appropriate intervention programmes to promote exclusive breast-feeding and hand-washing practices with soap and water after cleansing children's defaecation, and before and after feeding children.

Vibrio cholerae non-O1 as a causal pathogen in cholera patients in Yangon, Myanmar.

Vibrio cholerae non-O1 was studied in patients with rice watery diarrhoea admitted to the Infectious Diseases Hospital, Yangon. The study was conducted during 1993-1994 to determine the association of the pathogen with the disease. Altogether 771 rectal swabs were collected and examined. V. cholerae were isolated by the standard methods. The seasonal, age and sex distribution, serotyping and susceptibility of these isolates to antibiotics were investigated, V. cholerae were isolated from 233 (3O.2%) samples. Among them, V. cholerae O1 were isolated from 117 (5O%) samples and V. cholerae non-O1 from 116 (5O%) samples. The seasonal, age and sex distribution was identical in both V. cholerae O1 and V. cholerae non-O1 groups. V. cholerae O139 was isolated during February 1994. Thus V. cholerae non-O1 was also one of the causal pathogens of cholera, like V. cholerae O1 in this community.

Serotype distribution and antimicrobial susceptibility of Shigellae isolated from diarrhoeal patients in Yangon, Myanmar.

In Myanmar there is a changing pattern in the prevalence of Shigella strains with an increasing antimicrobial resistance, and, thus the serotype prevalence and antibiotic sensitivity pattern of Shigellae were studied in 1993. Dysenteric stool samples were collected from the laboratory of Infectious Diseases Hospital, Yangon during January-June 1993. The Shigella isolates were identified by the standard bacteriologic procedures. Four hundred and sixty stool samples containing blood and mucous were collected in this study, and Shigella spp. were isolated from the 108 (23.5%) samples. The increasing antimicrobial resistance of shigellosis from 1980 to 1993 in this community was also discussed.

Effectiveness of potash alum in decontaminating household water.

To evaluate the effectiveness of potash alum in purifying household water, this study was carried out in a suburban community in Yangon, Myanmar. It was designed to test whether the application of potash alum (0.05%) regularly into household water storage vessels during water replenishment was capable of decontaminating household water in homes using shallow well water. It was conducted in 100 households (50 each in intervention and control groups). After alum (0.05%) was added, the contamination level of water decreased on the 2nd and 3rd days. The alum-treated water was well tolerated by the users; only one member complained of a metallic taste. We conclude that potash alum was effective and acceptable in this community in decontaminating household water.

Vibrio spp. isolated from natural waters of the city of Yangon, Myanmar.

Virulence properties of the environmental isolate of vibrios from natural waters of Yangon, Myanmar were studied. Vibrio spp. were isolated for identification by the membrane filtration method and cultured on thio-sulphate-bile-sucrose media. No Vibrio cholerae O1 were isolated. V. cholerae non-O1 were the major vibrio species isolated from the samples. None of them were detected for cholera-toxin-like toxin, thermostable direct haemolysin, or heat-stable enterotoxin. Sixty-one isolates gave haemolytic activity; 27 V. cholerae non-O1 and 6 V. fluvialis isolates produced protease.

Bacteriologic studies of food and water consumed by children in Myanmar: 1. The nature of contamination.

To isolate major bacterial pathogens from children's food and drinking water, a 3-month study was conducted in a suburban community in Yangon, Myanmar. From the morning meals and stored drinking water of 208 randomly selected children, 775 food and 113 water samples were collected and were cultured using standard methods. Escherichia coli, Vibrio cholerae non-01, and Salmonella were isolated from 505, 28 and 6 food samples respectively, and E. coli and V. cholerae non-01 were isolated from 29 and 5 water samples respectively. Among the E. coli isolates, 8 produced heat-stable toxin (ST) and 3 were enteroinvasive. Nine V. cholerae non-01 produced cholera-like toxin. Of the 29 E. coli isolates from the samples of drinking water, 3 produced ST. All water samples were negative for Salmonella. The study underscores the importance of bacterial contamination of children's food and drinking water and stresses the need to improve environmental sanitation.

Bacteriologic studies of food and water consumed by children in Myanmar: 2 Lack of association between diarrhoea and contamination of food and water.

The association between contamination of morning samples of food and water of 208 children aged 6-29 months and the incidence of diarrhoea was investigated for 3 months in Yangon, Myanmar. Contamination of the samples was determined by isolation of faecal coliforms (FC) by standard methods. The children were divided into three groups, high, medium and low, according to the proportion of food and water samples found to be contaminated. The incidence of diarrhoea was recorded by weekly recall. Of the 779 food samples, 504 (65%), and of the 860 drinking water samples, 187 (22%) were positive for FC. The association between food and water contamination and the incidence of diarrhoea was assessed by comparing the cumulative incidences in the high and medium groups with that in the low group which served as reference. Diarrhoea risk ratios (RR) for children in the medium and high contamination groups (food, RR = 1.04 in medium and 0.78 in high vs 1 in low; water, RR = 0.73 and 0.73 vs 1) were not significantly different from those who were in the low-contamination group even after controlling for the confounding variables.

Contamination of drinking water during collection and storage.

Drinking water contamination during abstraction, storage and use was determined in a suburban community in Rangoon, Burma, by detecting faecal coliforms (FC) with membrane filtration method. Increasing contamination during water collection, from the source to home storage, was found in all the studied households using 4 different types of drinking water. The implications of the findings are discussed.