The seasonal variation in the microbial agents implicated in the etiology of diarrheal diseases among children in Lao People's Democratic Republic.

During 1994-1995, the etiological structure of children's diarrhea was monitored in outpatients at Mahosot Hospital, Vientiane, Lao PDR. Of the 191 children studied, 42% had stool specimens positive for enteropathogens; 22% had rotavirus, 21.5% enteropathogenic E. coli, 4.7% Shigella flexneri, 2.9% Campylobacter jejuni, 2.1% Shigella sonnei, and 0.5% each of Giardia intestinalis and Entamoeba histolytica. No Vibrio cholerae and Salmonella spp. was detected in this monitoring. In children under five years, rotaviruses were detected almost all round the year with a maximum prevalence in January in the dry season. Shigella species were highly detected in June to July in the rainy season.

Bacterial diarrhea in Laos, a region where cholera was endemic.

There were cholera outbreaks in Lao PDR since 1993. Two provinces were epidemic areas of cholera in 1993. However the area of cholera occurrence increased to 7 provinces through 1994. Then a bacterial survey had done for the purpose of public health improvement. EPEC was markedly isolated from the hospital in Vientiane. In apparent infection of Salmonella and non-01 Vibrio cholerae with soldiers stationed in the island in Mekong River belong to Vientiane were pointed out. The outbreak of diarrhea in suburban village of Vientiane, the diarrhea was not due to cholera but due to Shigella dysenteriae and Aeromonas sobria. As far as results in the capital city Vientiane and the Vientiane province go, it could say that there was no record and isolation of V. cholerae or non-01 V. cholerae 0139 in this study. On the contrary, Vibrio cholerae 01 serotype Eltor Ogawa was isolated although the community declared the end of the cholera outbreak. This study pointed out the importance of establishing sanitary conditions and health education systems in Lao PDR.

Characterization of Aeromonas hydrophila: a comparative study of strains isolated from diarrheal feces and the environment.

Thirty-five strains of Aeromonas hydrophila isolated from feces of diarrheal patients and from the environments were collected from Thailand and Japan. The physiological, biochemical, and serological characteristics, antibiotic resistance patterns and cell surface-related properties were compared. The diarrheal and environmental isolates of A hydrophila were found to be remarkably consistent in general culture and biochemical characteristics, with the exception of the reaction to D-arabinose in which the diarrheal strains were positive and environmental strains were negative. The plasmid patterns and cell surface-related properties of the environmental and diarrheal isolates were different. All strains produced Vero cell cytotoxin, hemolysin and lecithinase at 37 degrees, 30 degrees and 15 degrees C. In contrast, 83% of the environmental strains produced these virulence factors even at 4 degrees C. All strains indicated almost uniform susceptibility to the 16 antibiotics tested. Variations were found in the plasmid profile, toxin production in relation to the differences of temperature and cell surface-related properties of the strains. These variations between the clinical and environmental isolates could have potential as epidemiological markers for the sources of strains.