Ruminants Contribute Fecal Contamination to the Urban Household Environment in Dhaka, Bangladesh.

Environmental science & technology

PubMedID: 27045990

Harris A, Pickering AJ, Harris M, Doza S, Islam MS, Unicomb L, Luby S, Davis J, Boehm AB. Ruminants Contribute Fecal Contamination to the Urban Household Environment in Dhaka, Bangladesh. Environ Sci Technol. 2016;.
In Dhaka, Bangladesh, the sensitivity and specificity of three human, three ruminant, and one avian source-associated QPCR microbial source tracking assays were evaluated using fecal samples collected on site. Ruminant-associated assays performed well, whereas the avian and human assays exhibited unacceptable cross-reactions with feces from other hosts. Subsequently, child hand rinses (n = 44) and floor sponge samples (n = 44) from low-income-households in Dhaka were assayed for fecal indicator bacteria (enterococci, Bacteroidales, and Escherichia coli) and a ruminant-associated bacterial target (BacR). Mean enterococci concentrations were of 100 most probable number (MPN)/2 hands and 1000 MPN/225 cm(2) floor. Mean concentrations of Bacteroidales were 10(6) copies/2 hands and 10(5) copies/225 cm(2) floor. E. coli were detected in a quarter of hand rinse and floor samples. BacR was detected in 18% of hand rinse and 27% of floor samples. RESULTS
suggest that effective household fecal management should account not only for human sources of contamination but also for animal sources.The poor performance of the human-associated assays in the study area calls into the question the feasibility of developing a human-associated marker in urban slum environments, where domestic animals are exposed to human feces that have been disposed in pits and open drains.