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

Abstract

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.

Nonnative Cattle Ownership, Diet, and Child Height-for-Age: Evidence from the 2011 Uganda Demographic and Health Survey

“…47,48 Child exposure to animal fecal contamination within the living environment has been reported in studies from Zimbabwe, 13 Peru, 49 and Bangladesh. 12,50 Since information on animal corralling was not collected as part of the 2011 UDHS, we were unable to examine these relationships in more detail.…”

“…10 In nonindustrialized countries, where the majority of rural and urban households raise livestock, 11 a potential route for the transmission of infectious diarrhea from animals to humans is through contact with the feces of domestic animals. 12,13 Infants and young children may be especially vulnerable to ingesting pathogens when playing in and around households contaminated with the feces of domestic animals. 14 Until recently, there was little evidence on the relationship between the presence of domestic animals in the household and child health.…”

Quantitative assessment of fecal contamination in multiple environmental sample types in urban communities in Dhaka, Bangladesh using SaniPath microbial approach

“…A laboratory supervisor received the environmental samples within 4 hours of collection and analyzed the samples for E. coli using the IDEXX-Quanti-tray ® 2000 technique with Colilert-24 media (IDEXX Laboratories, Westbrook, Seattle, WA) [31] to quantify the most probable number (MPN) of E. coli per unit of sample. E. coli is commonly used as an indicator of fecal contamination in water, food, and environmental samples [13,32,33]. We chose to use E. coli to allow for comparison with other studies.…”

“…Limited studies have been conducted to quantify levels of fecal contamination in different environmental compartments in urban Dhaka [12][13][14][15]. Direct ingestion of fecal contamination through contaminated drinking water has been studied extensively both at household and community levels in urban Bangladesh by measuring fecal indicator bacteria [16][17][18][19].…”

“…Direct ingestion of fecal contamination through contaminated drinking water has been studied extensively both at household and community levels in urban Bangladesh by measuring fecal indicator bacteria [16][17][18][19]. Other exposure pathways in urban Bangladesh, including contaminated soil [13], market produce [12], and street food [14] have been linked to adverse health outcomes such as diarrhea, environmental enteric dysfunction, and stunting [20,21]. Yet the contribution of these pathways to total fecal exposure remains understudied.…”