Peter Kjær Mackie Jensen

The microbiological quality of water is usually assessed by fecal coliform bacteria, and the presence of E. coli as an indicator of fecal contamination is widely recommended by international guidelines. This study aimed to assess the prevalence of diarrheagenic pathogens, in both public and personal domain water sources and examine the reliance on the WHO drinking water risk assessment guidelines. This study was conducted in a low-income urban community in Dhaka, Bangladesh between September 2014 and October 2015. Polymerase chain reaction (PCR) was used to detect the marker and virulence genes of Escherichia coli, Vibrio cholerae, Salmonella species, and Campylobacter species, and the culture method was employed for the quantitative assessment of E. coli. According to the WHO guidelines, 48% of the public domain source water and 21% of the personal domain point-of-drinking water were classified in the low-risk group, i.e., 0 CFU of E. coli/100 mL. However, when using PCR, we detected pathogens in 39% (14/36) of the point-of-drinking water samples and 65% (74/114) of the public domain water source samples classified in the low-risk group. Our study showed that relying solely on E. coli detection as a measure of water quality may overlook the presence of other pathogens in the drinking water. In addition to the culture-based method, the detection of virulence genes by PCR should also be considered to add more scrutiny to the detection of diverse types of pathogens.

The water sanitation and hygiene (WASH) sector has provided beneficiaries in low and middle-income countries with latrines and clean water for decades. However, we still need good evidence documenting the expected health impact. This paper investigates why we lack this evidence and ways to move forward. Using mTEC agar, we monitored E. coli contamination on selected “hotspot” surfaces within the kitchen environments of 32 low-income households in Dhaka, Bangladesh, every six weeks for two years. Despite being washed, the highest average contamination was found on food plates, at 253 cfu/10 cm², followed by cutting knives, with 240 cfu/10 cm². The drinking vessel surfaces and the latrine doorknobs had the lowest contaminations, with E. coli means of 167 and 73 cfu/10 cm², respectively. These findings imply a need to measure an individual’s pathogen exposure as close to the mouth as possible to estimate the true pathogen exposure. The paper proposes introducing the new “personal domain”—the point of consumption—as the physical sphere in which WASH interventions should be assessed. With this approach, we can observe and quantify the different pathogen exposure routes and, with this, further improve WASH interventions.

Most cholera outbreaks in Bangladesh are seasonal, peaking in the dry and post-monsoon periods. Therefore, we investigated whether changes in water, sanitation, and hygiene (WASH) behavior in three populations in Bangladesh during the year could help explain why these two periods are particular to cholera transmission. The study used a mixed-method design, including a repeated cross-sectional study, focus group discussions, and key informant interviews. Through a repeated cross-sectional study, WASH-related variables were assessed during the dry, monsoon, and control seasons in 600 households from coastal Satkhira, inland Sirajganj, and the Dhaka slums. Seasonal behavioral changes were observed in all study areas. Dhaka and Satkhira had an increased mean distance to water sources during the dry and monsoon seasons (Dhaka: control season, 12 m [95% CI, 11–13]; dry season, 36 m [95% CI, 18–55]; and monsoon season, 180 m [95% CI, 118–243]; Satkhira: control season, 334 m [95% CI, 258–411]; dry season, 669 m [95% CI, 515–822]; and monsoon season, 2,437 m [95% CI, 1,665–3,209]). The participants attributed this to pollution of the usual water source. Perceived water quantity was lowest during the dry season in Dhaka and Sirajganj, and during the monsoon season in Satkhira. Handwashing with soap declined in all areas during the dry and monsoon seasons. Open defecation was frequent among children younger than 5 years, increasing during seasonal climate hazards. Results show that WASH-related behavior changed seasonally, increasing the risk of cholera transmission through multiple hygiene-related transmission pathways. Future research would benefit by ensuring that the length of studies covers all seasons throughout the year and also by looking in more detail at people’s behavior and hygiene practices.

There is a paucity of recent research on direct water quantity measurement for personal and domestic hygiene. We aimed to measure the water quantity used for personal and domestic hygiene and to explore the reasons and determinants for variation of water usage. We conducted this study from September 2014 to June 2016 in a low-income urban community in Dhaka. In 12 households, the team conducted a day-long bimonthly ethnographic observation for one year to measure the volume of water used per activity per person. They conducted 28 in-depth interviews to explore the reasons for changes of water usage. Participants used a median of 75 L (61–100) of water per capita per day (LCPD) and of this 75 LCPD they used a median of 39 LCPD (26–58) for personal hygiene. Women used less water than men. Individual and social norms, beliefs, and weather determinants determined personal hygiene. Water availability determined domestic hygiene (e.g., washing dishes, toilets and bathrooms). This study helps to elucidate a range of determinants of water usage of the participants from the participants’ perspective. The quantity of water used for domestic and personal hygiene and its relationship to fecal-oral transmitted disease can be explored in future research.

Improving hygiene practices is considered to be the single most cost-effective means of reducing the global health burden of infectious diseases. Hygiene promotion and disease prevention interventions often portray and promote “hygiene” from a biomedical perspective, which may not be optimally effective for achieving their goal of changing people’s behaviors. This study aimed to educe the meaning of hygiene for the residents of a low-income community in Bangladesh and how that meaning shapes their personal hygiene practices. We conducted this study in the Tongi township in Dhaka, Bangladesh, from September 2014 to June 2016. The research team purposively selected 24 households. The team conducted day-long observations using the participant observation approach and in-depth interviews with specific members of the 24 households. The concept of “hygiene” had two separate meanings to the study participants: cleanliness and holiness. The participants reported that cleanliness was required to remove odors, grease, hot spices and dirt. The motivation for cleanliness was to feel fresh, avoid heavy feelings, feel light and feel comfortable. To maintain the holiness of the body, bathing and ablution needed to be performed following particular religious rules/rituals. The motivation of holiness was derived from their accountability to God. The participants also reported that the cleansing processes and methods for the body and the home for cleanliness reasons were also different from those for holiness reasons. The notion of “hygiene” was multidimensional for the residents of the low-income urban community in Bangladesh. Our study participants did not explicitly conceptualize a notion of hygiene that was based on the germ theory of diseases but rather a notion that was based on individual physical comfort and cultural belief systems. Future studies on the prevention of hygiene-related diseases should combine and link the biomedical aspect to religious and cultural rituals to promote improved hygiene practices.

The minimal health impact observed in large-scale water sanitation and hygiene (WASH) intervention studies motivated us to investigate the contribution of contaminated food and drinking water to the total daily Escherichia coli load ingested by the average adult in a low-income, urban area. Leftover food (food left at room temperature for more than 6 hours) from 32 households was collected eight times at 6-week intervals in 2014–2015 in the low-income area of Arichpur, Dhaka, Bangladesh. In total, 117 samples were obtained from four food types: fish, lentils, rice, and vegetables, which comprise approximately 85.2% of the average adult’s personal daily food consumption. Samples were analyzed for E. coli using selective chromogenic media. For an average adult, the daily consumption of the four food types at mean contamination levels of E. coli can contribute 4.45 log colony-forming units (cfu)/day (95% confidence interval 4.06–4.84). Drinking water quality was measured 211 times at the point of drinking, with a mean, median, and maximum contamination of 1.9, 1.2, and 2.82 log E. coli cfu/100 mL, respectively. If the typical adult in Arichpur were able to drink water with 0 E. coli cfu/100 mL, it would only remove < 5.2% of the total E. coli ingested per day with a mean-contaminated diet. These approximations may suggest why insignificant effects have been observed for water quality interventions in similar, low-hygiene settings. In Arichpur, the E. coli contribution from drinking water to the total E. coli load was insufficient to exert a substantial effect.

This study aimed to investigate the origin of diverse pathotypes of E. coli, isolated from communal water sources and from the actual drinking water vessel at the point-of-drinking inside households in a low-income urban community in Arichpur, Dhaka, Bangladesh, using a polymerase chain reaction (PCR). Forty-six percent (57/125, CI 95%: 41−58) of the isolates in the point-of-drinking water and 53% (55/103, CI 95%: 45−64) of the isolates in the source water were diarrheagenic E. coli. Among the pathotypes, enterotoxigenic E. coli (ETEC) was the most common, 81% (46/57) of ETEC was found in the point-of-drinking water and 87% (48/55) was found in the communal source water. Phylogenetic group B1, which is predominant in animals, was the most frequently found isolate in both the point-of-drinking water (50%, 91/181) and in the source (50%, 89/180) water. The phylogenetic subgroup B2₃, usually of human origin, was more common in the point-of-drinking water (65%, 13/20) than in the source water (35%, 7/20). Our findings suggest that non-human mammals and birds played a vital role in fecal contamination for both the source and point-of-drinking water. Addressing human sanitation without a consideration of fecal contamination from livestock sources will not be enough to prevent drinking-water contamination and thus will persist as a greater contributor to diarrheal pathogens.

Cholera, a devastating diarrheal disease that caused several global pandemics in the last centuries, may share some similarities with the new COVID-19. Cholera has affected many populations in history and still remains a significant burden in developing countries. The main transmission route was thought to be predominantly through contaminated drinking water. However, revisiting the historical data collected during the Copenhagen 1853 cholera outbreak allowed us to re-evaluate the role of drinking-water transmission in a city-wide outbreak and reconsider some critical transmission routes, which have been neglected since the time of John Snow. Recent empirical and cohort data from Bangladesh also strengthened the dynamic potentiality of other transmission routes (food, fomite, fish, flies) for transmitting cholera. Analyzing this particular nature of the cholera disease transmission, this paper will describe how the pattern of transmission routes are similar to COVID-19 and how the method of revisiting old data can be used for further exploration of new and known diseases.

The illness cost borne by households, known as out-of-pocket expenditure, was 74% of the total health expenditure in Bangladesh in 2017. Calculating economic burden of diarrhea of low-income urban community is important to identify potential cost savings strategies and prioritize policy decision to improve the quality of life of this population. This study aimed to estimate cost of illness and monthly percent expenditure borne by households due diarrhea in a low-income urban settlement of Dhaka, Bangladesh. We conducted this study in East Arichpur area of Tongi township in Dhaka, Bangladesh from September 17, 2015 to July 26, 2016. We used the World Health Organization (WHO) definition of three or more loose stool in 24 hours to enroll patients and enrolled 106 severe patients and 158 non-severe patients from Tongi General Hospital, local pharmacy and study community. The team enrolled patients between the first to third day of the illness (≤ 72 hours) and continued daily follow-up by phone until recovery. We considered direct and indirect costs to calculate cost-per-episode. We applied the published incidence rate to estimate the annual cost of diarrhea. The estimated average cost of illness for patient with severe diarrhea was US$ 27.39 [95% CI: 24.55, 30.23] (2,147 BDT), 17% of the average monthly income of the households. The average cost of illness for patient with non-severe diarrhea was US$ 6.36 [95% CI: 5.19, 7.55] (499 BDT), 4% of the average monthly income of households. A single diarrheal episode substantially affects financial condition of low-income urban community residents: a severe episode can cost almost equivalent to 4.35 days (17%) and a non-severe episode can cost almost equivalent to 1 day (4%) of household’s income. Preventing diarrhea preserves health and supports financial livelihoods. The illness cost borne by households, known as out-of-pocket expenditure was 74% of the total health expenditure in Bangladesh in 2017. Most of the studies in Bangladesh that estimated the cost of diarrheal illness collected data from hospital patients and mostly targeted under-five children. Information on economic burden of diarrhea borne by households of low-income urban communities who commonly had ≤ 2 US$ dollar income per capita per day still remained unknown. We conducted this study in East Arichpur area of Tongi township in Dhaka, Bangladesh from September 2015 to July 2016 to estimate cost of illness and monthly percent expenditure borne by households due diarrhea in a low-income urban settlement of Dhaka, Bangladesh. The estimated average cost of illness for patient with severe diarrhea was US$ 27.39 (2,147 BDT) and non-severe diarrhea was US$ 6.36 (499 BDT). A single diarrheal episode substantially affects financial capability of the low-income urban community: a severe episode can cost 4.35 days (17%) and a non-severe episode can cost 1 day (4%) of income of a households. Preventing diarrhea preserves health and supports financial livelihoods.

This study collected rectal swabs from diarrheal patients and in-house environmental samples from low-income households in Dhaka City, Bangladesh, over a 4-month period and investigated these to determine the domestic transmission pathways of Escherichia coli-associated diarrhea. The environmental samples included swabs from four frequently touched surfaces, drinking water and food. Both the rectal swabs and environmental samples were examined for virulence genes characteristic of diarrheagenic E. coli pathotypes by PCR. In addition, each sample was cultured for E. coli, and the strains were analyzed for virulence profile and subjected to multilocus sequence typing (MLST). The results showed that 31% (73 of 233) of all samples including rectal swabs and household samples were positive for one or more of the diarrheagenic E. coli virulence factors. PCR analyses showed that 28% (10/36) of the rectal swabs, 43% (58/136) of household swabs, 9% (3/32) of the food, and 7% (2/29) of the water samples were positive for various virulence genes. 6 Out of the 36 rectal swab samples and associated household samples were shown to have similar E. coli pathotypic genes, and the drinking vessel surface was identified as the major source of contamination. EAEC and CTEC were the most commonly identified pathotypes in the cultured isolates. The phylogenetic tree constructed by MLST data showed that the diarrheagenic isolates were clustered in several diversified lineages. This study supports the hypothesis that there are high-risk hotspots, particularly those surfaces associated with food consumption, for diarrheagenic E. coli contamination within the household environments of Bangladesh.