An assessment of latrine front-end characteristics and associated surface E. coli indicated faecal contamination in rural Fiji

Abstract

In Fiji, 90% of the population has access to basic sanitation; however, there are still persistent health risks from endemic faecal-oral diseases such as typhoid fever. There is a need to assess the contribution of existing sanitation facilities in the faecal pathogen transmission pathway. This study was conducted as part of a larger planetary health study across 29 rural communities within five river catchments. This specific research aimed to characterise latrine front-ends, both infrastructure and usage behaviour, and to assess the faecal contamination levels on various frequently contacted latrine surfaces in rural Fiji. A sanitation survey, along with observation and latrine swab sampling, was conducted in households over three phases: baseline (n = 311) (Aug-Dec 2019), endline (n = 262) (Jun-Sep 2022) and an in-depth front-end study (n = 12) (Oct-Nov 2022). Of 311 households, almost all had pedestal-type latrines, predominately cistern-flush (83%), followed by pour-flush (13%), and then hole-type (pit) latrines (4%). Washable latrine floors had significantly higher E. coli densities (6.7 × 10² CFU/25 cm²) compared to non-washable floors (1.3 × 10² CFU/25 cm²) (p = 0.05), despite washable floors indicating improved latrines. The in-depth front-end analysis found that moist latrine surfaces had significantly elevated E. coli densities (1.2 × 10³ CFU/25 cm²) compared to the dry ones (14.3 CFU/25 cm²) (p < 0.001), highlighting the importance of maintaining dry latrine surfaces. Latrine floors and mid-walls were the most frequently contaminated surfaces, emphasising the need to clean and disinfect these surfaces. Only 46% of the households reported always using soap for handwashing after defecation, exacerbating the risk of transmitting faecal pathogens. This study highlights that latrine cleanliness and hygiene are as crucial as latrine infrastructures for the effective disruption of faecal pathogens transmission during latrine use.

Keywords: Faecal pathogen transmission pathways; Frequent human contact surfaces; Latrine surfaces; Latrine usage behaviour; Microbial risks; Pacific Islands; Sustainable Development Goal 6.

Fig. 1

Overview of latrine swab collection process for assessing faecal contamination levels on latrine front-end surfaces in rural Fiji included in this study

Fig. 2

In-depth front-end sampling locations of a cistern-flush latrine at Natadradave, Dawasamu, catchment. The yellow circles with numbers represent the sampling locations

Fig. 3

Latrine front-end types based on flush mechanisms observed in rural Fiji

Fig. 4

E. coli density on latrine floors (CFU/25 cm²) with a total of 142 latrine floor swabs from baseline and endline study compared to latrine front-end characteristics. The box plot represents the median, quartiles, outlier (grey dots) and mean ( ×). a E. coli and type of latrine floors; b E. coli and latrine front-end flush type; c E. coli and latrine ownership (one missing data); d E. coli and latrine location with reference to households (one missing data); e E. coli and the number of users per latrine (one missing data); f E. coli and reported diarrhoea by the household in the previous month (two missing data). The lower limit of detection is 1.0 CFU/25 cm². Non-detects were substituted with half of the lower limit of detection values. The E. coli densities data presented are raw continuous data

Fig. 5

E. coli density (CFU/ 25 cm²) on various sampling locations of 12 household latrines, including outside door (n = 12), inside door (n = 12), latrine floor (n = 12), latrine cover (n = 9), latrine seat (n = 12), flush button (n = 6), mid-wall (n = 12) and lower wall (n = 12). The mean is represented by ( ×) for each surface. The lower limit of detection is 1.0 CFU/25 cm². Non-detects were substituted with half of the lower limit of detection values. The E. coli density data presented are raw continuous data