Domestic River Water Use and Risk of Typhoid Fever: Results From a Case-control Study in Blantyre, Malawi

Abstract

Background Typhoid fever remains a major cause of morbidity and mortality in low- and middle-income settings. In the last 10 years, several reports have described the reemergence of typhoid fever in southern and eastern Africa, associated with multidrug-resistant H58 Salmonella Typhi. Here, we identify risk factors for pediatric typhoid fever in a large epidemic in Blantyre, Malawi. Methods A case-control study was conducted between April 2015 and November 2016. Cases were recruited at a large teaching hospital, and controls were recruited from the community, matched by residential ward. Stepwise variable selection and likelihood ratio testing were used to select candidate risk factors for a final logistic regression model. Results Use of river water for cooking and cleaning was highly associated with risk of typhoid fever (odds ratio [OR], 4.6 [95% confidence interval {CI}, 1.7–12.5]). Additional risk factors included protective effects of soap in the household (OR, 0.6 [95% CI, .4–.98]) and >1 water source used in the previous 3 weeks (OR, 3.2 [95% CI, 1.6–6.2]). Attendance at school or other daycare was also identified as a risk factor (OR, 2.7 [95% CI, 1.4–5.3]) and was associated with the highest attributable risk (51.3%). Conclusions These results highlight diverse risk factors for typhoid fever in Malawi, with implications for control in addition to the provision of safe drinking water. There is an urgent need to improve our understanding of transmission pathways of typhoid fever, both to develop tools for detecting S. Typhi in the environment and to inform water, sanitation, and hygiene interventions.

Meteorological and social conditions contribute to infectious diarrhea in China

“…The major concern about the water safety is water pollution 61 . Existing researches demonstrate that not only the polluted water for drinking, but also the polluted water for using can bring infectious diarrhea 42 , 52 , 53 . The water pollution may trigger diarrhea through pathogens contamination and cause physical function degeneration.…”

“…For instance, it has been found that medical and technical personnel per thousand persons were significantly negatively related to the risk of bacterial dysentery in Sichuan province of China 41 . Use of river water for cooking and cleaning was highly associated with risk of typhoid fever in Blantyre, Malawi 53 . Septic system densities were associated with infectious diarrhea in central Wisconsin 51 .…”

“…The first one is the resource of public health, like medical and technical personnel 41 , access of hygienic conditions 42 – 44 and nutrition status 45 – 49 . The second one is the safety of water, in particular, the quality and quantity of clean water available for cooking, drinking and washing 42 , 50 – 53 . The third one is the fecal contamination, like the septic system densities 51 , access to private sanitation 54 .…”

Optimized methods for detecting Salmonella Typhi in the environment using validated field sampling, culture and confirmatory molecular approaches

“…Whilst other studies have isolated S. Typhi from sewage and heavily contaminated domestic use water (Roy et al, 2016), here we present the first description for the isolation of S. Typhi from river water and river-borne environmental samples since the 1980s (Sears et al, 1986;Sears et al, 1984). We previously developed a methodology that places the genomes of clinically isolated organisms in the spatial context of human cases of infection to predict environmental hotspots of typhoid transmission (Gauld, 2020;Gauld et al, 2019). Geolocating the homes of typhoid fever patients allowed for the development of an optimized method for field sampling, targeting the environmental sampling in areas of known transmission and large numbers of cases.…”

A Bayesian approach for estimating typhoid fever incidence from large-scale facility-based passive surveillance data

“…In Malawi, the odds ratio for having typhoid fever was 2.0 (95% CI: 1.3-2.5) comparing those who did not use soap after defecation to those who did [20]. In Nepal, the odds ratio for having typhoid fever was 5.7 (2.3-14.4) comparing those who did not share a household latrine to those who did [21].…”