Drinking Water Quality and Human Dimensions: a case study of the 2017 - 2018 cholera outbreak in Karonga, Malawi

Abstract

The aim of this study was to assess drinking water source quality and human dimensions: a case study of the 2017–2018 cholera outbreak in Karonga, Malawi. The study analysed 120 drinking water samples using standard methods and survey data linked to 236 cholera patients. Kruskal-Wallis One-way Analysis of Variance (ANOVA); One sample T-test, Mann Whitney test, Chi-square test and descriptive statistics were used to analyse data. Results showed that many samples (98/120) met the Malawi Bureau of Standards (MBS) criteria for thermotolerant coliforms of 50 cfu/100 ml, while half (60/120) met the more stringent World Health Organization (WHO) criteria of 0 cfu/100 ml. Microbiological quality of water was in the range of 0 to >200 cfu/100ml. Majority of the samples were within MBS limits for pH (93%) and turbidity (89%). All the samples were within MBS and WHO limit for Total Dissolved Solids (TDS) while majority of the samples were within WHO limit for EC (91%). Physico-chemical quality results were in the following ranges: 6 - 9.98 (pH); <5 ->500 JTU (turbidity); 18.8 - 1393μS/cm (electrical conductivity); 9.40 - 696.5 mg/l (TDS) and 0.02 - 0.70 PSU (salinity). About 70% of respondents reported to have treated their water, and knowledge of prevention, transmission and treatment of cholera was generally high (67%, n = 236). A few patients (38%, n = 32) who had poor drinking water source quality (>200cfu/100ml) reported feeling no risk of contracting cholera in the future. There was a significant correlation (p = 0.046) between the number of assets owned by a household and water treatment practice at household level (r = -0.148). The increase in number of households which did not practice water treatment corresponded with a decreased in number of assets. To control and eliminate the risk of cholera there is a need to promote household water treatment using chlorine, behavioural change interventions accounting for social and cultural norms and provision of potable water sources for the 22 geographic areas which had drinking water of poor quality.