Assessment of environmental factors associated with endemic cholera in Lukanga swamps of Kapiri Mposhi District in Central Province of Zambia

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Sikwiiya, Simeon
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University of Zambia
Cholera, an acute diarrheal disease, caused by the bacteria Vibrio cholerae and is usually transmitted through water or food contaminated with faecal matter. This study assessed the environmental factors associated with endemic cholera in Lukanga Swamps from 2010 to January, 2018. This was a Time Series Correlational Study design. The data on cholera cases was collected from Kapiri Mposhi DHIS and outbreak line listing database system. Air temperature and precipitation data was collected from 19 lagoons using satellite remote sensing from 2010 to 2016. Water samples for analysis were collected from 19 Lagoons of the Lukanga Swamps. Data was analysed in Stata Version 14 and the results from standard poison regression (PR) model were compared with those obtained from Zero-inflated negative binomial regression (ZINBR) using Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC) to determine the best fit model and ZINBR fitted the data well. The study revealed that there were 133 cholera cases in the period under study and that cholera broke out mainly during the dry season between the months of May and October. Air temperature from January, 2010 to December, 2016 in the Lukanga Swamps ranged from 16oc and 28oc and the lowest was in the month of June, 2010 while the highest was in October, 2016. Precipitation had a wider range from as low as 0.05mm in April, 2016 to as high as 248mm in December, 2013. The study also found that increased rainfall was associated with decreased risk of cholera cases (IRR = 0.992, 95% CI: 0.988 – 0.997, P=0.002). The study found that one degree increase in temperature increases the risk of cholera cases by 27% and was statistically significant with ( IRR = 1.265, 95% CI: 1.142 – 1.402, P= 0.0001). Water quality monitoring tests from 19 lagoons revealed that 19/36 (53%) of water samples had faecal coliforms. The study further revealed pH range of 7.1 to above 8.5. No V. cholerae from the 164 water samples was isolated. The results have shown that air temperature was strongly associated with cholera outbreaks in the Lukanga Swamps and it showed ability in predicting these outbreaks with a lag time of two months prior to temperature rise. The study also revealed that increased amount of rainfall was associated with decreased risk of cholera cases. The microhabitat conditions were promotive of the V. cholerae growth in the swamps. Therefore, a multifaceted approach and combination of surveillance, water, sanitation and hygiene, social mobilization and water treatment should be used to prevent and control cholera in Lukanga Swamps. Keywords: Endemic cholera, Environmental factors, Lukanga Swamps
Endemic cholera , Environmental factors , Lukanga Swamps