Availability of safe drinking-water: the answer to cholera outbreak? Nabua, Camarines Sur, Philippines, 2012

• Main Authors: Alethea De Guzman, Vikki Carr de los Reyes, Ma Nemia Sucaldito, Enrique Tayag
• Format: Article
• Language: English
• Published: World Health Organization Regional Office for the Western Pacific 2015-08-01
• Series: Western Pacific Surveillance and Response
• Subjects: safe drinking-water; cholera outbreak; Camarines Sur-Philippines
• Online Access: http://ojs.wpro.who.int/ojs/index.php/wpsar/article/view/301/531
• ISSN: 2094-7321; 2094-7313

Background: In May 2012, there were increasing diarrhoea cases and deaths reported from Nabua, Camarines Sur to the Philippines event-based surveillance system. An investigation was conducted to identify risk factors and determine transmission dynamics. Methods: A suspected case was defined as a resident of Nabua with at least three episodes of watery diarrhoea per day from 16 March to 22 June 2012. A confirmed case was defined as a suspected case positive for Vibrio cholerae. An environmental investigation was conducted and rectal swabs and water samples sent to the national reference laboratory for bacterial isolation. A 1:2 case-control study matching for age and sex was conducted. Data were analyzed using Epi Info. Results: There were 309 suspected cases with two deaths, and the most affected age group was children under five years (45%). Eight cases were positive for Vibrio cholerae Ogawa El Tor and one for Non-01. Water samples were positive for faecal coliforms and Aeromonas caviae. The case-control study showed that cases had a higher odds than controls of using unchlorinated water sources (odds ratio [OR] = 3.6; 95% confidence interval [CI]:1.6–8.5) and having toilets located within 20 metres of a septic tank (OR = 2.7; 95% CI: 1.4–5.3). In multivariate analysis, the only significant factor was drinking from piped water (OR = 0.21; 95% CI: 0.09–0.49). Discussion: In this cholera outbreak, drinking-water from unchlorinated wells was a significant risk factor. Future cholera control efforts should include not just improving water and sanitation systems but also intensified behaviour change campaigns.