Factors Associated with Emergence and Spread of Cholera Epidemics and Its Control in Sarawak, Malaysia between 1994 and 2003

Abstract

Cholera is a water and food-borne infectious disease that continues to be a major public health problem in most Asian countries. However, reports concerning the incidence and spread of cholera in these countries are infrequently made available to the international community. Cholera is endemic in Sarawak, Malaysia. We report here the epidemiologic and demographic data obtained from nine divisions of Sarawak for the ten years from 1994 to 2003 and discuss factors associated with the emergence and spread of cholera and its control. In ten years, 1672 cholera patients were recorded. High incidence of cholera was observed during the unusually strong El Niño years of 1997 to 1998 when a very severe and prolonged drought occurred in Sarawak. Cholera is endemic in the squatter towns and coastal areas especially those along the Sarawak river estuaries. The disease subsequently spread to the rural settlements due to movement of people from the towns to the rural areas. During the dry seasons when tributary gravity fed tap waters cease to flow, rural communities rely on river water for domestic use for consumption, washing clothes and household utensils. Consequently, these practices facilitated the spread of water borne diseases such as cholera. The epidemiologic and demographic data were categorized according to ethnic group, gender, occupation, and age of the patients. Large outbreaks occurred in north Sarawak (Bintulu, Miri, and Limbang) rather than the central (Kapit, Sarikei, Sibu)and south (Kuching, Samarahan, Sri Aman). The indigenous people, the Orang Ulu and the Iban live in longhouses built along the rivers in the low-lying areas. Whereas the Malays live in coastal areas that eat traditional uncooked seafood causing frequent water-borne infections. Data analysis showed a high incidence of cholera among low-income laborers and rural house wives as opposed to the well paid workers from government and private sectors. Infants and non-school children were 15% of the cases. This suggests household transmission widely occurs. Two cholera cases infecting cooks in a school canteen revealed poor hygiene during food preparation resulting in 229 infections of school children. The majority of the patients were the active adult group from 19 to 59 years. This finding was typical of many food-borne outbreaks where adults gathered to attend festive parties or funeral feasts. Various intervention activities and preventive measures such as surveillance, quarantine, treatment, monitoring and improving community sanitation, and health education of poor communities were performed by the Health Department and the local authorities during and after the major 1997-99 epidemics. These measures effectively prevented the emergence and spread of further epidemics.