Dengue Risk Factors and Community Participation

To look for risk factors for dengue and community participation in dengue control in Binh Thuan Province, Vietnam, three communes with a low incidence of dengue and three with a high incidence, in Binh Thuan Province, were compared. Knowledge, perception and preventive practice of dengue were measured by means of a structured questionnaire. A check list of environmental observations was used to evaluate environmental factors. Focus group discussion was conducted to evaluate perceptions of key factors for dengue vector control and community participation. One hundred ninety households in 6 communes were included in the study. Several statistically significant differences between low and high incidence communities were identified. The factors associated with a higher risk of dengue fever on the logistic regression were occupation (farmer) (RR 7.94; 95%CI 2.29-27.55), number of children less than 15 years old in the household (RR 1.54; 95%CI 1.06-2.23), no experience with dengue fever in the household (RR 2.334; 95%CI 1.124.88), a garden near the house (RR 2.22; 95% CI 1.18-4.17) and water containers having mosquito larvae (RR 1.64; 95%CI 1.02-2.62). Television was the most important source of information. There were differences in risk factors for dengue among communes with low and high incidences. Communication regarding dengue prevention should be improved in high incidence communes. Community participation in dengue vector control should be promoted to make the dengue control programs more efficient with greater coordination of resources. cases (439 cases/100,000 population) and 342 deaths (Ha et al, 2000). In a recent study we showed the incidence of primary infections has been quite stable over the past decade (Thai et al, 2005). In 2002, 31,754 cases with 52 deaths were reported in southern Vietnam. In 2003, these numbers were 31,754 and 72, respectively (WHO, 2004, 2005). Since then, the National Dengue Fever Control Program was launched in Vietnam. This program aims to promote health education and communication, strengthen the role and responsibilities of steering committees at different levels and to improve surveillance, early diagnosis and treatment. INTRODUCTION Dengue fever and dengue hemorrhagic fever (DF/DHF) are among the leading causes of disease in Vietnam. Since 1963, the number of reported cases has steadily increased. During the dengue pandemic of 1998, 1.2 million cases were reported in 56 countries, southern Vietnam was severely hit with 234,866 reported SOUTHEAST ASIAN J TROP MED PUBLIC HEALTH 80 Vol 39 No. 1 January 2008 Similar to when Surgeon General William Crawford Gorgas (http://history.amedd. army.mil/tsgs/Gorgas.htm) tried to change undisciplined domestic behavior in workers on the Panama canal, a top down approach to public health services to control the aedes mosquito is not always popular and nearly unfeasible in large urbanized areas. Community participation is therefore pivotal for effective dengue vector control (Parks and Lloyd, 2004). It is surprising to realize that in Vietnam, where community participation has always been such a strong component of the public health services, a national dengue control program was launched significantly later than in surrounding countries (Cheng, 2005; Phuanukoonnon et al, 2005) while the National Malaria Control Program, initiated in 1992, received compliments for being so successful (Hung et al, 2002; Nam et al, 2005). The main reason was the mortality rate of malaria dictated prioritization over dengue, as well as the different social and political determinants of dengue and malaria vector control. In Asia, anopheles mosquitoes live mainly in forested areas, and malaria is typically a disease that “descends out of the dark” (of the forest) on poor inhabitants of rural and forested areas. In contrast, aedes thrives on the small improvements in housing that people make following economic progress, such as replacing a thatched roof with a corrugated roof with gutters and barrels to collect water. To a certain extent, dengue transmission is a consequence of human behavior and therefore its control requires strong community participation. In Binh Thuan Province, southern Vietnam, dengue fever is responsible for one-third of cases of acute undifferentiated fever (Phuong et al, 2006b). The estimated annual incidence of cases of dengue fever in this province is 11.7% (Thai et al, 2005). Cases of complicated dengue are routinely notified to the Provincial Center for Preventive Medicine, mostly without laboratory confirmation. The annual incidence of notified cases of complicated dengue fever varied in communities from 0.2/1,000 to 7.9/1,000 population between 1999 and 2003. To investigate household conditions, knowledge and perceptions about dengue, which are possible determinants of community participation in dengue control, we conducted this study. The differences were observed in these incidence data between communities provided the opportunity to analyse risk factors by comparing communities with high and low incidence data. MATERIALS AND METHODS Study site and population The study was performed in Binh Thuan Province with a population of 1.12 million persons, in 206,748 households, in an area of 7,992 km2. The reported DF/DHF incidences for the years 1999 through 2003 are shown in Fig 1. Incidence data over these years were averaged and six communities (three with high mean incidence data and three with low mean incidence data), that were more or less equally accessible for household surveys, were selected and compared. Cooperation by local authorities was also an additional criterion for selection. A low incidence community was Fig 1–Incidence of complicated dengue in Binh Thuan Province from 1999 to 2003. 900,000 950,000 1,000,000 1,050,000 1,100,000 1,150,00