Dengue risk factors and community participation in Binh Thuan Province, Vietnam, a household survey.

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 1.12- 4.88), 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.

Anemia, malaria and hookworm infections in a Vietnamese ethnic minority.

The aim of this study was to determine the prevalence of anemia and evaluate the relationship of malaria and helminth infections on anemia status in Phan Tien village, a mountainous ethnic minority community in southern Vietnam. This longitudinal study was performed from April 1997 to 2000 by measuring the hemoglobin concentration of 2,767 people who participated in six annual surveys at the end of the rainy seasons. Ferritin concentration was measured in 2000 to evaluate the proportion of iron deficiency anemia. The relation between malaria and intestinal helminth infections with anemia was investigated. Anemia was always over 43% and mainly associated with iron deficiency (80.1%). Using generalized estimating equations, a small but significant decline of the anemia prevalence was detected (OR: 0.805; p < 0.0001). Malaria was significantly associated with anemia (OR: 2.408; p = 0.0006). There was no significant effect of the control of intestinal helminth infections on the time course of anemia (95% CI: -0.1548 to 0.1651).

Intestinal helminth infection in an ethnic minority commune in southern Vietnam.

A program to control intestinal helminth infections, based on stool surveys, mass treatment of children below 17 years, improvement of sanitation and health education was performed between 1997 and 1999 in Phan Tien, an ethnic minority community in mountainous southern Vietnam. Before intervention, 28.6% of children excreted eggs of at least one parasite, hookworm being the most common (23%), followed by Trichuris trichiura (1.9%), Hymenolepis nana (1.9%), Enterobius vermicularis (0.9%), Ascaris lumbricoides (0.5%), and multiple kinds of helminthes (0.5%). Strongyloides stercoralis was never detected. Poor sanitation and personal hygiene, and walking barefoot were considered the main risk factors for intestinal helminth infections. The success of 400 mg albendazole single dose mass treatment was initially frustrated by the poor quality of the drug formulation used, only containing half of the indicated amount of albendazole. Using another formulation quickly reduced the hookworm infection rate. Praziquantel was used to treat H. nana infections. After three years of intervention, intestinal helminth infections were reduced to 3.3% (p<0.0001). We conclude that interventions combining health education, improvement of sanitation and mass treatment effectively control intestinal helminth infections, but the quality of the drugs used is an important factor.