Dengue and dengue and vector behaviour in Cáqueza, Colombia, 2004.

Abstract

OBJECTIVE: Describing the behaviour of dengue and its vector in Cáqueza, Colombia (1746 masl) by serological, entomological and virological monitoring between March and June 2004. METHODS: Two types of study were carried out. One was a cross-sectional study for serologically monitoring the population and taking entomological indicators; participants were selected from the general population by random conglomerate sampling. The second study consisted of monitoring febrile cases suspected of dengue during a four-week period. Vector behaviour (bite-rate and hours of activity) was also included by using the landing-on-humans technique; a rubbish-collecting day was run during the same period for evaluating this intervention's short-term effectiveness. RESULTS: Total prevalence of infection by dengue (IgG positive) was 23.3% in 252 people examined in the surveyed population. Household infestation index was 32.9%; deposit index was 8.4%; and Breteau index was 43.9. Following the rubbish-collection day, the infestation index became reduced by 56% (14.5% post-intervention), deposit index by 43% (4.8% post-intervention) and Breteau index by 59% (17.9% post-intervention). Two of the febrile patients (n=83) were IgM positive. CONCLUSIONS: The study showed that dengue's urban vector can reach dangerous levels of infestation above 1700 masl; however, a deeper study of its bionomy is needed at these heights above sea-level during different times of the year for improving knowledge regarding climatic and environmental factors affecting their efficiency as vector in these conditions.