We visited houses and inspected water-holding containers to determine the potential risks of dengue transmission during different seasons. This survey was conducted in 2 neighbourhoods of Nha Trang City in July and December 2006, which correspond to the middle of the hot-dry season and the beginning of the cool-wet season, respectively. We inspected a total of 1,438 wet containers in 196 premises during both survey periods; 20% of the containers were positive for Aedes aegypti larvae and 8% for Ae. aegypti pupae. Indoor water-holding containers, which were sparsely distributed, exhibited high pupal productivity and efficiency (pupal productivity of a type of container/prevalence of that type of container) in either the first survey conducted in July, or the second, conducted in December. Although rainfall may not influence the number and distribution of water-holding containers in the city, the high average temperature in the first survey period resulted in a higher potential risk of dengue transmission.Our analysis suggests that if intensive source reduction is conducted in summer and containers with high pupal productivity and efficiency are targeted, the risk of dengue transmission in the city could be effectively reduced.
Abstract. To determine the effect of peridomestic environments on Aedes aegypti infestation in urban premises, we conducted two consecutive surveys in the hot-dry and cool-wet seasons. Most Ae . aegypti pupae (79%) were recovered from premises where preadult forms (larvae and/or pupae) had been detected in both surveys. Hence, repeated infestation appears to be a useful parameter to identify premises associated with a high potential risk of dengue transmission. Multivariate analysis revealed that not only the persistent presence of containers discarded outdoors, wells, large plastic buckets, jars, and concrete toilet basins in the premises (adjusted odds ratios [aORs] = 63.3, 23.3, 22.5, 6.6, and 5.6, respectively) but also the presence of six or more residents was significantly associated with repeated infestation (aOR = 6.1). Premises with six or more residents along with specific container types from which a large number of pupae were recovered should be targeted in dengue-control programs.
Dengue is at risk of being underestimated and chikungunya is not systematically detected. Changes in detection and surveillance procedures are therefore discussed to increase efficiency of dengue detection and continue the monitoring the emergence of CHIKV in Dong Thap province and in Vietnam.
There is a positive correlation between the population density of A. aegypti and the number of human cases and duration of outbreaks. This was not observed for Aedes albopictus. Three pools of A. aegypti were positive with dengue virus, two with DENV-1 and one with DENV-2.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.