The study was conducted at five communes from regions (Hµ T©y, Thõa Thiªn HuÕ, §µ N½ng, Kh¸nh Hßa, and Kiªn Giang province). The results indicated that the key breeding places of Aedes aegypti is different from region to region. In the Northern field trial, key breeding sites of Aedes aegypti are concrete tanks (65.6%); aquarium tanks (10.0%); and flower vases (15%). In the Central region, key breeding sites of Aedes Aegypti are wells, drums, ant traps, aquariums, toilette tanks. In the South, Aedes aegypti larvae are concentrated in big-size jars (67%), small-breeding sites of dengue vectors was changed after applying the intervention methods. It is clearly that the identification of key breeding places of Aedes aegypti are useful to propose the appropriate, effective control methods, and to evaluate the success of intervention measures.
Dengue ; Aedes ; Dengue Hemorrhagic Fever

From 1994 to 1997, 6747 water containers have been investigated on type, volume, number of Aedes larvae living in. The result showed that 6 types of water containers being breeding sites of Ae.aegypti were drums (38.4%), concrete tanks (26.2%), jars (26%), discarded object (5.1%), aquarica (3.5%) and buckets (0.4%). Ae.aegypti was dominants species in this area (87.2% of total 47.479 Aedes larvae collected) and its key breeding places was big containers drums, tanks and jars (91.7% Ae.aegypti larvae in these containers). There was no significant change on the type of breeding site by month, but the number of larvae increases 2.2 times higher in the rainy season compared with this of the rest of the year
Larva ; Breeding ; Water

A prospective case–control study was conducted in urban districts in Hanoi, northern Vietnam to evaluate the effect of migration on the risk of hospitalisation for dengue in a Vietnamese urban population. We enrolled laboratory-confirmed dengue patients aged >18 years who were hospitalised in local hospitals in November and December 2010. Four neighbourhood-matched controls for each case were recruited within a week of hospitalisation. Sociodemographic data were collected by interviews, and the number of immature and adult mosquitoes within household premises was counted by entomological survey. Matched-pair analyses were conducted using conditional logistic regression models. Among 43 cases and 168 controls, 84% and 83% were migrants from rural areas, respectively. Although statistical significance was marginal, recent migration (residing in study area for <5 years) independently increased the risk of hospitalisation for dengue compared with inhabitants after controlling for potential confounders (adjusted odds ratio [aOR] = 3.78; 95% confidence interval [CI] = 0.99–14.27), whereas longer-term migration (residing in study area for >6 years) did not change the risk (aOR = 1.1; 95% CI = 0.30–4.05). Younger age (18–34 years) (aOR = 7.26; 95% CI = 2.39–22.06) and higher adult Aedes aegypti infestation level within household premises (aOR = 9.25; 95% CI = 1.68–51.09) were also independently associated with hospitalisation for dengue. Recent migration from rural areas seems to increase the risk of hospitalisation for dengue in urban populations in endemic areas. Further research including cohort study should be done to confirm the impact of migration on the risk of dengue in urban areas.