In this study, we compared the efficacy of the newly available BG-Sentinel with an established "gold standard,", the CDC Backpack Aspirator, and a CO2-baited EVS trap for the collection of Aedes aegypti (L.) in Cairns, Australia. BG-Sentinels collected significantly more (P = 0.017) female Ae. aegypti (mean per collection, 1.92 +/- 0.39) than both the CDC Backpack Aspirator (1.00 +/- 0.35) and the EVS trap (0.71 +/- 0.27). Male-only and combined male-female Ae. aegypti collections for th BG-Sentinel and the CDC Backpack Aspirator were also greater than EVS trap collections. The CDC Backpack Aspirator and the BG-Sentinel captured proportionally fewer females compared with the EVS trap. The BG-Sentinel was the most Ae. aegypti specific collection method. The CDC Backpack Aspirator collected proportionally more bloodfed Ae. aegypti than the other methods, which collected a greater proportion of nullipars. The data presented here will aid researchers in deciding what Ae. aegypti sampling device best suits their needs. BG-Sentinels and CDC Backpack Aspirators should be considered as alternatives to human-bait collections for Ae. aegypti sampling.

Sticky ovitraps (patent pending) were used to sample female Aedes aegypti (L.) weekly in a focus of dengue activity in Cairns, Queensland, Australia. In February 2003, transmission of dengue virus serotype 2 began in the suburb of Parramatta Park, peaking in mid-March 2003. This suburb features many older, unscreened houses with high populations of Ae. aegypti. Highest densities (2-3.5 females per trap per week) were obtained during peak dengue transmission (January and February) before mosquito control was initiated. Beginning in late March, female Ae. aegypti collected in sticky ovitraps were tested for dengue viral RNA by using a TaqMan reverse transcription-polymerase chain reaction assay. Dengue viral RNA was detected in six pools of Ae. aegypti collected in late March. The highest minimum infection rate was 116/1000 mosquitoes. After the initiation of larval control (containers treated with S-methoprene or lambda-cyhalothrin) and adult control (interior harborage sites sprayed with lambda-cyhalothrin) in early March, trap collections dropped to <0.5 per trap per week, and no virus was detected in trapped mosquitoes. Human cases subsequently dropped from a high of seven cases per day in mid-March to only sporadic cases in late April, with the final reported onset of 7 May. Sticky ovitraps have potential as a monitoring device for gravid Ae. aegypti and can be used to assess control efficacy and dengue virus activity. A sticky ovitrap index (mean number of female Ae. Aegypti per trap per week) could be useful in gauging the risk of dengue transmission.

In Cairns, Australia, the impacts on Aedes aegypti L. (Diptera: Culicidae) populations of two types of 'lure & kill' (L&K) lethal ovitraps (LOs), the standard lethal ovitrap (SLO) and the biodegradable lethal ovitrap (BLO) were measured during three mass-trapping interventions. To assess the efficacy of the SLO, two interventions (one dry season and one wet season) were conducted in three discrete areas, each lasting 4 weeks, with the following treatments: (i) SLOs (>200 traps, approximately 4/premise), BG-sentinel traps (BGSs; approximately 15, 1/premise) and larval control (container reduction and methoprene treatment) and (ii) larval control alone, and (iii) untreated control. Female Ae. aegypti populations were monitored for 4 weeks pre- and post-treatment in all three areas using BGSs and sticky ovitraps (SOs) or non-lethal regular ovitraps (ROs). In the dry season, 206 SLOs and 15 BGSs set at 54 and 15 houses, respectively, caught and killed an estimated 419 and 73 female Ae. aegypti, respectively. No significant decrease in collection size of female Ae. aegypti could be attributed to the treatments. In the wet season, 243 SLOs and 15 BGSs killed approximately 993 and 119 female Ae. aegypti, respectively. The mean number of female Ae. aegypti collected after 4 weeks with SOs and BGSs was significantly less than the control (LSD post-hoc test). The third mass-trapping intervention was conducted using the BLO during the wet season in Cairns. For this trial, three treatment areas were each provided with BLOs (>500, approximately 4/premise) plus larval control, and an untreated control area was designated. Adult female Ae. aegypti were collected for 4 weeks pre- and post-treatment using 15 BGSs and 20 SOs. During this period, 53.2% of BLOs contained a total of 6654 Ae. aegypti eggs. Over the intervention period, collections of Ae. aegypti in the treatment areas were significantly less than in the control area for BGSs but not SOs. An influx of relatively large numbers of young females may have confounded the measurement of changes in populations of older females in these studies. This is an important issue, with implications for assessing delayed action control measures, such as LOs and parasites/pathogens that aim to change mosquito age structure. Finally, the high public acceptability of SLOs and BLOs, coupled with significant impacts on female Ae. aegypti populations in two of the three interventions reported here, suggest that mass trapping with SLOs and BLOs can be an effective component of a dengue control strategy.

Summaryobjectives To describe the meteorological influences on adult dengue vector abundance in Australia for the development of predictive models to trigger pre-emptive control operation.methods Multiple linear regression analyses were performed using meteorological data and female Aedes aegypti collection data from BG-Sentinel Mosquito traps placed at 11 monitoring sites in Cairns, north Queensland.results Considerable regression coefficients (R 2 = 0.64 and 0.61) for longer-and shorter-term factor models respectively were derived. Longer-term factors significantly associated with abundance of adult vectors were mean minimum temperature (lagged 6 month) and mean daily temperature (lagged 4 month), explaining the predictable increase in abundance during the wet season. Factors explaining fluctuation in abundance in the shorter term were mean relative humidity over the previous 2 week and current daily average temperature. Rainfall variables were not found to be strong predictors of A. aegypti abundance in either longer-or shorter-term models.conclusions The implications of these findings for the development of useful predictive models for vector abundance risks are discussed. Such models can be used to guide the application of pre-emptive dengue vector control, and thereby enhance disease management.