We aimed to have a motor with the same aspirating power of the CDC-BP because blowers that have more suction generally injure or kill mosquitoes (Clark et al. 1994 (link)). We measured the aspiration power of a brand-new CDC-BP (John W.Hook, Gainesville, FL) and of the Prokopack at 0, 5, and 10 cm from end of collection cup by using a hand-held digital wind gauge (Kestrel 4000; Kestrel Meters, Sylvan Lake, MI). For each aspiration device and distance, we recorded the average wind speed over a 1-min interval for a total of 10 repetitions.
From 24 November 2008 to 11 March 2009, two combined sewer overflow (CSO) tunnels (Greensferry and Tanyard Creek) in Atlanta, GA, were visited to collect overwintering mosquitoes by using one Prokopack in the upper walls (above 1.5 m) and ceiling and one CDC-BP in the lower walls (<1.5 m). Seven 10-m sections of the tunnels (three in Greensferry and four in Tanyard) were carefully aspirated by three field technicians with the aid of flashlights to spot overwintering mosquitoes. Collection effort was fixed (≈20 min per tunnel section) for each aspirator. We aimed to assess how our collections could be improved by aspirating on the upper wall and ceiling. The tunnel concrete surface walls were uneven and required maneuvering around pipes and drains, the ceilings were high (up to 5 m), and some surfaces were partially wet. Collected mosquitoes were kept alive in glass breeding chambers (30×30×30 cm) containing a 10% sucrose solution and then identified by species and individually stored at −80°C for further virus testing.
During 7–22 May 2009, a paired trial between the Prokopack and the CDC-BP was performed in 71 houses in Iquitos, Peru. Randomly selected houses were visited by two field technicians who tested the performance of each mosquito aspirator in indoor collections. At each house, a collection sequence alternating the use of the CDC-BP and the Prokopack in the lower (<1.5 m) walls and furniture was followed. After using one of the aspirators (e.g., Prokopack), the same technician was in charge of repeating the collection with the alternative aspirator (e.g., CDC-BP), making sure to cover a similar area as in the initial collection. Concurrently with the lower wall collections, a Prokopack with an extension pole was used to collect the mosquitoes resting on the higher (>1.5 m) walls and the ceiling. Collection effort in each house was fixed (≈10 min) for each aspirator. Aspiration was performed in all rooms and hallways of each house as described by Scott et al. (2000) (link) and collected mosquitoes were processed as described above. In a first assessment, we found several damaged mosquitoes, because the collection cups were too close to the aspirator fan. We fixed this problem by adding a rigid wire transversally at 2.5 cm from the end of the rubber coupler (see 2b in Fig. 1A).