Evaluating Surveillance Methods for Arboviral Vectors of La Crosse Virus and West Nile Virus of Southern Appalachia

Abstract

To monitor mosquito-borne diseases, public health departments conduct mosquito and pathogen surveillance. Our objective was to evaluate mosquito monitoring methods for collecting La Crosse virus (LACV) and West Nile virus (WNV) vectors (Aedes and Culex mosquitoes, respectively) in southern Appalachia. Centers for Disease Control and Prevention (CDC) light traps baited with carbon dioxide (CO(2)), CDC light traps baited with CO(2) and BG lure, BG-Sentinel traps baited with CO(2), gravid traps baited with oak (Quercus)-water infusion, and resting traps were compared in eastern Tennessee in 2013. Traps operated at 8 different urban sites throughout Knox County were randomly assigned to and rotated among 6 plots within each site. Results were specific for each vector; the BG-Sentinel trap was the best method for Aedes triseriatus, the CDC trap baited with CO(2) and BG lure was the best method for Ae. albopictus, and the gravid trap was the best method for Ae. japonicus. Culex erraticus collections varied by week and trapping method, indicating no single method was best, but the questing traps collected more mosquitoes. There was no significant trapping difference for Cx. pipiens complex in this region using the methods tested. The results suggest using a combination of trapping methods when sampling for LACV and/or WNV mosquito vectors in southern Appalachia. Effective trapping methods are necessary to enable accurate surveillance, improve control methods, enhance understanding of dispersal, and use for early detection of vectors and pathogens.

Spatial-temporal clusters of host-seeking Aedes albopictus, Aedes japonicus, and Aedes triseriatus collections in a La Crosse virus endemic county (Knox County, Tennessee, USA)

“…albopictus to Ae. triseriatus mosquitoes in a single mixed-forested hardwood setting was described as 1.2:1 [16], and we reported varying densities at additional Knox county sites which included previously LACV-positive homes [18,19]. Combined, this indicates that the Aedes populations are heterogeneous across space and time making targeted control difficult without surveillance.…”

“…A Center for Disease Control (CDC) light trap (model 512 John W. Hock, Gainesville, Florida) with the light removed was baited with~1kg of dry ice inside a punctured sports cooler and a Biogents sweet scent lure (Biogents AG, Regensburg, Germany). The trap and bait combination has been shown to be an effective way to collect LACV vectors and removing the light is a way to eliminate by-catch or non-targets which can damage mosquitoes for identification [18]. These traps operated for~24 hours in hidden and/or shaded areas of the site to ensure they were not stolen or disrupted by the public.…”

“…albopictus populations emerge in June and peak in August / September; Ae. japonicus populations are still poorly understood in Tennessee [16][17][18][19]. The density of Ae.…”

Field Trials to Evaluate the Effectiveness of the Biogents®-Sweetscent Lure in Combination with Several Commercial Mosquito Traps and to Assess the Effectiveness of the Biogents-Mosquitaire Trap with and Without Carbon Dioxide

“…The BG-Lure, which is essentially the same attractant as the BG-Sweetscent, was previously shown to increase the Ae. albopictus catch rates of BG-Sentinel (Pombi et al 2014, Roiz et al 2016 and CDC light traps (Urquhart et al 2016), especially when used together with CO 2 . The performance of 16 268 (16.8) 55 (3.4)92 (5.8) 6 (0.4) 435 (27.2) Fig.…”

Surveillance of Mosquitoes for Zika Virus in Westchester County, New York

“…Unfortunately, BG traps are quite expensive. However, using CDC light traps that have been altered by using BG lures has been reported to be almost as effective as using standard BG traps [17], thus providing a potentially cost-effective method for enhancing surveillance.…”