Evaluating sampling strategies for Venezuelan equine encephalitis vectors in Florida and Panama

Establishing methods that effectively sample the full complement of vector species is essential in elucidating transmission cycles of vector-borne diseases. The Spissipes section of the subgenus Melanoconion of Culex represent an understudied group of mosquitoes which transmit enzootic subtypes of Venezuelan equine encephalitis viruses (VEEV) in North and South America. The objective of this study was to determine optimal trapping methods for the Spissipes section of Melanoconion. Six methods were used to collect mosquitoes during the 2019 field season in both Darien, Panama, and Florida, USA. These methods included commercially available traps, BG-Sentinel and light trap, and novel methods, including large-diameter (35cm) and small-diameter (7.5 cm) aspirators, artificial pop-up resting shelters, and a novel “mosquito drift fence” which captures mosquitoes by intercepting their natural flight paths. In Panama, the resting shelter and drift fence were most effective methods for capturing an average of 6.5 Culex spissipes and 3.6 Culex pedroi, respectively. In Florida, the mosquito drift fence was the most efficient method for collecting both Culex cedecei and Culex panocossa at averages of 16.6 and 6.9 mosquitoes per trap respectively. The large-diameter aspirator and BG-Sentinel trap were also considered efficient for Spissipes section species, capturing 6.9 Cx. panocossa, and 11.25 Cx. cedecei on average respectively. Results of the study demonstrate that no one sampling method should be relied upon exclusively for collecting enzootic vectors of VEEV, however the drift fence and resting shelter, were found to be effective for capturing the full complement of Spissipes section mosquitoes.