Killing of flies in electrocuting insect traps releases bacteria and viruses

Electrocuting insect traps (EIT) are popular devices frequently used by hom eowners and food handlers attempting to localize the control of flying inse cts, including the ubiquitous house fly (Musca domestica L.). The traps con tain a visual attractant and a high-voltage metal grid. Upon contact with t he grids, the insects are disintegrated by the high voltage. As part of a s ystematic evaluation of EITs and their role in infectious disease spread, w e quantitated spread of bacteria and a bacterial virus during electrocution or house flies. We loaded flies with Serratia marcescens or with the Esche richia coli phage Phi X174 and placed sprayed or fed flies into a room cont aining an EIT. While flies were being electrocuted, liberated particles and bacteria were assayed via agar plates or via air filtration samplers. Spra yed flies released one of every 10,000 of the added bacteria or viruses, an d fed flies released one of every 1,000,000 of the consumed bacteria or vir uses. Results of our studies suggest EITs could play a role in the spread o f infectious disease agents, but the potential is influenced by the insect' s route of contamination.