Outlook on RNAi-based strategies for controlling Culicoides biting midges

Authors: OSBORNE, CAMERON - Kansas State University; Cohnstaedt, Lee; SILVER, KRISTOPHER - Kansas State University

Submitted to: Pathogens
Publication Type: Literature Review
Publication Acceptance Date: 10/11/2023
Publication Date: 10/17/2023
Citation: Osborne, C.J., Cohnstaedt, L.W., Silver, K.S. 2023. Outlook on RNAi-based strategies for controlling Culicoides biting midges. Pathogens. 12(10). Article 1251. https://doi.org/10.3390/pathogens12101251.
DOI: https://doi.org/10.3390/pathogens12101251

Interpretive Summary: Culicoides are small biting fly that can transmit important livestock pathogens around much of the world, and their impacts on animal welfare are likely to expand. Hemorrhagic diseases resulting from fly transmitted viruses, for example, can lead to millions of dollars in economic damages for producers. Chemical insecticides can reduce biting fly abundance but may not suppress population numbers enough to prevent pathogen transmission. These insecticides can also cause negative effects on non-target organisms and ecosystems. RNA interference (RNAi) is a cellular regulatory mechanism which degrades messenger RNA and suppresses gene expression. Studies have examined the utility of this mechanism for insect pest control, and with it, have described the hurdles towards producing, optimizing, and applying these RNAi-based products. These methods hold promise for being highly specific and environmentally friendly when compared to chemical insecticides and are more temporary, easier, and more socially accepted than engineering transgenic or genetically modified insects. Given the lack of available control options for biting flies RNAi-based products may be an option to treat large areas with minimal environmental impact. Here, we describe the state of current Culicoides control methods, successes and hurdles towards using RNAi for pest control, and the necessary research required to bring an RNAi-based control method to fruition for Culicoides midges.

Technical Abstract: Culicoides are small biting midges with the capacity to transmit important livestock pathogens around much of the world, and their impacts on animal welfare are likely to expand. Hemorrhagic diseases resulting from Culicoides-vectored viruses, for example, can lead to millions of dollars in economic damages for producers. Chemical insecticides can reduce Culicoides abundance but may not suppress population numbers enough to prevent pathogen transmission. These insecticides can also cause negative effects on non-target organisms and ecosystems. RNA interference (RNAi) is a cellular regulatory mechanism which degrades mRNA and suppresses gene expression. Studies have examined the utility of this mechanism for insect pest control, and with it, have described the hurdles towards producing, optimizing, and applying these RNAi-based products. These methods hold promise for being highly specific and environmentally benign when compared to chemical insecticides and are more transient than engineering transgenic insects. Given the lack of available control options for Culicoides, RNAi-based products may be an option to treat large areas with minimal environmental impact. Here, we describe the state of current Culicoides control methods, successes and hurdles towards using RNAi for pest control, and the necessary research required to bring an RNAi-based control method to fruition for Culicoides midges.