House flies are underappreciated yet important reservoirs and vectors of microbial threats to animal and human health

Authors: Nayduch, Dana; NEUPANE, SARASWOTI - Kansas State University; PICKENS, VICTORIA - Kansas State University; Purvis, Tanya; OLDS, CASSANDRA - Kansas State University

Submitted to: Microorganisms
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/24/2023
Publication Date: 2/25/2023
Citation: Nayduch, D., Neupane, S., Pickens, V., Purvis, T.J., Olds, C. 2023. House flies are underappreciated yet important reservoirs and vectors of microbial threats to animal and human health. Microorganisms. 11(3). Article 583. https://doi.org/10.3390/microorganisms11030583.
DOI: https://doi.org/10.3390/microorganisms11030583

Interpretive Summary: House flies are well-recognized as filth-associated organisms and unwelcome guests even by laypeople. House flies create sanitation issues when they bridge the gap between microbe-rich breeding environments like animals or their waste and areas of healthy animals or human habitation. Dozens of scientific surveys have demonstrated that house flies harbor bacterial pathogens that pose a threat to humans and animal health. Many of these surveys cultured live bacteria from flies. More recently, within the last few decades, more extensive and informative surveys incorporating next-generation sequencing technologies have shown that house fly carriage of pathogens and harmful genetic elements, such as antimicrobial resistance genes, is more widespread and dangerous than previously studies estimated. Furthermore, there is a strong body of research confirming that flies not only harbor but also transmit live bacterial pathogens that could cause infection and disease. Some of these pathogens replicate and persist in the fly, which could permit prolonged shedding and dissemination as the fly disperses throughout the environnment. The potential range of dispersal of flies and their associated pathogens can be very extensive and the drivers of dispersal have yet to be fully determined. Despite this evidence, the house flies’ role as reservoirs, disseminators, and true, yet facultative, transmitters (vectors) for pathogens have been greatly underestimated and underappreciated. In this review we present key studies that bolster the house fly’s role both an important player in microbial ecology and population biology and as transmitters of microbial threats to animal and human health.

Technical Abstract: House flies are well-recognized as filth-associated organisms and public nuisances. House flies create sanitation issues when they bridge the gap between microbe-rich breeding environments and animal/human habitations. Numerous scientific surveys have demonstrated that house flies harbor bacterial pathogens that pose a threat to humans and animals. More extensive and informative surveys incorporating next-generation sequencing technologies have shown that house fly carriage of pathogens and harmful genetic elements, such as antimicrobial resistance genes, is more widespread and dangerous than previously thought. Further, there is a strong body of research confirming that flies not only harbor but also transmit viable, and presumably infectious, bacterial pathogens. Some pathogens replicate and persist in the fly, permitting prolonged shedding and dissemination. Finally, although the drivers still have yet to be firmly determined, the potential range of dissemination of flies and their associated pathogens can be extensive. Despite this evidence, the house flies’ role as reservoirs, disseminators, and true, yet facultative, vectors for pathogens have been greatly underestimated and underappreciated. In this review we present key studies that bolster the house fly’s role both an important player in microbial ecology and population biology and as transmitters of microbial threats to animal and human health.