The Blowfly Chrysomya megacephala as a Vector of Pathogens Associated with Infectious Diseases

Chrysomya megacephala is a synanthropic fly with a high potential to act as a mechanical vector of pathogenic bacteria, surpassing Musca domestica in both bacterial load and diversity. Native to Asia and Africa, it has become a cosmopolitan species, successfully adapting to a wide range of environments, including natural ecosystems. In Colombia, studies on its role as a vector are limited and have largely relied on traditional culturing methods. This study aimed to characterize the pathogenic bacterial microbiota associated with C. megacephala using 16S rRNA gene sequencing in urban, rural, and forest settings of a coastal tourist city. Flies were collected using Van Someren Rydon traps with attractants and sterile materials. Bacterial identification was performed through Oxford Nanopore MinION sequencing (Manufactured by Oxford Nanopore Technologies, Oxford, UK). A total of 49 bacterial species were identified, with urban environments showing the highest taxonomic richness. The forest environment was characterized by a highly dominant community structure, led by Vagococcus carniphilus. Notably, 20 bacterial species of public health relevance were detected, including Clostridium botulinum, Clostridium perfringens, Ignatzschineria ureiclastica, Escherichia coli, and Streptococcus agalactiae. These findings indicate that bacterial community composition varies by environment and underscore the potential role of C. megacephala as a mechanical vector, highlighting the importance of surveillance for its public health implications.