Potential for Transmission of Pseudomonas Aeruginosa and Other Bacterial and Parasitic Infectious Agents by Drosophila sp. (Fruit Flies) as Mechanical Vectors

Abstract

Introduction: Drosophila melanogaster, a fruit fly, has for more than 100 years played a pivotal role in scientific research, particularly in genetics and developmental biology.  However, the Drosophila just like any other fly may act as a mechanical vector aiding in the transmision of parasitic and bacterial infectious agents. This fly has philia not only for fruits and moist food, but also for other moist environments including sinks, toilets, latrines, urinaries, sewages, soaps, sponges, towels, bathooms, mops, and plants. The fact that these flies alternate between these moist filthy environments and food suggests that they have the potential for transmiting pathogens such as  Entamoeba histolytica, Giardia lamblia,Trichuris trichiura, Ascaris lumbricoides, Salmonella tyhi, Shigella dysenteriae, Vibrio cholera, Escherichia coli, Campylobactor jejuni ,and even, Pseudomonas aeruginosa from the moist filthy environments to food. Of particular concern  is the possible relationship between Pseudomonas aeruginosa and Drosophila. Pseudomonas aeruginosa is an opportunistic pathogen, and one of the top three bacterial pathogens responsible for nosocomial infections.

Hypotheses: Drosophila sp. could be a mechanical vector for Pseudomonas aeruginosa and other bacterial and parasitic infectious agents. There could be a relationship between Pseudomonas aeruginosa and Drosophila sp. Pseudomonas aeruginosa thrives in moist environments, produces a fruity odor, and two types of soluble pigments: the fluorescent pigment pyoverdin and the blue pigment pyocyanin, just like a juicy fruit does hence attracting fruit flies to act as their mechanical vectors. This study is designed to investigate a possible role of Drosophila sp. as a mechanical vector of infectious agents.

Methodology: D. melanogaster samples were collected from bathrooms, toilets/latrines, kitchens and hospital wards using improvised sterilized Drosophila traps. These versatile traps (plastic containers; with a transparent base and colored lids) have a patented food grade attractant (a mixture of sterilized ripe banana paste and bread crumbs with small amounts of ethyl acetate added) that readily attracts several species of Drosophila. The baited flies were then analyzed for bacterial and parasitic infectious agents using  culture and biochemical tests, and concentration techniques (e.g. formal ether), respectively. Determination of whether fruit flies may transmit various infectious agents or not, was achieved by computing their proportions for the 40 sampled areas analyzed. Determination of whether there is a statistically significant relationship between fruit fly attraction, bait type, and color, was achieved by comparing the geometric means of number of fruit flies for the various colors and bait type groups. T-test and ANOVA were used to compare difference in geometric means at significance levels of 5%.

Results: The most commonly isolated bacterial infectious agents were P. aeruginosa and E. coli, while parasitic infectious agents being S. stercoralis. Candida albicans the only fungal infectious agent was also isolated from D. melanogaster. The P. aeruginosa cultures attracted D. melanogaster while the different color types did not.

Conclusion: D. melanogaster is probably a mechanical vector for various bacterial, parasitic, and fungal pathogens. P. aeruginosa attracts D. melanogaster thus enhancing its transmission. To prevent the flies from breeding bushes should be cleared, dust bins emptied and cleaned regularly, and stagnating water drained around our residence and hospitals environment.

Keywords: Drosophila Melanogaster, Pseudomonas aeruginosa, Musca domestica, Strongyloides stercoralis, Rhamnolipid