In news bound to make the common germophobe even more paranoid about that fly buzzing around the picnic table, a team of researchers has found that house flies and blow flies can spread a whole host of bacteria that was previously unsuspected to hitch a ride on the insects. The recently published study also suggests that a fly's bacteria-carrying capability could be hijacked and used in a public health surveillance capacity to track pathogen outbreaks.

We've long known that the common housefly can spread a number of diseases, but a new study has just revealed that we may have underestimated the volume, and breadth, of bacteria that these annoying insects can transmit. An international team led by Nanyang Technological University developed a new way to collect flies without contaminating them with other microorganisms and then sequence the DNA of every part of their body. This allowed species of bacteria they picked up on their travels to be identified.

"Our study has shown that bacteria can 'fly' by hitching a ride on common flies," says Stephean Schuster, a research director leading the study. "They pick up the microbiome on their feet, spread them across their wings in a similar way like how we might comb our hair, and then proceed to disperse them on surfaces that they land on."

The researchers sequenced the genetic material of 116 species of housefly and blow fly. After separating out all the genetic data that corresponded with the fly's own chromosomes and symbiotic bacteria, the remaining DNA and RNA was sorted against a database of all known bacteria.

The study frighteningly found that flies have the capacity to carry, and spread, hundreds of different bacteria, some linked to human diseases. One bacteria, for example, called Helicobacter pylori was found on some flies. This bacteria, which is known to cause stomach ulcers and is a major risk factor for gastric cancer, had never before been shown to be transmitted by flies.

It's not all bad news though, with the researchers suggesting this discovery could be put to a positive use. The study notes that lab-reared flies could be successfully bred to be germ-free and released into the environment to act as bacterial surveillance drones. With the ability to get into tiny nooks and crannies, the flies could then be recaptured using bait traps and their microbiome sequenced to reveal the types of bacteria they had encountered on their travels.

"Such 'autonomous bionic drones' could be particularly useful in agriculture, if we want to detect a plant pathogen outbreak," says Professor Schuster. "Through regular monitoring, if we know that a particular pathogen is affecting the crops and is becoming an outbreak, then farmers could organize a targeted treatment that only eradicates that pathogen, leaving the other parts of the ecosystem intact."

The study was published in the journal Scientific Reports.