House flies are common insects found globally, often seen as nuisances. Their presence in unsanitary environments, like garbage and decaying matter, leads to a perception of them being “dirty.” This is accurate, as flies interact with and spread microorganisms, posing a public health concern.
How Flies Carry and Transfer Germs
Flies possess physical characteristics that enable efficient germ transfer. Their bodies are covered in tiny hairs, and their legs have sticky footpads called pulvilli. These readily collect particles, including pathogens like bacteria and viruses, from contaminated surfaces such as decaying organic material, feces, and waste. This allows for the mechanical transfer of germs as the fly moves to clean surfaces or food.
Flies also transmit germs through their feeding habits and waste. Unable to chew solid food, house flies regurgitate digestive juices onto food to liquefy it. This process, called vomitus, can deposit pathogens from their digestive system onto food or surfaces. Additionally, flies contaminate surfaces and food through defecation, releasing bacteria and other microorganisms from their intestinal tract. Pathogens can persist within the fly’s digestive system, remaining viable for transmission.
Health Risks from Fly Contamination
Flies carry a range of pathogens, posing health risks. They can harbor over 100 types of disease-causing organisms, including bacteria, viruses, and parasitic eggs. Common bacteria transmitted by flies include E. coli, Salmonella, and Shigella, which cause food poisoning, gastroenteritis, and diarrheal diseases. E. coli can cause severe gastrointestinal issues, and Salmonella is linked to typhoid fever.
Flies also transmit illnesses like dysentery and cholera. They can carry cholera microbes on their surfaces and within their bodies for several days, contaminating food. Beyond bacteria, flies carry parasitic cysts and eggs, including Entamoeba histolytica, Giardia lamblia, and helminths like Ascaris lumbricoides and hookworms. These can lead to intestinal infections and parasitic conditions.
Strategies for Fly Control
Controlling fly populations requires sanitation and exclusion. A clean environment is crucial, as flies are attracted to and breed in decaying organic matter, garbage, and animal waste. Regularly disposing of trash in sealed containers, cleaning food spills promptly, and managing pet waste reduce attractants and breeding sites. Cleaning drains and areas with moisture and organic debris also eliminates breeding grounds.
Exclusion methods prevent flies from entering indoor spaces. Installing tight-fitting screens on windows and doors is an effective barrier. Sealing cracks and gaps around entry points, like doors and windows, further limits access. Fly swatters or commercial traps can eliminate individual flies that get inside. Reducing breeding sites and preventing entry mitigate health risks.