House Flies Spread a Range of Diseases

The house fly (Musca domestica) is the most common flies all over the world. The house fly lives closely with humans and domestic animals and is often found in areas of human activities such as restaurants, hospitals, food centers, food markets, fish markets, and slaughterhouses.

On average, the life cycle of a house fly only lasts for around 30 days. House flies can lay up to 500 eggs in their lifetime which are usually in batches of around 75 to 150.

House flies live on a liquid diet, as they lack the mouthparts needed to chew food, so instead, they have to drink it. A house fly will regurgitate digestive juices onto solid foods and these juices break down the food into small pieces, allowing them to use their mouthparts to drink the meal. House flies defecate every time they land, even if it’s on their next meal.

Flies Spread a Range of Diseases

House flies do not serve as a secondary host or act as a reservoir of any bacteria of medical or veterinary importance, but they do serve as mechanical vectors to over 100 pathogens.

House flies can carry and transmit a variety of bacterial pathogens such as salmonella, shigella, E. coli, vibrio cholerae, staphylococcus aureus, and campylobacter. Houseflies can carry and transmit a variety of viral pathogens as enteroviruses, and hepatitis A virus.

House flies can carry cysts of protozoan parasites such as Giardia lamblia and Entamoeba histolytica, leading to gastrointestinal diseases like giardiasis and amoebiasis.

House flies can carry helminth eggs such as eggs of parasitic worms such as Ascaris lumbricoides (roundworm), Trichuris trichiura (whipworm), and various species of hookworms. These can cause a range of infections leading to malnutrition, intestinal obstruction, and other health issues.

House flies can act as vectors for candida and other fungal spores, contributing to the spread of opportunistic fungal infections.

Effect of Climate Change on House Flies

Flies are taking over thanks to climate change. Climate change can significantly impact the behavior, population dynamics, and distribution of house flies, potentially increasing their role as vectors of disease.

Higher temperatures can accelerate the breeding cycle of house flies, leading to more frequent and larger populations. Warmer conditions can shorten the developmental stages from egg to adult, resulting in more generations of flies per year.

Rising temperatures can allow houseflies to inhabit regions that were previously too cold for them. This can lead to the spread of house fly-related diseases to new areas. In temperate regions, warmer temperatures can extend the active season of houseflies, increasing the period during which they can transmit diseases.

Increased rainfall and flooding can create more breeding sites for house flies, such as standing water and decaying organic matter.

Extreme weather events can disrupt waste management systems and sanitation infrastructure, creating environments conducive to house fly proliferation.

Climate change can exacerbate urbanization and changes in agricultural practices, leading to more waste and organic matter that house flies can use for breeding.

As house fly populations grow and spread, the risk of disease transmission to humans and animals can increase, especially in regions with inadequate public health measures.

Climate change increases disease transmission by house fly. With the potential for larger and more widespread populations, houseflies may play a greater role in the mechanical transmission of pathogens. This can lead to increased cases of diseases such as foodborne illnesses due to more frequent contamination of food supplies, enteric diseases, and spread of parasitic diseases in new regions.

Mechanism of Pathogen Transmission

House flies act as mechanical vectors, meaning they physically carry and transfer pathogens from contaminated sources to humans or animals without the pathogens undergoing biological development within the fly. The legs, feet, mouthparts, body surface, gut, and feces of house flies all play roles in the transmission of pathogens, making them effective mechanical vectors for a variety of diseases.

House flies have hairy legs and feet that can pick up and carry pathogens from contaminated surfaces. When they land on food or other surfaces, these pathogens can be transferred.

House flies have sponging mouthparts that they use to feed on liquids. They regurgitate digestive enzymes and partially digested food, which can contain pathogens, onto new surfaces or food they are feeding on.

The entire body of the house fly, including its wings and abdomen, can carry pathogens. The hairs on the fly's body can trap and hold microorganisms, which can be transferred to surfaces they contact.

Pathogens ingested by the fly can survive and sometimes multiply in the fly’s digestive system. These pathogens can be regurgitated or excreted in the fly's feces, contaminating surfaces, food, and water.

House flies excrete frequently, and their feces can contain a high concentration of pathogens. When flies defecate on food, food preparation areas, or other surfaces, they can leave behind infectious agents.

Preventive Measures

By maintaining good hygiene and employing effective pest control measures, the risk of disease transmission by house flies can be significantly reduced.

Keep living and eating areas clean, dispose of garbage properly, and ensure that fecal matter is not exposed. Store food in sealed containers, cover food, and avoid leaving food out in the open.

Use screens on windows and doors, employ fly traps, and use fly repellents. Dispose of waste properly and regularly to minimize breeding sites for flies.

To mitigate the impact of climate change on house fly populations and their role in disease transmission, several measures can be taken:

Improved Sanitation: Enhance waste management and sanitation infrastructure to reduce breeding sites.

Public Health Measures: Implement robust public health surveillance and response systems to monitor and control house fly populations.

Research and Monitoring: Conduct research to understand the changing dynamics of house fly populations and their impact on disease transmission.

Climate Action: Address the root causes of climate change through policies and actions aimed at reducing greenhouse gas emissions.

By understanding and addressing the ways in which climate change affects house flies, we can better prepare for and mitigate the associated public health risks.