Maggots, the larvae of flies, look alarming, but the ones most people find in a bin or on old food don’t bite or burrow into healthy skin. What they do carry is germs from the rotting material they feed on, so the everyday risk is contamination rather than attack.1Oregon State University Extension Service. Integrated Pest Management of Nonbiting Flies in Schools The serious danger is a different situation: larvae living in the tissue of a person or animal, most often in an untreated open wound on someone who can’t care for it.2European Surgery. Wound myiasis in Western Europe: prevalence and risk factors in a changing climate scenario The same eating habit that makes maggots harmful in those cases is also put to use by doctors to clean stubborn wounds.3PubMed Central. Mechanisms of Maggot-Induced Wound Healing: What Do We Know, and Where Do We Go from Here?
Maggots in Your Trash or Kitchen
Common flies breed in garbage, animal droppings, dead animals and drain sludge.4Oregon State University Extension Service. Integrated Pest Management of Nonbiting Flies in Schools Those places are rich in bacteria, viruses, parasites and worm eggs.5Oregon State University Extension Service. Integrated Pest Management of Nonbiting Flies in Schools The maggots, and the flies they become, can carry those germs onto surfaces and food.
Maggots can also hold and release live bacteria. Maggots that fed on staph bacteria later shed live staph onto surfaces.6PubMed Central. Maggots as potential vector for pathogen transmission and consequences for infection control in waste management Maggots raised on chicken droppings carried germs including E. coli, Salmonella and staph, some of them resistant to several antibiotics.7Environmental Sciences Europe. Molecular characterization of antibiotic-resistant bacteria associated with maggots obtained from chicken droppings So food that maggots have crawled over should be treated as contaminated, not just picked clean.
If you find maggots in food, throw out the whole item, not only the visible part, because eggs and smaller larvae hide deeper. Bag it tightly so larvae can’t crawl out and pupate nearby. Wash the container, counter and nearby surfaces with hot soapy water, and check other food in the same cupboard or fruit bowl for eggs or larvae.
Touching maggots briefly is not an emergency. Household maggots can’t bite into or burrow through intact, healthy skin. The concern is germs on your hands, and washing with soap handles that. If you have open cuts on your hands, wear gloves when cleaning out an infested bin.
Babies, older adults and people with weak immune systems are more affected by food germs, so they need extra care around infested food. Pets that eat from infested trash can pick up the same bacteria.
What Happens If You Swallow Maggots
Stomach acid kills most swallowed maggots.8HealthTap. What could happen if you accidentally ate maggots? A few may survive because of their tough outer coating.9HealthTap. What could happen if you accidentally ate maggots? Possible effects include nausea, vomiting, diarrhea, food poisoning and, in some people, an allergic reaction.10HealthTap. What could happen if you accidentally ate maggots?
The bigger danger is usually the food itself. Food with maggots in it is spoiled and contaminated with bacteria from where the flies bred.11Oregon State University Extension Service. Integrated Pest Management of Nonbiting Flies in Schools
In the next day or two, mild nausea or a single bout of diarrhea that settles on its own is the usual course. Drink fluids and rest, as with any mild food poisoning. See a doctor for blood in the stool, a high fever, vomiting that won’t stop, or signs of dehydration. Get urgent help for hives, swelling of the lips or throat, or trouble breathing.
Edible insect larvae are a different case. Larvae such as black soldier fly are farmed as feed and food under controlled conditions. Even these carry risks from germs, toxins absorbed from what they ate, and allergies, so processing such as heating matters.12ScienceDirect. The Black Soldier Fly (Hermetia illucens)
When Maggots Infest the Body
A maggot infestation of the body is called myiasis, and it comes in three main types: boil-like, creeping, and wound infestations.13PubMed Central. Cutaneous myiasis: a review of the common types of myiasis In the boil-like type, larvae of certain tropical flies enter the skin and grow in a painful lump that looks like a boil or infected cyst.14PubMed Central. Myiasis: A Traveler’s Dilemma This type develops slowly, which is why it’s often first mistaken for an ordinary boil.15PubMed Central. Myiasis: A Traveler’s Dilemma
A lump might be larvae if the sore doesn’t come to a head or heal with usual care, especially after tropical travel. Look for a small central hole, sometimes leaking fluid, and a feeling of movement or sharp pain. Tell the doctor where you travelled, since that points to which fly is likely. Don’t squeeze it; a doctor can remove the larva whole.
Travellers pick up skin myiasis in a few ways. Some tropical flies attach their eggs to other insects such as mosquitoes, which deposit them during a bite. Others lay eggs on damp laundry dried outdoors, so ironing clothes in those regions helps. Insect repellent and covered skin lower the risk.
How dangerous myiasis is depends on where the larvae are.16PubMed Central. Vidi, vini, vinci: External ophthalmomyiasis infection that occurred, and was diagnosed and treated in a single day: A rare case report Larvae on the surface of the eye usually cause problems that clear up.17PubMed Central. Vidi, vini, vinci: External ophthalmomyiasis infection that occurred, and was diagnosed and treated in a single day: A rare case report But some species, such as cattle grub larvae, can burrow into the eye and cause severe inflammation or loss of vision.18PubMed Central. Vidi, vini, vinci: External ophthalmomyiasis infection that occurred, and was diagnosed and treated in a single day: A rare case report In one reported case, a child with ear pain, discharge and itching had ten live maggots in the ear canal and recovered fully after removal and antibiotics.19PubMed Central. Aural Myiasis by Wohlfahrtia magnifica: Case Report
Who Is Most at Risk From Wound Maggots
Wound myiasis is an infestation of neglected open wounds by fly larvae.20European Surgery. Wound myiasis in Western Europe: prevalence and risk factors in a changing climate scenario Common risk factors are older age, poor hygiene, poor nutrition, living alone, diabetes, cancer and poor circulation in the legs.21European Surgery. Wound myiasis in Western Europe: prevalence and risk factors in a changing climate scenario In one reported case, a 77-year-old woman who couldn’t move developed bedsores that became infested.22PubMed Central. Cutaneous myiasis in an elderly debilitated patient
Diabetes and poor circulation cause slow-healing sores, often on the feet, where they go unnoticed. Reduced feeling in the feet means a person may not sense a wound or the larvae in it. Immobile people can’t clean or reach their own wounds, especially bedsores. And the smell of an untreated wound attracts egg-laying flies.
If a relative is at risk, check their feet, bedsores and dressings daily, especially in warm weather. Keep wounds covered with clean dressings and change them as directed. Keep flies out of the room with screens and by removing food waste. For older people living alone, arrange regular visits or home nursing.
Flesh-Eating Screwworms
The New World screwworm is a fly whose larvae must feed on the living flesh of warm-blooded animals and people.23CDC. About New World Screwworm The flies lay eggs in wounds and in the nose, eyes, ears and mouth.24CDC. About New World Screwworm Eggs hatch in 10 to 20 hours and the larvae start eating live flesh.25Journal of the American Veterinary Medical Association. Screwworms They tear tissue with sharp mouth hooks, so the wound grows deeper as more hatch.26USDA Animal and Plant Health Inspection Service. New World Screwworm The worst infestations, with up to 3,000 larvae in one wound, usually killed the animal within 7 to 10 days if untreated.27Journal of the American Veterinary Medical Association. Screwworms
A screwworm wound keeps getting larger and deeper instead of healing. It is painful and smells foul.28CDC. About New World Screwworm Many larvae are packed together, burrowing in rather than sitting on the surface.
Most common fly larvae feed on dead tissue and waste, while screwworms feed on living tissue, which is why they’re so damaging. Screwworm is closely watched, so report suspected cases in people or animals to a doctor, vet or animal health authority.
Maggots on Pets and Livestock
In flystrike, maggots feed on an animal’s skin and wool and burrow into its tissue.29Cornell Integrated Pest Management. Managing Flystrike (Myiasis) in Sheep Toxins from damaged tissue and ammonia from the maggots enter the bloodstream, and the animal becomes ill.30NADIS. NADIS – Blowfly Strike Bacterial infections often follow and can be fatal.31NADIS. NADIS – Blowfly Strike About 5 in 100 affected sheep die.32Cornell Integrated Pest Management. Managing Flystrike (Myiasis) in Sheep
Pets get flystrike too. Rabbits, older dogs and cats with soiled fur around the tail are most at risk. Signs include restlessness, a bad smell, damp matted fur and visible maggots. In warm weather, check the rear end daily and keep it clean and dry. If you see signs, take the animal to a vet the same day, because it can worsen within hours.
What to Do About Maggots in a Wound
Removal is mechanical and done in stages. The first step is wiping maggots out with damp gauze.33Royal Darwin Palmerston Hospital. What to do if you find maggots on a patient Rinsing with saline or water then lifts medium-sized maggots off shallow wounds, but small ones stick in crevices.34Royal Darwin Palmerston Hospital. What to do if you find maggots on a patient Some doctors found that pouring on diluted hydrogen peroxide stunned maggots so they could be wiped away in groups.35PubMed Central. Wound Myiasis Management: What Works, What Doesn’t Antiseptics such as povidone-iodine kill maggots, and doctors rinse them off before dressing to protect the tissue.36Royal Darwin Palmerston Hospital. What to do if you find maggots on a patient
Hidden larvae need other tricks. Maggots move away from light, so shining a bright light on the wound for 10 to 20 seconds can drive hidden ones out where they can be picked off.37Royal Darwin Palmerston Hospital. What to do if you find maggots on a patient A thick layer of paraffin ointment or gel cuts off their air, and they come away in the dressing after 24 hours.38Royal Darwin Palmerston Hospital. What to do if you find maggots on a patient
At home, wear gloves and gently wipe or rinse visible maggots with clean water. Don’t dig into the wound or use sharp tweezers, which damage tissue. Cover it with a clean dressing and see a doctor the same day, since deeper larvae and infection need treatment. Go urgently if maggots are in the ear, nose, eye or a deep wound.
At the clinic, staff remove the larvae, clean the wound and check how deep it goes. Antibiotics may be given for infection, as in the ear case. A follow-up visit confirms all larvae are gone.
Maggot Allergies in Anglers
Anglers and workers handling live bait maggots have developed allergic reactions.39PubMed. Allergy to asticot maggots. Identification of allergens. Tiny particles from the larvae float in the air and are breathed in.40Allergologia et Immunopathologia. Rhinoconjunctivitis and asthma provoked by Asticot maggots They can cause a runny nose, itchy eyes and asthma.41Allergologia et Immunopathologia. Rhinoconjunctivitis and asthma provoked by Asticot maggots
To cut your exposure, keep bait containers closed and away from your face. Wear gloves and wash your hands before touching your eyes. If sneezing or wheezing follows every fishing trip, see a doctor.
How to Keep Maggots Away
Bins are the main breeding site. Bag and tie trash in sturdy bags, and use outdoor bins with liners and tight or self-closing lids.42Oregon State University Extension Service. Integrated Pest Management of Nonbiting Flies in Schools Bins without tight lids can breed flies, and mature maggots crawl out to find a place to turn into flies.43PubMed Central. A Review of Alternative Controls for House Flies Keep bins closed and clean them often, including diaper pails and compactors.44PubMed Central. A Review of Alternative Controls for House Flies
A few habits help. Put meat and fish scraps out close to collection day, or freeze them until then. Rinse bins with hot water and detergent and let them dry. Clear drains and pet waste, which also breed flies, and use window screens in summer.
For maggots already in a bin, boiling water poured over them kills them quickly. Then bag them and clean the bin.
Why Doctors Use Maggots on Purpose
Medical maggots release digestive juices that turn dead tissue to liquid, which they then drink.45PubMed Central. Mechanisms of Maggot-Induced Wound Healing: What Do We Know, and Where Do We Go from Here? Each maggot can clear about 25 mg of dead tissue in 24 hours.46PubMed Central. Mechanisms of Maggot-Induced Wound Healing: What Do We Know, and Where Do We Go from Here? In one group of hard-to-heal wounds, about 9 in 10 were fully cleaned.47PubMed. Maggot therapy for the treatment of intractable wounds In lab tests, maggot secretions slowed or killed bacteria including MRSA.48PubMed. Detection and partial characterisation of two antibacterial factors from the excretions/secretions of the medicinal maggot Lucilia sericata and their activity against methicillin-resistant Staphylococcus aureus (MRSA)
These are not the maggots from your bin. They’re raised germ-free, while trash maggots carry bacteria. They’re a species that leaves living tissue alone. And they’re applied under a dressing and removed after a few days by staff.
When the Fear Isn’t Real Maggots
Delusional parasitosis is a fixed belief of being infested by parasites with no evidence of it.49PubMed. Delusional parasitosis: an entomological perspective after a 20-years-experience in two public medical and veterinary entomology laboratories It is more common in women over 50 and can spread within families.50PubMed. Delusional parasitosis: an entomological perspective after a 20-years-experience in two public medical and veterinary entomology laboratories People often see insect experts or skin doctors rather than a mental health professional.51PubMed. Delusional parasitosis: an entomological perspective after a 20-years-experience in two public medical and veterinary entomology laboratories
If this sounds familiar, bring any samples to a doctor, who can check them properly. If tests find nothing, a referral to mental health care is real help, not dismissal. Self-harm in an attempt to remove imagined parasites is a warning sign that needs urgent care.52PubMed. Delusional parasitosis: an entomological perspective after a 20-years-experience in two public medical and veterinary entomology laboratories