To remove a botfly larva, doctors usually cut off its air supply first: the larva breathes through a small hole in the skin, so covering the hole with petroleum jelly or an adhesive film makes it move up to the surface, where it can be pulled out whole with tweezers. If it doesn’t come out, a doctor removes it through a small cut under local anesthetic. Never squeeze a botfly lump. Crushing the larva leaves pieces in the skin and can cause infection or a severe reaction.
This guide covers the signs of a botfly, safe removal from people and pets, aftercare, and how to avoid botflies when you travel.
Table of Contents
Signs of a Botfly Larva Under the Skin
- A red, raised lump like a boil or a large pimple that doesn’t come to a head
- A tiny central hole (the breathing pore), often with clear, yellowish or bloody fluid
- A feeling of movement inside the lump, and sudden sharp, stabbing pain
- Itching around the lump
- Sometimes a small white tip visible in the hole when the larva comes up to breathe
Lesions often start out looking like an insect bite or skin infection that won’t heal. The clue is recent travel: the human botfly lives in Central and South America, from Mexico to Argentina, and most cases in the US and Europe are travelers returning from those regions.
How to Remove Botfly Larvae From Human Skin
See a doctor, urgent care clinic or travel medicine clinic, especially if the lump is on the face, near an eye, on the scalp or genitals, or if you have more than one. These are the methods doctors use:
1. Suffocation (occlusion)
Petroleum jelly, a thick ointment or a clear adhesive film is placed over the breathing hole. Starved of air, the larva moves toward the surface within hours, often overnight. It can then be gripped with tweezers at the tip and eased out slowly with steady pressure. Some larvae die under the covering and still need to be removed.
2. Extraction through a small cut
If the larva won’t come out, a doctor numbs the area and widens the opening with a small incision, then lifts the larva out in one piece. The larva has backward-pointing spines, which is why pulling or squeezing without widening the hole tends to tear it.
3. Medication
Doctors sometimes use topical or oral ivermectin to kill the larva or make it leave the skin, particularly when there are several lesions. This needs a prescription.
What not to do
- Don’t squeeze the lump like a pimple. A burst larva leaves fragments that cause inflammation and infection.
- Don’t leave it to come out on its own. Waiting risks painful inflammation and bacterial infection.
- Don’t dig at it with needles or knives at home.
Aftercare
Wash the wound with soap and water, cover it with a clean dressing and watch for infection: spreading redness, warmth, pus or fever. The hole usually heals within one to two weeks. Check that your tetanus vaccination is up to date.
Botfly Removal From Dogs, Cats and Pets
In North America, pets get a different botfly, Cuterebra, the rabbit and rodent botfly. Dogs and cats pick up the larvae by nosing around rabbit burrows and rodent nests, usually in late summer and early fall. Outdoor cats are most at risk.
- Signs: a lump about 1 cm (under half an inch) across with a breathing hole, usually on the head, neck or chest, with matted fur and heavy licking or grooming at the spot.
- Removal: take your pet to the vet. The vet widens the breathing pore and lifts the larva out whole with forceps, then flushes the wound.
- Don’t squeeze it. The Merck Veterinary Manual warns that rupturing the larva can cause a long-lasting reaction, with reports of anaphylaxis.
- Watch for warning signs. Larvae sometimes wander into the nose, eyes or brain. Violent sneezing, seizures, blindness or odd behavior need an urgent vet visit.
Healing takes weeks, and the wound should be kept clean. Horses get their own botflies (Gasterophilus), which lay eggs on the legs and are controlled with routine deworming.
What Is a Botfly?
Botflies are large, hairy flies in the family Oestridae whose larvae grow inside living mammals. The adult human botfly, Dermatobia hominis, looks like a bumblebee-sized bluish fly, about 12 to 18 mm long. Adults have no working mouthparts, don’t bite and live only days to a couple of weeks.
Botfly life cycle
- The female botfly catches a mosquito or other biting insect and glues her eggs to it.
- When the mosquito lands on a person or animal to feed, body heat makes the eggs hatch.
- The larva drops onto the skin and burrows in through the bite or a hair follicle.
- It grows under the skin for about 5 to 10 weeks, breathing through the hole.
- The mature larva leaves the skin, drops to the ground and pupates, then emerges as an adult.
How to Prevent Botflies When Traveling
- Use an insect repellent with DEET or picaridin; botfly eggs arrive on mosquitoes.
- Wear long sleeves and trousers, ideally treated with permethrin, in forests and rural areas.
- Sleep under a mosquito net where screens are poor.
- Iron clothes dried outdoors in tropical regions, since some flies lay eggs on damp laundry.
Travel protection against botflies
- Picaridin or DEET repellent for skin in mosquito areas
- Permethrin clothing spray to treat trousers, shirts and socks
- Travel mosquito net for sleeping where screens are poor
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Botfly FAQs
Cover the breathing hole with petroleum jelly or an adhesive film to cut off air, which makes the larva move to the surface, then grip it with tweezers and ease it out whole. A doctor can also remove it through a small cut under local anesthetic. Don’t squeeze it.
You shouldn’t. Squeezing can burst the larva and leave pieces in the skin, causing inflammation and infection. In pets, rupturing the larva has been linked to severe reactions.
A human botfly larva leaves on its own after about 5 to 10 weeks, but waiting is not recommended because of pain, inflammation and infection risk. Have it removed.
The human botfly lays its eggs on mosquitoes and other biting insects. When they bite, the eggs hatch and the larvae burrow into the skin. It happens in Central and South America.
Botfly larvae rarely cause serious harm to people, but they are painful and can lead to infection. In pets, larvae occasionally migrate to the nose, eyes or brain, which needs urgent veterinary care.
Sources
- Merck Manual Professional: Cutaneous myiasis
- Merck Veterinary Manual: Cuterebra infestation in small animals
- The Lancet Infectious Diseases: Treating infestations of the human botfly
Facts in this guide are checked against the sources above and reviewed when they change. See how we research in our editorial policy.
This article is general information, not medical or veterinary advice. See a doctor or vet to remove a botfly larva.
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