Belize's Bot Flies: Why This Country?

Botflies are a common issue in Belize, a small Central American country bordered by Mexico, Guatemala, and the Caribbean Sea. The human botfly (Dermatobia hominis) is a large, hairy fly that resembles a bumblebee. It is commonly found in Central and South America and is known to infest humans, particularly in rural areas.

The female botfly deposits its eggs on another insect, typically a mosquito or fly, which then transfers the eggs to a human host when it bites them. The eggs hatch into larvae, which burrow into the skin and breathe through a small hole, causing an itchy lesion. While botfly infestations are rarely seen in the US, they are a common skin problem in Central America.

To prevent botfly bites, it is recommended to wear protective clothing, use bug repellent, and bathe regularly. If bitten, it is important to remove the larvae as soon as possible. Various methods can be used, including suffocation with petroleum jelly or pork fat, manual extraction with tweezers, or surgical excision.

Botfly eggs are deposited on a human host by a mosquito

Botflies, also known as warble flies, heel flies, and gadflies, are a family of flies known as Oestridae. The female botfly captures an arthropod, usually a mosquito, and lays her eggs on its body. This is known as phoresy or phoresia. The mosquito then feeds on the blood of a mammal, and the warmth of the host's body causes the botfly eggs to hatch and fall into the hole created by the mosquito's proboscis. The maggots then burrow into the skin, either through the mosquito bite or any other openings in the skin, such as hair follicles.

The human botfly, Dermatobia hominis, is the only species of botfly known to routinely parasitize humans. It is native to Central and South America, including Belize, and occasionally occurs in the United States. The larvae of the human botfly can be removed by covering the area with petroleum jelly or nail polish to suffocate the larva and force it out, or by surgical excision.

The larvae can be removed by covering the area with Vaseline

The human botfly, scientifically known as Dermatobia hominis, is a species of botfly whose larvae parasitise humans. The female botfly captures a mosquito and attaches its eggs to its body, then releases it. The mosquito then feeds on the blood of mammals, and once it has had its dinner, the botfly eggs fall into the hole created by the mosquito's proboscis. The eggs hatch and the larvae develop inside the subcutaneous layers for about eight weeks, then drop out to pupate.

Other methods of removal include using a venom extractor syringe, applying several coats of nail polish to the area to weaken the larva, or oral use of ivermectin, an antiparasitic medicine.

Botfly infestations are rarely seen in the US

Botflies, also known as warble flies, heel flies, and gadflies, are a family of flies known as Oestridae. Their larvae are internal parasites of mammals, with some species growing in the host's flesh and others within the gut. The human botfly, Dermatobia hominis, is the only species of botfly whose larvae routinely parasitise humans.

In the US, botfly infestations are so rare that doctors are often unfamiliar with them and may recommend unnecessary surgery. In contrast, communities in the tropics have developed their own home remedies for dealing with botflies. For example, locals in Belize suffocate the larvae by applying substances like petroleum jelly, bacon strips, nail polish, or plant extracts over the lesion. After a few hours, the larvae emerge head-first, and tweezers can be used to extract them.

While botfly infestations are uncommon in the US, they can occur, especially for those who travel to tropical regions where botflies are endemic. It is important for travellers to be aware of this potential risk and to take preventive measures, such as using insect repellent and wearing protective clothing, to avoid botfly infestations.

The female botfly deposits eggs on the body of another insect, such as a mosquito

The female botfly is a fascinating creature with a gruesome life cycle. After mating, the female botfly captures a mosquito by holding onto its wings with her legs. She then attaches her eggs—anywhere from 15 to 30 of them—to the mosquito's abdomen. The mosquito, now an unwitting accomplice, goes about its business as usual. When the mosquito lands on a human to feed, the warmth of the human body stimulates the botfly eggs, causing them to hatch and drop onto the skin. The botfly larvae then burrow into the skin through the mosquito bite wound, hair follicles, or other bodily crevices.

The female botfly's choice of mosquito as an intermediary is an ingenious strategy. Mosquitoes are blood-sucking insects that feed on mammals. By depositing her eggs on a mosquito, the female botfly ensures that her offspring will have access to a warm-blooded host, which is necessary for their survival. The mosquito acts as a vehicle, delivering the botfly larvae to their ideal environment.

Once the larvae are on human skin, they begin the process of burrowing and creating a breathing hole to survive. This is when their presence may be noticed by the human host, often in the form of a pimple-like lesion with a hole in the centre. The human botfly, with the scientific name Dermatobia hominis, is the only species of botfly that routinely parasitizes humans. While botfly infestations are rare in the United States, they are a common occurrence in Central America, including Belize.

The good news is that botfly larvae are not lethal to their human hosts. The wounds caused by the larvae will typically heal within a few days or weeks after the larvae exit the skin. However, the process of having botfly larvae living and feeding under one's skin is undoubtedly a disturbing and unpleasant experience.

The larvae breathe through a central punctum

The human Botfly (D. hominis) is native to Central and South America. The female human Botfly lays her eggs on the body of an intermediate host, usually a mosquito, or fly, which acts as a vector onto the human skin when it feeds. The heat of the skin causes the eggs to hatch into larvae. The larvae form a tumour (called a warble) in the subdermal zones of their host and remain at this location until larval development is complete. Larval development varies among species, ranging from 20 to 60 days. Before pupating, the larvae leave the host's skin and drop to the soil.

The clinical presentation of myiasis is a localised, itchy, erythematous raised skin lesion with a central punctum through which the larva may occasionally be seen and through which it breathes. A serous, bloody and rarely purulent discharge can occur.

The larvae of the human botfly do not migrate far into the skin from its point of entrance. This is in contrast to other subfamilies of the botfly.

Frequently asked questions