What is myiasis, causes, types, treatments and more


What is myiasis

Myiasis is a skin infection caused by fly larvae that are deposited in necrotic skin tissues or not. The larvae host can be any vertebrate, even humans.

More frequent in tropical and subtropical countries, such as those in Central America, South America, Africa and components of the Caribbean Islands, the disease ends up affecting more people in underdeveloped countries most of the time, because they do not have adequate sanitation and basic hygiene conditions. But it is important to keep in mind that anyone who does not take appropriate preventive or treatment care is also vulnerable to contracting the disease.

Types of Myiasis

Myiasis can be classified into three types, which vary according to the way in which the eggs of the transmitting fly were deposited.

Primary myiasis or furunculoid

In primary myiasis, the fly’s eggs are deposited on the healthy skin and, when they hatch, the larvae invade the host’s subcutaneous tissues. The primary myiasis larvae are popularly known as berne.

Secondary myiasis

In this type of myiasis, the fly’s eggs are deposited in open wounds and their larvae feed on this already necrotic tissue. Popularly, these larvae are known as bicheira.

Accidental myiasis or pseudomyiasis

Less common in humans, accidental myiasis occurs when someone eats a food that is infected with fly larvae, which can consequently cause serious disorders.

What are the causes of myiasis

As already mentioned, myiasis occurs due to fly larvae that develop in skin tissues, whether they are human or not. Therefore, the main cause of acne is some types of flies, which we explain in more detail which are below.

Primary myiasis

Primary myiasis is caused by the larvae of the following flies:

  • Dermatobia hominis , the blowfly;
  • American callitroga .

The eggs of these species hatch in 24 hours and their larvae develop in healthy skin areas of the host, as previously mentioned.

Secondary myiasis

Secondary myiasis is caused by fly larvae belonging to the following species:

  • Cochliomyia hominivorax .

This species of fly usually “attacks” the open wounds of the host or in its cavities, such as nose, ear, eye and mouth.

Accidental myiasis

This type of myiasis happens rarely, but it can be caused by 4 different types of larvae:

  • Stratyomidae ( Hermetia illuscens );
  • Syrphidae ;
  • Muscidae ;
  • Tephritidae (guava bug).

Myiasis risk groups

The disease can affect anyone, even when they are in healthy clinical conditions, but people who fit into the groups below need to be aware of their hygiene, as they tend to be an easier target.

The groups most at risk of contracting myiasis are:

  • Sick patients;
  • Seniors;
  • Mentally handicapped.

Read more: Passion fruit heel: what it is, cause and treatment

Is myiasis contagious?

The contagion of myiasis occurs only through the deposit of fly eggs and there is no possibility of it being done through one person to another.

Symptoms of Myiasis

In most cases, a lump forms where the larva has entered the person’s body. In addition, the sensation of discomfort may be recurrent in the region, since the larva, once it begins to develop, moves around different skin locations.

Symptoms of primary myiasis

In the case of this type of myiasis, the main symptom is the formation of a reddish nodular lesion with a central orifice, through which yellowish pus or with blood remains.

This lump can occur anywhere on the body and is usually itchy and stinging in the area.

Secondary myiasis symptoms

Secondary myiasis occurs, as already explained, in open wounds or in the body cavities. When the fly lays its eggs in these places, and they hatch, the larvae begin to feed quickly on the skin tissue, whether it is healthy or not.

They are usually able to penetrate the tissue they are in, which ends up forming large cavities in the body. The larvae present themselves in a large quantity at once.

Myiasis diagnosis and treatment

If you have symptoms of myiasis, the ideal is to immediately seek a dermatologist, a doctor specializing in skin diseases, so that he can diagnose you.

The diagnosis basically consists of the clinical analysis of the signs that exist in your body. The hosted larva needs to come out of the hole, from time to time, to breathe. When there is a realization that she is really there, the doctor starts the treatment.

Treatment of primary myiasis

For this myiasis, it is normal for the doctor to expel the larva from its body by expressing the nodule or, as most of the times, by slightly widening the hole for the removal of the host with forceps.

Once this is done, topical antiseptics or antibiotics are applied to the wound to protect it from any subsequent injuries.

Treatment of secondary myiasis

Treatment of this type depends largely on the location and extent of the cavity formed by the larvae. What the doctor usually does is prescribe a medication orally (usually Ivermectin ) so that the animals die and thus are removed from the host’s body.

The cleaning and care of the secondary myiasis wound, after the removal of the larvae, is the same as that of the primary.


NEVER self-medicate or stop using a medication without first consulting a doctor. Only he will be able to tell which medication, dosage and duration of treatment is the most suitable for his specific case. The information contained on this site is only intended to inform, not in any way intended to replace the guidance of a specialist or serve as a recommendation for any type of treatment. Always follow the instructions on the package insert and, if symptoms persist, seek medical or pharmaceutical advice.

What are the complications of myiasis?

Complications of myiasis usually arise from the primary type of the disease and they are:

  • Abscesses (swelling produced by the accumulation of pus);
  • Lymphangitis (inflammation of the lymphatic vessels);
  • Tetanus (the one more rarely).

How do I prevent myiasis?

In the first instance, personal hygiene helps a lot when it comes to preventing the disease. But in addition, there are other ways to prevent myiasis, such as:

  • If you travel to places where the disease is frequent, try to keep a large part of your body covered, avoiding mosquito bites. In addition, always use repellent.
  • If you live in places with high incidence of myiasis, protect yourself by using window screens and mosquito nets.
  • In tropical areas, iron all the clothes you leave to dry on the clothesline.

Other than that, share this article with your acquaintances. Remember: the more people who know about the disease, the more prevention it will have around the world!