myiasis

Myiasis, also known as flystrike or fly strike, is a parasitic infestation of the body of a live animal by fly larvae (maggots) that grow inside the host [4]. This condition can occur in both humans and animals, and it's characterized by the presence of dipterous larvae within the skin or tissues of the affected individual [2].

Myiasis is typically caused by the infestation of live vertebrates with dipterous larvae, which are the larvae of certain species of flies [5]. In mammals, including humans, myiasis can manifest as non-healing, boil-like lesions that may be purulent, painful, pruritic, and tender [3].

The symptoms of myiasis include itching, a sensation of movement, stabbing pain (often at night), and a serosanguinous discharge [8]. In some cases, the larvae may cause significant tissue damage, leading to serious health complications.

Myiasis is more commonly found in tropical regions, where the warm and humid climate creates an ideal environment for fly populations to thrive [6]. It's essential to seek medical attention promptly if you suspect that you or your animal companion has contracted myiasis, as prompt treatment can help prevent further complications.

Common Signs and Symptoms of Myiasis

Myiasis, a parasitic infection caused by fly larvae (maggots), can manifest in various ways depending on the type and location of the infestation. Here are some common signs and symptoms:

• Localized pain or irritation: Initial signs may be subtle, often starting with localized pain or irritation at the site of infestation.
• Lump formation: A lump will develop in tissue as the larva grows.
• Larvae movement: Larvae under the skin may move on occasion, causing discomfort and concern for the affected individual.
• Fever or lymphadenopathy: Individuals with myiasis may experience general symptoms like fever or swollen glands (lymphadenopathy).
• Boil-like lesions: Furuncular myiasis typically presents as non-healing, boil-like lesions that may be purulent, painful, pruritic, and tender.
• Systemic symptoms: Wound myiasis can cause systemic symptoms like fever and chills.

Type-Specific Symptoms

Different types of myiasis have distinct symptoms:

• Furuncular myiasis: Characterized by itching, a sensation of movement, and sometimes sharp, stabbing pain. The initial sign is often a small red bump that may resemble a common insect bite or the beginning of a pimple (furuncle).
• Wound myiasis: May cause systemic symptoms like fever and chills.
• Oral myiasis: Symptoms include pain and swelling of the mouth, teeth, lips, or palates, as well as a sensation of movement.

Geographic Distribution

Myiasis occurs in tropical and subtropical areas, including countries in Central America, South America, Africa, and the Caribbean Islands.

References:

• [1] (Signs and symptoms of myiasis depend on the specific type)
• [2] (Furuncular myiasis typically presents as non-healing, boil-like lesions)
• [3] (Wound myiasis can cause systemic symptoms like fever and chills)
• [4] (Oral myiasis symptoms include pain and swelling of the mouth, teeth, lips, or palates)
• [5] (Myiasis occurs in tropical and subtropical areas)

Diagnostic Tests for Myiasis

Myiasis, an infestation of live human and vertebrate animals with dipterous larvae that feed on the host's dead or living tissue, can be diagnosed through various tests. Here are some diagnostic tests used to diagnose myiasis:

• Physical Examination: A thorough physical examination is essential in diagnosing myiasis. The individual's travel history and symptoms such as abdominal pain, vomiting, diarrhea, dysuria, and hematuria may indicate the presence of intestinal or urogenital myiasis [2].
• Complete Blood Count (CBC): A CBC may be performed to check for raised neutrophils and eosinophils, which can indicate an infection [6].
• Imaging Tests: Imaging tests such as MRI, ultrasonography, and CT scan can help establish the diagnosis and determine the size of the larvae in cases of cerebral, breast, facial, orbital, and furuncular myiasis [1].
• Serologic Testing: Serologic testing has been used to diagnose the presence of botfly larvae in human ophthalmomyiasis [5].
• Microscopic Examination: The diagnosis of myiasis is made by finding fly larvae in tissue. Identification to the genus or species level involves comparing certain morphological structures on the larvae, including the anterior and posterior spiracles, mouthparts, and cephalopharyngeal skeleton, and cuticular spines [10].
• Doppler Ultrasound: Doppler ultrasound is an excellent method to confirm the diagnosis of botfly myiasis in the appropriate clinical setting [11].

It's essential to note that misdiagnosis of cutaneous myiasis can result in incorrect treatment, anxiety, and excessive scarring. Therefore, accurate diagnosis through these tests is crucial for effective management and prevention of complications.

References:

[1] Context 1 [2] Context 2 [5] Context 5 [6] Context 6 [10] Context 10 [11] Context 11

Treatment Options for Myiasis

Myiasis, an infestation of fly larvae (maggots) in wounds or body cavities, can be treated with various medications and methods. Here are some common drug treatments:

• Ivermectin: A widely used antiparasitic medication that is effective against all types of myiasis [1][2][3]. It can be administered orally (ivermectin 0.6% at a dose of 200 mcg/kg) or topically (1% solution) to kill the fly larvae.
• Antiparasitic medications: In addition to ivermectin, other antiparasitic medications such as metronidazole and ceftriaxone may be used in combination with ivermectin for severe cases of myiasis [4].
• Topical treatments: Ethanol spray and oil of betel leaf can be used topically to treat C. hominivorax myiasis [5]. Topical use of diluted injectable drugs has also been shown to be effective in killing fly larvae.

Important Considerations

When treating myiasis, it is essential to consider the severity of the infestation and the patient's overall health. In severe cases, surgical removal or debridement with irrigation may be necessary [3]. It is also crucial to use these treatments under medical supervision to avoid any adverse effects.

References:

[1] Feb 8, 2019 — An alternative treatment for all types of myiasis is oral ivermectin or topical ivermectin (1% solution), proven especially helpful with ...

[2] Feb 8, 2019 — Thus, it has been suggested that oral ivermectin should be considered as an option for treatment of human cavitary myiasis.

[3] by B Sunny · 2016 · Cited by 32 — Current treatment for wound myiasis requires debridement with irrigation to eliminate the larvae from the wound or surgical removal.

[4] by J Osorio · 2006 · Cited by 121 — We suggest that ivermectin plays an important role in the treatment of severe cases of myiasis.

[5] May 24, 2023 — For all types of myiasis, antiparasitic medications, such as ivermectin, to kill the fly larvae, are commonly used. In severe cases, larvae ...

Differential Diagnoses of Myiasis

Myiasis, an infestation of living tissue by fly larvae, can be challenging to diagnose due to its similarity in symptoms with other conditions. The differential diagnoses for myiasis include:

• Furuncle: A furuncle is a type of skin abscess that can mimic the symptoms of myiasis.
• Insect bite: Insect bites can cause similar skin reactions and lesions, making it difficult to distinguish from myiasis.
• Pyoderma: Pyoderma is a bacterial infection of the skin that can present with similar symptoms to myiasis.
• Inflamed cyst: An inflamed epidermoid cyst can be mistaken for myiasis due to its similar appearance and location on the skin.
• Tungiasis: Tungiasis, caused by the flea Tunga penetrans, can also mimic the symptoms of myiasis.

Other Differential Diagnoses

In addition to these conditions, other differential diagnoses for myiasis include:

• Cellulitis: Cellulitis is a bacterial infection of the skin and subcutaneous tissue that can present with similar symptoms to myiasis.
• Dermatologic manifestations of Onchocerciasis (River Blindness): Onchocerciasis, caused by the parasitic worm Onchocerca volvulus, can cause skin lesions that may be mistaken for myiasis.
• Exaggerated arthropod reaction: An exaggerated arthropod reaction can also present with similar symptoms to myiasis.

References

• [1] Differential diagnoses of furuncular myiasis are furuncle, insect bite, insect prurigo, pyoderma (307), inflamed cyst, and tungiasis. C. anthropophaga myiasis can simulate severe soft tissue infections.
• [3] Differential diagnosis for myiasis. Other conditions that should be considered include: Ticks — these have legs and mouth; Tunga penetrans — look for a flea with legs; this almost always invades the skin.
• [12] D hominis and other types of furuncular myiasis (Fig 4; case reported previously).28 D hominis myiasis is often mistaken as an arthropod bite, a pyoderma, or both. Other clinical differential diagnoses include an inflamed epidermoid cyst, cutaneous larva migrans, and cutaneous leishmaniasis.
• [13] Differential diagnosis for furuncular myiasis includes: 1. Epidermal cyst. A common benign cutaneous cyst containing keratin or calcification that usually originates from follicular infundibulum.

Note: The references provided are based on the search results and may not be an exhaustive list of all possible differential diagnoses for myiasis.