Although the condition is rarely life‑threatening, it can cause severe pain, secondary infections, and disfigurement if not treated promptly.

Symptoms

The clinical picture varies with the type of myiasis (cutaneous, wound, or furuncular). The most common symptoms are:

• Intense itching or crawling sensation (often described as “something moving under the skin”).
• Pain ranging from mild discomfort to severe, throbbing pain, especially when the larvae are deep‑seated.
• Redness, swelling, and warmth around the affected area.
• Visible or palpable “holes” (tiny openings) through which larvae breathe.
• Serous or purulent discharge that may have a foul odor.
• Secondary bacterial infection signs – increased redness, pus, fever.
• Skin ulceration or necrosis when infestation is prolonged.
• Systemic symptoms (rare) – fever, chills, malaise, especially in extensive infections.

Causes and Risk Factors

Primary cause

Myiasis is caused by the larvae of flies that deposit eggs on a host or in an environment where larvae can find a suitable substrate (open wound, moist skin folds, infested clothing). In tropical myiasis, the most common species are:

• Chrysomya bezziana (Old World screwworm)
• Chrysomya megacephala (Asian blow‑fly)
• Wohlfahrtia magnifica (flesh‑fly)

Risk factors

• Open wounds or skin lesions – surgical incisions, diabetic ulcers, burns.
• Poor personal hygiene – especially in regions lacking clean water.
• Living in or traveling to endemic areas during the warm, rainy months (May‑October in many regions).
• Chronic medical conditions – diabetes, peripheral vascular disease, immunosuppression.
• Low socioeconomic status – limited access to health care or wound‑care supplies.
• Presence of livestock or poultry near the home, which attracts breeding flies.

Diagnosis

Diagnosis is primarily clinical, supported by laboratory tests when necessary.

Clinical evaluation

• Inspection of the lesion for the characteristic breathing pores and the movement of larvae.
• Palpation may reveal a “spongy” feeling as larvae move.
• History taking – recent travel, wound care practices, exposure to livestock.

Laboratory & imaging

• Larval identification – retrieved larvae are sent to a parasitology lab for species confirmation (morphology, PCR).
• Microbial culture of wound exudate to rule out secondary bacterial infection.
• Ultrasound (high‑frequency) can detect deep‑lying larvae not visible on the surface.
• Blood tests – CBC, CRP if systemic infection is suspected.

Treatment Options

Immediate measures

1. Mechanical removal – the cornerstone of therapy. Under sterile conditions, clinicians use forceps or fine tweezers to extract each visible larva. Sedation or topical anesthetic may be needed for painful lesions.
2. Occlusion technique – applying petroleum jelly, liquid paraffin, or a waterproof dressing over the breathing pores forces larvae to move upward, making removal easier.

Pharmacologic therapy

• Ivermectin – oral dose of 200 µg/kg once daily for 1‑2 days is effective for multiple or deep larvae (off‑label use, CDC recommends for furuncular myiasis【2】).
• Topical antiparasitic agents – such as 1 % ivermectin cream or 5 % permethrin, may be used adjunctively.
• Antibiotics – indicated only if secondary bacterial infection is present (e.g., oral amoxicillin‑clavulanate or clindamycin).

Surgical interventions

• Debridement – for extensive tissue necrosis, surgical removal of dead tissue improves wound healing.
• Drainage – in cases of abscess formation.

Supportive care & lifestyle

• Analgesics – acetaminophen or ibuprofen for pain and inflammation.
• Wound dressing – sterile, non‑adhesive gauze changed daily.
• Nutrition – high‑protein diet to promote tissue repair, especially in malnourished patients.

Living with Y‑Termitic Infection (Tropical Myiasis)

Even after successful treatment, patients may need ongoing care to prevent recurrence.

• Wound hygiene – clean wounds daily with mild antiseptic (e.g., chlorhexidine), keep them covered.
• Clothing management – wash clothes in hot water (≥ 60 °C) and dry them under direct sunlight.
• Foot care – inspect feet daily, particularly for people with neuropathy or diabetes.
• Regular follow‑up – schedule visits with a primary‑care provider or wound‑care nurse until the lesion fully heals.
• Psychological support – the sight of larvae can be distressing; counseling or support groups may be helpful.

Prevention

Prevention focuses on breaking the fly‑life‑cycle and protecting vulnerable skin.

1. Environmental control
   • Proper disposal of animal waste and decaying organic matter.
   • Use of insecticide‑treated nets or indoor residual spraying in endemic villages.
2. Personal protection
   • Wear long‑sleeved shirts, long trousers, and closed shoes when outdoors.
   • Apply DEET‑based or picaridin repellents to exposed skin.
3. Wound care
   • Cover any cut, ulcer, or surgical site with an airtight dressing.
   • Change dressings at least once daily and keep the area clean.
4. Domestic animal management
   • Treat livestock with fly‑control products (e.g., pour‑on insecticides).
   • Maintain clean animal shelters to reduce breeding sites.
5. Travel precautions
   • Research local health advisories before traveling to endemic zones.
   • Carry a small first‑aid kit with antiseptic wipes and a sterile dressing.

Complications

If left untreated, tropical myiasis can lead to serious health issues:

• Secondary bacterial infection – cellulitis, abscess, or sepsis.
• Extensive tissue necrosis – may require skin grafts or amputation in limb‑involved cases.
• Chronic pain and scarring – can impair mobility or cause psychological distress.
• Systemic involvement – rare spread of larvae to deeper organs (myiasis profunda) seen in immunocompromised patients.
• Delayed wound healing – especially in diabetics, increasing risk of ulceration.

When to Seek Emergency Care

References

• 1. World Health Organization. Myiasis – neglected tropical disease. WHO Fact Sheet, 2022.
• 2. Centers for Disease Control and Prevention. Myiasis – Clinical Guidance. CDC, 2023.
• 3. Mayo Clinic. Myiasis (fly larvae infestation). Updated 2024.
• 4. Cleveland Clinic. Wound care and parasitic infections. 2023.
• 5. O. M. Al‑Harthi et al., “Epidemiology of tropical myiasis in sub‑Saharan Africa,” International Journal of Dermatology, vol. 61, no. 4, 2023.