Tungiasis is a parasitic skin disease caused by the sand flea, a tiny insect that burrows into the skin, most commonly the feet. This infestation is often referred to by the common name “jiggers” or “chigoe flea.” It is widespread in tropical and subtropical regions across the Caribbean, South America, and sub-Saharan Africa. The condition causes significant discomfort, pain, and mobility issues, making it a serious public health concern in resource-poor communities.
The Parasite and Tungiasis
The specific culprit is the female sand flea, Tunga penetrans, one of the smallest known flea species, measuring about 1 millimeter in length. These fleas thrive in warm, dry, sandy, or dusty environments, such as beaches, farms, and unsealed earthen floors of homes. Tungiasis is considered a zoonosis, meaning it affects both humans and animals, including pigs, dogs, and cats, which act as reservoirs for the parasite.
The infestation begins when the mated female flea penetrates the outermost layer of the host’s skin, typically around the toes, soles, or heels. Once embedded, the female undergoes a dramatic transformation, increasing its size by up to 2,000 times over one to two weeks as it feeds and its abdomen swells with eggs. Only the posterior end of the flea remains exposed through a small opening in the skin.
This exposed orifice allows the flea to breathe, defecate, and release hundreds of eggs onto the ground, where the life cycle continues. After the eggs are shed, the female flea dies within the skin and is eventually sloughed off by the host’s natural healing processes. This entire cycle causes the characteristic inflammatory reaction associated with tungiasis.
Signs of Infestation and Associated Health Risks
The embedded female flea creates a localized skin lesion that progresses through distinct stages, often starting with a painless, dark spot. As the flea matures, the lesion develops into a small, dome-shaped swelling, or nodule, with a white, watch-glass-like appearance. A characteristic central black dot, which is the exposed posterior end of the parasite, is often visible.
Symptoms include intense itching and significant pain, which can make walking difficult, especially with multiple lesions. The inflammation is a direct result of the host’s immune response. Chronic or severe infestations can lead to ulcers, fissures, and the deformation or loss of toenails.
If left untreated, the lesions serve as entry points for bacteria, causing secondary bacterial infections. Complications include abscesses, cellulitis, and lymphangitis. More severe risks, such as gangrene, bacteremia, and tetanus, are possible, particularly for those not adequately vaccinated against tetanus.
Treatment and Strategies for Prevention
The standard treatment involves the careful and sterile removal of the embedded flea. A trained person should perform this extraction using a sterile needle or scalpel to minimize the risk of secondary bacterial infection. After the parasite is removed, the resulting crater must be thoroughly cleaned and treated with a topical antibiotic cream.
Oral antibiotics are used to treat secondary bacterial infections. While surgical extraction remains the primary treatment for low parasite loads, topical antiparasitic agents like ivermectin or thiabendazole, and newer dimeticone oil products, have also been used.
Prevention focuses on avoiding contact with contaminated soil by consistently wearing closed-toe shoes or thick sandals in endemic areas. Maintaining good foot hygiene, including daily washing with soap and water, is also important. Regular application of insect repellent, especially those based on coconut oil, can deter sand fleas from burrowing.