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Tungiasis – Painful Feet in a Tropical Traveler
Abstract & Commentary
By Michele Barry, MD, FACP, and Brian G. Blackburn, MD Dr. Barry is the Senior Associate Dean of Global Health at Stanford University School of Medicine.
Dr. Blackburn is a Clinical Assistant Professor in the Division of Infectious Diseases and Geographic Medicine at Stanford University School of Medicine. Dr. Barry is a consultant for the Ford Foundation, and her program receives funding from the Johnson & Johnson Corporate Foundation.
Dr. Blackburn reports no financial relationships relevant to this field of study.
Synopsis: Tungiasis is an ectoparasite caused by the impregnated female sand flea Tunga penetrans. This is a case report of a traveler who presented with painful foot lesions after spending four weeks in the Pantanal region of Brazil.
Source: Hakeem MJML, Morris AK, Bhattacharyya DN, et al. Tungiasis A cause of painful feet in a tropical traveller. Travel Medicine and Infectious Disease 2010;8:29-32.
A 39-year-old man had traveled for four weeks to the Pantanal region of Brazil, a popular ecotourism area, where he had walked barefoot on several occasions. Ten days before returning to the UK, he noted painful lesions on his feet that were white/pale yellow with a central black punctum. (See Figure 1.) He was afebrile and had no associated lymphadenopathy. Microscopy of excised samples confirmed Tunga penetrans infestation. (See Figure 2.)
Tungiasis is a parasitic skin infestation caused by the female sand flea T. penetrans, or Chigoe flea, which burrows into the epidermis of the host. The flea is endemic in Central and South America as well as the West Indies and sub-Saharan Africa. Its main habitat is warm dry soil and sandy beaches, and the organism is more prevalent during the dry season. To reproduce, the flea requires a warm-blooded host. Domestic animals, rodents, and other wild animals may act as reservoir hosts, as can humans. Once impregnated, the female flea feeds on host blood and releases eggs after a one- to three-week period. Death of the flea follows, and the eggs hatch on the ground, become larvae, and pass through their life cycle.
Severe infestations of more than 100 sand fleas have been described, and secondary superinfection can occur. Surgical extraction of the fleas under sterile conditions is the most appropriate treatment, although oral ivermectin has been reported to be effective.1 A subsequent randomized study has not confirmed the usefulness of ivermectin therapy for this condition.2
A complaint of painful feet with lesions occurring after a tropical trip has a defined differential diagnosis. Cutaneous larval migrans caused by dog and cat hookworm presents as very pruritic lesions, usually on the feet, and they often have a serpentine thread-like subcutaneous lesion that can move slowly through the skin. Botfly or Tumbu fly lesions present a boil-like lesion with a central opening where the larvae head can be seen and even coaxed out with bacon. Other painful foot considerations include verruca vulgaris (plantar warts), various mycoses, pyogenic infections, infected insect bites, dracunculiasis, and melanoma. In short, the best treatment of tungiasis is prevention by wearing shoes and socks as well as by using DEET repellent. The flea is a poor jumper and tends to penetrate the periungual area of the toes, heels, and soles of feet. Thus, flip-flops are not adequate for beach protection, and short socks and shoes should be considered for endemic areas.