A young Australian zoologist presented in Perth, Western Australia, with a lesion on his foot (Fig. 1). He stated that he had recently returned from an expedition to West Africa. While there, the lesion on his foot had appeared. It had started as a small papule and had increased in size and ulcerated. On examination of the lesion, a number of tiny white bead-like globules had fallen out.
Fig. 9.1 - Lesion on foot of patient (Courtesy, Dr Keith Ott)
The patient is suffering from tungiasis - infection with the jigger (chigoe) flea, Tunga penetrans. This flea was originally native to parts of Latin America, but was introduced into Angola in West Africa from Brazil. It has subsequently spread into East and Central Africa (Alexander, 1984) and has been described from Zimbabwe (Goldsmid, 1981). It has also spread to Madagascar, and to India and Pakistan. (Alexander, 1984).
The flea inhabits sandy soil, but the pregnant females require blood meals for completion of their life cycles. They thus seek out a suitable mammalian hosts such as pigs or humans. The female flea burrows into the skin of people walking barefoot and the abdomen of the flea swells until it is packed with eggs. The eggs are discharged from the lesion to fall onto the ground and develop into flea larvae which then pupate and eventually give rise to adult male and female fleas in the soil (Alexander. 1984).
Diagnosis is made on clinical grounds, lesions (single or multiple) being associated with an itch and mild pain in patients with a history of travel to known endemic areas. Lesions may ulcerate and secondary bacterial infection may result. Discharge of the eggs from the lesion may give a clue to the aetiology of the lesion. Probing the lesion and a biopsy may reveal fragments of the female flea (Fig.2) which may, however, be difficult to identify. Occasionally, if carefully and skilfully done, probing may remove the female flea complete, allowing a definitive diagnosis to be made (Fig. 3).
Fig. 9.1 - Photomicrograph of histological section of
jigger flea in biopsy from a lesion
Fig. 9.3 - Adult female Tunga penetrans removed from a lesion (Note greatly enlarged and swollen abdomen and “angled” head)
Alexander, J.O’D (1984) Arthropods and Human Skin. Springer-Verlag. Berlin
Goldsmid, J.M. (1981). Tungiasis in Zimbabwe. C.Afr.J.Med. 27; 151-152