Investigations on the biology, epidemiology, pathology and control of Tunga penetrans in Brazil: I. Natural history of tungiasis in man

Abstract

Tungiasis is an important health problem in poor communities in Brazil and is associated with severe morbidity, particularly in children. The causative agent, the female flea Tunga penetrans, burrows into the skin of its host, where it develops, produces eggs and eventually dies. From the beginning of the penetration to the elimination of the carcass of the ectoparasite by skin repair mechanisms, the whole process takes 4-6 weeks. The present study is based on specimens from 86 patients, for some of whom the exact time of penetration was known. Lesions were photographed, described in detail and biopsied. Biopsies were examined histologically and by means of scanning electron microscopy (SEM). Based on clinical, SEM and histological findings, the ''Fortaleza classification'' was elaborated. This allows the natural history of tungiasis to be divided into five stages: (1) the penetration phase, (2) the phase of beginning hypertrophy, (3) the white halo phase, (4) the involution phase and (5) residues in the host's skin. Based on morphological and functional criteria, stages 3 and 4 are divided into further substages. The proposed Fortaleza classification can be used for clinical and epidemiological purposes. It allows a more precise diagnosis, enables the assessment of chemotherapeutic approaches and helps to evaluate control measures at the community level.

Treatment of Tungiasis with Dimeticone: A Proof-of-Principle Study in Rural Kenya

“…Individuals, aged ≥5 years, with at least one lesion in stage IIa – IIIa of the Fortaleza classification on each foot were eligible [14]. In IIa the sand flea is already completely embedded in the skin of the host and has started to hypertrophy [14].…”

“…The mechanisms underlying the inflammation are complex and only partially understood [11], [12], [13]. Immediately after a successful penetration the female sand flea starts to hypertrophy reaching the size of a pea after 10 days [14]. Through its abdominal rear cone the parasite remains in contact with the environment [14].…”

“…Immediately after a successful penetration the female sand flea starts to hypertrophy reaching the size of a pea after 10 days [14]. Through its abdominal rear cone the parasite remains in contact with the environment [14]. The tiny opening in the skin (250 to 500 µm) is needed for copulation with male sand fleas, breathing, defecation and expelling eggs [14].…”

“…Through its abdominal rear cone the parasite remains in contact with the environment [14]. The tiny opening in the skin (250 to 500 µm) is needed for copulation with male sand fleas, breathing, defecation and expelling eggs [14]. After expulsion of all eggs the female sand flea dies in situ and is discarded from the epidermis by tissue repair mechanisms [14].…”

Health and Safety Issues for Travelers Attending the World Cup and Summer Olympic and Paralympic Games in Brazil, 2014 to 2016

“…The periungual regions of the toes are the preferred penetration site of T penetrans , but they can penetrate skin anywhere on the body. 52 Tungiasis is common in impoverished areas of Brazil. 53 Wearing closed-toe shoes may limit exposure; treatment requires extraction of the parasite.…”