High exposure to Tunga penetrans (Linnaeus, 1758) correlates with intensity of infestation

Abstract

Tungiasis is a parasitic skin disease widespread in resource-poor urban and rural communities in Brazil. Inhabitants of an urban slum in Northeast Brazil were examined for the presence of tungiasis lesions and followedup twice a week for a period of three weeks. Each time the number, stages, and topographic localization of lesions were recorded on a documentation sheet. The infestation rate (number of newly embedded sand fleas per individual and day) remained stable during the observation period. The infestation rate was significantly related to the intensity of infestation (total number of lesions present) (rho = 0.70, p < 0.0001) and the proportion of viable lesions (rho = 0.28, p < 0. 0001). The results indicate that in an endemic area the infestation intensity and the proportion of viable lesions can be used as a proxy to assess the exposure of individuals at risk for tungiasis. Persistently high infestation rates during the transmission season favour the use of prevention measures against invading sand fleas (such as a repellent) rather than a drug to kill already embedded parasites.Key words: tungiasis -Tunga penetrans -epidemiology -morbidity -Brazil Tungiasis is a neglected parasitic skin disease of impoverished populations (Heukelbach et al. 2001). The ectoparasitosis occurs in Central and South America, the Caribbean and sub-Saharan Africa (Ade-Serrano & Ejezie 1981, Arene 1984, Matias 1989, Chadee 1994, 1998, Carvalho et al. 2003. In Brazil it is widespread in urban squatter settlements, villages in the rural hinterland and in traditional fishing communities along the coast (Wilcke et al. 2002, Carvalho et al. 2003.Community-based studies have consistently shown prevalences between 16 and 55% in typical endemic areas with a peak of age-specific disease occurrence in children 5 to 14 years and the elderly, and a preponderance of infestation in the male sex (Ade-Serrano & Ejezie 1981, Arene 1984, Matias 1989, Chadee 1994, Wilcke et al. 2002, Muehlen et al. 2003.There is a considerable seasonal variation in the intensity of infestation indicating that transmission varies during the year (Heukelbach et al. 2005a). In the semi-arid Northeast Brazil, attack rates decrease as soon as the rainy season begins and re-increase when the weather becomes dryer. Environmental determined patterns in off-host propagation and development of T. penetrans seem to underlie the seasonal variation of attack rates.In contrast to other ectoparasitoses such as scabies and pediculocis, tungiasis is a self-limiting disease with duration of four to six weeks . As reinfestation is the rule and new lesions may appear close to already embedded fleas, cross-sectional surveys cannot be used to infer on local transmission dynamics. However, anecdotal observations from colonial times suggest that transmission dynamics vary considerably from location to location and that attack rates differ between individuals living in the same area (Karsten 1865, Jolly 1926, Gordon 1941.In fact, the number of embedded sand fleas per individual varies ...

Morbidity assessment in sand flea disease (tungiasis)

“…In the endemic area, constant reinfestation is the rule, and individuals may experience up to ten newly embedded sand fleas per day (Feldmeier et al 2006a). Preliminary findings suggest that the accumulation of parasites at certain predilection sites is a risk factor for the development of severe disease .…”

“…Preliminary findings suggest that the accumulation of parasites at certain predilection sites is a risk factor for the development of severe disease . The correlation between the infestation rate and the number of embedded fleas has been shown previously (Feldmeier et al 2006a). To assess the association between the degree of infestation and morbidity, we developed severity scores for acute and chronic clinical pathology in patients with tungiasis.…”

“…The individual infestation rate was determined by dividing the number of newly embedded sand fleas diagnosed at an examination through the number of days passed since the last examination (Feldmeier et al 2006a). …”

Tungíase disseminada tratada com ivermectina

“…Norte. 4,6,7 Tanto os machos quanto as fêmeas se alimentam de sangue, de maneira intermitente, mas a infestação do parasita na epiderme de alguns mamíferos, entre eles o homem, se dá por fêmeas grávidas. 1,4 A história natural da tungíase desenvolve-se em cinco fases, de acordo com a classificação de Fortaleza.…”

Tungiasis - Traveler's Ectoparasitosis of the Foot: A Case Report

“…The most frequent sequelae of Tungiasis are autoamputations of digits, deformation and loss of nails, development of chronic ulceration, gangrene, and difficulty in walking. 8 One also observes the following symptoms during evaluation: erythema, edema, tenderness, itching, pain, shiny skin, desquamation, hyperkeratosis, fissures, pustules, suppuration, ulcers, and difficulty in walking or gripping. 6 The most common location of the lesions is on the feet and between the toes, 10 although an unusual case has been reported of ectopic Tungiasis in the inguinal zone.…”