Topographic Distribution of the Sand Flea Tunga penetrans in Wistar Rats and Humans in Two Endemic Areas in Brazil

Abstract

Abstract. Tungiasis is a zoonosis caused by Tunga penetrans. In Brazil, tungiasis is endemic in many resource-poor communities, in which various domestic and sylvatic animals act as reservoirs. Eighty laboratory-raised Wistar rats were exposed to T. penetrans in areas of intense transmission: a fishing village and an urban shantytown in Ceará State, northeast Brazil. The topographic distribution of lesions in Wistar rats was compared with the distribution of lesions in humans in the same area. Our results show that the topographic distribution of embedded sand fleas was almost identical in Wistar rats and humans and that lesions were confined to the feet. In humans, 76% of all lesions were located periungually, whereas in Wistar rats, 67% of lesions were located at the distal end of the digits (P = 0.73). Both had the majority of lesions at the toes and digits: 70.2% versus 65.7% (P = 0.79). The Wistar rat model mirrors human tungiasis in topographic distribution.

Tungiasis-associated morbidity in pigs and dogs in endemic villages of Uganda

“…Unlike humans, where sand fleas localise randomly at various sites of the feet [ 10 , 28 , 29 ], this study has revealed that in the case of pigs and dogs, sand fleas on feet preferentially embed at claw coronary bands and nail basement, respectively. Similar to Wistar rats [ 26 ], both pigs and dogs, had more lesions on hind than front legs.…”

“…Indeed all lesions in infected dogs and the majority of lesions in pigs (99.3 %) were located on the limbs. Localization of sand fleas predominantly on feet is not unique to dogs and pigs but this is also the case in most susceptible animal species [ 26 ] and humans [ 10 , 27 ]. This has been attributed to the small size and poor jumping ability of sand fleas [ 9 ].…”