Investigations on the life cycle and morphology of Tunga penetrans in Brazil

Abstract

In the present study, the life cycle of Tunga penetrans was established in Wistar rats in the laboratory, and the morphology of the resulting developmental stages was studied by means of light and scanning electron microscopy. It was seen that the females enter at a nonfertilized stage through the skin of their hosts. Only there the copulation occurs, while females and males brought together in a Petri dish showed no interest in each other. In any way -- fertilized or not -- the females start about 6 days after penetration and hypertrophy with the ejection of eggs. While fertilized eggs proceed to development, the unfertilized ones remain arrested. The eggs are ovoid and measure about 600 x 320 mum. The larvae hatch from the eggs 1-6 days (mean 3-4) after ejection. Formation of larvae 2 took at least another day, while 4 up to 10 days more were needed until this larva starts pupation (mean 5-7 days). The formation of the adult fleas inside the puparium occurred within 9-15 days (with a maximum hatch at day 12). Adult female fleas having reached the skin of a host start blood sucking within 5 min and prepare to enter the skin. After 24 h, the flea stacked already with two thirds of its body inside the skin. After 40 h, the penetration was completed, and feeding and hypertrophical enlargement started, which was completed on day 6, when eggs became ejected. When studying the morphology of the fleas obtained from different hosts, slight variations were seen, which, however, are not significant for a species separation but may be an indication of the presence of different strains/races or the beginning of such a formation.

Neosomes of tungid fleas on wild and domestic animals

“…Another category of host is experimental animals, such as Mus musculus (Lavoipierre et al 1979) and Wistar rats (an albino strain of Rattus norvegicus ), which are used to establish the life cycle of T. penetrans in the laboratory (Feldmeier et al 2007; Nagy et al 2007), or dogs, which are used to test the efficacy of drugs against tungiasis (Klimpel et al 2005). …”

“…The choice of these respective sites depends upon the following factors: (i) regions that regularly contact the soil, such as the feet in humans and domestic and wild animals or the ventral abdominal region in both domestic and wild mammals; (ii) areas from which the hosts have the greatest difficulty dislodging the parasites by grooming or eating, such as the ears and tail in rats or the ventral abdominal region in edentates, which are devoid of incisor teeth and nails; and (iii) the structure of the hair and thickness of the coat related to microclimates such as temperature and skin structure, as in bats and pangolins (Marshall 1981). According to Nagy et al (2007), older cats and dogs have fewer neosomes than young individuals because of the thicker skin on their paws. Because species of Tunga have a reduced pleural arch (Traub 1972) and, consequently, are unable to jump very high, the lesions produced by T. penetrans are more concentrated or confined to the feet of animals, as reported by Klimpel et al (2005).…”

Assessment of Socioeconomic status and the Prevalence of Tungiasis in Jimma and Wolaita sodo, Ethiopia

“…Most of the houses were of kacha or semipucca type with muddy or sandy floorings. The inadequate health care and unhygienic behavior of the population also contributed a significant role in the spreading of the disease [9,12]. Close contact with the animals also an important factor in the high prevalence of this disease in the studied area (8) .…”

“…As this disease affects both human and animal, close contact of the animals increases the chance of infection [8,9]. Tunga penetrans complete its life cycle in the sandy or muddy floor of the houses and it premises.…”

In VitroEfficacy of Four Insecticides Against Eggs of Tunga penetrans (Siphonaptera)

“…To obtain fertile T. penetrans eggs, laboratory-raised Wistar rats were exposed according to procedures described previously on compounds in the outskirts of Uberlândia where tungiasis occurs [15][16][17].…”