The life history of Pygidiopsis macrostomum Travassos, 1928 (Digenea: Heterophyidae)

Abstract

Pygidiopsis macrostomum Travassos, 1928, originally described based on a single specimen from Rattus norvegicus (Erxleben) in Brazil, has also been reported from a piscivorous bat, Noctilio leporinus mastivus Ribeiro, in Cuba (Odening 1969, Zdzitowiecki & Rutkowska 1980. We have previously redescribed this species from the holotype and adults obtained from hamsters Mesocricetus auratus Waterhouse experimentally infected with metacercariae from naturally infected guppies Poecilia vivipara Bloch and Schneider taken from Rodrigo de Freitas Lagoon in Rio de Janeiro (RJ), Brazil (Simões et al. 2005). However, other aspects of the life history and biology of this species, especially in relation to the first intermediate host, still need to be elucidated. In this work, the life cycle was completed under laboratory conditions and we provide new host records along with the first descriptions of the redia and cercaria. MATERIALS AND METHODSThe guppies Poe. vivipara, Phalloptychus januarius (Hensel) and Jenynsia multidentata (Jenyns) were collected on the edge of the Rodrigo de Freitas Lagoon, RJ, Brazil (22º57'2"S, 43º11'9"W) and examined for metacercariae. A hydrobiid snail, Heleobia australis (d´Orbigny), was collected in the same lagoon and examined for cercariae. Poe. vivipara and H. australis were reared in the laboratory in filtered lagoon water to provide specimens devoid of infection.Two experimental infections (summer and winter) were performed. For each experiment, one hamster M. auratus was fed with the mesenteries of four naturally infected Poe. vivipara and, on the fourth day postinfection (dpi) each was examined for ovigerous adults of Pyg. macrostomum. Two uninfected stocks of snails (summer and winter) were exposed to infection by placing the eggs of adult Pyg. macrostomum, obtained experimentally from hamsters in their aquaria. Laboratory-reared Poe. vivipara (4 in each experiment for summer and winter) were exposed to cercariae obtained from these experimentally infected H. australis. One hamster for each experiment was fed with the mesenteries of the experimentally infected fish and later examined at four dpi for adults of Pyg. macrostomum.All larval stages and adults were studied live, with or without vital stains. Semi-permanent slides were prepared in glycerine jelly (Moravec 1994) and glycerine/picric acid (Ergens 1969). Other specimens were fixed in 70% alcohol or hot 4% formaldehyde solution, stained with Gomori's trichrome or alcoholic chloridric carmine, cleared in beechwood creosote and mounted in Canada balsam. Illustrations were made with the aid of a drawing attachment on a Leica DM LS2 microscope. Measurements are presented as the range, with the mean in parentheses.For scanning electron microscopy (SEM), specimens were fixed for 1h at rt with 2.5% glutaraldehyde in 0.1 M Na-cacodylate buffer and washed in the same buffer. Specimens were post-fixed for 3 h at rt in a solution of 1% osmium tetroxide in 0.1 M Na-cacodylate buffer, dehydrated in an ascending acetone series, dried by criticalpo...

Molecular characterization and confocal laser scanning microscopic study of Pygidiopsis macrostomum (Trematoda: Heterophyidae) parasites of guppies Poecilia vivipara

“…The Syrian hamster ( Mesocricetus auratus Waterhouse, 1814) was used successfully as an experimental definitive host (Simões, Barbosa & Santos ; Simões et al . ).…”

“…pindoramensis, but no genetic or cytochemical data have been reported for either parasite species (Simões et al . , , ).…”

“…In Brazil, the common rat Rattus norvegicus (Erxleben, 1777) has been reported as a natural definitive host, as has a piscivorous bat, Noctilio leporinus mastivus True, 1884, from Cuba (Travassos 1928;Odening 1969;Zdzitowiecki & Rutkowska 1980). The Syrian hamster (Mesocricetus auratus Waterhouse, 1814) was used successfully as an experimental definitive host (Simões, Barbosa & Santos 2005;Simões et al 2009).…”

“…Previous studies have described the morphology and life cycle of A. (P.) pindoramensis, but no genetic or cytochemical data have been reported for either parasite species (Simões et al 2005(Simões et al , 2006(Simões et al , 2009.…”

Hidden diversity in spring snails from the Andean Altiplano, the second highest plateau on Earth, and the Atacama Desert, the driest place in the world

“…The group is characterized by small species that live in marine, brackish, and freshwater environments, and whose shells generally are less than 10 mm in length (Biese 1944(Biese , 1947Hershler and Thompson 1992). The species have a wide range of ecological tolerances and reproductive strategies Marcus 1963, 1965;Cazzaniga 1982a;Martín 2002;Neves et al 2010;Collado and Méndez 2011), and some of them serve as intermediate hosts in the life cycles of digenean trematodes (Etchegoin and Martorelli 1997;Simões et al 2008Simões et al , 2009Simões et al , 2010Alda et al 2010;Merlo and Etchegoin 2011). Kroll et al (2012) studied the phylogenetic relationships of species mainly distributed in the Altiplano region and its major internal Lake Titicaca, and this is the only phylogenetic study performed in the genus Heleobia.…”