Life history of Pygidiopsis crassus n. sp. (Trematoda, Digenea, Heterophyidae) in the neotropical region

Núñez, Margarita Ostrowski de

doi:10.1590/s0074-02761995000100005

Cited by 14 publications

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“…In Argentina the evaluation of freshwater trematodes has focused on morphological descriptions and on the study of the life cycles of diff erent species, whereas considerations of environmental variables aff ecting cercarial emergence have been restricted principally to the infl uence of lightfor example, the number of cercariae emerging per h after exposure to the light (Martorelli, 1984(Martorelli, , 1989(Martorelli, , 1990Ostrowski de Nuñez, 1995;Ostrowski de Nuñez et al, 2003;Davies & Ostrowski de Nuñez, 2012;Fernandez et al, 2013a,b). According to several authors, cercarial emergence from the snail is stimulated by light by means of a larval positive phototropism occurring at the time when the snail tissues emerge -a timing that is, in turn, governed by the circadian light-dark cycle along with temperature differences as Zeitgebers (Morley et al, 2010).…”

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confidence: 99%

Effect of temperature changes on the cercarial-shedding rate of two trematodes

Achiorno

Martorelli

2016

Iheringia, Sér. Zool.

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ABSTRACT. Since temperature is a key condition in the initiation of cercarial emergence, the objective of the work reported here was to evaluate the eff ect of that variable on the shedding of two morphologic and taxonomic types of cercariae. Bioassays were accordingly performed with snails naturally infected with either monostome or pleurolophocercous cercariae because those two cercarial types were found to be the most prevalent in the environment under study. The snails were placed in 6-ml circular plastic dishes with soft plastic stoppers containing 3 ml of reconstituted water and then sequentially exposed for 24 h to a 14:10-h light:dark cycle at 20, 25, or 30 °C. The data were analyzed at a signifi cance level of p <0.05 by means of the InfoStat program. The optimum temperature for cercarial emergence was typically in the range of 25 °C and decreased signifi cantly at 30 °C. We observed no signifi cant diff erence in the number of cercariae emerging between the two morphologic types.KEYWORDS. Parasites, cercarial emergence, freshwater, temperature, bioassay.RESUMEN. Efecto de cambios en la temperatura sobre la emergencia de cercarías de dos trematodes. Considerando que la temperatura es un factor clave en la emergencia de cercarias, el objetivo de este trabajo fue evaluar el efecto de ésta variable sobre la emergencia de dos tipos morfológicos de cercarias. Los bioensayos se realizaron con caracoles naturalmente infectados con cercarias de los tipos monostoma o pleurolofocerca, debido a que estos dos tipos fueron los más prevalentes en el ambiente en estudio. Los caracoles fueron ubicados en cápsulas plásticas de 6 ml conteniendo 3 ml de agua reconstituida, y entonces fueron secuencialmente expuestos por 24 h con un ciclo 14:10 h luz:oscuridad a 20, 25 y 30 °C. Los datos fueron analizados a un nivel de signifi cación de p<0.05 con el programa InfoStat. Los resultados mostraron que la temperatura óptima de la emergencia de cercarias estuvo en el rango de 25 °C, y disminuyó signifi cativamente a 30 °C. Se observó también que no existía diferencia signifi cativa en el número de cercarias emergentes entre los dos tipos morfológicos.PALABRAS-CLAVE. Parásitos, emergencia de cercarias, agua dulce, temperatura, bioensayo.

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Effect of temperature changes on the cercarial-shedding rate of two trematodes

Achiorno

Martorelli

2016

Iheringia, Sér. Zool.

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“…crassus (i.e. 605 vs. 376 µm) (Ostrowski de Núñez 1995). Cercaria of both species possess seven pairs (3+4+4+3) of penetration glands and an identical flame-cell formula 2[(2+2+2) + (2+2+2)] = 24, but differ in the size of tail, which is smaller in Pyg.…”

Section: Discussionmentioning

confidence: 99%

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

Simões¹,

Barbosa

Santos³

2009

Mem. Inst. Oswaldo Cruz

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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...

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“…Indirect immunocytochemistry and phalloidin-fluorescence techniques, allied with confocal laser scanning microscopy, were also used by Borges et al [ 8 ] to describe the muscular and neuronal structures of Pygidiopsis macrostomum , revealing the complex arrangement of muscular fibers and ganglia within the body. Pygidiopsis crassus was reported from Argentina and Venezuela while Pygidiopsis australis only from Argentina; metacercariae were found in small fish, and adults in Himantopus melanurus (Viellot, 1817) and experimentally infected Gallus gallus (Linnaeus, 1758) [ 5 , 6 , 41 , 42 ].…”

Section: Taxonomy and Life Cyclesmentioning

confidence: 99%

Current Knowledge of Small Flukes (Digenea: Heterophyidae) from South America

Santos

Borges

2020

Korean J Parasitol

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Fish-borne heterophyid trematodes are known to have a zoonotic potential, since at least 30 species are able to infect humans worldwide, with a global infection of around 7 million people. In this paper, a ‘state-of-the-art’ review of the South American heterophyid species is provided, including classical and molecular taxonomy, parasite ecology, host-parasite interaction studies and a list of species and their hosts. There is still a lack of information on human infections in South America with undetected or unreported infections probably due to the information shortage and little attention by physicians to these small intestinal flukes. Molecular tools for specific diagnoses of South American heterophyid species are still to be defined. Additional new sequences of Pygidiopsis macrostomum, Ascocotyle pindoramensis and Ascocotyle longa from Brazil are also provided.

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Life history of Pygidiopsis crassus n. sp. (Trematoda, Digenea, Heterophyidae) in the neotropical region

Cited by 14 publications

References 0 publications

Effect of temperature changes on the cercarial-shedding rate of two trematodes

Effect of temperature changes on the cercarial-shedding rate of two trematodes

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

Current Knowledge of Small Flukes (Digenea: Heterophyidae) from South America

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