A new morphological analysis of eggs and miracidia of Paratanaisia bragai (Digenea: Eucotylidae)
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ORIGINAL ARTICLE
A new morphological analysis of eggs and miracidia of Paratanaisia bragai (Digenea: Eucotylidae) Vanessa Barreto Xavier 1,7 & Aleksandra Oliveira-Menezes 2 & Viviane Sant’anna de Souza 3 & Solange Viana Paschoal Blanco Brandolini 4 & Wanderley de Souza 3 & Renato A. DaMatta 5 & Jairo Pinheiro 6 Received: 10 June 2020 / Accepted: 11 September 2020 # Institute of Zoology, Slovak Academy of Sciences 2020
Abstract Paratanaisia bragai is a trematode that reaches sexual maturity in the kidney collecting ducts of domestic and wild birds, while the gastropods Subulina octona and Leptinaria unilamellata serve as its intermediate hosts. The morphology of P. bragai eggs is described here for the first time, using light, scanning and transmission electron microscopy. Embryonic eggs, obtained from adult worms collected from naturally infected definitive hosts, appeared elliptical, with an evident operculum, by all three microscopic techniques employed. Scanning electron microscopy revealed that the abopercular region presents a prominent U-shaped knob, which stands out from the egg surface. The thickness of the eggs, measured from ultrathin sections, were 0.34 ± 0.06 µm (0.29–0.50) at the ends and 0.31 ± 0.05 µm (0.24–0.36) in the middle region. The internal shell layer was more electrondense and thinner than the middle layer, which comprised nearly the entire shell, while the external layer was less electron-dense and thinner than the internal layer. Rupture of the eggs, by the coverslip pressure, revealed the miracidia of P. bragai that was characterized by light and transmission electron microscopy. Keywords Paratanaisia bragai . Eggs . Microscopy . Miracidium . Larval trematode . Ultrastructure
Introduction Paratanaisia bragai (Santos, 1934) Freitas, 1959 is a trematode that reaches sexual maturity in the kidney collecting ducts of domestic and wild birds. For larval development, it mainly uses the snail Subulina octona (Bruguière, 1798), although Leptinaria unilamellata (d’Orbigny, 1837) (Mollusca, Gastropoda, Pulmonata) has also been reported as an intermediate host in Brazil (Brandolini et al. 1997).
* Jairo Pinheiro [email protected] 1
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The embryonated eggs are eliminated with the excretion products of the definitive hosts and the snail becomes passively infected. After the miracidia hatching, two generations of sporocysts develop inside the snail. The cercariae and metacercariae begin to be visualized 32 days after infection. The definitive host becomes infected by ingesting the parasitized snail (Maldonado 1945; Keller and Araujo 1992; Brandolini and Amato 2006).
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Departamento de Biologia Animal, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro (UFRRJ) , Seropédica, RJ, Brasil
Laboratório de Biologia e Ecologia de Helmintos, Departamento de Biologia Animal, Instituto de Ciências Biológicas e da Saúde, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Seropédica, RJ, Brasil
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Laboratório de Biologia Celular e Tecidual, Centro de
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