DIGENEA PARASITES OF JELLYFISH AND CTENOPHORES

 

INTRODUCTION

Digeneans are abundant parasites of vertebrates and invertebrates in marine environmental. They usually have (with exceptions) three host life histories with two intermediate hosts and one definitive host, a vertebrate that harbor the adults. The metacercaria infect the second intermediate host and is an important resting stage that allowing the parasite to survive until it can reach the definitive host. The gelatinous zooplakton could act as hosts of different metacercariae. Numerous metacercariae has been reported, mainly in the North Hemisphere. Lebour (1916) reported the metacercaria of Opechona bacillaris (Molin, 1859) in Cosmetira pilosella Fobres, 1898, Obelia sp., Leuckartiara octona (Fleming, 1823), and Pleurobrachia pileus (Fabricius, 1780). Dollfus (1963) reported all the well-known metacercariae until that moment, and mentioned don't know if jellyfishes are intermediate hosts for digeneans or only are accidental hosts, since the metacercariae were always unencysted. Rebeq (1964), in a revision of digeneans found in planktonic organisms, concluded that in some cases these invertebrates could be occasional or facultative hosts for digeneans. Stunkard (1967, 1969, 1974, 1978a, 1978b, 1980a, and 1980b) described different unencysted metacercariae in jellyfishes and ctenophores and considered these as paratenic or reservoir hosts. However for Neopechona pyriforme (Linton 1900) , the same author, mentioned that metacercariae from jellyfishes was immediately infective and the jellyfishes could be in this case true intermediate hosts. Reimer et al. (1971) reported three metacercariae in plankton samples of the North Sea, and mentioned for the metacercaria of O. bacillaris that all the planktonic host found could be considered as second intermediate host. Køie (1975, 1979, 1983, 1985a, 1985b) reported several life histories of digeneans that uses jellyfishes and ctenophores as second intermediate hosts. These author also mentioned that these invertebrates are true intermediate host for O. bacillaris and Lepidapedon rachion (Cobbold, 1858), (Lepocreadiidae). In this parasites the cercariae penetrated actively for the mesoglea of the jellyfishes. The same author also mentions that hemiurid metacercaria of Derogenes varicus (Muller, 1784), Brachiphalus crenatus Rudolphi, 1802, and Hemiurus communis Odnher, 1905 that use copepods as intermediate hosts, could uses in addition ctenophores and quetognates as transport hosts. Køie (op. cit.) also comments that metacercariae found in jellyfishes and ctenophores didn't need to encyst, like a protection against the host=s response. Lauchner (1980a, and 1980b) compiled all the know parasites from jellyfishes and ctenophores, and explained that these invertebrates served as intermediate or paratenic host for helminthes. More recently Matsumoto et al. (1997) reported high prevalence (49 %) and intensity (up to 100) for an unencysted metacercaria hemiuridae in the manubrium of the deep-sea trachymedusa Benthocodon pedunculata (Bigelow, 1913) in California. Back to top

South Atlantic

Digeneans parasites of planktonic organisms in the Southern Atlantic Ocean are still little known. Only three metacercariae have been reported in the Argentine Sea : Opechona sp. in Olindias sambaquiensis Delle Chiaje 1841 (Martorelli, 1991); Monaschus filiformis(Rudolphi, 1819) in Phialidium sp., Liriope tetraphylla Chamizo & Eysenhardt,1821, Eucheilota ventricularis Mc. Crady, 1857 and Aglauropsis kawari Moreira, 1972 (Girola, et al., 1992; Martorelli & Cremonte, 1998); an encysted lepocreadioid metacercaria in Phialidium sp., Liriope tetraphylla and Mnemiopsis mccradyi (Martorelli, 1996).Finally Martorelli (2001) reported 3 metacercariae of Bacciger sp., Opechona sp. and an unidentified Hemiuridae from M. mccradyi,

Phiallidium sp. and Liriope tetraphylla.

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Contact Information

sergio@cepave.edu.ar

sergio.martorelli@gmail.com

Other Web

www.parasitosypatogenos.com.ar

www.zoologiageneral.com.ar

Phone 54-221-4233471 int 22

FAX 54-221-4232327

 

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Current Projects On Jellyfish

*   PARASITES OF JELLYFISH AND CTENOPHORES,FROM MISSISSIPPI SOUND AREA (samples collected from 1998 to 2000),

*    LIFE CYCLES OF DIGENEA WITH METACERCARIAE IN GELATINOUS PLANKTON FROM THE SOUTH ATLANTIC OCEAN.

* OTHER PARASITES IN JELLIES FROM THE SOUTH ATLANTIC OCEAN

 

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Biographical Information

Curriculum Vita

 

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Others Research Goals

*    Parasites of FIshes From Estuarine Areas of Argentina

*    Parasites and Epizooic Organisms of Shrimps and Crabs

*    Pathogens of Penaeids Shrimps

*    Life Histories of Digenea in Estuarine Environments

 

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