摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f69-070

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Insisting on the difficulty of identifying species of the genusDiphyllobothrium, the author draws attention to the peculiar life cycle ofDiphyllobothrium norvegicum, which needs four hosts.Diphyllobothrium pacificum(Nybelin, 1931) Margolis, 1956, evolves entirely in a marine habitat; it is a tapeworm of sea lions and is much more frequent in man in Peru than was supposed (60 cases). Because of the ecological food chain in the Peru Current and the fact that the anchoveta is only used for fish meal, the author concludes that man is infested through a paratenic host. Although more than 700 current food fish have been examined for plerocercoid larvae, it has not been possible to identify with certainty a particular plerocercoid since both human and canine experimental infestations were unsuccessful. The mode of human infestation is without doubt through the Peruvian national dish known ascebiche, consisting of raw fish steeped in lime juice with peppers, which is sold not only in restaurants but also on the streets. It is also more than likely thatD.pacificumwas already a parasite of pre-Columbian man.

ISSN:0706-652X    

DOI:10.1139/f69-071

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

A critical review of the Sporozoa is presented with consideration of changes in taxonomic arrangement as different morphological and developmental features have influenced opinion on systematics in the group. Infections of fishes receive primary attention, especially those produced by members of the Microsporidia. Although chiefly parasites of invertebrates, certain species cause severe infections in fishes. The bionomics, life cycles, and taxonomy of these species are still equivocal.

ISSN:0706-652X    

DOI:10.1139/f69-072

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Procedures for the maintenance ofSchistocephalus solidusin the laboratory are described: recovery of eggs from low bulk faeces; incubation and hatching of eggs at 25 C; and infection ofCyclops agilis,Diaptomus gracilis, andMesocyclops leuckartiwith procercoids that at 25 C become infective in 10, 8, and 8 days, respectively. Methods for infectingGasterosteus aculeatuswith specific numbers of plerocercoids, and procedures for maintaining infected sticklebacks, are described. The rate of growth ofS.solidusinG.aculeatusat 19 C has been determined up to day 83, by which time plerocercoids are infective and weigh 50 mg fresh weight. The problem of speciation inSchistocephalusis discussed with reference to the conflicting evidence concerning the number of proglottids in the plerocercoid. Statistical evidence shows the number of proglottids increases slowly during growth contrary to previous statements, and ontogenesis is discussed with reference to metamerism. Problems of growth ofSchistocephalusin the fish host are enumerated.

ISSN:0706-652X    

DOI:10.1139/f69-073

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Eighteen species of metacercariae of the order Strigeatoidea (Trematoda, Digenea) are described from tropical and subtropical freshwater fishes of Argentina. Sixteen of them belong to the superfamily Strigeoidea and two to Clinostomatoidea. Ten are new species, five belong to previously known trematode species, and three are not specifically named.On the basis of the morphology of these metacercariae, probable life cycles and host–parasite relations are discussed. A general conclusion is drawn that the South American trematodes are more primitive than their counterparts from other continents.Different groups of fish hosts are recognized, each with a different history of association with their present environment. Originally marine fishes adapted to life in fresh water with the aid of increased endocrine activity, primarily thyroid activity. The high levels of endocrine secretions affected the parasites of these fishes, causing metacercariae to develop neotenically. The hosts which were originally freshwater appear to exert less influence on their parasites. Their metacercariae have a more or less normal course of development.Attention is drawn to the evolution in behaviour of strigeoid metacercariae. Primitive species infect less protected sites in the host. With progressive evolution, increasingly more protected sites are selected by the parasite. The evolution culminates in infection of the lens of the eye, which offers the best protection to the parasite against destructive influences of the environment.It is suggested that the metacercariae are guided to their selected infection site by an "engram," or a specific memory, developed and fixed in the course of many generations. New research into parasite behaviour is urged.

ISSN:0706-652X    

DOI:10.1139/f69-074

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The following three new genera and new species of hemiurid trematodes (subfamily Lecithasterinae) are described: (1)Saturnius segmentatusfromMugil cephalusL., characterized by a peculiar internal pseudosegmentation; (2)Bilacinia australisfromNaso annulatus(Quoy & Gaimard), with a pair of bilobed, postacetabular flaps; and (3)Unilacinia asymmetricafromNaso annulatus, with a single, unilateral acetabular flap.

ISSN:0706-652X    

DOI:10.1139/f69-075

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

A checklist is provided for nematode parasites removed from fishes, amphibians, and reptiles taken by the U.S. Naval Medical Research Unit No. 2 expedition to North Borneo (Sabah), Malaysia. Very few parasites have been reported previously from the vertebrates of North Borneo.

ISSN:0706-652X    

DOI:10.1139/f69-076

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

Lepidophyllum cameronin.sp., parasitic in the urinary bladder of a cottid fish,Hemilepidotus hemilepidotus(Tilesius), from Burke Channel, British Columbia, is described and illustrated. The genusParalepidophyllumYamaguti, 1934, is reduced to synonymy withLepidophyllumOdhner, 1902,Lepidophyllum pyriforme(Yamaguti, 1934) resulting as a new combination.

ISSN:0706-652X    

DOI:10.1139/f69-077

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

One blue shark (Prionace glauca(L.)), 107 spiny dogfishes (Squalus acanthiasL.), and 17 thorny skates (Raja radiataDonovan) were examined for parasites during the period August 1967–August 1968. All fish were obtained in Newfoundland waters. Four species of cestodes were recovered from the blue shark. The spiny dogfishes were infected with 13 species of parasites, and the thorny skates with 11 species. A total of 18 species of parasites were recovered from the spiny dogfishes and thorny skates, namely, two species of Monogenea, four of Digenea, six of Cestoda, four of Nematoda, one of Hirudinea, and one of Copepoda. Several new host records were noted.

ISSN:0706-652X    

DOI:10.1139/f69-078

出版商:NRC Research Press    

年代:1969

数据来源: NRC

摘要:

The acquisition of parasites by pink salmon during their initial phase of marine life is described. The parasites found were the trematodesLecithaster gibbosus,Parahemiurus merus, andPentagramma petrowi, the cestodePhyllobothriumsp. larva, and the nematodeContracaecumsp. larva. An attempt is made to account for the occurrence of the more predominant species, particularly the trematodeL.gibbosus.

ISSN:0706-652X    

DOI:10.1139/f69-079

出版商:NRC Research Press    

年代:1969

数据来源: NRC