Anna Kohn

Spermatogenesis and spermiogenesis in Didymocystis wedli Ariola, 1902 (Didymozoidae, Digenea).

The ultrastructure of the male reproductive system of Didymocystis wedli was studied for the first time, demonstrating spermiogenesis and spermatogenesis at different cell stages. The spermatozoa morphology was compared with that of other Digenea species. It was observed that the different cells of the spermatogenesis process follow the classic pattern reported for the majority of the parasitic platyhelminthes. During spermiogenesis, rootlet fibers, electrondense bodies and median cytoplasmic process were not observed. The mature spermatozoa of D. wedli were filiform, presenting nucleus, mitochondrion and two 9+1 axonemes, with a biflagellate distal extremity.

Helminths parasites of freshwater fishes from Pirassununga, SP, Brazil

Twelve species of parasitic helminths, seven trematodes, four nematodes and one acanthocephalan are reported from various hosts. Creptotrema lynchi, a parasite from Bufo marinus in Colombia, is described for the first time in fish and from Brazil, parasitizing two different species. A list of the host species, measurements and figures of most parasites are included with particular reference to the tegument of Bellumcorpus major recovered from a new host. The genus Zonocotyloides Padilha, 1978 is considered a synonym of Zonocotyle and the new combination: Zonocotyle haroltravassosi is proposed to the species Zonocotyloides haroltravassosi Padilha, 1978. The nematodes Cucullanus pinnai and Procamallanus (Spirocamallanus) inopinatus and the trematode Pararhipidocotyle jeffersoni are reported in new hosts. The description of the acanthocephalan Neoechinorhynchus curemais (new locality record) is supplemented. Other parasites recovered include the nematodes Travnema travnema (new locality record), Rondonia rondoni and the digenetic trematodes Cladocystis intestinalis, Pseudosellacotyla lutzi (new locality record), Teratotrema sp. and Zonocotyle bicaecata.

Helminths of freshwater fishes in the reservoir of the Hydroelectric Power Station of Itaipu, Paraná, Brazil

This study presents results from several expeditions in 1985, 1991-1995 and 2003 to the Medium Parana River in the section that begins below the Itaipu Dam and ends at the trinational border of Brazil, Argentina and Paraguay, in the lotic and lentic zones of the reservoir of the Hydroelectric Power Station of “Itaipu Binacional” (localities Foz do Iguacu, Santa Helena and Guaira). Ninety-eight species of freshwater fishes belonging to 22 families were examined for helminths. A host-parasite list based on Acanthocephala, Cestoda, Digenea, Monogenea and Nematoda collected from the region in question is provided. New host records are presented for Digenea and Nematoda. The Monogenea and Acanthocephala are being studied.

Estudo comparativo dos helmintos parasitos de peixes do rio Mogi Guassu, coletados nas excursões realizadas entre 1927 e 1985

This paper concerns the parasitism of Nematoda, Trematoda, Acanthocephala and Cestoda from 1027 fishes of 45 species from Mogi Guassu river, examined in the years 1927, 1946, 1947, 1962, 1983 and 1985 as a contribution to the knowledge of the parasitological fauna in 58 years. Thirty two species of nematodes, 21 of trematodes, 3 of acanthocephalans and 2 of cestodes are reported. New hosts are presented for the nematodes Cucullanus pinnai, Spirocamallanus inopinatus and Travnema travnema, for the trematode Pararhipidocotyle jeffersoni and for the acanthocephalan Gorytocephalus spectabilis. New measurements for the trematode Creptotrema lynchy, tables, graphics and a list of the examined hosts with their parasites are presented.

Saccocoelioides godoyi n.sp. (Haploporidae) and other trematodes parasites of fishes from the Guaiba estuary, RS, Brazil

One hundred and fourteen specimens of eleven different species of freshwater fishes from the Guaiba estuary, were examined for digenetic flukes. Saccocoelioides godoyi n.sp. proposed herein, is closest to S. magniovatus and to S. szidati; S. magniovatus is much smaller with comparably larger eggs and S. szidati has larger hermaphroditic sac and considerably larger testis. Creptotrema creptotrema is referred to a new host; Acanthostomum gnerii, Crepidostomum platense, Eocreadium intermedium (immature form), Parspina argentinensis and Zonocotyle bicaecata are reported. This paper confirms the similatary between the parasites of freshwater fishes from Argentina and Brazil. Measurements and original figures of all species are given.

Trématodes parasites de poissons marins du littoral de Rio de Janeiro, Brésil

From July 1985 through February 1986 255 specimens of marine fishes of 35 species of commercial importance were examined for trematodes. In this paper 17 species of digenetic trematodes are presented; four are recorded for the first time in Brazil: Diphtherostomum americanum, Diplomonorchis floridensis, Pancreadium otagoensis and Neomegasolena chaetodiptiteri; nine were found in new hosts: D. americanum, Diplangus paxillus, Hurleytrema shorti, Lecthochirum microstomum, Monascus filliformis, Neolebouria multibatus. P. otagoensis, Pleorchis mollis and Opechona bacillaris, one species Vitellibaculum spinosum was detected in a new host in Brazil and five had previously been seen in this country: Acanthocollaritrema umbilicatum, Bucephalopsis callicotyle, Bucephalus varicus, Parahemiurus merus and Tergestia pauca. Tergestia selenei is regarded as a synonym of T. pauca. The principal measures of each species are given.

Activity of the artemether in experimental schistosomiasis mansoni

The action of the ether of artemisinin (artemether) on Schistosoma mansoni in mice and hamsters experimentally infected with the LE strain was studied. In mice, the drug showed high schistosomicidal activity using a single intramuscular dose of 100 mg/kg/day. By the oral route, this dose showed a low activity. Mice treated with a single intramuscular dose of 200 mg/kg/day, and examined 15 days after treatment, presented 100% alteration of the oogram; when examined 45 days after treatment, the oogram was normal. With doses of 100 mg/kg/day, i.m., during 3 or 5 consecutive days, the death rate of mice was very high. Morphologic analysis of the worms collected by perfusion of mice treated with a single dose of 100 mg/kg/day, i.m., detected a marked decrease in the length of male and female worms, degenerative alterations in the parenchyma and in the reproductive system of the females, with the reduction of vitellinic material and in ovary volume; the intestinal contents presented a marked despigmentation. In the male worms significant alteration was not apparent by optical microscopy.

Kritskyia moraveci n. g., n. sp. (Monogenea: Dactylogyridae) from the urinary bladder and ureters of Rhamdia quelen (Quoy & Gaimard, 1824) (Pisces: Pimelodidae) in Brazil

Kritskyia n. g. is proposed for K. moraveci n. sp. from the urinary bladder and ureters of Rhamdia quelen (Quoy & Gaimard, 1824), a pimelodid fish from the reservoir of the Hydroelectric Power Station of “Passo Fundo”, Rio Grande do Sul State, Brazil. The new genus is most closely related to Acolpenteron Fischthal & Allison, 1940, from which it differs by having a male copulatory complex composed of a coiled cirrus and a bipartite accessory piece, a sinistral vagina, and an antero-ventrally concave haptor which possesses 14 ventrally directed marginal hooks, but lacks an anterior rim and 4A hooks.

Redescription of Prosthenhystera obesa (Diesing, 1850) (Callodistomidae, Digenea) with New Host Records and Data on Morphological Variability

Prosthenhystera obesa (Diesing,1850) Travassos, 1922 from the gall bladder of Astyanax bimaculatus, Caranx gibbosus, Galeocharax humeralis, Leporinus copelandii, Pimelodus fur, Pseudopimelodus roosevelti, Salminus brevidens, Salminus maxillosus and from the new hosts, Cynopotamus amazonum and Triurobrycon lundii is redescribed, demonstrating a large morphological variation, mainly in body and testes size and shape. New hosts harbouring immature specimens of P. obesa are presented: Brycon sp., Leporellus vittatus, Pachyurus squamipinnis, Pimelodus clarias, Pseudoplatystoma corruscans and Salminus hilarii . Scanning electron microscopy micrographies, original figures and measurements of adult and immature specimens from different Brazilian hosts and localities are presented.

On the Brazilian species of halipegine genera (Trematoda: Derogenidae) from fishes, with new morphological data, hosts and synonyms

The genus Genarchella Travassos, Artigas & Pereira, 1928 is reinstated for some species from South American fishes previously attributed to Halipegus Looss, 1899. Aspects of the morphology of G. genarchella Travassos, Artigas & Pereira, 1928 and G. parva Travassos, Artigas & Pereira, 1928 are redescribed. Astyanax bimaculatus, Moenkhausia doceana, Oligosarcus robustus and Salminus maxillosus are recorded as new hosts of G. parva, and H. cryptorchis Mané-Garzon & Gascón, 1973 and H. szidati Yamaguti, 1971 [= G. tropica of Szidat (1954)] are listed amongst new synonyms of this species. Aspects of the morphology of Thometrema magnifica (Szidat, 1954) and T. overstreeti (Brooks, Mayes & Thorson, 1979) are redescribed. T. rioplatense Lunaschi, 1989 is considered a synonym of T. overstreeti. New host-records of T. overstreeti are Pimelodus maculatus and Rhamdia sp. G. genarchella of Hamann (1986) is considered as synonym of T. overstreeti. Paravitellotrema Watson, 1976, Caballeroiella Lamothe-Argumedo, 1977 and Quadripaludus Jimenez, Guajardo & Briseno, 1981 are considered synonyms of Genarchella. The features distinguishing Halipegus, Genarchella and Thometrema Amato, 1968 are discussed.