Diversity of Nematoda and Digenea from different species of characiform fishes from Tocantins River, Maranhão, Brazil.

During a survey of the helminth fauna of characiform fishes from the Tocantins River, Brazil, 185 fish specimens from 22 species were studied. Twelve species of Nematoda and nine species of Digenea were collected. Some of these helminth species were reported for the first time in their hosts, thus representing new host records: Procamallanus (Spirocamallanus) sp. in Bivibranchia notata, Brycon pesu, Chalceus macrolepidotus, Hemiodus microlepis and Hemiodus unimaculatus; Procamallanus (Spirocamallanus) inopinatus in Triportheus elongatus; Goezia sp. (larva) in Boulengerella cuvieri; Rhabdochona acuminata in Brycon pesu and Triportheus trifurcatus; Raphidascaris sp. (larva) in Caenotropus labyrinthicus; Cosmoxynema vianai in Cyphocharax gouldingi; Rondonia rondoni in Leporinus fasciatus and Mylesinus paucisquamatus; Klossinemella iheringi in Mylesinus paucisquamatus; Cucullanidae gen. sp. in Myloplus rubripinnis; Rhabdochona sp. in Triportheus elongatus; Alphamphistoma sp. in Myleus setiger; Chalcinotrema sp. in Cyphocharax gouldingi; Pacudistoma guianense in Hemiodus unimaculatus and Myleus torquatus; Pseudocladorchis cylindricus in Hemiodus unimaculatus; Dadaytrema oxycephala in Mylesinus paucisquamatus; Travassosinia dilatata in Myloplus asterias; and Genarchella genarchella in Raphiodon vulpinus. Studies identifying new hosts and new localities for parasites have contributed to the knowledge of local biodiversity. A list of previous records of helminths included in the present study, providing hosts, localities, and references, is presented here.

Neonematobothrium annakohnae n. sp. (Digenea: Didymozoidae) parasitizing Euthynnus alletteratus (Perciformes: Scombridae) in the Southwest Atlantic Ocean.

PURPOSE: Describe a new species of didymozoid digenean Neonematobothrium Yamaguti, 1965 from the operculum of the scombrid fish, Euthynnus alletteratus (Rafinesque, 1810), in the Southwest Atlantic Ocean off Brazil. METHODS: Thirty-four specimens of E. alletteratus were collected in the coastal zone of the state of Rio de Janeiro and obtained from local fishermen between 2006 and 2018 in the municipal market of São Pedro in Niterói, Brazil. The parasites were fixed in AFA (93% ethanol 70%, 5% formaldehyde, 2% glacial acetic acid) without pressure, stained with Langeron alcoholic acid carmine, dehydrated in an alcohol series, cleared in beachwood creosote or clove oil and mounted in Canada balsam as permanent slides. RESULTS: Neonematobothrium annakohnae n. sp. is a member of the genus based on a combination of the following characteristics: body free, uncapsulated; body long and dorsoventrally flattened; esophagus surrounded by gland cells; ovary and vitellarium single, long, narrow and unbranched in the anterior and posterior halves of the body, respectively; uterus with three loops; and site of infection in subcutaneous tissue of scombrid fish. The new species differs from the two recognized species of the genus mainly by the size of the body, which is much larger, the shape of the genital pore, which is differentiated in a structure similar to a small sucker and by esophagus without diverticula. CONCLUSIONS: Neonematobothrium annakohnae n. sp. parasite of E. alletteratus from the Southwest Atlantic Ocean, described herein, represents the third species of Didymozoidae belonging to the genus Neonematobothrium. The two known species Neonematobothrium kawakawa Yamaguti, 1965 and Neonematobothrium dorsale Yamaguti, 1970 were described from fish belonging to the same genus of the host from Pacific Ocean. The diagnosis of the genus is enlarged to "esophagus with or without diverticula", to fill the characteristics presented by the new species. The description of N. annakohnae n. sp. demonstrates the need to expand the studies of these interesting and intriguing group of parasites, due to the fact that number of known didymozoids taxa in the Atlantic Ocean is far from representing the real situation.

First record of a mermithid worm (Nematoda, Mermithidae) parasitizing a third instar nymph of Triatoma sordida (Stål, 1859) (Hemiptera, Reduviidae, Triatominae) from Mato Grosso, Brazil.

A juvenile specimen of a mermithid (Nematoda) was found parasitizing a third instar nymph of Triatoma sordida from Mato Grosso, Brazil. This is the first record of mermithid parasitism in a triatomine species. The Mermithidae represents a family of nematodes that are specialized insect parasites. Entomonematodes are one of the highly influential agents regulating the population dynamics of insects. This report introduces the opportunity to think about mermithids as a possible candidate for use as triatomine biological control.

Nematofauna of red piranha Pygocentrus nattereri (Kner, 1958) (Characiformes: Serrasalmidae) from Amazonia, Brazil.

Between March and October 2008, 355 specimens of Pygocentrus nattereri were collected from the lowland lakes of Central Amazonia, Brazil, to study their nematode fauna. A total of 1.116 specimens of Nematoda were collected, belonging to six species. Procamallanus (Spirocamallanus) inopinatus was the species with the highest parasite indices. Larvae of Anisakis sp. have zoonotic potential and were found parasitizing the intestine and liver of Pygocentrus nattereri. Some of these nematode species were new records for the host P. nattereri. The diversity of nematodes that use P. nattereri as a host indicates the important role of this fish species in the maintenance of these six nematode species in the lowland lakes of Central Amazonia.

New records of Monogenoidea (Platyhelminthes) from three marine fish species from the coast of Angra dos Reis, Rio de Janeiro, Brazil

During a survey of helminth parasites, five monogenoid species were reported from marine fishes from the coast of Angra dos Reis, littoral of Rio de Janeiro State, Atlantic Ocean. A total of 810 monogenoids were collected: Pseudotagia pomadasys Hernández-Vale, Bunkley-Williams & Williams Jr, 2016, Pseudoeurysorchis travassosi Caballero & Bravo-Hollis, 1962 in Haemulopsis corvinaeformis (Steindachner, 1868) (=Pomadasys corvinaeformis), Neodiplectanum mexicanum (Mendoza-Franco, Roche & Torchin, 2008) Domingues, Diamanka & Pariselle, 2011 and Aristocleidus hastatus Mueller, 1936 in Diapterus rhombeus (Cuvier, 1829) and Acanthocercodes bullardi Kritsky & Diggles, 2015 in Polydactylus virginicus (Linnaeus, 1758). The presence of P. pomadasys, P. travassosi and A. hastatus in the Southwest Atlantic Ocean represents a new geographical distribution for these species. Haemulopsis corvinaeformis represents a new host record for P. travassosi and A. bullardi is reported in the present paper for the first time parasitizing the gills of a polynemid in South Atlantic Ocean. The findings show that they belong to species previously recorded from the same or congeneric hosts from Central America and Mexico, representing new data on hosts and geographical records.(AU)

Seasonality of parasitic helminths of Leporinus macrocephalus and their parasitism rates in farming systems in the Amazon.

The objective of the present study was to analyze the seasonality of parasitic helminths of Leporinus macrocephalus from fish farms in the municipality of Cruzeiro do Sul, Acre, Brazil, and their parasitism rates. Between June 2014 and March 2015, 200 specimens were sampled from two fish farms: one with a semi-intensive system and the other with an extensive system (100 fish from each farm: 50 during the dry season and 50 during the rainy season). Fifteen species of parasites were found, with seasonal variations of some according to the farming system. In the semi-intensive fish farm, there was greater prevalence of infection during the dry season. Also, Urocleidoides paradoxus, Procamallanus (Spirocamallanus) inopinatus, Goezia leporini and Rhabdochona (Rhabdochona) acuminata presented differences in their parasitism rates between the seasons. In the extensive fish farm, no variation in the prevalence of infection was observed between the seasons and two species Tereancistrum parvus and G. leporini demonstrated differences only regarding the mean intensity of infection. The data presented here may help fish farmers to understand the parasite dynamics of L. macrocephalus in farming systems during the dry and rainy seasons in the state of Acre.

Diversity of Nematoda and Digenea from different species of characiform fishes from Tocantins River, Maranhão, Brazil / Diversidade de Nematoda e Digenea coletados em diferentes espécies de Characiformes provenientes do rio Tocantins, Maranhão, Brasil

During a survey of the helminth fauna of characiform fishes from the Tocantins River, Brazil, 185 fish specimens from 22 species were studied. Twelve species of Nematoda and nine species of Digenea were collected. Some of these helminth species were reported for the first time in their hosts, thus representing new host records: Procamallanus (Spirocamallanus) sp. in Bivibranchia notata, Brycon pesu, Chalceus macrolepidotus, Hemiodus microlepis and Hemiodus unimaculatus; Procamallanus (Spirocamallanus) inopinatus in Triportheus elongatus; Goezia sp. (larva) in Boulengerella cuvieri; Rhabdochona acuminata in Brycon pesu and Triportheus trifurcatus; Raphidascaris sp. (larva) in Caenotropus labyrinthicus; Cosmoxynema vianai in Cyphocharax gouldingi; Rondonia rondoni in Leporinus fasciatus and Mylesinus paucisquamatus; Klossinemella iheringi in Mylesinus paucisquamatus; Cucullanidae gen. sp. in Myloplus rubripinnis; Rhabdochona sp. in Triportheus elongatus; Alphamphistoma sp. in Myleus setiger; Chalcinotrema sp. in Cyphocharax gouldingi; Pacudistoma guianense in Hemiodus unimaculatus and Myleus torquatus; Pseudocladorchis cylindricus in Hemiodus unimaculatus; Dadaytrema oxycephala in Mylesinus paucisquamatus; Travassosinia dilatata in Myloplus asterias; and Genarchella genarchella in Raphiodon vulpinus. Studies identifying new hosts and new localities for parasites have contributed to the knowledge of local biodiversity. A list of previous records of helminths included in the present study, providing hosts, localities, and references, is presented here.(AU)

Durante a pesquisa da fauna helmintológica de Characiformes do rio Tocantins, Maranhão, Brasil, 185 peixes pertencentes a 22 espécies foram estudados. Doze espécies de Nematoda e nove espécies de Digenea foram coletadas. Algumas espécies de helmintos estão sendo registradas pela primeira vez em seus hospedeiros, representando novos registros: Procamallanus (Spirocamallanus) sp. em Bivibranchia notata, Brycon pesu, Chalceus macrolepidotus, Hemiodus microlepis e Hemiodus unimaculatus; Procamallanus (Spirocamallanus) inopinatus em Triportheus elongatus; Goezia sp. (larva) em Boulengerella cuvieri; Rhabdochona acuminata em Brycon pesu e Tripotheus trifurcatus; Raphidascaris sp. (larva) em Caenotropus labyrinthicus; Cosmoxynema vianai em Cyphocharax gouldingi; Rondonia rondoni em Leporinus fasciatus e Mylesinus paucisquamatus; Klossinemella iheringi em Mylesinus paucisquamatus; Cucullanidae gen. sp. em Myloplus rubripinnis; Rhabdochona sp. em Triportheus elongatus; Alphamphistoma sp. em Myleus setiger; Chalcinotrema sp. em Cyphocarax gouldingi; Pacudistoma guianense em Hemiodus unimaculatus e Myleus torquatus; Pseudocladorchis cylindricus em Hemiodus unimaculatus; Dadaytrema oxycephala em Mylesinus paucisquamatus; Travassosinia dilatata em Myloplus asterias; e Genarchella genarchella em Raphiodon vulpinus. Estudos que identificam novos hospedeiros e novas localidades para parasitos têm contribuído para o conhecimento da biodiversidade local. Uma lista dos registros prévios dos helmintos incluídos no presente estudo, com hospedeiros, localidades e referências é apresentada.(AU)

Diversity of Nematoda and Digenea from different species of characiform fishes from Tocantins River, Maranhão, Brazil / Diversidade de Nematoda e Digenea coletados em diferentes espécies de Characiformes provenientes do rio Tocantins, Maranhão, Brasil

Durante a pesquisa da fauna helmintológica de Characiformes do rio Tocantins, Maranhão, Brasil, 185 peixes pertencentes a 22 espécies foram estudados. Doze espécies de Nematoda e nove espécies de Digenea foram coletadas. Algumas espécies de helmintos estão sendo registradas pela primeira vez em seus hospedeiros, representando novos registros: Procamallanus (Spirocamallanus) sp. em Bivibranchia notata, Brycon pesu, Chalceus macrolepidotus, Hemiodus microlepis e Hemiodus unimaculatus; Procamallanus (Spirocamallanus) inopinatus em Tripttheus elongatus; Goezia sp. (larva) em Boulengerella cuvieri; Rhabdochona acuminata em Brycon pesu e Tripotheus trifurcatus; Raphidascaris sp. (larva) em Caenotropus labyrinthicus; Cosmoxynema vianai em Cyphocharax gouldingi; Rondonia rondoni em Leporinus fasciatus e Mylesinus paucisquamatus; Klossinemella iheringi em Mylesinus paucisquamatus; Cucullanidae gen. sp. em Myloplus rubripinnis; Rhabdochona sp. em Tripttheus elongatus; Alphamphistoma sp. em Myleus setiger; Chalcinotrema sp. em Cyphocarax gouldingi; Pacudistoma guianense em Hemiodus unimaculatus e Myleus torquatus; Pseudocladorchis cylindricus em Hemiodus unimaculatus; Dadaytrema oxycephala em Mylesinus paucisquamatus; Travassosinia dilatata em Myloplus asterias; e Genarchella genarchella em Raphiodon vulpinus. Estudos que identificam novos hospedeiros e novas localidades para parasitos têm contribuído para o conhecimento da biodiversidade local. Uma lista dos registros prévios dos helmintos incluídos no presente estudo, com hospedeiros, localidades e referências é apresentada.

New host record and geographical distribution of Nematoda parasitizing Hypophthalmus marginatus Valenciennes (Siluriformes) from the Tocantins River, Brazil

Hypophthalmus marginatus is among the most commercialized fish from the Amazon region, with fish fillets exported to Southeastern Brazil and other countries. In the present study, the H. marginatusanalyzed were parasitized by third-stage larvae of Hysterothylaciumsp. and Anisakissp. These nematodes are being reported for the first time in H. marginatus collected from the Tocantins River, representing a new host and geographical records, and expanding knowledge of the hosts of these nematodes in the Neotropical Region. A brief description with original measurements is presented.(AU)

New host record and geographical distribution of Nematoda parasitizing Hypophthalmus marginatus Valenciennes (Siluriformes) from the Tocantins River, Brazil

Hypophthalmus marginatus is among the most commercialized fish from the Amazon region, with fish fillets exported to Southeastern Brazil and other countries. In the present study, the H. marginatusanalyzed were parasitized by third-stage larvae of Hysterothylaciumsp. and Anisakissp. These nematodes are being reported for the first time in H. marginatus collected from the Tocantins River, representing a new host and geographical records, and expanding knowledge of the hosts of these nematodes in the Neotropical Region. A brief description with original measurements is presented.

A new species of diplectanid (Monogenoidea) from Paranthias colonus (Perciformes, Serranidae) off Peru.

Pseudorhabdosynochus jeanloui n. sp. (Monogenoidea, Diplectanidae) is described from specimens collected from the gills of the Pacific creolefish, Paranthias colonus (Perciformes, Serranidae) from a fish market in Chorrillos, Lima, Peru. The new species is differentiated from other members of the genus by the structure of its sclerotized vagina, which has two spherical chambers of similar diameter. This is the first Pseudorhabdosynochus species described from the Pacific coast of America, the third species of the genus reported from South America and the first described from a member of Paranthias.

Nematofauna of red piranha Pygocentrus nattereri (Kner, 1958) (Characiformes: Serrasalmidae) from Amazonia, Brazil / Nematofauna de piranha-vermelha Pygocentrus nattereri (Kner, 1958) (Characiformes: Serrasalmidae) da Amazonia, Brasil

Between March and October 2008, 355 specimens of Pygocentrus nattereri were collected from the lowland lakes of Central Amazonia, Brazil, to study their nematode fauna. A total of 1.116 specimens of Nematoda were collected, belonging to six species. Procamallanus (Spirocamallanus) inopinatus was the species with the highest parasite indices. Larvae of Anisakis sp. have zoonotic potential and were found parasitizing the intestine and liver of Pygocentrus nattereri. Some of these nematode species were new records for the host P. nattereri. The diversity of nematodes that use P. nattereri as a host indicates the important role of this fish species in the maintenance of these six nematode species in the lowland lakes of Central Amazonia.(AU)

Entre março e outubro de 2008, foram coletados 355 espécimes de Pygocentrus nattereri para o estudo da Nematofauna, provenientes dos lagos de várzea da Amazônia Central, Brasil. Um total de 1.116 espécimes de Nematoda foram coletados, pertencentes a seis espécies. Procamallanus (Spirocamallanus) inopinatus foi a espécie com índices parasitários mais elevados. Larvas de Anisakis sp. apresentam um potencial zoonótico, e foram encontradas parasitando o intestino e o fígado de P. nattereri. Algumas espécies de nematoides estão sendo registradas em P. nattereri pela primeira vez. A diversidade de espécies de nematoides que utilizam P. nattereri como hospedeiro indica seu importante papel na manutenção destas cinco espécies nos lagos de várzea da Amazônia Central.(AU)

Nematofauna of red piranha Pygocentrus nattereri (Kner, 1958) (Characiformes: Serrasalmidae) from Amazonia, Brazil / Nematofauna de piranha-vermelha Pygocentrus nattereri (Kner, 1958) (Characiformes: Serrasalmidae) da Amazonia, Brasil

Abstract Between March and October 2008, 355 specimens of Pygocentrus nattereri were collected from the lowland lakes of Central Amazonia, Brazil, to study their nematode fauna. A total of 1.116 specimens of Nematoda were collected, belonging to six species. Procamallanus (Spirocamallanus) inopinatus was the species with the highest parasite indices. Larvae of Anisakis sp. have zoonotic potential and were found parasitizing the intestine and liver of Pygocentrus nattereri. Some of these nematode species were new records for the host P. nattereri. The diversity of nematodes that use P. nattereri as a host indicates the important role of this fish species in the maintenance of these six nematode species in the lowland lakes of Central Amazonia.

Resumo Entre março e outubro de 2008, foram coletados 355 espécimes de Pygocentrus nattereri para o estudo da Nematofauna, provenientes dos lagos de várzea da Amazônia Central, Brasil. Um total de 1.116 espécimes de Nematoda foram coletados, pertencentes a seis espécies. Procamallanus (Spirocamallanus) inopinatus foi a espécie com índices parasitários mais elevados. Larvas de Anisakis sp. apresentam um potencial zoonótico, e foram encontradas parasitando o intestino e o fígado de P. nattereri. Algumas espécies de nematoides estão sendo registradas em P. nattereri pela primeira vez. A diversidade de espécies de nematoides que utilizam P. nattereri como hospedeiro indica seu importante papel na manutenção destas cinco espécies nos lagos de várzea da Amazônia Central.

Parasites of native Cichlidae populations and invasive Oreochromis niloticus (Linnaeus, 1758) in tributary of Amazonas River (Brazil).

This study provides the first investigation on acquisition of parasites in invasive O. niloticus by parasite species of native Cichlidae from the Igarapé Fortaleza basin, Northern Brazil. There were examined 576 specimens of 16 species of native cichlids and invasive O. niloticus collected in the main channel and the floodplain area of this tributary of Amazon River. The invasive O. niloticus was poorly parasitized having only Ichthyophthirius multifiliis, Trichodina centrostrigeata, Paratrichodina africana, Trichodina nobilis (Protozoa) and Cichlidogyrus tilapiae (Monogenoidea), and this host has not acquired any parasite species common to the native ichthyofauna region. In contrast, species of native cichlids showed rich fauna of parasites with predominance of Monogenoidea species, larvae and adults of Nematoda, Digenea, Cestoidea and Acanthocephala, besides four species of Protozoa and four Crustacea. However, only T. nobilis was acquired by native fish, the Aequidens tetramerus, which is a new host for this exotic Trichodinidae. In O. niloticus, well established in the region, the small number of helminth species may be associated with its rusticity, good adaptation in the new environment and also the presence of native parasites with relative specificity, but without ability to complete its life cycle in this invasive host of this ecosystem.

Monogenoidea from Eucinostomus argenteus and Eucinostomus gula (Perciformes, Gerreidae) from the littoral of the State of Rio de Janeiro, Brazil

Monogenoidea de Eucinostomus argenteus e Eucinostomus gula (Perciformes, Gerreidae) do litoral do estado do Rio de Janeiro, Brasil. Eucinostomus argenteus e E. gula (Perciformes, Gerreidae) provenientes de Angra dos Reis, litoral do Estado do Rio de Janeiro, Brasil, estavam parasitados pelos monogenóideos Darwinoplectanum figueiredoi (Diplectanidae) e Microcotyle guanabarensis (Microcotylidae). Neste estudo, um novo detalhe morfológico é adicionado à barra ventral de D. figueiredoi e um novo hospedeiro, Eucinostomus gula, é registrado para essa espécie. Os índices parasitários de ambas espécies são apresentados.

Seasonality of parasitic helminths of Leporinus macrocephalus and their parasitism rates in farming systems in the Amazon / Sazonalidade de helmintos parasitos de Leporinus macrocephalus e seus índices parasitários em sistemas de cultivo na Amazônia

The objective of the present study was to analyze the seasonality of parasitic helminths of Leporinus macrocephalus from fish farms in the municipality of Cruzeiro do Sul, Acre, Brazil, and their parasitism rates. Between June 2014 and March 2015, 200 specimens were sampled from two fish farms: one with a semi-intensive system and the other with an extensive system (100 fish from each farm: 50 during the dry season and 50 during the rainy season). Fifteen species of parasites were found, with seasonal variations of some according to the farming system. In the semi-intensive fish farm, there was greater prevalence of infection during the dry season. Also, Urocleidoides paradoxus, Procamallanus (Spirocamallanus) inopinatus, Goezia leporini and Rhabdochona (Rhabdochona) acuminata presented differences in their parasitism rates between the seasons. In the extensive fish farm, no variation in the prevalence of infection was observed between the seasons and two species Tereancistrum parvus and G. leporini demonstrated differences only regarding the mean intensity of infection. The data presented here may help fish farmers to understand the parasite dynamics of L. macrocephalus in farming systems during the dry and rainy seasons in the state of Acre.(AU)

O presente estudo teve como objetivo analisar a sazonalidade dos helmintos parasitos de Leporinus macrocephalus provenientes de pisciculturas no município de Cruzeiro do Sul, Acre, Brasil e seus índices parasitários. Durante o período de junho de 2014 a março de 2015 foram coletados 200 espécimes obtidos de duas pisciculturas, uma de sistema semi-intensivo e outra de sistema extensivo, sendo 100 peixes em cada, durante as estações seca e chuvosa, 50 espécimes por estação. Foram registradas quinze espécies de parasitos, com variação sazonal de ocorrência de alguns nos sistemas de cultivo. Na piscicultura semi-intensiva houve maior prevalência de infecção na seca, e Urocleidoides paradoxus, Procamallanus (Spirocamallanus) inopinatus, Goezia leporini e Rhabdochona (Rhabdochona) acuminata apresentaram diferenças dos índices parasitários entre as estações. Na piscicultura extensiva não foi detectada variação da prevalência de infecção entre as estações e duas espécies, Tereancistrum parvus e G. leporini assinalaram diferença apenas na intensidade média de infecção. Os dados apresentados neste estudo podem auxiliar os piscicultores na compreensão da dinâmica parasitária de L. macrocephalus em sistemas de cultivos durante as estações seca e chuvosa no estado do Acre.(AU)

Seasonality of parasitic helminths of Leporinus macrocephalus and their parasitism rates in farming systems in the Amazon / Sazonalidade de helmintos parasitos de Leporinus macrocephalus e seus índices parasitários em sistemas de cultivo na Amazônia

Abstract The objective of the present study was to analyze the seasonality of parasitic helminths of Leporinus macrocephalus from fish farms in the municipality of Cruzeiro do Sul, Acre, Brazil, and their parasitism rates. Between June 2014 and March 2015, 200 specimens were sampled from two fish farms: one with a semi-intensive system and the other with an extensive system (100 fish from each farm: 50 during the dry season and 50 during the rainy season). Fifteen species of parasites were found, with seasonal variations of some according to the farming system. In the semi-intensive fish farm, there was greater prevalence of infection during the dry season. Also, Urocleidoides paradoxus, Procamallanus (Spirocamallanus) inopinatus, Goezia leporini and Rhabdochona (Rhabdochona) acuminata presented differences in their parasitism rates between the seasons. In the extensive fish farm, no variation in the prevalence of infection was observed between the seasons and two species Tereancistrum parvus and G. leporini demonstrated differences only regarding the mean intensity of infection. The data presented here may help fish farmers to understand the parasite dynamics of L. macrocephalus in farming systems during the dry and rainy seasons in the state of Acre.

Resumo O presente estudo teve como objetivo analisar a sazonalidade dos helmintos parasitos de Leporinus macrocephalus provenientes de pisciculturas no município de Cruzeiro do Sul, Acre, Brasil e seus índices parasitários. Durante o período de junho de 2014 a março de 2015 foram coletados 200 espécimes obtidos de duas pisciculturas, uma de sistema semi-intensivo e outra de sistema extensivo, sendo 100 peixes em cada, durante as estações seca e chuvosa, 50 espécimes por estação. Foram registradas quinze espécies de parasitos, com variação sazonal de ocorrência de alguns nos sistemas de cultivo. Na piscicultura semi-intensiva houve maior prevalência de infecção na seca, e Urocleidoides paradoxus, Procamallanus (Spirocamallanus) inopinatus, Goezia leporini e Rhabdochona (Rhabdochona) acuminata apresentaram diferenças dos índices parasitários entre as estações. Na piscicultura extensiva não foi detectada variação da prevalência de infecção entre as estações e duas espécies, Tereancistrum parvus e G. leporini assinalaram diferença apenas na intensidade média de infecção. Os dados apresentados neste estudo podem auxiliar os piscicultores na compreensão da dinâmica parasitária de L. macrocephalus em sistemas de cultivos durante as estações seca e chuvosa no estado do Acre.