Helmintos gastrointestinais de toninha, Pontoporia blainvillei (Cetartiodactyla; Pontoporiidae), do litoral de São Paulo, Brasil.
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Data
2018-02-20
Autores
Seabra, Camila Brandão
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Universidade Estadual Paulista (Unesp)
Resumo
As infecções parasitárias são muito comuns em mamíferos marinhos e o estudo da helmintofauna em cetáceos tem sido utilizado como uma ferramenta para determinar aspectos biológicos e ecológicos dos hospedeiros, entre eles a definição de nichos, rotas de dispersão, hábitos alimentares e diferenciação de estoques populacionais. A toninha, Pontoporia blainvillei, pequeno cetáceo endêmico do Atlântico Sul Ocidental tem como principal causa de mortalidade em toda sua área de distribuição a captura acidental. O trato gastrointestinal de 87 toninhas, coletados de carcaças provenientes de captura acidental ou encalhe, no período de 2005 a 2017, no litoral de São Paulo foram analisados para identificar as espécies componentes da fauna parasitária gastrointestinal e avaliar variações nos níveis de infecção conforme o sexo, fase de desenvolvimento, sazonalidade e área de distribuição dos hospedeiros. Foram coletados 4.171 espécimes de helmintos, classificadas em cinco espécies: Anisakis sp. (Nematoda: Anisakidae); Andracantha sp., Bolbosoma turbinella, Corynosoma cetaceum (Acanthocephala: Polymorphidae), e Synthesium pontoporiae (Trematoda: Brachycladiidae). Os helmintos C. cetaceum, exclusivo do estômago e S. pontoporiae, encontrado tanto no estômago quanto no intestino apresentaram os maiores índices parasitológicos, enquanto as outras três espécies foram consideradas raras devido aos baixos índices parasitários. Houve diferença significativa na carga parasitária apenas para as fases de desenvolvimento, na qual indivíduos adultos e juvenis apresentaram maiores índices parasitológicos do que indivíduos filhotes. Os índices parasitológicos não variaram significativamente entre os sexos, sazonalidade ou área de distribuição dos hospedeiros. A comunidade parasitária componente do trato gastrointestinal de P. blainvillei no litoral de São Paulo difere parcialmente daquela descrita anteriormente, compreendendo duas espécies: Corynosoma cetaceum (Acanthocephala: Polymorphidae) e Synthesium pontoporiae (Digenea: Brachycladiidae). As espécies Anisakis sp., Bolbosoma turbinella e Andracantha sp. consistem em infecção acidental por ingestão de presa infectada e, portanto, não fazem parte da fauna parasitária do hospedeiro nesta área de estudo. Foram observadas variações de comprimento e forma em 18% (n= 377) dos helmintos Synthesium pontoporiae coletados, tratando-se de espécimes sexualmente maduros com tamanho inferior e superior ao descrito para a espécie. São necessários estudos moleculares para complementar a investigação sobre as causas da diferenciação de Synthesium pontoporiae em três morfotipos distintos no litoral de São Paulo, Brasil.
Parasitic infections are very common in marine mammals and the study of helminthfauna in cetaceans has been used as a tool to determine biological and ecological aspects of the hosts, as the definition of niches, dispersal routes, feeding habits and differentiation of population stocks. The franciscana dolphin, Pontoporia blainvillei, is a small cetacean endemic to the Western South Atlantic, beeing the bycath events the main cause of mortality throughout its distribution area. The gastrointestinal tract of 87 franciscanas, collected from carcasses from bycatch or stranding, from 2005 to 2017, in the coast of São Paulo were analyzed to identify the component species of parasitic gastrointestinal fauna and to evaluate variations in levels of infection according to sex, stage of development, seasonality and range of the hosts. A total of 4,171 specimens of helminths were collected and classified into five species: Anisakis sp. (Nematoda: Anisakidae); Andracantha sp., Bolbosoma turbinella, Corynosoma cetaceum (Acanthocephala: Polymorphidae), and Synthesium pontoporiae (Trematoda: Brachycladiidae). The helminths C. cetaceum, exclusive to the stomach and S. pontoporiae, found in both, stomach and intestine, presented the highest parasitological indexes, while the other three species were considered rare due to the low parasitic indexes. There was a significant difference in parasite load only for the developmental stages, in which adult and juvenile individuals had higher parasitological indexes than calves. Parasitological indices did not vary significantly between the sexes, seasonality or range of the hosts. The parasite community component of the gastrointestinal tract of P. blainvillei on the São Paulo coast differs partially from that described previously, comprising two species: Corynosoma cetaceum (Acanthocephala: Polymorphidae) and Synthesium pontoporiae (Digenea: Brachycladiidae). The species Anisakis sp., Bolbosoma turbinella and Andracantha sp. consists of accidental infection by ingestion of infected prey and, therefore, are not part of the host parasitic fauna in this area of study. Length and shape variations were observed in 18% (n= 377) of the collected Synthesium pontoporiae parasites, being sexually mature specimens with inferior and superior sizes to those described for the species. Molecular studies are needed to complement the research on the causes of the differentiation of Synthesium pontoporiae in three distinct morphotypes in the coast of São Paulo.
Parasitic infections are very common in marine mammals and the study of helminthfauna in cetaceans has been used as a tool to determine biological and ecological aspects of the hosts, as the definition of niches, dispersal routes, feeding habits and differentiation of population stocks. The franciscana dolphin, Pontoporia blainvillei, is a small cetacean endemic to the Western South Atlantic, beeing the bycath events the main cause of mortality throughout its distribution area. The gastrointestinal tract of 87 franciscanas, collected from carcasses from bycatch or stranding, from 2005 to 2017, in the coast of São Paulo were analyzed to identify the component species of parasitic gastrointestinal fauna and to evaluate variations in levels of infection according to sex, stage of development, seasonality and range of the hosts. A total of 4,171 specimens of helminths were collected and classified into five species: Anisakis sp. (Nematoda: Anisakidae); Andracantha sp., Bolbosoma turbinella, Corynosoma cetaceum (Acanthocephala: Polymorphidae), and Synthesium pontoporiae (Trematoda: Brachycladiidae). The helminths C. cetaceum, exclusive to the stomach and S. pontoporiae, found in both, stomach and intestine, presented the highest parasitological indexes, while the other three species were considered rare due to the low parasitic indexes. There was a significant difference in parasite load only for the developmental stages, in which adult and juvenile individuals had higher parasitological indexes than calves. Parasitological indices did not vary significantly between the sexes, seasonality or range of the hosts. The parasite community component of the gastrointestinal tract of P. blainvillei on the São Paulo coast differs partially from that described previously, comprising two species: Corynosoma cetaceum (Acanthocephala: Polymorphidae) and Synthesium pontoporiae (Digenea: Brachycladiidae). The species Anisakis sp., Bolbosoma turbinella and Andracantha sp. consists of accidental infection by ingestion of infected prey and, therefore, are not part of the host parasitic fauna in this area of study. Length and shape variations were observed in 18% (n= 377) of the collected Synthesium pontoporiae parasites, being sexually mature specimens with inferior and superior sizes to those described for the species. Molecular studies are needed to complement the research on the causes of the differentiation of Synthesium pontoporiae in three distinct morphotypes in the coast of São Paulo.
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Palavras-chave
Cetacea, Pontoporia blainvillei, helmintos gastrointestinais, Synthesium pontoporiae, Litoral de São Paulo, Cetacea, Pontoporia blainvillei, gastrointestinal helminths, Synthesium pontoporiae, Sao Paulo coast