Occurrence of microsporidians Glugea hertwigi and Pleistophora ladogensis, in smelt Osmerus eperlanus from two German rivers, North Sea coast

• Autor(a) principal: Costa, G.
• Data de Publicação: 2016
• Outros Autores: Melo-Moreira, E., Carvalho, M. A. P. de
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.13/4646
• topic: Microsporidia; Glugea hertwigi; Pleistophora ladogensis; Smelt; Osmerus eperlanus; .; Faculdade de Ciências da Vida

Monthly samples of smelt Osmerus eperlanus (Linnaeus, 1758) were collected from July 1985 to May 1986, in the river Elbe (Germany), and examined for infections with microsporidi ans. Two microsporidians were found: Glugea hertwigi Weissenberg, 1911, infecting the digestive tract and Pleistophora ladogenis Voronin, 1978, infecting the skeletal musculature. G. hertwigi in fection led to the formation of xenomas, whereas P. ladogensis was characterized by diffuse infec tions, with the production of macroscopic visible thread-like or oval-shaped infection foci. Develop ment of G. hertwigi in the host cells showed characteristics typical of the genus Glugea. The ultrastructural development of P. ladogensis showed features typical of the genus Pleistophora, without evidence of the production of 2 types of spores. Host reaction consisted of inflammatory tis sue surrounding some of the infection foci as well as phagocytosis of spores. G. hertwigi was only found in juvenile smelt (<10 cm in length), whereas P. ladogensis infected smelts from 6 to 26 cm in length. Prevalence increased with fish length to a maximum value of 9.6%. Seasonal fluctuations in prevalence of infection were also found, with the lowest value in the winter months (2.5% in January 1986) and the highest in summer (11.8% in July 1985). The differences in prevalence of in fection with fish length and date of sampling were significant. Additionally, samples of smelt caught in April 1986 from the rivers Eider and Ems revealed infections with P. ladogensis in the first river system only.