Parvicapsula pseudobranchicola infections in farmed Atlantic salmon in Norway are associated with low-grade to significant mortalities. The parasite is found as mature spores in pseudobranchs, but has also been detected in the gills, liver and kidney. Diagnosis has relied on the detection of Parvicapsula spores, with the pseudobranch being the preferred organ. A better understanding of the epizootiology of this myxosporean is a prerequisite for appropriate management and control. Hence, early detection of infections and life cycle studies are needed. We sequenced the small subunit (ssu) rDNA (18S) from P. pseudobranchicola and developed a sensitive diagnostic PCR protocol. This allowed us to (1) identify appropriate tissues for diagnostic assays, (2) examine the intraspecific variation in ssu rDNA in the parasite's Norwegian range, (3) examine annelid potential primary hosts and (4) obtain additional ssu rDNA sequences of marine Parvicapsula species to perform a phylogenetic study. Primers were constructed targeting the ssu rDNA from P. minibicornis. With these we obtained a partial ssu sequence of the P. pseudobranchicola type isolate. A new set of primers (PCF3/PCR3) was constructed for diagnostic purposes. These were tested against DNA from the host and several myxozoan species infecting Norwegian salmon. The primers give a positive product of 203 bp and pick out P. pseudobranchicola in salmonids. They also amplify the congeners P. unicornis and P. asymmetrica infecting unrelated fish. The PCR protocol developed showed a greater sensitivity than light microscopy. The pseudobranchs were always positive and are the recommended organ for PCR diagnostics. There was no sequence variation between geographic isolates from farmed salmon. Preliminary examinations of marine polychaetes and oligochaetes collected from farm sites with parvicapsulose problems were negative. A comparison of the sequence of the ssu rDNA from P. pseudobranchicola with that of other myxozoans shows that it groups closely together with P. unicornis and P. asymmetrica. The closest relative to this group is P. minibicornis.
Spectrolebias brousseaui is described from a temporary pool from the upper río Mamoré basin, Departamento Santa Cruz, Bolivia. The new species is distinguished from all congeners, by the overall dark blue coloration on the posterior two-thirds of body with bright blue iridescent spots vertically aligned in males. Spectrolebias brousseaui differs from all other species of the genus, except S. filamentosus, for having pelvic fins separated by a space (vs. pelvic fins in contact), long filaments at the tip of the dorsal and anal fins in males (vs. absence of filaments or presence only on dorsal fin in S. semiocellatus and S. inaequipinnatus, or the presence on the anal fin in S. chacoensis), and presence of contact organs on the scales of the flanks in males (vs. absence of contact organs on flanks in all remaining Spectrolebias species).Spectrolebias brousseaui é descrita de uma poça temporária localizada na região superior da bacia do río Mamoré, departamento de Santa Cruz, Bolívia. A espécie nova distingue-se de todos os congêneres pelo padrão de cor azul escuro nos dois terços posteriores do corpo com pontos azuis claros iridescentes alinhados verticalmente em machos. Spectrolebias brousseaui difere das outras espécies do gênero, exceto S. filamentosus, por ter as nadadeiras pélvicas separadas por um espaço (vs. nadadeira pélvicas juntas), longos filamentos nas extremidades das nadadeiras dorsal e anal em machos (vs. ausência de filamentos ou a presença apenas na nadadeira dorsal em S. semiocellatus e S. inaequipinnatus, ou pela presença de filamentos na nadadeira anal em S. chacoensis), e presença de órgão de contato nas escamas do flanco em machos (vs. ausência).
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