The emergence of epitheliocystis in the upper Rhone region: evidence for Chlamydiae in wild and farmed salmonid populations
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We present the first study comparing epitheliocystis in a wild and farmed salmonid in Europe. Sampling three tributaries to the Lake Geneva, including one from headwaters to river mouth, revealed an unequal distribution of epitheliocystis in brown trout (Salmo trutta). When evaluated histologically and comparing sites grouped as wild versus farm, the probability of finding infected trout is higher on farms. In contrast, the infection intensities, as estimated by the number of cysts per gill arch, were higher on average and showed maximum values in the wild trout. Sequence analysis showed the most common epitheliocystis agents were Candidatus Piscichlamydia salmonis, all clustering into a single clade, whereas Candidatus Clavichlamydia salmonicola sequences cluster in two closely related subspecies, of which one was mostly found in farmed fish and the other exclusively in wild brown trout, indicating that farms are unlikely to be the source of infections in wild trout. A detailed morphological analysis of cysts using transmission electron microscopy revealed unique features illustrating the wide divergence existing between Ca. P. salmonis and Ca. C. salmonicola within the phylum Chlamydiae.
KeywordsBrown trout Candidatus Piscichlamydia salmonis Candidatus Clavichlamydia salmonicola River Farm
We thank the fish farmers at the Venoge who provided the brown trout for examination. Further we thank Aurelie Rubin and the team of the Centre for Fish and Wildlife Health, Bern for help during the sampling. This study was partly financed by the ESKAS-Bundesstipendien für ausländische Studierende, Kunstschaffende und Forschende, Bern, Switzerland.
Compliance with ethical standards
Conflict of interest
The authors declare they have no competing interests and they were notified about the content of the manuscript.
Animal rights statement
All animals were treated according to the Swiss welfare regulations (permission number: 2871).
- Abowei JFN, Briyani OF (2011) A review of some bacterial diseases in African culture fisheries. Asian J Med Sci 3(5):206–217Google Scholar
- Draghi A, Popov VL, Kahl MM, Stanton JB, Brown CC, Tsongalis GJ, West AB, Frasca S Jr (2004) Characterization of “Candidatus Piscichlamydia salmonis” (Order Chlamydiales), a Chlamydia-like bacterium associated with epitheliocystis in farmed Atlantic salmon (Salmo salar). J Clin Microbiol 42:5286–5297CrossRefPubMedPubMedCentralGoogle Scholar
- Fehr A, Walther E, Schmidt-Posthaus H, Nufer L, Wilson A, Svercel M, Richter D, Segner H, Pospischil A, Vaughan L (2013) Candidatus Syngnamydia venezia, a novel member of the phylum Chlamydiae from the broad nosed pipefish, Syngnathus typhle. PLoS One 8:e70853CrossRefPubMedPubMedCentralGoogle Scholar
- Schmidt-Posthaus H, Polkinghorne A, Nufer L, Schifferli A, Zimmermann DR, Segner H, Steiner P, Vaughan L (2012) A natural freshwater origin for two chlamydial species, Candidatus Piscichlamydia salmonis and Candidatus Clavochlamydia salmonicola, causing mixed infections in wild brown trout (Salmo trutta). Environ Microbiol 14:2048–2057CrossRefPubMedGoogle Scholar
- Steigen A, Nylund A, Karlsbakk E, Akoll P, Fiksdal IU, Nyland S, Odong R, Plarre H, Semyalo R, Skår C, Watanabe K (2013) ‘Cand. Actinochlamydia clariae’ gen. nov., sp. nov., a unique intracellular bacterium causing epitheliocystis in catfish (Clarias gariepinus) in Uganda. PLoS One 8:e66840CrossRefPubMedPubMedCentralGoogle Scholar
- Steigen A, Karlsbakk E, Plarre H, Watanabe K, Øvergård AC, Brevik Ø, Nylund A (2015) A new intracellular bacterium, Candidatus Similichlamydia labri sp. nov. (Chlamydiaceae) producing epitheliocysts in ballan wrasse, Labrus bergylta (Pisces, Labridae). Arch Microbiol 197:311–318CrossRefPubMedPubMedCentralGoogle Scholar
- Stride MC, Polkinghorne A, Miller TL, Groff JM, LaPatra SE, Nowak BF (2013a) Molecular characterization of “Candidatus Parilichlamydia carangidicola”, a novel Chlamydia-like epitheliocystis agent in yellowtail kingfish, Seriola lalandi (Valenciennes), and the proposal of a new family, “Candidatus Parilichlamydiaceae” fam. nov. (order Chlamydiales). Appl Environ Microbiol 79:1590–1597CrossRefPubMedPubMedCentralGoogle Scholar
- Stride MC, Polkinghorne A, Miller TL, Nowak BF (2013b) Molecular characterization of “Candidatus Similichlamydia latridicola” gen. nov., sp. nov. (Chlamydiales: “Candidatus Parilichlamydiaceae”), a novel Chlamydia-like epitheliocystis agent in the striped trumpeter, Latris lineata (Forster). Appl Environ Microbiol 79:4914–4920CrossRefPubMedPubMedCentralGoogle Scholar