Myxosporea (Myxozoa), a group of parasitic Cnidaria, use mostly bony fishes (Teleostei) as intermediate hosts; however, they can also parasitize other vertebrates such as cartilaginous fish (Chondrichthyes). Molecular data of myxosporeans from sharks and rays (Elasmobranchii) revealed these parasites to be one of the most basal representatives in the myxosporean phylogenetic tree, suggesting their ancient evolutionary history. A new myxosporean species, Bipteria vetusta n. sp., was found in the gall bladder of rabbit fish, Chimaera monstrosa (Holocephali; Chondrichthyes), and ssrDNA-based phylogeny revealed its basal position within the marine myxosporean lineage. Molecular dating based on ssrDNA analysis suggested the origin of a stem lineage leading to the marine myxosporean lineage at the time of the origin of Chondrichthyes in the Silurian era. The two common lineages of Myxozoa, Myxosporea and Malacosporea, were estimated to have split from their common ancestor in the Cambrian era. Tracing the history of evolution of the "vertebrate host type" character in the context of molecular dating showed that cartilaginous fish represented an ancestral state for all myxosporeans. Teleosts were very likely subsequently parasitized by myxozoans four times, independently. Myxosporean radiation and diversification appear to correlate with intermediate host evolution. The first intermediate hosts of myxosporeans were cartilaginous fish. When bony fish evolved and radiated, myxosporeans switched and adapted to bony fish, and subsequently greatly diversified in this new host niche. We believe that the present study is the first attempt at molecular dating of myxozoan evolution based on an old myxosporean species – a living myxosporean fossil.

• MeSH
• Biological Evolution * MeSH
• Phylogeny MeSH
• Host-Parasite Interactions * MeSH
• Molecular Sequence Data MeSH
• Myxozoa classification   genetics   growth & development   isolation & purification   MeSH
• DNA, Ribosomal chemistry   genetics   MeSH
• RNA, Ribosomal, 18S genetics   MeSH
• Fishes parasitology   MeSH
• Sequence Analysis, DNA MeSH
• Cluster Analysis MeSH
• Gallbladder parasitology   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

UNLABELLED: Myxosporeans (Myxozoa), microscopic metazoan parasitic organisms, are poorly studied in the Arctic region. Our survey of benthic and pelagic fish (n = 234) collected in Isfjorden (Svalbard, Norway) together with detailed morphological and molecular examination revealed the presence of nine myxosporean species. We compared observed myxosporean diversity with diversity documented in regions close to the Arctic and revealed that water depth rather than geographic distribution is an important factor influencing myxosporean fauna. WE DESCRIBE THREE NEW MYXOSPOREAN SPECIES: Zschokkella siegfriedi n. sp. from kidney of Boreogadus saida, Parvicapsula petuniae n. sp. from the urinary bladder of Gymnocanthus tricuspis, and Sinuolinea arctica n. sp. from the urinary bladder of Myoxocephalus scorpius. We characterise Latyspora-like organism from kidney of Clupea harengus. We provide new data for Ceratomyxa porrecta, Myxidium gadi, Myxidium finnmarchicum, Schulmania aenigmatosa, and Parvicapsula irregularis comb. nov. The phylogenetic analyses including the newly obtained SSU and LSU rDNA data revealed that most of the species studied cluster in the marine urinary clade within the marine myxosporean lineage. Newly obtained sequences including the first molecular data for the member of the genus Schulmania, substantially enriched the Zschokkella subclade. C. porrecta and the two Myxidium species cluster within the Ceratomyxa and marine Myxidium clade, respectively. Newly described species, Z. siegfriedi n. sp., was revealed to be morphologically indistinguishable but genetically diverse from Zschokkella hildae known from numerous gadid fish. Therefore, we consider Z. siegfriedi to be a cryptic myxosporean species that might be misidentified with Z. hildae. A Latyspora-like organism was found to be taxonomically problematic due to its suture line and its distant phylogenetic position from the type species Latyspora scomberomori did not allow us to assign it to the genus Latyspora. Based on an increased taxon sampling and SSU + LSU rDNA-based phylogeny, evolutionary trends within the marine urinary clade are investigated.

• Publication type
• Journal Article MeSH

Cryptosporidium spp. infection in captive exotic mammals was investigated using staining and molecular biological methods. A total of 323 fecal samples from 100 mammalian species (62 Artiodactyla, 33 Rodentia, 3 Perissodactyla, and 2 Paenungultata) in 4 zoological gardens in the Czech Republic was examined. Only in a reticulated giraffe (Giraffa camelopardalis reticulata) sample was Cryptosporidium sp. infection detected. The partial small subunit rRNA sequence obtained from the isolate was identical to sequences of Cryptosporidium muris in rock hyrax (Procavia capensis) and Bactrian camel (Camelus bactrianus). Neonatal BALB/c mice inoculated with 1 x 10(3) fresh oocysts of the C. muris giraffe isolate did not produce a detectable infection.

• MeSH
• Artiodactyla parasitology   MeSH
• Biological Assay veterinary   MeSH
• Cryptosporidium classification   genetics   isolation & purification   MeSH
• Feces parasitology   MeSH
• Cryptosporidiosis epidemiology   parasitology   veterinary   MeSH
• Mice, Inbred BALB C MeSH
• Mice MeSH
• Animals, Newborn MeSH
• Polymerase Chain Reaction veterinary   MeSH
• Prevalence MeSH
• DNA, Protozoan chemistry   isolation & purification   MeSH
• RNA, Ribosomal genetics   MeSH
• Animals, Zoo parasitology   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Geographicals
• Czech Republic MeSH