title: The development of Myxobolus pavlovskii (Myxozoa: Myxobolidae) includes an echinactinomyxon-type actinospore.
abstract: Echinactinomyxon-type actinospores were found in a mixed-species oligochaete culture originating from the Temperate Water Fish Hatchery near Budapest, Hungary. On the basis of DNA sequence analysis, the actinospores were identified as Myxobolus pavlovskii (Akhmerov, 1954), the 18S rDNA sequence from myxospores of which is available in GenBank. Silver carp Hypophthalmichthys molitrix (Valenciennes) fry specimens were successfully infected by cohabitation with the echinactinomyxon-releasing oligochaetes, which confirmed the molecular data congruence. The echinactinomyxons and the myxospores that developed in the gills of exposed fish fry were analysed morphologically and on DNA basis. The infected gill tissue was examined histologically. As typical characters of M. pavlovskii, numerous small plasmodia were observed in the epithelia of gill lamellae. Plasmodia contained thousands of myxospores with polar capsules unequal in size and witl; large intercapsular processes. The 18S rDNA sequence from actinospores and those from myxospores originating from the experimentally infected fish were identical. The oligochaete species releasing actinospores was morphologically determined as Limnodrilus sp. This is the first record of an echinactinomyxon as an alternate stage within the genus Myxobolus.
authors.affiliation: Veterinary Medical Research Institute, Hungarian Academy of Sciences, P.O. Box 18, H-1581 Budapest, Hungary.
authors.forename: Szilvia
authors.initials: S
authors.lastname: Marton
authors.forename: Edit
authors.initials: E
authors.lastname: Eszterbauer
mesh_terms: D000818:Animals; D001483:Base Sequence; D002347:Carps / Q000469:parasitology*; D004275:DNA, Ribosomal / Q000737:chemistry; D005393:Fish Diseases / Q000469:parasitology*; D005880:Gills / Q000469:parasitology; D006814:Hungary; D055766:Myxobolus / Q000145:classification / Q000235:genetics / Q000254:growth & development*; D009835:Oligochaeta / Q000469:parasitology; D010273:Parasitic Diseases, Animal / Q000469:parasitology*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013170:Spores / Q000145:classification / Q000235:genetics / Q000648:ultrastructure
chemical_list: D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S