Kudoa Hypoepicardialis N. Sp. (Myxozoa: Kudoidae) and Associated Lesions From the Heart of Seven Perciform Fishes in the Northern Gulf of Mexico

Abstract

Kudoa hypoepicardialis n. sp. infects the space between the epicardium and the compact myocardium and, in intense infections, the pericardial chamber of man-of-war fish (Nomeus gronovii) (Nomeidae) (the type host), blue runner (Caranx crysos) (Carangidae), Warsaw grouper (Epinephelus nigritus) (Serranidae), Atlantic tripletail (Lobotes surinamensis) (Lobotidae), northern red snapper (Lutjanus campechanus) (Lutjanidae), black drum (Pogonias cromis) (Sciaenidae), and bluefish (Pomatomus saltatrix) (Pomatomidae) in the northern Gulf of Mexico. This is the first report of a Kudoa sp. from the heart of a fish in the Gulf of Mexico, and of these hosts, only the bluefish was previously identified as a host for a species of Kudoa. Spores of the new species varied slightly in size among these hosts but were regarded as conspecific based on their nearly identical (99.9%) small-subunit (SSU) ribosomal DNA (rDNA) sequence. The new species differs both from the 4 nominal species of Kudoa reported from fishes in the Gulf of Mexico and from K. pericardialis, an allopatric species that infects the pericardial cavity, by the combination of having a large spore, a small polar capsule, and a polar filament with a single coil. The new species is morphologically and genetically most similar to K. shiomitsui, an allopatric species that infects the heart and pericardial cavity, but is distinguished from it based on a 4.2% difference in the SSU rDNA sequence. Heart lesions primarily were restricted to the vicinity of plasmodia and included a layer of fibrinous inflammation characterized by lymphocytes, macrophages, and granulomas as well as epithelioid encapsulations around plasmodia. Heavily infected hosts had melanin-like deposits and adipose cells beneath the epicardium. and the epicardium was discontinuous and apparently breached by plasmodia in some regions. Cardiac muscle, gill, liver, spleen, intestine, and kidney were normal.

Kudoa alliaria in flesh of Argentinian hoki Macruronus magellanicus (Gadiformes; Merlucciidae)

“…This sequence was compared to those of other related Kudoa species as determined from previous analyses (Blaylock et al 2004, Abollo et al 2005, Diamant et al 2005) and using the basic local alignment search tool (BLAST) on GenBank (Altschul et al 1990). Sequences were aligned with Clustal X (Thompson et al 1997) and pairwise sequence similarities were generated with BioEdit version 7.0.5 (Hall 1999).…”

Development and validation of an RNA- and DNA-based quantitative PCR assay for determination of Kudoa thyrsites infection levels in Atlantic salmon Salmo salar

“…There was only 1 mismatch in the reverse primer for K. miniauriculata 18S rDNA, whereas K. hypoepicardialis 18S rDNA differed at 10 sites. These results were not unexpected because analyses of the 18S rDNA sequences consistently clustered K. thyrsites and K. miniauriculata together, while K. hypoepicardialis was more divergent, showing only 91.9% sequence identity to K. thyrsites compared with 96.3% between K. miniauriculata and K. thyrsites (Kent et al 2001, Blaylock et al 2004). …”

“…However, 18S rDNA primers crossreacted with 18S rDNA from Kudoa miniauriculata. Analysis of 18S rDNA sequences showed that the forward primer used to amplify K. thyrsites 18S rDNA differed from K. miniauriculata 18S rDNA at only 3 sites, but showed 9 mismatches for this gene in K. hypoepicardialis (Blaylock et al 2004). There was only 1 mismatch in the reverse primer for K. miniauriculata 18S rDNA, whereas K. hypoepicardialis 18S rDNA differed at 10 sites.…”

Myxidium scripta n. sp. identified in urinary and biliary tract of Louisiana-farmed red-eared slider turtles Trachemys scripta elegans

“…is 16.6 to 20.4 µm) and by the presence of obliquely angled valvular striae in M. chelonarum versus longitudinal striae in M. scripta n. sp. Morphological or pathological variation among myxozoa have often been interpreted as intraspecific variation (Jirk°u et al 2006, Whipps & Diggles 2006 and molecular analyses have both supported (Blaylock et al 2004) and rejected (Adlard et al 2005, Easy et al 2005 this assertion. Thus, morphological differences may be either interor intraspecific, and molecular analyses have illuminated the more likely alternative.…”