Supplemental diagnosis of Kudoa funduli (Myxozoa) parasitizing Fundulus heteroclitus (Cyprinodontidae) from coastal northeastern North America

The diagnosis of Kudoa funduli (Hahn, 1915) Meglitsch, 1948 (Myxozoa), is supplemented through study of new material collected from Fundulus heteroclitus (Cyprinodontidae) in coastal waters of Nova Scotia, Canada, and Connecticut. Plasmodia normally develop intracellularly in striated muscle of the flank and head, eventually rupturing and releasing spores. Spores disperse along adjacent epimysium, sometimes as far as the skin surface. Some plasmodia develop extracellularly within the bony cavities of vertebrae. Formalin-fixed spores viewed with a light microscope possess rounded edges, an inconspicuous apical region, thin sutural ridges, measure 6.6-7.4 microm wide, 4.3-5 microm thick, and 5.1-5.4 microm long, and have 4 equally sized polar capsules, 1.7-2.3 microm length by 1.4-1.7 microm width. Scanning electron microscopy revealed that spores are almost stellate, with inconspicuous uplifted tips, and that, within intracellular plasmodia, are embedded in an extensive honeycomb-like matrix. Prevalence of infection of K. funduli was 100% in host populations sampled in both Nova Scotia and Connecticut. Molecular sequence data of the 18S ribosomal DNA (737 base pairs) reveal that K. funduli is a valid species and a member of a clade that includes Kudoa dianae Dyková, Avila, and Fiala, 2002, Kudoa miniauriculata Whitaker, Kent, and Sakanari, 1996, and Kudoa paniformis Kabata and Whitaker, 1981.     

The histopathology and prevalence of Henneguya sebasta and Kudoa clupeidae in the rockfish, Sebastes paucispinis of southern California

The pathogenesis of two histozoic myxosporidans, Henneguya sebasta and Kudoa clupeidae, was studied from the Pacific rockfish, Sebastes paucispinis. Infection of the bulbus and truncus arteriosus with H. sebasta was observed in 30 of 100 fish. The parasite metastasized throughout the tissue causing necrosis, hyperplasia and hypertrophy of the connective tissue and smooth muscle. K. clupeidae, found in 37 of 100 fish, caused necrosis and atrophy of host skeletal muscle. The unattractive appearance of Kudoa cysts in rockfish filets detracted from their commercial value.     

Brain infecting kudoids of Australia's coral reefs, including a description of Kudoa lemniscati n. sp. (Myxosporea: Kudoidae) from Lutjanus lemniscatus (Perciformes: Lutjanidae) off Ningaloo Reef, Western Australia

A survey of the myxosporean fauna of Australian marine fishes revealed the presence of a number of putative species of Kudoidae (Multivalvulida) forming pseudocysts between the outer meningeal layer and the outer surface of the brains of the lutjanids Caesio cuning, Lutjanus carponotatus, Lutjanus ehrenbergii and Lutjanus fulviflamma and the mugilid Liza vaigiensis from Lizard Island on the Great Barrier Reef, Australia and Lutjanus lemniscatus off Ningaloo Reef, Western Australia. Morphometric data combined with Bayesian inference and maximum likelihood analyses of small subunit (SSU) and large subunit (LSU) ribosomal DNA (rDNA) was used for species identification and to explore relationships among these taxa. The brain-infecting taxa examined here formed a well-supported clade to the exclusion of non-brain infecting species in the phylogenetic analyses. The combined diagnostic approach identified an undescribed taxon, Kudoa lemniscati n. sp., from the brain of L. lemniscatus (Perciformes: Lutjanidae) off Ningaloo Reef, Western Australia, which we describe and characterise here. K. lemniscati n. sp. can be distinguished from all other species of Kudoa based on the combination of the distinct tropism for forming pseudocysts in the brain tissue, spores with 7 or 8 equal shell valves and 7 or 8 polar capsules, spore size and the differences in the SSU and LSU rDNA sequence data relative to other kudoids. Kudoa chaetodoni was found in the lutjanids C. cuning and L. carponotatus, expanding the known host range for this species to include chaetodontids and lutjanids. L. ehrenbergii and L. fulviflamma were infected with Kudoa lethrini off Lizard Island, a parasite previously known only from lethrinids. Specimens putatively identified as Kudoa yasunagai from Liza vaigiensis and Lutjanus ehrenbergii were morphologically similar and genetically identical over the SSU rDNA dataset to previously reported specimens, but differed by 4 to 11 nucleotides over the LSU dataset from the remaining isolates examined here. While these data are not definitive, they suggest the presence of a K. yasunagai complex.     

First report of three Kudoa species from eastern Australia: Kudoa thyrsites from mahi mahi (Coryphaena hippurus), Kudoa amamiensis and Kudoa minithyrsites n. sp. from sweeper (Pempheris ypsilychnus)

Fish species around the world are parasitized by myxozoans of the genus Kudoa, several of which infect and cause damage of commercial importance. In particular, Kudoa thyrsites and Kudoa amamiensis infect certain cultured fish species causing damage to muscle tissue, making the fish unmarketable. Kudoa thyrsites has a broad host and geographic range infecting over 35 different fish species worldwide, while K. amamiensis has only been reported from a few species in Japanese waters. Through morphological and molecular analyses we have confirmed the presence of both of these parasites in eastern Australian waters. In addition, a novel Kudoa species was identified, having stellate spores, with one polar capsule larger than the other three. The SSU rDNA sequence of this parasite was 1.5% different from K. thyrsites and is an outlier from K. thyrsites representatives in a phylogenetic analysis. Furthermore, the spores of this parasite are distinctly smaller than those of K. thyrsites, and thus it is described as Kudoa minithyrsites n. sp. Although the potential effects of K. minithyrsites n. sp. on its fish hosts are unknown, both K. thyrsites and K. amamiensis are associated with flesh quality problems in some cultured species and may be potential threats to an expanding aquaculture industry in Australia.     

Kudoa hypoepicardialis n. sp. (Myxozoa: Kudoidae) and associated lesions from the heart of seven perciform fishes in the northern Gulf of Mexico

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.     

Systemic infection of Kudoa lutjanus n. sp. (Myxozoa: Myxosporea) in red snapper Lutjanus erythropterus from Taiwan

A new species of Kudoa lutjanus n. sp. (Myxosporea) is described from the brain and internal organs of cultured red snapper Lutjanus erythropterus from Taiwan. The fish, 260 to 390 g in weight, exhibited anorexia and poor appetite and swam in the surface water during outbreaks. Cumulative mortality was about 1% during a period of 3 wk. The red snapper exhibited numerous creamy-white pseudocysts, 0.003 to 0.65 cm (n = 100) in diameter, in the eye, swim bladder, muscle and other internal organs, but especially in the brain. The number of pseudocysts per infected fish was not correlated with fish size or condition. Mature spores were quadrate in apical view and suboval in side view, measuring 8.2 +/- 0.59 microm in width and 7.3 +/- 0.53 microm in length. The 4 valves were equal in size, each with 1 polar capsule. Polar capsules were pyriform in shape, measuring 3.62 +/- 0.49 microm in length and 2.2 +/- 0.49 microm in width. Mild inflammatory responses or liquefaction of host tissue were associated with K. lutjanus n. sp. infection. The junction of shell valves appeared as overlapping, straight lines. The polar filament formed 2 to 3 coils. A general PCR (polymerase chain reaction) primer for Kudoa amplified the small subunit (SSU) rDNA sequences, and the amplified gene was sequenced. It was evident from the phylogenetic tree that the 3 strains tested, AOD93020M, AOD93028M and AOD93028B, were identical and belonged to the Kudoa SS rRNA subgroup. The evolutionary tree showed that these strains form a unique clade, at a distance from other Kudoa species and myxosporeans. The spore's morphological and ultrastructural characteristics, as well as the SS rDNA properties of the isolates, were also essentially identical and served to distinguish them from representative Kudoa. It is, therefore, proposed that the strains isolated from the diseased red snapper be assigned to a new species.     

Phylogeny of the multivalvulidae (Myxozoa: Myxosporea) based on comparative ribosomal DNA sequence analysis

Fish parasites of the Multivalvulida (Myxozoa, Myxosporea) are widespread and can be associated with mortality or poor flesh quality in their commercially important marine hosts. Traditional classifications divide members of this order into families based on spore valve and polar capsule numbers. Analyses of the small-subunit (SSU) ribosomal DNA (rDNA) sequences from all representative families in the order (Trilosporidae, Kudoidae, Pentacapsulidae, Hexacapsulidae, and Septemcapsulidae) indicate that a revision of the taxonomy and nomenclature is warranted. In our phylogenetic analysis of (SSU and large subunit) rDNA sequences, members of Pentacapsula, Hexacapsula, and Septemcapsula root within a clade of Kudoa species with Unicapsula (Trilosporidae) as an outlier to these genera. Therefore, we propose to synonymize Pentacapsulidae, Hexacapsulidae, and Septemcapsulidae with Kudoidae alter the diagnosis of Kudoidae and Kudoa to accommodate all marine myxozoan parasites having 4 or more shell valves and polar capsules.     

Detection and characterization of Kudoa thunni from uncooked yellowfin tuna (Thunnus albacares) in Southeast Asia

Myxosporean parasites Kudoa spp. have been reported in several marine fish species worldwide. However, little is known about the contamination of these parasites in raw fish in Southeast Asia, where the consumption demand of uncooked fish is increasing. In 2019, the occurrence of several cases of raw yellowfin tuna (Thunnus albacares) obtained from retail shops with the presence of unknown white, nodular cysts within the musculature have raised public health concerns for the consumption of raw marine fish in Vietnam. Microscopic examination revealed numerous myxospores with the quadratic shape of the Kudoidae. Morphologically, stained spores detected in this study are suspected to Kudoa thunni. To confirm the suspected Kudoa species, further examination of the 18S small-subunit (SSU) was conducted and the results of nucleotide sequence analysis obtained from nodular cysts revealed 99.18–100% identity to that of Kudoa thunni sequences available in GenBank. Detection of K. thunni infection in tuna in Southeast Asia highlights the need for appropriate surveillance and control measures to ensure high quality standards and safety on raw fish production and consumption.     

Intra-specific variation of Kudoa spp. (Myxosporea: Multivalvulida) from apogonid fishes (Perciformes), including the description of two new species, K. cheilodipteri n. sp. and K. cookii n. sp., from Australian waters

Kudoa spp. from the musculature and intestinal mucosa of species of the teleost family Apogonidae were examined for their taxonomic identity. Two novel species are characterised: Kudoa cheilodipteri n. sp. from the musculature of Cheilodipterus quinquelineatus Cuvier, Ostorhinchus cyanosoma (Bleeker) and O. aureus (Lacépède); and Kudoa cookii n. sp. from the submucosa of the intestines of O. cookii (Macleay) only. Both species are characterised using morphology, small subunit ribosomal DNA (SSU rDNA), large subunit ribosomal DNA (LSU rDNA), and biological characters. Three new host records, O. cyanosoma, O. aureus and Apogon doederleini, and associated geographical, morphological and genetic data are also provided for Kudoa whippsi Burger & Adlard, 2010. Morphological and molecular intra-specific variation of all isolates assigned to K. whippsi is also examined. Phylogenetic analyses further support the idea that tissue tropism is a distinguishing character between morphologically similar species; species reported here display close relatedness to morphologically similar species infecting the same tissue within their hosts.     

Characterization of Kudoa monodactyli n. sp. (Myxosporea: Multivalvulida) from the Muscle of Monodactylus argenteus (Teleostei: Monodactylidae) from Moreton Bay, Queensland, Australia

Kudoa monodactyli n. sp. is described from the somatic musculature of Monodactylus argenteus from several localities in southern Queensland, Australia. This is the first record of a myxozoan parasite from the family Monodactylidae. The spores typically have five polar capsules, making this species similar to the four other five-valved Kudoa species (K. neurophila, K. muscularis, K. shulmani, K. cutanea) that have been described to date. However, morphometric measurements particularly of spore length and width make the species from M. argenteus distinct from the other species. Comparison of the small subunit ribosomal DNA sequence of this species with its congeners for which sequence data are available, provides further evidence of novelty. Kudoa monodactyli n. sp. displays 38 (of 1,554) nucleotide differences compared with rDNA sequence of Kudoa neurophila, which on phylogenetic analysis places these species in clades exclusive of each other. Phylogenetic analyses also provide evidence that the number of valves per spore in this genus is an imperfect indicator of relatedness.     

Kudoa prunusi n. sp. (Myxozoa: Multivalvulida) from the brain of Pacific bluefin tuna Thunnus orientalis (Temminck & Schlegel, 1844) cultured in Japan

Kudoa prunusi n. sp. (Myxozoa; Multivalvulida) is described from the brain of Pacific bluefin tuna Thunnus orientalis cultured in Japan. Numerous white cysts, up to 0.5mm in size, were found on and in the brain. Spores having typically five spore valves and five polar capsules resembled a five-petal cherry blossom in apical view and were conical shape with a round bottom in side view. Average spore size was 9.63 (8.5-10.3) μm in width and 7.50 (6.7-8.6) μm in length. The spore dimensions of K. prunusi overlapped with those of Kudoa yasunagai ex Sillago ciliata having five to six spore valves, but they were clearly distinct in spore shape, 18S rDNA and 28S rDNA sequences (0.3% and 1.7% differences, respectively). Phylogenetic analysis of 18S rDNA revealed that K. prunusi grouped with the brain-infecting multivalvulid species, K. yasunagai, K. chaetodoni, K. lethrini and K. neurophila, rather than five-valved Kudoa spp. Combined with morphological, molecular and biological differences, K. prunusi was proven to be a new species.     

Two unusual myxozoans,Kudoa quadricornis n. sp. (Multivalvulida) from the muscle of goldspotted trevally (Carangoides fulvoguttatus) and Kudoa permulticapsula n. sp. (Multivalvulida) from the muscle of Spanish mackerel (Scomberomorus commerson) from the Great Barrier Reef,Australia

Two unusual myxozoan parasites are described from the somatic muscle of 2 reef fishes from Australia's Great Barrier Reef. Kudoa quadricornis n. sp. from the somatic muscle of Carangoides fulvoguttatus is morphologically consistent with other Kudoa sp., having 4 polar capsules and 4 shell valves. Kudoa quadricornis n. sp. is unique in that it has a pyriform spore body with a greater length than width (7.82-9.95 and 5.94-8.66 microm, respectively) and distinct posterolateral projections. Spores of Kudoa permulticapsula n. sp. observed within pseudocysts of the somatic muscle tissue of Scomberomorus commerson are different from those of all other myxozoans. The ovoid spores (length, 4.69-6.65 microm; width, 8.42-9.92 microm; thickness, 6.36-8.33 microm) contain 13 polar capsules with an equal number of shell valves. Phylogenetic analysis using small subunit ribosomal DNA sequences of K. quadricornis n. sp. and K. permulticapsula n. sp. showed that these parasites cluster within a clade comprised of Kudoa species. This brings into question the division of parasites of the Multivalvulida into genera based solely on polar capsule numbers.     

Kudoa iwatai (Myxosporea: Multivalvulida) in wild and cultured fish in the Red Sea: redescription and molecular phylogeny

Gilt-head sea bream, Sparus aurata L., the Mediterranean's most important mariculture species, has been cultured for the last 30 yr in Eilat (Israeli Red Sea). Kudoa sp. was the first myxosporean parasite reported from this species. In recent years, an increase in prevalence in both land-based and sea-cage facilities in Eilat has been observed. Infections with the same Kudoa species appeared in cultured European sea bass Dicentrarchus labrax (L.) and grey mullet Mugil cephalus in the same farms, as well as in 10 species of wild Red Sea reef fish, indicating that Kudoa sp. is not fastidious with regard to its host. All affected species displayed 1- to 2-mm (up to 5 mm) whitish, spherical, or oval polysporous plasmodia. The parasite established multiple site infections, most commonly in the muscles and intracranial adipose tissue of the brain and eye periphery. Other sites were subcutaneous adipose tissue, nerve axons, mouth, eye, mesenteries, peritoneum, swim bladder, intestinal musculature, heart, pericardium, kidney, and ovary. On the basis of spore morphology, the parasite was identified as Kudoa iwatai Egusa and Shiomitsu, 1983. Ultrastructural features were comparable to those of previously studied Kudoa species. The 18S rDNA from 7 Red Sea isolates was sequenced and compared with the sequence of the same gene from K. iwatai isolated from cultured red sea bream, Pagrus major, in Japan. The phylogenetic position of K. iwatai within the genus was determined using sequence analysis of all related taxa available in GenBank. The 3 isolates of K. iwatai clustered together on a newly formed, highly supported clade. The Red Sea strain of K. iwatai is apparently native to the region. In the absence of records of this Kudoa sp. from the extensive Mediterranean sea bream and sea bass production industries, introduction with its Mediterranean hosts seems unlikely. Therefore, we conclude that K. iwatai is an Indo-Pacific species that, in the Red Sea, has extended its host range to include the allochthonous gilt-head sea bream, European sea bass, and grey mullet.     

Myxosporean plasmodial infection associated with ulcerative lesions in young-of-the-year Atlantic menhaden in a tributary of the Chesapeake Bay,and possible links to Kudoa clupeidae

Ulcers in Atlantic menhaden Brevoortia tyrannus (Latrobe) (Clupeidae), observed along the USA east coast, have been attributed to diverse etiologies including bacterial, fungal and, recently, harmful algal blooms. To understand the early pathogenesis of these lesions, we examined juvenile Atlantic menhaden collected during their seasonal presence in Chesapeake Bay tributaries from April to October 1999 and from March to August 2000. We conducted histopathological examinations of young-of-the-year fish from the Pocomoke River tributary, which has a history of fish mortalities and high lesion prevalence. Kudoa clupeidae (Myxozoa: Myxosporea) spores were present in the muscles of fish collected in both years. Of the fish assessed by histology in April, 5 to 14% were infected, while in May 90 to 96% were infected. Infection rates remained high during the summer. Mature spores were primarily located within myomeres and caused little or no observable pathological changes. Ultrastructure showed spores with capsulogenic cells bearing filamentous projections, and a basal crescentic nucleus with mottled nucleoplasm containing cleaved, condensed chromatin. Also, a highly invasive plasmodial stage of a myxozoan was found in the lesions of juvenile Atlantic menhaden. The plasmodia were observed in fish collected between May and July, with the maximum occurrence in late June 1999 and late May 2000. Plasmodia penetrated and surrounded muscle bundles, causing grossly observable raised lesions in 73% of all fish infected with this invasive stage. Plasmodia were also detected in the visceral organs, branchial arches, and interocular muscles of some fish. Some of the invasive extrasporogonic plasmodial lesions were associated with ulcers and chronic inflammatory infiltrates. The plasmodial stage appeared to slough out of the tissue with subsequent evidence of wound healing. Ultrastructure showed plasmodia with an elaborate irregular surface, divided into distinct ectoplasm and endoplasm; the latter contained numerous spherical vegetative nuclei, secondary generative cells, and occasional cell doublets. Our ultrastructural studies indicate that the plasmodial organisms, which are important in the etiology of the skin lesions, are myxozoans, and they may represent early stages of K. clupeidae.     

Phylogeography of the cosmopolitan marine parasite Kudoa thyrsites (Myxozoa: Myxosporea)

Kudoa thyrsites (Myxozoa: Multivalvulida) is a cosmopolitan marine parasite of fishes associated with post-mortem tissue degradation. Financial losses incurred as a result of these infections are of concern to commercial fisheries. There is conflicting evidence whether K. thyrsites represents a cryptic species complex. Myxospore morphology is very similar for K. thyrsites across its range, but preliminary genetic analyses show some differences. Kudoa thyrsites and the morphologically similar Kudoa histolytica were examined from hosts in British Columbia, Canada, Oregon, USA, Chile, England, South Africa, Australia, and Japan. We compared myxospore morphology and DNA sequences of heat shock protein 70 and the small subunit, large subunit, and internal transcribed spacer 1 of the ribosomal DNA. There was some morphological variation between regional representatives, inconsistent with genetic analyses. Phylogenetically, major separations correlated to four broad geographic regions: Japan, Australia, eastern Pacific, and eastern Atlantic. Within these regions there was little additional genetic structure. These data are evidence for regional subdivision of K. thyrsites suggesting global transplantation of fishes has yet to homogenize these distinctions. Within regions, parasite gene flow appears to be high between host species, suggesting little host specificity and minimal cryptic speciation. Our data also indicate that K. histolytica is not a valid species, as it was morphologically and genetically indistinguishable from K. thyrsites.     

Two multivalvulid myxozoans causing postmortem myoliquefaction: Kudoa megacapsula n. sp. from red barracuda (Sphyraena pinguis) and Kudoa thyrsites from splendid alfonso (Beryx splendens)

Postmortem myoliquefaction associated with multivalvulid myxozoans was found in fillets of red barracuda (Sphyraena pinguis) and splendid alfonso (Beryx splendens), which were imported to Japan from China and South Africa, respectively. Morphological examinations of the myxozoans from the somatic muscle of red barracuda revealed that spores (30.3-44.7 microm in maximum thickness) had 4 distinct winglike valves, in which 1 extremely large (12.7 x 5.8 microm), 2 small, and 1 vestigial polar capsule were present. The small subunit ribosomal DNA sequence analysis showed that the myxozoan cluster within a clade was composed of Kudoa thyrsites, Kudoa minithyrsites, and Kudoa lateolabracis, all having stellate spores with 1 polar capsule larger than the other 3. On the basis of these characteristics, we describe this parasite as Kudoa megacapsula n. sp. Morphological and molecular analyses of the myxozoan from splendid alfonso identified it as K. thyrsites, which has been described from many marine fishes. To our knowledge, this is the first record of K. thyrsites in splendid alfonso.     

Phyllodistomum funduli n. sp. (Trematoda: Gorgoderidae) from Fundulus sciadicus Cope from Cedar Creek in western Nebraska

Phyllodistomum funduli n. sp. is described from the urinary bladder and ureters of the plains topminnow, Fundulus sciadicus, from Cedar Creek in Keith County, Nebraska (41 degrees 11.18'N, 101 degrees 21.77'W). Phyllodistomum funduli differs from most other Phyllodistomum species reported in possessing an oral sucker that is larger than the acetabulum. Currently, 7 other species of Phyllodistomum have been reported to possess this trait. A comparison of P. funduli with these 7 other species indicates that P. funduli is a distinct species, lacking notches, posterior body folds, caudal projections, or cephalic glands found in some congeners. There is no published report on parasites other than monogeneans inhabiting the plains topminnow, and there is no other report of members from the Gorgoderidae inhabiting any members of the Fundulidae.     

Life history, pathology, and description of Kudoa ovivora n. sp. (Myxozoa, Myxosporea): an ovarian parasite of Caribbean labroid fishes

We describe Kudoa ovivora n. sp. from ovaries of bluehead wrasse, Thalassoma bifasciatum, and record its presence in 6 species (Labroidei) collected in the San Blas Islands. Panama. Kudoa ovivora spores are quadrate with rounded edges in apical view, oval-shaped with apical valve extensions in side view (mean spore dimensions: length 6.5 microns, width 7.7 microns, thickness 6.9 microns; mean polar capsule dimensions: length 2.1 microns, width 1.5 microns). This is the first Kudoa species from gonads of fishes. Prevalence of infection varied among labrids (Thalassoma bifasciatum, Halichoeres bivittatus, Halichoeres garnoti, Halichoeres poevi), with T. bifasciatum exhibiting the greatest prevalence. Density of infection, measured as percent infected eggs, also varied among species with highest densities occurring in H. garnoti. Kudoa ovivora may not require an intermediate host because fishes fed infected tissue developed more infections than unfed fish. Infected eggs are inviable and larger and heavier than uninfected eggs. Infected eggs contain more organic and inorganic material, indicating that K. ovivora increases resource allocation to eggs. Therefore, infected females may have reduced growth, fecundity, and/or spawning activity. Because males were uninfected and all identified hosts are protogynous sequential hermaphrodites, further studies of K. ovivora may provide new insights on the costs/benefits of sex change.