Light and electronic observations on Henneguya ghaffari (Myxosporea,Bivalvulida) infecting the gills and intestine of Nile perch Lates niloticus (Pisces: Teleostei) from Chad and Senegal

Henneguya ghaffari Ali, 1999, described for the first time in Egypt, has been found on gills and intestine of Nile perch Lates niloticus L. from Chad and Senegal (Africa). It formed plasmodia which induced lesions of infected tissues. In fresh state, the spore body was ovoid and its size was 11.07 +/- 0.7 (range 11 to 13) x 7.7 +/- 0.4 (range 7 to 8) microm. The length of the caudal appendages was 44.2 +/- 1.7 (42 to 48) microm. The polar capsules were pyriform, of equal size, with the polar filament showing 4 coils, and measuring 3.17 +/- 0.1 (range 3 to 4) x 2.2 +/- 0.1 (range 1 to 2) microm. The total length of the spore was 55.73 +/- 1.7 (range 53 to 61) microm. At ultrastructural level, our results confirm that in Henneguya species, the sporoplasm is binucleate and the pansporaoblast is disporous.     

Henneguya cartilaginis n. sp. (Myxozoa: Myxosporea) in the head cartilage of masu salmon Oncorhynchus masou masou

Henneguya cartilaginis n. sp. (Myxozoa: Myxosporea) is described from wild masu salmon Oncorhynchus masou masou in Hokkaido, Japan. H. cartilaginis n. sp. produced white cysts, up to 3mm in size, in the head of masu salmon. Infected fish exhibited cranial protrusion due to the cysts. Spores (11.4 × 8.6μm) of H. cartilaginis n. sp. were egg-shaped with the posterior end more pointed and possessed two caudal appendages (34.2μm average length). Histological observations revealed that large plasmodia possessing fine fibrous pseudopodia on the surface developed in the head cartilage. H. cartilaginis n. sp. resembles H. cerebralis, which was described from the cranial cartilage of Kosogol grayling Thymallus nigrescens in Mongolia. However, they were distinguishable by spore morphology. Molecular analysis of the 18S rDNA sequences indicated that H. cartilaginis n. sp. was most closely related to Henneguya zschokkei, H. nuesslini and H. salminicola of salmonid fish, with genetic similarities of 95.3%, 95.1% and 93.9%, respectively. Based on these differences in spore morphology, molecular data, the site of infection and geographical distribution, the present species is considered to be a new species.     

Potential fishery of Nile perch Lates niloticus Linne (Pisces: Centropomidae) in Nyanza Gulf of Lake Victoria,East Africa

From bottom trawls, Lates niloticus (Lin.) in Nyanza Gulf was observed to have a gulf-wide distribution. Lates dominated the catch at Homa point. Catch rates in kg h^-1 varied from one location to another and from month to month.Its estimated production is 11 000 metric tons, netting about 22 000 000 Kenya shillings (US $2 000 000).Abundance of food items such as freshwater shrimps of the genus Caridina, and Engraulicypris argenteus, have been used as basis for estimating the growth and production of Lates.     

A new species of Myxozoa, Henneguya rondoni n. sp. (Myxozoa), from the peripheral nervous system of the Amazonian fish, Gymnorhamphichthys rondoni (Teleostei)

Henneguya rondoni n. sp. found in the peripheral lateral nerves located below the two lateral lines of the fish Gymnorhamphichthys rondoni (Teleostei, Rhamphichthyidae) from the Amazon river is described using light and electron microscopy. Spherical to ellipsoid cysts measuring up to 110 microm in length contained only immature and mature spores located in close contact with the myelin sheaths of the nervous fibres. Ellipsoidal spores measured 17.7 (16.9-18.1)-microm long, 3.6 (3.0-3.9)-microm wide, and 2.5 (2.2-2.8)-microm (n=25) thick. The spore body measuring 7.0 (6.8-7.3)-microm long was formed by two equal symmetric valves, each with an equal tapering tail 10.7 (10.3-11.0) microm in length. The tails were composed of an internal dense material surrounded by an external homogeneous sheath of hyaline substance. The valves surrounded two equal pyriform polar capsules measuring 2.5 (2.2-2.8)-microm long and 0.85 (0.79-0.88)-microm (n=25) wide and a binucleated sporoplasm cell containing globular sporoplasmosomes 0.38 (0.33-0.42) microm (n=25) in diam. with an internal eccentric dense structure with half-crescent section. Each polar capsule contains an anisofilar polar filament with 6-7 turns obliquely to the long axis. The matrix of the polar capsule was dense and the wall filled with a hyaline substance. The spores differed from those of previously described species. Based on the ultrastructural morphology of the spore and specificity to the host species, we propose a new species name H. rondoni n. sp.     

Henneguya tunisiensis n. sp. (Myxosporea: Bivalvulida), a new gill parasite of Symphodus tinca (L.) (Teleostei: Labridae) off Tunisia

Henneguya tunisiensis n. sp., a new myxosporean, is described from the gill-arches of the East Atlantic peacock wrasse Symphodus tinca (L.) collected from off the Kerkennah Islands, Tunisia. It is characterised by the presence of elongate white plasmodia of 1–1.5 × 1.5–2 mm in size. The mature spores are rounded in frontal view and have two identical polar capsules and two caudal appendages which taper considerably at the end. Both light and electron microscopical data show that this species differs in several morphological features from all previously described Henneguya spp. A molecular analysis, based on 18S rDNA sequence data, indicates that H. tunisiensis n. sp. is readily distinguishable from other myxozoan DNA sequences in GenBank. Phylogenetically, the new species is placed in the marine Henneguya clade, which is a sister group of marine Myxobolus spp. from perciform fishes in Tunisian waters.     

An ultrastructural and histopathological study of Henneguya pellucida n. sp. (Myxosporea: Myxobolidae) infecting Piaractus mesopotamicus (Characidae) cultivated in Brazil

During a study of myxosporean parasites of cultivated freshwater fish, a new myxosporean species, Henneguya pellucida n. sp., was discovered. Of the 120 Piaractus mesopotamicus sampled, only 10 specimens (8.3%) were infected. Yellow, round plasmodia measuring 0.5-3 mm were found in the serous membrane of the visceral cavity and in the tunica externa of the swim bladder. Sporogenesis was asynchronous, with the earliest developmental stages aligned prevailingly along the endoplasmic periphery and mature spores in the central zone. The mature spores were pear shaped (total length: 33.3 +/- 1.5 microm, mean +/- SD; width: 4.1 +/- 0.4 microm; body length: 11.4 +/- 0.3 microm; caudal process length: 24.1 +/- 1.5 microm). The polar capsules were elongated (length: 4.0 +/- 0.4 microm; width: 1.6 +/- 0.2 microm). The development of the parasite in the swim bladder produced thickening of the tunica externa and a granulomatous reaction. There was no correlation between the prevalence of the parasite and the chemical and physical characteristics of the water. Infection was recorded only in juvenile specimens ranging in size from 9.5 to 20 cm.     

Ceratomyxa hungarica n. sp. and Chloromyxum proterorhini n. sp. (Myxozoa: Myxosporea) from the freshwater goby Proterorhinus marmoratus (Pallas)

When studying the parasite fauna of freshwater gobies Proterorhinus marmoratus collected from the reaches of the River Danube around Budapest, two species of Myxosporea were recovered, a renal and a gall-bladder form. Previously no myxosporeans had been reported from this fish species. The spores and pseudoplasmodia of the parasite described as Ceratomyxa hungarica n. sp. were found in the convoluted tubules of the kidney and in the cavity of Bowman's capsule. The pseudoplasmodia were loosely attached to the wall of the tubules, causing their distention. Within each pseudoplasmodium two spores were formed. In the case of Chloromyxum proterorhini n. sp. only spores floating freely in the contents of the gall-bladder were found. Since Ceratomyxa species are typically marine fish parasites, Proterorhinus marmoratus, a fish species which has adapted to freshwater, appears to have retained some of its marine myxosporean fauna.     

Myxobolus absonus sp. n. (Myxozoa: Myxosporea) parasitizing pimelodus maculatus (siluriformes: Pimelodidae), a South American freshwater fish

A new myxoporean species is described from a freshwater fish in Brazil. Myxobolus absonus sp. n. was found infecting Pimelodus maculatus captured in the river Piracicaba, State of S?o Paulo, Brazil. Cysts were found free in the opercular cavity. The spores are large (length--15.7 +/- 1.5 microns, width--10.2 +/- 0.7 microns; mean +/- S.D.) and oval in shape, with the anterior end slightly pointed. The spore valves are relatively thin, smooth, and asymmetrical in a frontal view. The polar capsules are pyriform in shape, and unequal in size; the largest are 6.4 +/- 0.7 microns long and 3.6 +/- 0.5 microns wide, while the smallest are 4.2 +/- 0.6 microns long and 2.5 +/- 0.5 microns wide.     

Changes in the diet of Nile perch,Lates niloticus (L), in the Mwanza Gulf,Lake Victoria

Samples of Nile perch (Lates niloticus L.) were collected for stomach analysis from trawl catches conducted in the Mwanza Gulf from September 1986 to September 1988. Initially haplochromine cichlids formed the main food item for the Nile perch. Despite their decline, haplochromines still formed the major part of its diet in 1986. After the virtually complete disappearance of the haplochromines in 1987 and 1988, the benthic shrimp Caridina nilotica, the pelagic cyprinid, Rastrineobola argentea and juvenile Nile perch became the main food of Nile perch. Twenty-four trawl sessions were conducted to determine the relative quantities of respective prey taken. When present, Caridina is the major prey, mainly taken by day. If absent, juvenile Nile perch constitute the main part of the diet. Seasonal differences in diet composition probably reflect seasonal fluctuations in the abundance of the main prey species.     

Henneguya adherens N. Sp. (Myxozoa, Myxosporea), Parasite of the Amazonian Fish, Acestrorhynchus falcatus

ABSTRACT. A new species of myxosporean from the gill filaments of the freshwater teleost fish, Acestrorhynchus falcatus collected in the Amazon river is described from light and transmission electron microscope observations. The mature spores (total length 32.3 [30.7–35.1] μ) and all developmental stages were found in the same sporogonic plasmodium. The ellipsoidal spore body consists of 2 unequal shell valves adhering together along the suture lines. Each valve, tapering as a caudal projection, forms a long tail (length 20.5 [18.0–21.7] μm). The tail was surrounded by a homogeneous sheath on its length. The polar capsules measuring 3.1 × 1.2 μm contain 3–4 coils of the polar filament. All surfaces of the immature and mature spores were surrounded by a closely adherent homogenous structural sheath, mainly thicker around the tails. The taxonomic affinities of this parasite to other species are discussed.     

Henneguya schizodon n. sp. (Myxozoa, Myxobolidae), a parasite of the Amazonian teleost fish Schizodon fasciatus (Characiformes, Anostomidae)

A new histozoic species of myxosporean (Henneguya schizodon n. sp.) is described from the Amazon River teleost fish Schizodon fasciatus Spix & Agassiz, 1892 (Characiformes, Anostomidae). The plasmodia, which showed asynchronous development, were located in the kidney of the host. The spore body was ellipsoidal and was 13.1 (12-14) micron long by 3.3 (3-4) micron wide. The total length of the spore was 28.9 (27-30) micron, and each value had a caudal process measuring 16.3 (15-17) micron. The polar capsules were 5.4 (5-6) micron long by 1.3 (1-1.5) micron wide, and each had a polar filament with 8-10 coils. The characteristics of the species were compared with nearly all the species described so far, including all the species reported from South American fishes. This comparison allows to consider the materials as a new species, and the name Henneguya schizodon n. sp. is proposed.     

Ceratomyxa seriolae n. sp. and C. buri n. sp. (Myxozoa: Myxosporea) from the gall-bladder of cultured yellowtail Seriola quinqueradiata

Ceratomyxa seriolae n. sp. and C. buri n. sp. (Myxozoa: Myxosporea) were found in the gall-bladder of cultured yellowtail Seriola quinqueradiata Temminck & Schlegel (Carangidae) in Japan. Mature spores of C. seriolae n. sp. were elongate and 6.5 (6.0-7.5) m long and 33.7 (28.0-41.5) m thick. Disporous plasmodia of C. seriolae n. sp., 40-100 m in size, were amoeboid to spherical. C. buri n. sp. were elliptical with a flattened posterior end, 6.5 (5.5-7.5) m long and 14.3 (11.0-16.5) m thick. Spherical plasmodia of C. buri n. sp., 15-20 m in diameter, were disporous. In periodical sampling of yellowtail bile from August, 1999 to February, 2000, the two new species of Ceratomyxa, as well as Myxobolus spirosulcatus Maeno, Sorimachi, Ogawa & Kearn 1995, first appeared in October, and the prevalences were very variable (20-100%) during the study period.     

Description of a new blood-fluke,Cruoricola lates n. g., n. sp. (Digenea: Sanguinicolidae), from sea-bass Lates calcarifer (Bloch, 1790) (Centropomidae)

A new blood-fluke, Cruoricola lates n. g., n. sp., is described from sea-bass Lates calcarifer cultured in Malaysia. It is also found in Thailand and Australia. All fish examined over 15 cm in length were infected in the type-locality. This sanguinicolid is differentiated from other genera by: the spherical seminal vesicle; the large, single testis extending beyond the intestinal caeca; the medial, bi-lobed ovary; and the single column of sub-marginal, laterally directed, evenly spaced spines. It has separate genital pores which are close together. Adults are found predominantly in the mesenteric venules of the venous circulation. Juveniles are commonest in the caudal kidney.     

Ultrastructural aspects of the myxosporean Henneguya astyanax n. sp. (Myxozoa: Myxobolidae), a parasite of the Amazonian teleost Astyanax keithi (Characidae)

This study reports light and electron microscopical aspects of a myxosporean found in the gills of the freshwater teleost Astyanax keithi Géry, Planquete & Le Bail, 1996 (family Characidae), collected from the estuarine region of the Amazon River, near Belém, Brazil. The prevalence of infection was 23%. In interlamellar spaces of the gills, ellipsoidal whitish cyst-like plasmodia structures were present, which contained spores. The spores had a spermatozoa-like appearance (47.8 +/- 0.71 microm in total length) with a fusiform body (15.2 +/- 0.77 pm in length, 5.7 +/- 0.71 microm in width and 4.2 +/- 0.31 microm in thickness), and each of the 2 valves presented a tapering tail (32.6 +/- 1.11 microm in length). The valves surrounded a binucleate sporoplasm cell and 2 polar capsules (5.0 +/- 0.13 microm in length, 1.5 +/- 0.07 microm in width) that contained 8 to 9 coils of the polar filament. In the sporoplasm, several unique sporoplasmosomes were visible. A synoptic table of spore measurements of known Brazilian Henneguya species is presented. The spores differed from those of previously described species. Based on spore morphology, it is concluded that this species belongs to the family Myxobolidae, genus Henneguya, and that it constitutes a new species: H. astyanax n. sp.     

Henneguya michiganensis n. sp. (Cnidaria: Myxosporea) from the gills of muskellunge Esox masquinongy Mitchill(Esociformes: Esocidae)

Systematic Parasitology - Henneguya Thélohan, 1892 is the second most species rich genus of myxozoans, with reports from freshwater and marine fish worldwide. In the Great Lakes...     

Chloromyxum inexpectatum n. sp. and Sphaerospora colomani n. sp. (Myxozoa: Myxosporea), parasites of the urinary system of the sterlet,Acipenser ruthenus L.

During the parasitological examination of sterlets, Acipenser ruthenus L., caught for breeding, the developmental stages of two new coelozoic species of Myxosporea were demonstrated in the urinary passages. Chloromyxum inexpectatum n. sp. occurs attached to the epithelial cells of the ureters and urinary bladder. Sphaerospora colomani n. sp. forms bisporoblastic pseudoplasmodia in the lumen of the renal tubules. A further myxosporean species, Zschokkella sturionis Tripathi, 1948, was found in the biliary ducts. The occurrence of this parasite in sterlet has not been reported so far. Examination of blood smears revealed Cryptobia acipenseris and Haemogregarina acipenseris infection. Developmental stages of the coccidia Goussia acipenseris Molnár, 1986 and Goussia vargai Molnár, 1986 were frequently seen in the intestine of the dissected fish.     

The taxonomy of East African Nile Perch, Lates spp. (Perciformes, Centropomidae)

The type specimens of Lates albertianus, L. macrophthalmus, L. niloticus rudolfianus and L. niloticus longispinis are contrasted with each other, with riverine L. niloticus niloticus and with a collection of Nile Perch from Lake Victoria. Contrary to current belief L. niloticus niloticus was found to differ both from L. albertianus and from L. niloticus rudolfianus , but no significant difference was found between L. albertianus and L. niloticus rudolfianus . The Lake Victoria collection was found to differ from all other taxa, suggesting that the characters currently used in the taxonomy of Lates are inappropriate for this purpose. It is recommended that a reappraisal of Nile Perch taxonomy be made using more modern techniques and that studies are initiated to discover how characters change during development under differing environmental conditions.     

Henneguya mbakaouensis sp. nov., Myxobolus nounensis sp. nov. and M. hydrocyni Kostoingue & Toguebaye, 1994, Myxosporea (Myxozoa) parasites of Centropomidae, Cichlidae and Characidae (Teleosts) of the Sanaga basin in Cameroon (Central Africa)

The study of 102 teleost freshwater fishes of Sanaga basin in Cameroon revealed the presence of three myxosporean species, among which two were new. Host fishes were of three families: Centropomidae, Cichlidae and Characidae. New species were identified as Henneguya mbakaouensis sp. nov., a gill parasite of Lates niloticus and Myxobolus nounensis sp. nov. found in the kidney and spleen of Sarotherodon galilaeus and Tilapia mariae. Myxobolus hydrocyni Kosto?ngue & Toguebaye, 1994, previously described in Chad, was also found in Cameroon; complementary informations were given on that parasite which seemed to be specific to its host.     

Ultrastructure of Myxobolus brycon n. sp. (Phylum Myxozoa), parasite of the piraputanga fish Brycon hilarii (Teleostei) from Pantanal (Brazil)

Light and electron microscopy studies of a myxosporean, parasitizing the gill filaments of the freshwater fish Brycon hilarii (Valenciennes, 1850) (Characidae) collected in the Paraguay River (18°49'S, 57°39'W) (Pantanal), Brazil, is described. This parasite produces spherical to ellipsoidal polysporic histozoic plasmodia (Pmd) (up to ～180 μm in diameter) delimited by a double membrane and with several pinocytic channels. The plasmodial cyst contained the youngest developmental stages at the cortical periphery and immature and mature spores more internally. The Pmd developed near the cartilaginous structure of the gill filament, forming a prominent deformation where the gill lamellae disappear. Pyriform spores measured 6.9±0.6 (range 6.5-7.2) μm long, 4.2±0.5 (range 3.9-4.8) μm wide, and 2.5±0.7 (range 1.9-2.8) μm thick. The spores composed of two equal shell valves (～70 nm thick), adhering together along the straight suture line, surrounded two equal symmetric and elongated to pyriform polar capsules (PC) 4.2±0.6 (range 3.8-4.7) × 1.9±0.6 (1.7-2.5) μm; each PC contained a coiled polar filament with eight or nine (rarely 10) turns and a binucleated sporoplasm cell. Dense irregular masses were observed among the polar filaments coils. An intercapsular appendix was not observed. The sporoplasm contained several globular sporoplasmosomes randomly distributed among an extensive rough endoplasmic reticulum system with numerous vesicles and cisternae. Based on the morphological and ultrastructural differences and specificity of the host, we establish the new species, Myxobolus brycon n. sp.     

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.