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1.
Gyrodactylus infections in intensively-reared populations of Nile tilapia, Oreochromis niloticus niloticus, have been associated world-wide with high mortalities of juvenile fish. In this study, 26 populations of Gyrodactylus parasitising either O. n. niloticus or Mozambique tilapia, Oreochromis mossambicus, were sampled from fourteen countries and compared with type material of Gyrodactylus cichlidarum Paperna, 1968, Gyrodactylus niloticus (syn. of G. cichlidarum) and Gyrodactylus shariffi Cone, Arthur et Bondad-Reantaso, 1995. Representative specimens from each population were bisected, each half being used for morphological and molecular analyses. Principal component analyses (PCA) identified five distinct clusters: (1) a cluster representing G. cichlidarum collected from O. n. niloticus from 13 countries; (2) the G. shariffi paratype; (3) three specimens with pronounced ventral bar processes collected from two populations of Mexican O. n. niloticus (Gyrodactylus sp. 1); (4) four specimens collected from an Ethiopian population nominally identified as O. n. niloticus (Gyrodactylus sp. 2); (5) nine gyrodactylids from South African O. mossambicus (Gyrodactylus sp. 3). Molecular analyses comparing the sequence of the ribosomal transcribed spacer regions (ITS 1 and 2) and the 5.8S gene from the non-hook bearing half of worms representative for each population and for each cluster of parasites, confirmed the presence of G. cichlidarum in most samples analysed. Molecular data also confirmed that the DNA sequence of Gyrodactylus sp. 2 and Gyrodactylus sp. 3 (the morphologically-cryptic group of South African specimens from O. mossambicus) differed from that of G. cichlidarum and therefore represent new species; no sequences were obtained from Gyrodactylus sp. 1. The current study demonstrates that G. cichlidarum is the dominant species infecting O. n. niloticus, being found in 13 of the 15 countries sampled.  相似文献   

2.
The first record of Gyrodactylus species Nordmann, 1832 on the cichlid fish from Senegal is reported. Gyrodactylus parasites were found on four host species studied, Hemichromis fasciatus, Hemichromis letournaeuxi, Oreochromis niloticus, and Sarotherodon galilaeus. Gyrodactylus cichlidarum Paperna (Bamidgeh 13:14–29, 1968) were collected from H. fasciatus, and its identity was confirmed based on the morphometrical comparison with the holotype specimens of G. cichlidarum. Only one specimen of Gyrodactylus sp. was noted on H. letournaeuxi. The gyrodactylid specimens on O. niloticus and S. galilaeus were described as Gyrodactylus ergensi n. sp. based on the detailed morphometrical analysis supported by sequencing. The haptoral sclerites of G. ergensi n. sp., which closely resemble those of Gyrodactylus nyanzae Paperna, 1973, are compared with the type material and discussed. A partial sequence of the internal transcribed spacer recombinant DNA (ITS rDNA) was obtained from two specimens of G. ergensi, and a close relationship between G. ergensi n. sp. and G. cichlidarum is suggested based on 92% similarity in ITS rDNA region.  相似文献   

3.
An overview of Gyrodactylus infecting catfishes from the African continent is provided, including new data from Sudan, Senegal, Kenya and Mozambique. Haptoral sclerite morphometry and nuclear ribosomal DNA sequences revealed the presence of eight Gyrodactylus species. On Senegalese Synodontis nigrita, Gyrodactylus synodonti n. sp. and Gyrodactylus nigritae n. sp. are described. These are the first reports of gyrodactylid parasites from mochokid hosts. From the fins of North African catfish Clarias gariepinus collected in Mozambique, Gyrodactylus alekosi n. sp. and Gyrodactylus rysavyi were identified. G. rysavyi was also reported from Kenyan C. gariepinus and Senegalese Clarias anguillaris. From the fins of C. anguillaris studied in Senegal, two more species, Gyrodactylus transvaalensis and Gyrodactylus gelnari n. sp. were recognised. In addition, Gyrodactylus turkanaensis n. sp. from the gills of Kenyan C. gariepinus was described and an undescribed Gyrodactylus sp. was recorded from Sudanese representatives of the same host. Detailed morphometrical and molecular comparisons of the species are presented and discussed. The study highlights the hitherto understudied diversity of viviparous monogenean parasites throughout Africa.  相似文献   

4.
5.
Gyrodactylus malalai sp. nov. is described from the fin surface of cichlid fishes Oreochromis niloticus (L.) and Tilapia zillii (Gervais) caught in Lake Turkana (Kenya). The new species morphologically resembles Gyrodactylus nyanzae Paperna, 1973, but can be readily distinguished by the shape of the marginal hook sickles and the size of its hamuli. The sequence data of rDNA spanning partial 18S, internal transcribe spacer 1 and 2 and the 5.8S gene is unique within GenBank. Genetically, as most similar Gyrodactylus ergensi P?ikrylová, Matějusová, Musilová et Gelnar, 2009 was found (97.5%). Moreover, a specimen of G. cichlidarum from O. niloticus, and a specimen G. ergensi from Sarotherodon galilaeus (L.) were collected during sampling in Kenya. Likewise, additional sampling of O. niloticus from the Blue Nile in Sudan revealed the presence of the newly described species. These findings represent the first records of gyrodactylids in both African countries.  相似文献   

6.
Oreochromis karongae, one of the “chambo” tilapia species from Lake Malawi, has a karyotype of 2n = 38, making it one of the few species investigated to differ from the typical tilapia karyotype (2n = 44). The O. karongae karyotype consists of one large subtelocentric pair of chromosomes, four medium-sized pairs (three subtelocentric and one submetacentric) and 14 small pairs. The five largest pairs could be distinguished from each other on the basis of size, morphology and a series of fluorescence in situ hybridisation (FISH) probes. The largest pair is easily distinguished on the basis of size and a chromosome 1 (linkage group 3) bacterial artificial chromosome (BAC) FISH probe from Oreochromis niloticus. BAC clones from O. niloticus chromosome 2 (linkage group 7) hybridised to one of the medium-sized subtelocentric chromosome pairs (no. 5) of O. karongae, distinguishing the ancestral medium-sized pair from the three other medium-sized chromosome pairs (nos. 2, 3 and 4) that appear to have resulted from fusions. SATA repetitive DNA hybridised to the centromeres of all 19 chromosome pairs and also revealed the locations of the relic centromeres in the three fused pairs. Telomeric (TTAGGG)n repeats were identified in the telomeres of all chromosomes, and an interstitial telomeric site (ITS) was identified in three chromosomal pairs (no. 2, 3 and 4). Additionally, two ITS sites were identified in the largest chromosome pair (pair 1), confirming the origin of this chromosome from three ancestral chromosomes. SATA and ITS sites allowed the orientation of the fusions in pairs 2, 3 and 4, which all appear to have been in different orientations (q–q, p–q and p–p, respectively). One of these fusions (O. karongae chromosome pair no. 2) involves a small chromosome (equivalent to linkage group 1), which in O. niloticus carries the main sex-determining gene. 4′,6-Diamidino-2-phenyloindole staining of the synaptonemal complex in male O. karongae revealed the presumptive positions of the kinetochores, which correspond well to the centromeric positions observed in the mitotic karyotype.  相似文献   

7.
An intensive parasite survey was conducted in 2008 to better understand the parasite fauna occurrence, distribution and diversity in the commercial aquaculture fish species in Uganda. A total of 265 fish collected from hatcheries and grow-out systems were examined for parasites using routine parasitological techniques. The survey yielded 17 parasite species: 11 from Oreochromis niloticus and ten from Clarias gariepinus. Four parasites—Amirthalingamia macracantha, Monobothrioides sp., Zoogonoides sp. and a member of the family Amphilinidae—were recorded for the first time in the country. The parasite diversity was similar between hosts; however, O. niloticus was dominated by free-living stage-transmitted parasites in lower numbers, whereas both trophically and free-living stage-transmitted parasites were equally represented in C. gariepinus in relatively high intensities. The patterns in parasite numbers and composition in the two hosts reflect differences in fish habitat use and diet. A shift in parasite composition from monoxenous species-dominated communities in small-sized fish to heteroxenous in large fishes was recorded in both hosts. This was linked to ontogenetic feeding changes and prolonged exposure to parasites. Polyculture systems showed no effect on parasite intensity and composition. The gills were highly parasitized, mainly by protozoans and monogeneans. Generally, the occurrence and diversity of parasites in these fish species highlight the likelihood of disease outbreak in the proposed intensive aquaculture systems. This calls for raising awareness in fish health management among potential farmers, service providers and researchers.  相似文献   

8.
Thelohania parastaci sp. nov. infects the Australian freshwater crayfish, Cherax destructor. Data on morphology, developmental patterns and sequences from the small subunit (SSU) and internal transcribed spacer (ITS) regions of the ribosomal DNA (rDNA) of T. parastaci sp. nov. are described. The ultrastructural features of different life cycle stages are very similar to those of the European crayfish parasite Thelohania contejeani. T. parastaci sp. nov. exhibits simultaneous dimorphic sporogony in muscle tissue. Meronts, sporonts and spores are found in muscle tissue, within haemocytes in the hepatopancreas, and in the intestinal wall of infected crayfish. T. parastaci sp. nov. shows 92% sequence identity with T. contejeani and only 67% sequence identity with the fire ant pathogen T. solenopsae, when SSU rDNA sequences are compared. Analysis of SSU rDNA and ITS sequences of T. parastaci sp. nov. from crayfish from Victoria, Western Australia, and New South Wales indicate that the parasite has a wide geographical distribution in Australia.  相似文献   

9.
Alloglossidium fonti sp. nov. is described based on specimens from black bullheads (Ameiurus melas) collected from several localities in northwestern Minnesota. The new species is morphologically closest to A. corti and A. geminum. These two species were also found in the same region as A. fonti sp. nov. and sometimes in the same individual fish. Examination of numerous genetically marked specimens has demonstrated that the most reliable distinguishing feature among the three species is the position of anterior margin of the vitelline fields. In the new species they are situated at the level of anterior margin of ventral sucker while in A. corti it is at the level of intestinal bifurcation or even further anteriorly, and in A. geminum it is at the level of posterior margin of ventral sucker or further posteriorly. The new species has a relatively smaller cirrus sac than A. geminum. Despite rather minor, albeit stable morphological differences, the molecular data strongly supported the status of A. fonti sp. nov. as a new species. Moreover, molecular data and morphological examination of new material suggested that A. kenti, earlier synonymized with A. corti, is a valid species that is resurrected here. Comparison of 2420 base long sequences of nuclear rDNA (partial 18S, complete ITS region, and partial 28S) obtained from multiple specimens of all 4 species collected in Minnesota, North Dakota, Nebraska and Mississippi, showed essentially no intraspecific variability (except for 1 base difference in the ITS2 region of A. fonti sp. nov.), but has demonstrated pronounced interspecific differences. The new species was not found in the four examined catfish species from the Red River of the North (on the border between North Dakota and Minnesota) and neighbouring North Dakota.  相似文献   

10.
Falcaustra desilvai sp. nov. (Ascaridida, Kathlaniidae) from the large intestine of Cnemaspis aff. tropidogaster (Squamata, Gekkonidae) is described and illustrated. Falcaustra desilvai represents the 4th nematode species from Sri Lanka to be assigned to the genus and is distinguished from other Sri Lankan species by the distribution pattern of caudal papillae (12 precloacal, 2 adcloacal, 10 postcloacal, and 1 median), length of spicules (956–1046 μm) and absence of a pseudosucker.  相似文献   

11.
Proctocaecum blairi sp. nov. is described from specimens found in the intestine of an Australian freshwater crocodile, Crocodylus johnstoni, from Northern Territory, Australia. The most important diagnostic features of the new species are the body proportions and size, the position of the pharynx (relative length of the prepharynx and oesophagus), the relative length and position of the vitelline fields, and the number, shape and size of the circumoral spines. The new species is morphologically most similar to Proctocaecum atae, P. elongatum, P. crocodili, P. gairhei and Acanthostomum slusarskii. It differs from all of these species in having a much longer prepharynx, and differs from both P. atae and P. crocodili in having a much longer body and posteriorly situated vitelline fields. Proctocaecum blairi sp. nov. differs from P. elongatum in having a shorter body, a greater forebody to hindbody ratio, a much smaller ventral sucker, and a higher number of circumoral spines (23 vs 21 in P. elongatum). The new species differs from P. gairhei in possessing a much larger body length:width ratio and an ovary separated from the anterior testis by a seminal receptacle. Acanthostomum slusarskii lacks a gonotyl and has fewer circumoral spines than the new species. Proctocaecum blairi sp. nov. is the third species of Proctocaecum and the fourth cryptogonimid species known from crocodiles in Australia.  相似文献   

12.
Falcaustra sinensis sp. nov. collected from the feces of Indotestudo elongata (Blyth) is described and illustrated. The new species can be distinguished from the congeners by the arrangement of caudal papillae of the male (6 pairs precloacal, 4 pairs postcloacal, 1 median), length of spicules (3.84–4.74 mm) and the presence of pseudosucker.  相似文献   

13.
A new species of Soboliphyme from the endemic Iberian mole (Talpa occidentalis) is described. Soboliphyme occidentalis sp. nov. can be readily distinguished from all of its congeners primarily by the position of the vulva, which clearly shows a posterior oesophageal location, and the number of male caudal papillae. S. occidentalis sp. nov. is the only species that has four pairs of caudal papillae. S. abei, S. caucasica and S. jamesoni can be distinguished from S. occidentalis sp. nov. by not having a notched sucker, the anterior position of the vulva and two polar plugs in the eggs. S. jamesoni has an armate oral sucker and longer spicule; S. caucasica a longer spicule and shorter eggs, and S. abei has shorter eggs, which separate these species from S. occidentalis sp. nov. In the rest of the species with a notched oral sucker, S. baturini and S. hirudiniformis are differentiated from S. occidentalis sp. nov. by the anterior position of the vulva, two polar plugs in the egg and the spicule length in S. baturini and S. hirudiniformis and the size of eggs in S. baturini and S. hirudiniformis. S. ataahai, S. soricis and S. urotrichi have the vulva at the oesophago-intestinal junction, 9–10 male caudal papillae (S. ataahai and S. urotrichi), absence of male caudal papillae (S. soricis), armate oral sucker and long spicule in S. ataahai and one row of six circumoral spines in S. urotrichi. A key to the species of Soboliphyme is presented.  相似文献   

14.
Obviously, the present study reports the coccidian parasite so-called Goussia cichlidarum for the first time in Egypt. Altogether, 25 exogenous stages were clearly distinguished from specimens of naturally infected fishes of Oreochromis niloticus, O. auraeus, and Tilapia zillii from different locations. The total prevalence of infection was about 41%. Mostly, infected fish grossly seemed with a healthy body, although severe lesions have been detected microscopically in massive infection. Portions of thick wall swim bladder have been placed in vitro. The released parasitic stages have been photographed, sketched, measured, described, and compared with previously described species. Oocysts, sporocysts, and sporozoites have also been differentiated morphologically and morphometrically. Maturity stages of sporozoites containing sporocysts within either an oocyst or those released and sporulated outside the oocyst were considerably discernible. In addition, endogenous stages have also been investigated in histological sections included gamonts, merozoites, oocysts, and different stages of sporozoites.  相似文献   

15.
Saudi Arabia has a developing aquaculture industry that farms primarily tilapia. Although trichodinids are presumably the most usually encountered protozoan parasites in these cultured fish, they have rarely been studied in this context, and there is no data on the species that might infect cultured tilapia in Saudi Arabia. The present study was therefore carried out as a general survey to investigate the occurrence and identify the species of trichodinids that can infect cultured tilapia (Oreochromis niloticus) in Saudi Arabia. A total of 500 tilapia fish were collected from fish farms in Riyadh city and examined in order to determine the species of trichodinids present in the positive specimens. Three species of trichodinids (Trichodina maritinkae, T. centrostrigeata and T. frenata) were isolated and described as new records in Saudi Arabia. These trichodinids were found simultaneously in the same fish with overall prevalence of 20% (100/500). The identification and characterization of these three species are documented based on Riyadh specimens, for the first time. Additionally, the present paper confirms the existence of T. frenata for the second time globally and establishes this trichodinid as a new parasite for O. niloticus. T. maritinkae is highly specific to clariids, and previously, it has not been reported from any fish species other than clariids. The present work also confirmed that T. centrostrigeata can also infest cichlid fish. The list of host records of these species is expanded and their host specificity re-evaluated based on the results of this study in addition to the previously published data. We conclude that there is a need for further study of the impacts of these Trichodina spp. on Saudi Arabian fishery sector.  相似文献   

16.
Choanocotyle platti sp. nov. (Digenea, Choanocotylidae) is described from the northern long-necked turtle, Chelodina rugosa (Pleurodira, Chelidae) from the Daly and Mary Rivers, Northern Territory, Australia. This is the fifth known member of Choanocotyle. Choanocotyle platti sp. nov. differs from Choanocotyle nematoides Jue Sue et Platt, 1998 and Choanocotyle hobbsi Platt et Tkach, 2003 by smaller body length, larger oral sucker, relatively greater distance between tests, and prepharynx with an infolded posterior region. In addition the new species does not have the looped cirrus sac characteristic of Choanocotyle nematoides. Comparison of sequences of 18S, ITS (ITS1, 5.8S, ITS2) and partial 28S regions of nuclear rDNA among all 3 species strongly supports the status of Choanocotyle platti sp. nov. as a new species.  相似文献   

17.
The Gyrodactylus fauna of 274 fish taken from ten salmonid farms in Poland was sampled in 2006. Four fish species were investigated: rainbow trout Oncorhynchus mykiss, brown trout Salmo trutta (morphs fario, lacustris, and trutta), grayling Thymallus thymallus and huchen Hucho hucho. No parasites were observed on huchen. No indications of gyrodactylosis were observed, but an unexpected parasite species diversity was found. A molecular species identification by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) of ITS1 + 5.8S + ITS2 was utilized, with addition of morphometric methods. The most frequent parasite was a new record in Poland, G. teuchis. It was present in two molecular forms on brown trout and rainbow trout, which also carried G. derjavinoides and G. truttae. Three molecular forms of G. salaris/G. thymalli were found, the standard type ITS only on grayling. A heterozygous (or heterogenic) G. salaris type described earlier in Denmark was found in seven farms on rainbow trout, and a complementary homozygous clone which differs from the standard by three nucleotides, in two farms. This homozygous form has not been recorded earlier. The PCR-RFLP results were confirmed by sequencing ITS segment from representative specimens of each type and comparing them with all available salmonid-specific Gyrodactylus sequences in GenBank. The Polish fauna with seven different Gyrodactylus clones separated by PCR-RFLP was the most diverse reported in fish farms in any country so far. An erratum to this article is available at .  相似文献   

18.
Macroderoides texanus n. sp. is described based on 16 specimens collected from the intestine of the North American alligator gar, Atractosteus spatula. Of the five established species of Macroderoides, the new species is morphologically most similar to Macroderoides spiniferus and Macroderoides trilobatus. M. texanus n. sp. differs from M. spiniferus by having the ovary situated immediately posterior to the cirrus sac rather than at mid-way between the cirrus sac and anterior testis, the ventral sucker situated further posteriorly, and the vitelline fields extending somewhat posterior to posterior testis rather than to the middle of posterior testis. M. texanus n. sp. differs from M. trilobatus by having the ovary positioned immediately adjacent to, or overlapping the cirrus sac rather than at some distance posterior to it, and by having significantly larger eggs. Additionally, the new species has two distinctive rows of spines on the postero-ventral surface of the oral sucker that are lacking in M. spiniferus and M. trilobatus. Comparison of approximately 2,700-base-pair sequences of nuclear rDNA (partial 18S, complete ITS region and partial 28S) from M. texanus n. sp., M. spiniferus and M. trilobatus, strongly supports the status of M. texanus n. sp. as a new species.  相似文献   

19.
Two rhadinorhynchid species of acanthocephalans, Rhadinorhynchus dorsoventrospinosus sp. nov. and Rhadinorhynchus laterospinosus sp. nov. are described from the redtail scad, Decapterus kurroides Bleeker, and the trigger fish Balistes sp., respectively. The hosts were collected off Cat Ba Island, Halong Bay, Gulf of Tonkin, Vietnam in May, 2009. This brings the total number of species of Rhadinorhynchus Lühe, 1911 to 38. Specimens of the first species are characterized by having 11–12 proboscis hook rows with 30–31 hooks each, large dorsal and ventral spines in the posterior field of trunk spines, large eggs (100 × 20), and subterminal gonopore in both males and females. It is further characterized by many prominent fragmented nuclei in the body wall. The 1 female of the second species has 18 proboscis hook rows with 24 hooks each, smaller eggs (62 × 17), lateral trunk spines connecting those in the anterior and the posterior fields, and subterminal female gonopore. Notes on the genus Rhadinorhynchus, lists of the invalid and valid species, and a key to species are provided. Raorhynchus Tripathi, 1959 is proposed to be a junior synonym of Rhadinorhynchus pending a revision of the species of Raorhynchus.  相似文献   

20.
Trichuris suis was isolated from the cecum of two different hosts (Sus scrofa domestica—swine and Sus scrofa scrofa—wild boar) and Trichuris vulpis from dogs in Sevilla, Spain. Genomic DNA was isolated and internal transcribed spacers (ITS)1-5.8S-ITS2 segment from the ribosomal DNA (rDNA) was amplified and sequenced using polymerase chain reaction techniques. The sequence of T. suis from both hosts was 1,396 bp in length while that of T. vulpis was 1,044 bp. ITS1 of both populations isolated of T. suis was 661 nucleotides in length, while the ITS2 was 534 nucleotides in length. Furthermore, the ITS1 of T. vulpis was 410 nucleotides in length, while the ITS2 was 433 nucleotides in length. One hundred fifty-four nucleotides were observed along the 5.8S gene of T. suis and T. vulpis. Intraindividual and intraspecific variations were detected in the rDNA of both species. The presence of microsatellites was observed in all the individuals assayed. Sequence analysis of the ITSs and the 5.8S gene has demonstrated no sequence differences between T. suis isolated from both hosts (S. scrofa domestica—swine and S. scrofa scrofa—wild boar). Nevertheless, clear differences were detected between the ITS1 and ITS2 of T. suis and T. vulpis. Furthermore, a comparative molecular analysis between both species and the previously published ITS1-5.8S-ITS2 sequence data of Trichuris ovis, Trichuris leporis, Trichuris muris, Trichuris arvicolae, and Trichuris skrjabini was carried out. A common homology zone was detected in the ITS1 sequence of all species of trichurids.  相似文献   

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