Two new species of Unikaryon (Microsporidia) hyperparasitic in microphallid metacercariae (Digenea) from Florida intertidal crabs.

The genus Unikaryon (Microsporidia) holds exclusively hyperparasites of Platyhelminthes. Four species of Unikaryon are presently known from trematodes infecting mollusks and fish, and one from a cestode infecting a fish. Here we report two species of Unikaryon from microphallid trematode metacercariae parasitizing the brachyuran crabs, Panopeus herbstii and Pachygrapsus transversus, collected from intertidal habitats in Florida. The first microsporidium, which we assign here to a new species, Unikaryon panopei sp. n., was isolated from Microphallus sp. encysted in Panopeus herbstii from Tampa Bay. The specific designation for the second Unikaryon sp. (Unikaryon sp. 2), which occurred in metacercaria of Diacetabulum sp. found in P. transversus from the Florida Keys, is pending due to the lack of SSrDNA sequence data. Light and electron microscopy demonstrates that both species display characteristics of the genus Unikaryon including the arrangement of spores in sets of two, large posterior vacuole, and eccentric position of the polar filament. Spores of Unikaryon panopei sp. n., unlike those of Unikaryon sp. 2, assemble in large membrane-bound masses containing hundreds of organisms, and display a larger number of polar filament coils - 7-8, compared to 4-5 in Unikaryon sp. 2 The SSUrDNA-inferred phylogenetic analysis places Unikaryon panopei in one clade with Unikaryon legeri, the only other molecularly characterized member of the genus, with 94% of SSUrDNA similarity. These findings increase the number of species parasitizing trematodes and broaden the host range of Unikaryon spp.

Following the infection dynamics of the tropical trematode Oligogonotylus mayae in its intermediate and definitive hosts for 13 years.

We present a time series of 13 years (2003-2016) of continuous monthly data on the prevalence and mean abundance of the trematode Oligogonotylus mayae for all the hosts involved in its life cycle. We aimed to determine whether annual (or longer than annual) environmental fluctuations affect these infection parameters of O. mayae in its intermediate snail host Pyrgophorus coronatus, and its second and definitive fish host Mayaheros urophthalmus from the Celestun tropical coastal lagoon, Yucatan, Mexico. Fourier time series analysis was used to identify infection peaks over time, and cross-correlation among environmental forcings and infection parameters. Our results suggest that the transmission of O. mayae in all its hosts was influenced by the annual patterns of temperature, salinity and rainfall. However, there was a biannual accumulation of metacercarial stages of O. mayae in M. urophthalmus, apparently associated with the temporal range of the El Niño-Southern Oscillation (five years) and the recovery of the trematode population after a devasting hurricane. Taking O. mayae as an example of what could be happening to other trematodes, it is becoming clear that environmental forcings acting at long-term temporal scales affect the population dynamics of these parasites.

Phylogeny and morphology of Ovipleistophora diplostomuri n. sp. (Microsporidia) with a unique dual-host tropism for bluegill sunfish and the digenean parasite Posthodiplostomum minimum (Strigeatida).

Microsporidia are diverse opportunistic parasites abundant in aquatic organisms with some species hyperparasitic in digenean parasites. In the current study, we describe a unique microsporidian parasite, Ovipleistophora diplostomuri n. sp. that has a tropism for both the bluegill sunfish Lepomis macrochirus, and its digenean parasite Posthodiplostomum minimum. Though the microsporidium first infects a fish, the subsequent infection causes hypertrophy of the metacercarial wall and degeneration of the P. minimum metacercariae within the fish tissue. Genetic analysis placed this species within Ovipleistophora and ultrastructural characteristics were consistent with the genus, including the presence of dimorphic spores within sporophorous vesicles. Meronts did not have a surface coat of dense material, which has been previously reported for the genus. This is the first Ovipleistophora species described that does not have a tropism for ovary. Genetics demonstrated that O. diplostomuri n. sp. groups closely within fish microsporidia and not other species known to be hyperparasitic in digeneans, suggesting that it evolved from fish-infecting microsporidians and developed a secondary tropism for a common and widespread digenean parasite. The high genetic identity to Ovipleistophora species demonstrates the close relationship of this unique microsporidian with other microsporidia that infect ovary.

DISCRIMINATION 28S RIBOSOMAL GENE OF TREMATODE CERCARIAE IN SNAILS FROM CHIANG MAI PROVINCE, THAILAND.

Trematode cercariae are commonly found in many freshwater gastropods. These cercariae can serve to identify the occurrence of such trematodes as Centrocestus formosanus, Haplorchis taichui, Haplorchoides sp, and Stellantchasmus falcatus, which are important parasites in Chiang Mai Province, Thailand. As the species of these cercariae cannot be identified accurately based on morphology, this study employed sequencing of a fragment of 28S ribosomal DNA and phylogenetic analysis to identify the trematode cercariae found in freshwater gastropods in Chiang Mai Province. Eight types of trematode cercariae were identified, namely, distome cercaria (grouped with Philophthalmus spp clade), echinostome cercaria (grouped with Echinostoma spp clade), furcocercous cercaria (grouped with Posthodiplostomum sp/Alaria taxideae/Hysteromorpha triloba clade), monostome cercaria (grouped with Catatropis indicus clade), parapleurolophocercous cercaria (grouped with Haplorchoides sp clade), pleurolophocercous cercaria (grouped with Centrocestusformosanus clade), transversotrema cercaria (grouped with Transversotrema spp clade), and xiphidiocercaria (grouped with Prosthodendrium spp clade). These results provide important information that can be used for identifying these parasites in epidemiological surveys.

Monogenoidean parasites of the gill lamellae of the sheepshead Archosargus probatocephalus (Walbaum) (Perciformes: Sparidae) from the Indian River Lagoon, Florida, with descriptions of four new species of Euryhaliotrema Kritsky & Boeger, 2002 (Dactylogyridae).

Examination of the gill lamellae of three sheepshead Archosargus probatocephalus (Walbaum) from the Indian River Lagoon in Florida revealed six species of Monogenoidea: Microcotyle archosargi MacCallum, 1913 (Microcotylidae); Neobenedenia sp. (Capsalidae); and four new species of Euryhaliotrema Kritsky & Boeger, 2002 (Dactylogyridae). The prevalence of all helminths was 100%, except for Neobenedenia sp., which was represented by a single immature specimen. The four new species, Euryhaliotrema carbuncularium n. sp., E. dunlapae n. sp., E. amydrum n. sp. and E. spirulum n. sp., are described and with E. carbunculus (Hargis, 1955) Kritsky & Boeger, 2002 apparently constitute a monophyletic clade of Euryhaliotrema spp. that parasitise sparid hosts in the western hemisphere. The Indian River Lagoon in Florida represents a new locality record for M. archosargi, and the sheepshead is apparently a new host record for a member (Neobenedenia sp.) of the Capsalidae.

Are Melanoides tuberculata and Tarebia granifera (Gastropoda, Thiaridae), suitable first intermediate hosts of Clonorchis sinensis in Vietnam?

BACKGROUND: Two thiarid snail species, Melanoides tuberculata and Tarebia granifera have been reported as first intermediate hosts of the liver fluke Clonorchis sinensis; however, their role as true first intermediate hosts has not been verified. Thus, the present study aimed to clarify the suitability of these two snail species as first intermediate hosts of C. sinensis. This was accomplished by collecting snails from a highly endemic area for C. sinensis in Vietnam, the Thac Ba reservoir, and identifying shed cercariae using molecular techniques. We also conducted experimental infections of five snail species including M. tuberculata and T. granifera with eggs of C. sinensis. METHODOLOGY/PRINCIPAL FINDINGS: A total of 11,985 snails, representing 10 species were sampled. Five snail species, M. tuberculata, T. granifera, Lymnaea swinhoei, Parafossarulus manchouricus, and Bithynia fuchsiana were found shedding cercariae with an overall prevalence of infection ranging from 0.7% to 11.5%. Seven cercarial types were recorded. Cercariae of C. sinensis were only found in Parafossarulus manchouricus. Using a multiplex PCR approach for detecting C. sinensis infection, the prevalence in P. manchouricus was 4.2%. Additionally, all five snail species were experimentally exposed to C. sinensis eggs, however only P. manchouricus was successfully infected with an infection rate of 7.87%. CONCLUSIONS/SIGNIFICANCE: We confirmed that in the Thac Ba reservoir, Vietnam, the two thiarids, M. tuberculata and T. granifera are not suitable first intermediate hosts of C. sinensis. Only P. manchouricus was found infected by C. sinensis in nature, and was the only species that became infected experimentally.

Odds ratios and hurdle models: a long-term analysis of parasite infection patterns in endangered young-of-the-year suckers from Upper Klamath Lake, Oregon, USA.

We used odds ratios and a hurdle model to analyze parasite co-infections over 25 years on >20,000 young-of-the year of endangered Shortnose and Lost River Suckers. Host ecologies differed as did parasite infections. Shortnose Suckers were more likely to be caught inshore and 3-5 times more likely to have Bolbophorus spp. and Contracaecum sp. infections, and Lost River Suckers were more likely to be caught offshore and approximately three times more likely to have Lernaea cyprinacea infections. An observed peak shift seems likely to be due to a lower host size limit for Bolbophorus spp. (13.6 mm) compared with L. cyprinacea (23.4 mm). The large data set allowed us to generate strong hypotheses: (i) that a major marsh restoration project had unintended consequences that resulted in an increase in infections; (ii) that co-infection with Bolbophorus spp. increased the odds of infection by L. cyprinacea and Contracaecum sp.; (iii) that significant declines in the odds of infection over approximately 25 days were due to parasite-induced host mortality; (iv) that the fish's small size relative to L. cyprinacea and Contracaecum sp. might be directly lethal; (v) that the absence of L. cyprinacea infections in the early 1990s was associated with good year-class production of the suckers; and (vi) that parasites might increase the odds of vagrancy from the nursery ground.

Hyperparasitism by Paragordius varius (Nematomorpha: Gordiida) larva of Monostome redia (Trematoda: Digenea).

Gordiid larvae enter and encyst within a large variety of aquatic vertebrates and invertebrates. Cysts of a single species of gordiid have been found in such diverse hosts as insect larvae, snails, crustaceans, fish, and many others. One particularly surprising host report was made nearly 100 yr ago, i.e., cysts within adult trematodes. The origin of these cysts remained unclear, but it was suggested that the gordiid larvae gained entry into the adult flukes via their definitive, vertebrate host. In the present study, the finding is reported of gordiid cysts within monostome redia within a Physa gyrina snail. This is the first time gordiid cysts have been reported within redia, and this provides an alternative explanation for the presence of cysts within adult trematodes.

An improved genome assembly of the fluke Schistosoma japonicum.

BACKGROUND: Schistosoma japonicum is a parasitic flatworm that causes human schistosomiasis, which is a significant cause of morbidity in China and the Philippines. A single draft genome was available for S. japonicum, yet this assembly is very fragmented and only covers 90% of the genome, which make it difficult to be applied as a reference in functional genome analysis and genes discovery. FINDINGS: In this study, we present a high-quality assembly of the fluke S. japonicum genome by combining 20 G (~53X) long single molecule real time sequencing reads with 80 G (~ 213X) Illumina paired-end reads. This improved genome assembly is approximately 370.5 Mb, with contig and scaffold N50 length of 871.9 kb and 1.09 Mb, representing 142.4-fold and 6.2-fold improvement over the released WGS-based assembly, respectively. Additionally, our assembly captured 85.2% complete and 4.6% partial eukaryotic Benchmarking Universal Single-Copy Orthologs. Repetitive elements account for 46.80% of the genome, and 10,089 of the protein-coding genes were predicted from the improved genome, of which 96.5% have been functionally annotated. Lastly, using the improved assembly, we identified 20 significantly expanded gene families in S. japonicum, and those genes were primarily enriched in functions of proteolysis and protein glycosylation. CONCLUSIONS: Using the combination of PacBio and Illumina Sequencing technologies, we provided an improved high-quality genome of S. japonicum. This improved genome assembly, as well as the annotation, will be useful for the comparative genomics of the flukes and more importantly facilitate the molecular studies of this important parasite in the future.

Helminth-microbiota cross-talk - A journey through the vertebrate digestive system.

The gastrointestinal (GI) tract of vertebrates is inhabited by a vast array of organisms, i.e., the microbiota and macrobiota. The former is composed largely of commensal microorganisms, which play vital roles in host nutrition and maintenance of energy balance, in addition to supporting the development and function of the vertebrate immune system. By contrast, the macrobiota includes parasitic helminths, which are mostly considered detrimental to host health via a range of pathogenic effects that depend on parasite size, location in the GI tract, burden of infection, metabolic activity, and interactions with the host immune system. Sharing the same environment within the vertebrate host, the GI microbiota and parasitic helminths interact with each other, and the results of such interactions may impact, directly or indirectly, on host health and homeostasis. The complex relationships occurring between parasitic helminths and microbiota have long been neglected; however, recent studies point towards a role for these interactions in the overall pathophysiology of helminth disease, as well as in parasite-mediated suppression of inflammation. Whilst several discrepancies in qualitative and quantitative modifications in gut microbiota composition have been described based on host and helminth species under investigation, we argue that attention should be paid to the systems biology of the gut compartment under consideration, as variations in the abundances of the same population of bacteria inhabiting different niches of the GI tract may result in varying functional consequences for host physiology.

Community structure, population structure and topographical specialisation of Gyrodactylus (monogenea) ectoparasites living on sympatric stickleback species.

In order to disentangle the contribution of host and parasite biology to host specificity, we compared the structure and population dynamics of the Gyrodactylus (von Nordmann, 1832) flatworm community living on sympatric three-spined Gasterosteus aculeatus L. and nine-spined Pungitius pungitius (L.) stickleback. Between April 2002 and March 2003, a small lowland creek was sampled monthly. Species identity of about 75% of the worms per host was determined with a genetic nuclear marker (ITS1). Each stickleback species hosted a characteristic gill- and fin-parasitic Gyrodactylus: G. arcuatus Bychowsky, 1933 and G. gasterostei Gläser, 1974 respectively infecting the three-spined stickleback, with G. rarus Wegener, 1910 and G. pungitii Malmberg, 1964 infecting the nine-spined stickleback. Host size and seasonal dynamics were strong determinants of parasite abundance. A strong interaction between host and parasite species determined infection levels and affected three levels of parasite organisation: community structure, population structure and topographical specialisation. Community and population structure were shaped by asymmetric cross-infections, resulting in a net transmission of the Gyro-dactylus species typical of the nine-spined stickleback towards the three-spined stickleback. Host density was not a major determinant of parasite exchange. Aggregation and topographical specialisation of the Gyrodactylus species of the three-spined stickleback were more pronounced than that of the nine-spined stickleback.

Biomagnification and polychlorinated biphenyl congener distribution in an aquatic predator-prey, host-parasite system.

Biomagnification and polychlorinated biphenyl (PCB) congener distribution was examined in a predator-prey, host-parasite system, in which Atlantic salmon (Salmo salar) preyed upon sprat (Sprattus sprattus). Eubothrium crassum was an intestinal parasite in salmon that also "preyed upon" sprat, because the parasites gained access to foodstuffs via the host (salmon) gut. Salmon contained significantly higher concentrations of total PCBs compared to both parasites and prey (sprat), but no difference in PCB concentration was found between sprat and E. crassum. Salmon biomagnified several PCB congeners from their diet (sprat), whereas parasites did not, despite the fact that both salmon and their parasites ingested the same prey. Differences in nutrient uptake mechanisms between the host and their parasites, in addition to the lack of a gastrointestinal tract in the cestode, may explain the lack of biomagnification in E. crassum. No difference was found in PCB congener distribution between parasites, salmon, and sprat, and none of the animal types showed a preference for accumulating more or less lipophilic congeners (congeners with a high or low octanol/water partition coefficient [K(ow)]). Biomagnification factors for individual congeners in salmon did not increase with K(ow); rather, they were constant, as shown by a linear relationship for congener concentration in prey and predator.

Intertidal snail-trematode communities on the southern Thailand before and after the South Asia tsunami.

Intertidal snail-trematode communities in southern Thailand were examined before and after the South Asia tsunami. Infection rates and species diversity of cercaria in the host snail Cerithidea in tidal zones did not change significantly from one year before to one month after the tsunami. However, the host snails C. quadrata, C. alata and C. obtusa disappeared from greatly damaged sites. It is important to follow up on the intertidal snail-trematode community recovery process after destruction of the intertidal ecosystem.

Description of Lutziella swatensis sp. n (Trematoda: Dicrocoelidae) from Rattus rattus in Swat, Pakistan / Descrição de Lutziella swatensis sp. n (Trematoda: Dicrocoelidae) de Rattus rattus em Swat, Paquistão

A new species of the genus Lutziella (Rohde, 1966) Yamaguti, 1971 is described here and named Lutziella swatensis sp.nov. from the liver of rat (Rattus rattus L.). The new species is characterized by having body flat, smooth, longer than broad with maximum width at the level of the ovary, oral sucker with weak musculature, pharynx small; eosophagus long; caeca of irregular shape which bifurcate on the anterior border of the ovary in to unequal portions, acetabulum weakly muscular, post-testicular, testes lobed, cirrus pouch somewhat median, small in size containing winding seminal vesicle, prostatic complex and short ejaculatory duct. Genital pore median. Ovary post testicular, submedian; seminal receptacle overlapping ovary, laurer’s canal present. Vitellaria follicular extending on each side from almost the level of testes to anterior portion of posterior half of the body. Uterus filled with eggs occupying most of the body, eggs oval rather small, numerous, brownish in colour, excretory vesicle tubular with terminal pore. Lutziella swatensis n. sp. is the second species of the genus known from Pakistan as well as the second species described from murid rodents in the world.

Uma nova espécie do gênero Lutziella (Rohde, 1966) Yamaguti, 1971 é descrita aqui e denominada Lutziella swatensis sp.nov. do fígado do rato (Rattus rattus L.). A nova espécie é caracterizada por ter corpo liso, liso, mais longo que largo com largura máxima ao nível do ovário, otário oral com musculatura débil, faringe pequena; eosôfago longo; ceco de forma irregular que se bifurca na borda anterior do ovário em porções desiguais, acetábulo fracamente muscular, pós-testicular, testículos lobados, bolsa cirrus um pouco mediana, pequeno em tamanho contendo vesícula seminal sinuosa, complexo prostático e ducto ejaculatório curto. Mediana dos poros genitais. Ovário pós testicular, submediano; ovário sobreposto do receptáculo seminal, canal de laurer presente. Vitellaria folicular que se estende de cada lado de quase o nível dos testículos para a porção anterior da metade posterior do corpo. Útero cheio de ovos que ocupam a maior parte do corpo, oval ovos bastante pequenos, numerosos, de cor acastanhada, vesícula excretor tubular com poro terminal. Lutziella swatensis n. sp. é a segunda espécie do gênero conhecida do Paquistão, bem como a segunda espécie descrita de roedores do mundo.

Suppression of mRNAs encoding CD63 family tetraspanins from the carcinogenic liver fluke Opisthorchis viverrini results in distinct tegument phenotypes.

The liver fluke Opisthorchis viverrini infects 10 million people in Southeast Asia and causes cholangiocarcinoma (CCA). Fluke secreted and tegumental proteins contribute to the generation of a tumorigenic environment and are targets for drug and vaccine-based control measures. Herein, we identified two tetraspanins belonging to the CD63 family (Ov-TSP-2 and Ov-TSP-3) that are abundantly expressed in the tegument proteome of O. viverrini. Ov-tsp-2 and tsp-3 transcripts were detected in all developmental stages of O. viverrini. Protein fragments corresponding to the large extracellular loop (LEL) of each TSP were produced in recombinant form and antibodies were raised in rabbits. Ov-TSP-2 and TSP-3 were detected in whole worm extracts and excretory/secretory products of O. viverrini and reacted with sera from infected hamsters and humans. Antibodies confirmed localization of Ov-TSP-2 and TSP-3 to the adult fluke tegument. Using RNA interference, Ov-tsp-2 and tsp-3 mRNA expression was significantly suppressed for up to 21 days in vitro. Ultrastructural observation of tsp-2 and tsp-3 dsRNA-treated flukes resulted in phenotypes with increased tegument thickness, increased vacuolation (tsp-2) and reduced electron density (tsp-3). These studies confirm the importance of CD63 family tegument tetraspanins in parasitic flukes and support efforts to target these proteins for vaccine development.

Epidemiology of food-borne trematodes and other parasite infections in a fishing community on the Nam Ngum reservoir, Lao PDR.

Food-borne trematodes (FBT) are important causes of parasitic infections in many Asian countries. Parasitological surveys in Xai Udom, a small fishing community on the Nam Ngum reservoir, Lao People's Democratic Republic, revealed an overall parasitic infection rate in May 1999 of 68.8% (n = 173) and in December 1999 of 65.9% (n = 261). The liver fluke, Opisthorchis viverrini accounted for most of the infections (prevalences of 53.8% and 42.1%, during the first and second surveys, respectively). The prevalence and intensity showed increasing trends with age. Minute intestinal flukes were also present but with relatively low infection rates (3.8-10.9%). The second common group of parasites comprised soil-transmitted nematodes, Trichuris trichiura, Ascaris lumbricoides, hookworm and Strongyloides stercoralis, with prevalences of 22.4 and 17.6%, 20.8 and 8.0%, 16.8 and 13.4%, and 4.0 and 15.3% (first and second surveys, respectively). Most people had no or only light infections, with a few people having heavy infections. Coexisting intestinal protozoa were Giardia lamblia (5.2 and 4.9%) and Entamoeba coli (6.9 and 6.5%). Concurrent tapeworm infections were Taenia (1.7 and 1.1%) and Hymenolepis nana (0.7 and 0.6%) (first and second surveys, respectively). Despite the availability of effective anthelmintic drugs, the results of our study reaf-firm that FBT are still a major health threat in this fishing area of Lao PDR, similar to a decade ago.

Freshwater mollusks of medical importance in Kalasin Province, northeast Thailand.

A snail survey was performed in six districts around irrigation areas of Lampao Dam, in Kalasin Province. The survey caught a total of 5,479 live snails and classed them into five families, 12 genera and 15 species, of which 7 species are suspected of transmitting human parasitic diseases. The seven species were Pila polita, Pomacea canaliculata, Filopaludina (S.) m. martensi, Bithynia (Digoniostoma) siamensis goniomphalos, Melanoides tuberculata, Radix rubiginosa, and Indoplanorbis exustus. Of these, B. (D.) s. goniomphalos and I. exustus were found to harbor emergent cercariae. Only B. (D.) s. goniomphalos hosted several types of cercariae--Opisthorchis viverrini, unidentified species of intestinal flukes, echinostomes, xyphidio and furcocercous cercariae. Indoplanorbis exustus shed only echinostome cercariae. B. (D.) s. goniomphalos showed a rather high natural infection rate with O. viverrini, 1.3% in Yang Talat district, and 0.61% in Kamalasai district, in Kalasin Province.

Microhabitats, attachment of eggs and histopathology by the monogenean Allomurraytrema robustum on Acanthopagrus australis (Pisces: Sparidae).

Allomurraytrema robustum occurs normally in low numbers on the jaws, gill arch or upper palate; juveniles also occur on the lateral margins of the gill filaments. At high levels of infection the parasite occurs in large groups (> 30 worms) on the jaws and gill arches, and extends onto the lateral margins of the gill filaments. Large numbers of eggs become entangled among these groups of parasites. Ciliated oncomiracidia emerge from the eggs. The parasite attaches to the surface of epithelia by small hamuli and marginal haptoral hooklets, but an adhesive secretion may be involved as well. The parasite causes little damage when attached to thick epithelia, but on the surface of the gill filaments there is erosion and degeneration of the epithelium beneath and adjacent to the haptor. Infiltrating leucocytes enter the dermis, epidermis and the host-parasite interface. Intact infiltrating cell occur in the intestinal caeca of the parasite.

Laboratory diagnosis of worms and miscellaneous specimens.

This article outlines the procedures to be followed when a macroscopic object thought to be a worm or other type of parasite is submitted to the clinical laboratory. These are often collected and submitted by the patient, but also may be submitted by the attending physician, the surgeon, or the pathologist. Examples of the various parasites and parasite-like objects that have been submitted to clinical laboratories are listed. Methods for preserving and examining such objects, using materials and reagents available in the clinical laboratory, are presented.

Monogenea of Arabian Gulf fishes. 1. Descriptions of three Capsala spp. (Capsalidae) including Capsala naffari n. sp. infecting mackerel tuna Euthynnus affinis from coasts of Emirates.

Three species of the genus Capsala including Capsala naffari n. sp., C. neothunni (Yamaguti, 1968) and C. nozawae (Goto, 1894) are recorded and described from the buccal cavity of mackerel tuna Euthynnus affinis caught from Emirate coasts. Capsala naffari can be differentiated by its lateral spiniform teeth, which extend posteriorly, small measurements compared with the closely resembled C. gotoi and relatively large testes. This is the first record of the genus Capsala from Arabian Gulf fishes and E. affinis is a new host record.