Parasitic Crustaceans Research Articles

Two marine parasitic crustaceans new to the Belgian fauna

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Effects of a crustacean parasite and hyperparasite on the Japanese spiny oyster Saccostrea kegaki

Parasitism is one of the most common interspecific interactions, but little information exists on the detailed relationships among hosts, parasites, and hyperparasites (secondary parasites) in marine ecosystems. Pea crabs parasitize a wide variety of marine animals, and the crabs themselves are often parasitized by other animals. The present study investigated the relationships among the oyster Saccostrea kegaki, its parasite, the pea crab Pinnotheres boninensis, and a hyperparasite, the isopod Onychocepon resupinum. Field sampling was conducted during the oyster’s reproductive season (June–September 2014 and 2015) to evaluate effects of the pea crab on the body weight, maturation, and sex of the oyster in western Japan (Banshozaki, Shirahama Town, Wakayama Pref.; 33.41°N, 135.20°E). The relationship between the pea crab and the isopod and indirect effects of the isopod on the oyster were also investigated. The pea crab reduced the oyster’s body weight and affected its reproduction: the proportion of mature individuals was lower in infested oysters (39.1%) than in non-infested ones (86.2%). The isopod affected the crab’s sexual characteristics: infested female crabs had poorly developed ovaries, and infested males showed degrees of feminization and increased body size. The prevalence of the isopod was much higher in male (47.1%) than female (6.4%) crabs inside the oyster shells, suggesting that the parasitized male crabs became larger and were forced to remain inside the shells. Therefore, the isopod appears to have an indirect negative impact on the oyster by changing the male crab’s traits.

Hyperspora aquatica n.gn., n.sp. (Microsporidia), hyperparasitic in Marteilia cochillia (Paramyxida), is closely related to crustacean-infecting microspordian taxa.

The Paramyxida, closely related to haplosporidians, paradinids, and mikrocytids, is an obscure order of parasitic protists within the class Ascetosporea. All characterized ascetosporeans are parasites of invertebrate hosts, including molluscs, crustaceans and polychaetes. Representatives of the genus Marteilia are the best studied paramyxids, largely due to their impact on cultured oyster stocks, and their listing in international legislative frameworks. Although several examples of microsporidian hyperparasitism of paramyxids have been reported, phylogenetic data for these taxa are lacking. Recently, a microsporidian parasite was described infecting the paramyxid Marteilia cochillia, a serious pathogen of European cockles. In the current study, we investigated the phylogeny of the microsporidian hyperparasite infecting M. cochillia in cockles and, a further hyperparasite, Unikaryon legeri infecting the digenean Meiogymnophallus minutus, also in cockles. We show that rather than representing basally branching taxa in the increasingly replete Cryptomycota/Rozellomycota outgroup (containing taxa such as Mitosporidium and Paramicrosoridium), these hyperparasites instead group with other known microsporidian parasites infecting aquatic crustaceans. In doing so, we erect a new genus and species (Hyperspora aquatica n. gn., n.sp.) to contain the hyperparasite of M. cochillia and clarify the phylogenetic position of U. legeri. We propose that in both cases, hyperparasitism may provide a strategy for the vectoring of microsporidians between hosts of different trophic status (e.g. molluscs to crustaceans) within aquatic systems. In particular, we propose that the paramyxid hyperparasite H. aquatica may eventually be detected as a parasite of marine crustaceans. The potential route of transmission of the microsporidian between the paramyxid (in its host cockle) to crustaceans, and, the 'hitch-hiking' strategy employed by H. aquatica is discussed.

Records of new localities and hosts for crustacean parasites in fish from the eastern Amazon in northern Brazil.

The aim of this study was to investigate parasites crustacean fauna in Arapaima gigas, Cichla monoculus, Cichla ocellaris, Cichla jariina, Satanoperca jurupari, Leporinus friderici, Leporinus fasciatus, Hoplias malabaricus, Phractocephalus hemioliopterus, Serrasalmus altispinis, Pseudoplatystoma tigrinum and Potamotrygon motoro of the State Amapá and Pará, in northern Brazil. A total of 242 parasites, including Argulus elongatus, Argulus multicolor,Argulus juparanaensis, Argulus nattereri, Dolops discoidalis, Dolops longicauda, Braga patagonica, Braga fluviatilis, Livoneca guianensis and undetermined Lernaeidae, were collected from these hosts. The Argulus species had the greatest richness among the community of parasitic crustaceans. There was a low abundance of parasites among the hosts, other than D. discoidalis, was most abundant in the integument of A. gigas and P. tigrinum. Finally, the present study reported nine new hosts for the crustacean parasite species and expanded knowledge of the occurrence of some parasite species in the Jari River basin, in eastern Amazon.

Histology of gills of Labeo rohita infected by crustacean parasite Argulus sps.

Histology of gills of Labeo rohita infected by crustacean parasite Argulus sps.

Isopod Parasite Induced Secondary Microbial Infection in Marine Food Fishes

Isopods are parasitic crustaceans that pose serious threat to fisheries. Several studies have tried to explore the host-pathogen relationship between marine fishes and isopods. The present study aims to understanding the secondary infections in marine fishes pertaining to isopods. To assess the secondary infection in infected fishes, parasite infested and healthy tissues of fishes were collected. The samples were subjected to standard microbiological procedure to identify the presence of pathogenic bacteria and fungi. Our results showed the branchial region had the higher microbial load of non-sporulating cenocytic fungi in infected fishes. Moreover, fungal strains isolated from the parasitic lesion confirmed that the parasitation and body lesion facilitates the entry of several pathogenic microbes at the damaged host tissue. More over the immune regulation of fish fights back by producing minute cysts, trying to encapsulate the growing fungus. But this may eventually lead to systemic infestation and death of the fish.

Fighting fish parasites with photodynamically active chlorophyllin.

Water-soluble chlorophyll (chlorophyllin) was used in a phototoxic reaction against a number of fish ectoparasites such as Ichtyobodo, Dactylogyrus, Trichodina, and Argulus. Chlorophyllin is applied to the water at concentrations of several micrograms per milliliter for a predefined incubation time, and afterwards, the parasites are exposed to simulated solar radiation. Application in the dark caused only little damage to the parasites; likewise, light exposure without the addition of the photosensitizer was ineffective. In Ichthyobodo, 2μg/mL proved sufficient with subsequent simulated solar radiation to almost quantitatively kill the parasites, while in Dactylogyrus, a concentration of about 6μg/mL was necessary. The LD50 value for this parasite was 1.02μg/mL. Trichodina could be almost completely eliminated at 2μg/mL. Only in the parasitic crustacean Argulus, no killing could be achieved by a photodynamic reaction using chlorophyllin. Chlorophyllin is non-toxic, biodegradable, and can be produced at low cost. Therefore, we propose that chlorophyllin (or other photodynamic substances) are a possible effective countermeasure against several ectoparasites in ponds and aquaculture since chemical remedies are either forbidden and/or ineffective.

Validation of the synonymy of the teleost blenniid fish species Salariasphantasticus Boulenger 1897 and Salarias anomalus Regan 1905 with Ecsenius pulcher (Murray 1887) based on DNA barcoding and morphology.

As currently recognized, Ecsenius pulcher includes Salarias pulcher (type material has a banded color pattern), S. anomalus (non-banded), and S. phantasticus (banded). The color patterns are not sex linked, and no other morphological features apparently distinguish the three nominal species. The recent collection of banded and non-banded specimens of Ecsenius pulcher from Iran has provided the first tissue samples for genetic analyses. Here we review the taxonomic history of E. pulcher and its included synonyms and genetically analyze tissue samples of both color patterns. Salarias anomalus is retained as a synonym of E. pulcher because DNA barcode data suggest that they represent banded and non-banded color morphs of a single species. Furthermore, the large size of the largest type specimen of S. anomalus (herein designated as the lectotype) suggests that it belongs to E. pulcher. A single non-banded specimen from Iran is genetically distinct from E. pulcher and appears to represent an undescribed species. Salarias phantasticus is retained as a synonym of E. pulcher because the primary morphological difference between the two nominal species-presence of spots on the dorsal fin in E. pulcher and absence of those spots in S. phantasticus-is not a valid taxonomic character; rather, the spots represent galls that contain the larval stages of a parasitic crustacean. As males and females of Ecsenius species have been confused in the literature, we describe and illustrate the genital regions of both and comment on possible new blenniid synapomorphies that our investigation revealed.

Review on Major Parasitic Crustacean in Fish

In this paper the major description, epidemiology, pathogenesis and clinical sign, diagnosis, treatment and control of parasitic crustaceans in fish has been reviewed. The major crustaceans parasites commonly encountered in cultured and wild fish are: copepods (ergasilidea and lernaeidae), branchiura (argulidae) and isopods). Members of the branchiura and isopod are relatively large and both sexes are parasitic, while copepods are the most common crustacean parasites are generally small to microscopic with both free-living and parasitic stages in their life cycle. These parasitic crustaceans are numerous and have worldwide distribution in fresh, brackish and salt water. Most of them can be seen with naked eyes as they attach to the gills, bodies and fins of the host. They are increasingly serious problem in cultured fish and can infect wild population. Usually they cause only minor harm to their hosts when present in small numbers. However, in case of heavy infections severe damage to skin, muscles, and gills tissue accompanied with secondary infections, and resulting in decreased production. Good health management and good environment management are crucial in avoiding occurrence of crustacean parasites.

Prevalence and Histopathologic Study of Lernaea cyprinacea in Two Species of Ornamental Fish (Poecilia latipinna and Xiphophorus helleri) in Kerman, South-East Iran.

Lernaeids are crustacean parasites that are globally distributed among freshwater and marine fish. Approximately 110 species of Lernaeids have been divided into 14 genera. The most common species of Lernaeids is Lernaea cyprinacea, which has been transmitted to ornamental fish worldwide. The economic importance of L. cyprinacea is increasing because of the epidemic caused by the parasite in most of the ornamental fish breeding centers in different parts of the world. The parasite affects its host's health, decreases growth rate, and causes abnormal metabolic activity. Accumulation of these parasites in some parts of the body causes painful points and has harmful outcomes for the functioning and survival of the host. The present study was conducted to examine the prevalence of L. cyprinacea among ornamental fish within 1 year from September-October 2011 to September-October 2012. In total, 3520 fish [3380 mollies (Poecilia latipinna) and 140 swordtails (Xiphophorus helleri)] were collected from 10 fish maintenance and breeding centers in Kerman, Iran. Of 3520 fish, only 186 fish (5.3%) were infected with L. cyprinacea, and the remaining fish (94.7%) were not infected. The swordtails (X. helleri) and mollies (P. latipinna) showed the highest (10.7%) and the lowest (5.1%) level of infection, respectively. In other words, there was a significant correlation between species of fish and L. cyprinacea infection (p<0.05). The highest prevalence (39.4%) and the lowest prevalence (0%) of L. cyprinacea were observed during summer and winter, respectively, which can be attributed to the temperature difference between the two seasons. Also, the histopathologic examination of sections revealed some lesions in the epidermis, dermis, and muscles. Considering the existing L. cyprinacea infection in ornamental fish reproduction and breeding centers in Kerman, public knowledge should increase through management methods; physical and chemical treatments should also be applied to inform the public regarding the risk of infection and other internal diseases that may be associated with ornamental fish.

First 3D reconstruction of the rhizocephalan root system using MicroCT

Parasitic barnacles (Cirripedia: Rhizocephala) are highly specialized parasites of crustaceans. Instead of an alimentary tract for feeding they utilize a system of roots, which infiltrates the body of their hosts to absorb nutrients. Using X-ray micro computer tomography (MicroCT) and computer-aided 3D-reconstruction, we document the spatial organization of this root system, the interna, inside the intact host and also demonstrate its use for morphological examinations of the parasites reproductive part, the externa. This is the first 3D visualization of the unique root system of the Rhizocephala in situ, showing how it is related to the inner organs of the host. We investigated the interna from different parasitic barnacles of the family Peltogastridae, which are parasitic on anomuran crustaceans. Rhizocephalan parasites of pagurid hermit crabs and lithodid crabs were analysed in this study.

Time-lapse camera studies of sea-disposed chemical munitions in Hawaii

The interactions between fauna and sea-disposed munitions provide important evidence regarding whether munitions constituents affect the health of the ocean environment and its inhabitants. To date few studies of these interactions have been conducted at deep-water disposal sites; typically observations of fauna in the vicinity of sea-disposed munitions are limited to the few minutes or hours required to collect physical samples at a specific location. During the 2012 Hawaii Undersea Military Munitions Assessment (HUMMA) field program we deployed two deep-sea time-lapse camera systems with the objectives of cataloging the diversity of fauna visiting sea-disposed chemical munitions and observing faunal behavior and physiology. Over the 1- and 3-day deployments we recorded 28 different species of fishes, crustaceans, mollusks, cnidarians, and echinoderms at the two sites. Both cameras captured the previously undocumented behavior of brisingid sea stars repositioning themselves along chemical munitions casings. Despite the fact that brisingid sea stars are able to move, for the duration of both time-lapse experiments they remained on chemical munitions casings. We interpret this result to indicate that the advantages of residing on a hard substrate slightly elevated above the seafloor outweigh the effects of chemical munitions constituents for brisingid sea stars. One type of physiological anomaly observed on several arms of the brisingid sea stars at the time-lapse sites led to the collection and examination of six specimens. As reported by Mah (2015. Deep Sea Res. II, 2015, XX–XX), these physiological features are the result of parasitic crustaceans and are not caused by chemical munitions constituents.

High prevalence and infestation of Mothocya renardi (Isopoda, Cymothoidae) in marine fish Strongylura leiura (Bleeker 1850).

Cymothoid isopods are parasites that cause severe damage to the fish species. The present study was focused to carry out the parasitic infestation on the one of the important marine fish Strongylura leiura during the 2years period between June 2009 and May 2011. 272 fish specimens collected and about 157 (57.72%) fishes were infested by the cymothoid which were concealed under the gill arches of the host. Infested parasite was identified as Mothocya renardi. The prevalence rate of parasites during different seasons of the range of host specificity of isopods was studied. Variation of infestation rate also depends on the size, length and weight of the host. The sites of infestation by the parasitic crustaceans are highly specific. The infestation had affected the normal growth of the host fish and also probably leads the high levels of secondary infections.

The systematics of Echinorhynchus Zoega in Müller, 1776 (Acanthocephala, Echinorhynchidae) elucidated by nuclear and mitochondrial sequence data from eight European taxa.

The acanthocephalan genus Echinorhynchus Zoega in Müller, 1776 (sensu Yamaguti 1963) is a large and widespread group of parasites of teleost fish and malacostracan crustaceans, distributed from the Arctic to the Antarctic in habitats ranging from freshwaters to the deep-sea. A total of 52 species are currently recognised based on the conventional morphological species concept; however, the true diversity in the genus is masked by cryptic speciation. The considerable diversity within Echinorhynchus is an argument for subdividing the genus if monophyletic groups with supporting morphological characters can be identified. With this objective in mind, partial sequences of two genes with different rates of evolution and patterns of inheritance (nuclear 28S rRNA and mitochondrial cytochrome c oxidase subunit I) were used to infer the phylogenetic relationships among eight taxa of Echinorhynchus. These included representatives of each of three genus group taxa proposed in a controversial revision of the genus based on cement gland pattern, namely Echinorhynchus (sensu stricto), Metechinorhynchus Petrochenko, 1956 and Pseudoechinorhynchus Petrochenko, 1956. These groupings have previously been rejected by some authorities, because the diagnostic character is poorly defined; this study shows that Echinorhynchus (sensu stricto) and Metechinorhynchus are not natural, monophyletic groups. A revision of Echinorhynchus will require tandem molecular phylogenetic and morphological analyses of a larger sample of taxa, but this study has identified two morhological characters that might potentially be used to define new genera. The estimated phylogeny also provides insight into the zoogeographical history of Echinorhynchus spp. We postulate that the ancestral Echinorhynchus had a freshwater origin and the genus subsequently invaded the sea, probably several times. The freshwater taxa of the Echinorhynchus bothniensis Zdzitowiecki & Valtonen, 1987 clade may represent a reinvasion of freshwater by one or more ancestral marine species.

Fossil Crustaceans as Parasites and Hosts.

Numerous crustacean lineages have independently moved into parasitism as a mode of life. In modern marine ecosystems, parasitic crustaceans use representatives from many metazoan phyla as hosts. Crustaceans also serve as hosts to a rich diversity of parasites, including other crustaceans. Here, we show that the fossil record of such parasitic interactions is sparse, with only 11 examples, one dating back to the Cambrian. This may be due to the limited preservation potential and small size of parasites, as well as to problems with ascribing traces to parasitism with certainty, and to a lack of targeted research. Although the confirmed stratigraphic ranges are limited for nearly every example, evidence of parasitism related to crustaceans has become increasingly more complete for isopod-induced swellings in decapods so that quantitative analyses can be carried out. Little attention has yet been paid to the origin of parasitism in deep time, but insight can be generated by integrating data on fossils with molecular studies on modern parasites. In addition, there are other traces left by parasites that could fossilize, but have not yet been recognized in the fossil record.

Multiple parasitic crustacean infestation on belonid fish Strongylurastrongylura.

Simultaneous multiple infestation of parasitic crustacean species involving a cymothoid isopod, Cymothoa frontalis Milne Edward, 1840 and four species of copepods such as Lernanthropus tylosuri Richiardi, 1880, Caligodes lacinatus Kroyer, 1863, Bomolochus bellones Burmeister, 1833 and Dermoergasilus coleus Cressey & Collette, 1970 was frequently noticed on spot-tail needlefish, Strongylura strongylura (Belonidae) captured from the Malabar coast (Kerala, India) during the period from April 2011 to March 2012. All the 43 fishes (Strongylura strongylura) collected, were under the hyper-infection with parasitic crustaceans; a total of 388 parasitic crustaceans including 57 Cymothoa frontalis, 252 Lernanthropus tylosuri, 31 Caligodes lacinatus, 24 Bomolochus bellones and 32 Dermoergasilus coleus were recovered from the host fish. 4 members (9.30%) of host fish were under quadruple parasitism, in two different combinations. Seventeen (39.53%) host fishes showed triple parasitism and 20 (46.51%) members exhibited double parasitism, with four and five parasitic combinations respectively. Remaining two (4.65%) fishes were parasitized only by the copepod, Lernanthropus tylosuri. The infestations by all recovered parasitic crustaceans were highly site specific. The damage caused by the parasitic crustaceans was also discussed.

Morphology and phylogeny of Agmasoma penaei (Microsporidia) from the type host, Litopenaeus setiferus, and the type locality, Louisiana, USA

Since June 2012, samples of wild caught white shrimp, Litopenaeus setiferus, from the Gulf of Mexico, Plaquemines and Jefferson Parishes (Louisiana, USA) with clinical signs of microsporidiosis have been delivered to the Louisiana Aquatic Diagnostic Laboratory for identification. Infection was limited predominantly to female gonads and was caused by a microsporidium producing roundish pansporoblasts with eight spores (3.6×2.1μm) and an anisofilar (2–3+4–6) polar filament. These features allowed identification of the microsporidium as Agmasoma penaei Sprague, 1950. Agmasoma penaei is known as a microsporidium with world-wide distribution, causing devastating epizootic disease among wild and cultured shrimps. This paper provides molecular and morphological characterisation of A. penaei from the type host and type locality. Comparison of the novel ssrDNA sequence of A. penaei from Louisiana, USA with that of A. penaei from Thailand revealed 95% similarity, which suggests these geographical isolates are two different species. The A. penaei sequences did not show significant homology to any other examined taxon. Phylogenetic reconstructions using the ssrDNA and alpha- and beta-tubulin sequences supported its affiliation with the Clade IV Terresporidia sensu Vossbrink 2005, and its association with parasites of fresh and salt water crustaceans of the genera Artemia, Daphnia and Cyclops.

English

The present study has been carried out to find out the parasites of Schizothorax niger and Labeo rohita during different months of the year 2013 to 2014. Parasites belonging to two groups viz. ciliophoran (Chilodonella) and crustacean (Argulus) were recorded from 200 fishes of Rohu (L. rohita) and S. niger collected from different parts of Jammu and Kashmir. These two parasites belong to Ectoparasitic group and no other parasite was recorded in the present study. The highest prevalence (60%) of infection has been recorded in ciliophorans and the lowest was in crustacean (48%). It was observed that highest parasitic prevalence (54%) was recorded during winter season (December-February) while the lowest prevalence (0%) recorded during rainy season (June-August). Cyprinid fish S. niger infested with ciliophoran had no pathogenic signs and the clinical signs were represented as increase of mucus laden masses on the surface of gills. No pathogenic signs were seen in L. rohita infested with Crustacean parasite and clinical signs were represented as gasping air, pale skin color, sluggish swimming, increase of mucus production and floating on surface often causes mortality. This is first report of protozoan parasites from fishes of Jammu and Kashmir. Key words: Ectoparasites, Protozoan, Ciliophoran, Labeo rohita, Schizothorax niger.

In silico characterization of the peptidome of the sea louse Caligus rogercresseyi (Crustacea, Copepoda)

Copepods of the order Siphonostomatoida are a major concern for commercial aquaculture as many farmed fish serve as hosts for these parasitic crustaceans. Caligus rogercresseyi, a member of the Siphonostomatoida, is a significant problem for salmonid aquaculture in the Southern Hemisphere, and as such, a search for methods for controlling infestations of it is ongoing. One possibility for biological control of this and other copepod ectoparasites is endocrine manipulation. However, little is known about the native endocrine signaling systems in these animals. As part of an ongoing effort to characterize crustacean ectoparasite peptidergic systems, the publicly accessible C. rogercresseyi transcriptome shotgun assembly (TSA) was mined for peptide-encoding transcripts. Using the identified TSA sequences, precursor proteins were deduced and their mature peptides predicted. Thirty-three peptide-encoding transcripts were identified within the Caligus TSA dataset, with the structures of 131 distinct peptides characterized from the deduced pre/preprohormones. The predicted peptides included isoforms of allatostatin A, allatostatin B, bursicon α, bursicon β, corazonin, crustacean cardioactive peptide, crustacean hyperglycemic hormone, diuretic hormone 31, DXXRLamide, FLRFamide, FXGGXamide, GSEFLamide, insulin-like peptide (ILP), intocin, leucokinin, molt-inhibiting hormone, myosuppressin, neuroparsin, neuropeptide F (NPF), orcokinin and tachykinin-related peptide. The predicted ILPs are of particular note as they are the first members of this peptide family identified from a copepod. Similarly, the predicted complement of four distinct NPFs is larger than that known from other crustaceans. Taken collectively, these data greatly expand the known C. rogercresseyi peptidome and provide a foundation for initiating studies of peptidergic control in this species.

Distribution of isopod parasites in Carangid fishes from Parangipettai, Southeast coast of India.

Crustacean parasites absorb their nourishment directly from hosts for feeding. The present study was aimed at collecting information as possible on this so far neglected group of isopod parasites of the Carangid fishes of Parangipettai coastal environment. A very little information is available regarding the isopod parasites of Carangid fishes. In the present study six species of isopods belonging to 3 genera were found on four species of fishes. The distribution of Catoessa boscii is found throughout the year.