A parasitic scuticociliate infection in the Norway lobster (Nephrops norvegicus) (original) (raw)
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Journal of Invertebrate Pathology, 2013
Outbreaks of an unidentified ciliate have occurred on several occasions in blue crabs from Chesapeake Bay held during winter months in flow-through systems. The parasite was initially thought to be Mesanophrys chesapeakensis, but molecular analysis identified it as Orchitophyra stellarum, a facultative parasite of sea stars (Asteroidea). We investigated the host-parasite association of O. stellarum in the blue crab host. Crabs were inoculated with the ciliate, or they were held in bath exposures after experimentally induced autotomy of limbs in order to determine potential mechanisms for infection. Crabs inoculated with the ciliate, or exposed to it after experimental autotomy, rapidly developed fatal infections. Crabs that were not experimentally injured, but were exposed to the ciliate, rarely developed infections; thus, indicating that the parasite requires a wound or break in the cuticle as a portal of entry. For comparative purposes, fiddler crabs, Uca minax, were inoculated with the ciliate in a dose-titration experiment. Low doses of the ciliate (10 per crab) were sometimes able to establish infections, but high intensity infections developed quickly at doses over 500 ciliates per crab. Chemotaxis studies were initiated to determine if the ciliate preferentially selected blue crab serum (BCS) over other nutrient sources. Cultures grown on medium with BCS or fetal bovine serum showed some conditioning in their selection for different media, but the outcome in choice experiments indicated that the ciliate was attracted to BCS and not seawater. Our findings indicate that O. stellarum is a facultative parasite of blue crabs. It can cause infections in exposed crabs at 10-15°C, but it requires a portal of entry for successful host invasion, and it may find injured hosts using chemotaxis.
Diseases of Aquatic Organisms, 2000
Nucleotide sequence from the internal transcribed spacers (ITS1 and ITS2) and the 5.8s gene from the r~bosomal RNA gene cluster of isolates of the scuticociliate Orchitophrya stellarum from 4 asteroid hosts were compared. Surprisingly, these data (495 bp) were identical for 0. stellarum isolated from the testes of Astenas amurensis from Japan; Pisaster ochraceus from British Columbia, Canada; Asterias rubens from The Netherlands; and Astenas vulgaris from Prince Edward Island, Canada. These sequence data were compared to those from 3 scuticociliates which parasitise crustaceans: Mesanophrys pugettensis, M. chesapeakensis and Anophryoides haemophila. No difference was found in this region between the nucleotide sequence of M pugettensis and M. chesapeakensis The sequence of Mesanophrys spp. differed by 9 2 % in the ITS1 and 4.7 % in the ITS2 from that of 0. stellarum. The sequence from the ITS1 (135 bp) and ITS2 (233 bp) of A. haenlophila differed by 42 6 and 20.5% respectively from those of 0. stellarum. Therefore, nucleotide sequence of the ITS regions in these scuticociliates is highly conserved.
European Journal of Taxonomy, 2016
Generally, “ophrys- related” scuticociliates belong to a specialised group of ciliated protozoa that may act as commensals or pathogens of fishes and crustaceans. In the present study, four “ophrys- taxa” scuticociliates, i.e., Paramesanophrys typica gen. et sp. nov., Mesanophrys carcini (Grolière & Léglise, 1977) Small & Lynn in Aescht, 2001, Metanophrys sinensis Song & Wilbert, 2000, and Metanophrys similis Song et al., 2002, were collected from Chinese coastal waters or mariculture ponds and investigated. Paramesanophrys gen. nov. is assigned to the family Orchitophryidae and differs from its other genera mainly by the position of the paroral membrane relative to membranelle 1–3, i.e., the membrane extends anteriorly to the posterior end of membranelle 3. The type species P. typica gen. et sp. nov., is defined by an elongated body with the posterior end depressed where the caudal cilium is located; 20 or 21 somatic kineties; double-rowed membranelle 1 with eight to ten basal bodi...
Ectoparasitic copepods have been reported in a wide range of aquatic animals, including crustacean shellfish. However, with the exception of the salmon louse, Lepeophtheirus salmonis, our knowledge of such parasites in commercial species is rudimentary. The current study examines the morphology and pathology of the parasitic copepod, Nicothoë astaci (the ‘lobster louse’) in its host, the European lobster, Homarus gammarus. Lobsters were sampled from waters surrounding Lundy Island (Bristol Channel, UK) and all individuals collected were found to harbour female adult N. astaci in their gills, with a mean of 47·3 parasites/lobster. The majority of N. astaci were found in the basal region of pleurobranch gills. The parasite was found to attach to gill filaments via its oral sucker, maxillae and maxillipeds, and to feed on host haemolymph (blood) through a funnel-like feeding channel. It caused varying degrees of damage to the host gill, including occlusion of gill filaments and disruption to the vascular system in the central axis. Although there was evidence of extensive host response (haemocytic infiltration) to the parasite, it was displaced from the parasite attachment site and thus was observed in the central gill axis below. The region of gill filament immediately underlying the parasite feeding channel was devoid of such activity suggesting that the parasite interferes with the cellular defence and haemostatic mechanisms of the lobster in order to maintain invasion of the host.(Received January 06 2011)(Revised March 18 2011)(Revised April 21 2011)(Accepted May 10 2011)(Online publication July 15 2011)
Journal of invertebrate pathology, 2018
A parasite exhibiting Oomycete-like morphology and pathogenesis was isolated from discoloured eggs of the European lobster (Homarus gammarus) and later found in gill tissues of adults. Group-specific Oomycete primers were designed to amplify the 18S ribosomal small subunit (SSU), which initially identified the organism as the same as the 'Haliphthoros' sp. NJM 0034 strain (AB178865.1) previously isolated from abalone (imported from South Australia to Japan). However, in accordance with other published SSU-based phylogenies, the NJM 0034 isolate did not group with other known Haliphthoros species in our Maximum Likelihood and Bayesian phylogenies. Instead, the strain formed an orphan lineage, diverging before the separation of the Saprolegniales and Pythiales. Based upon 28S large subunit (LSU) phylogeny, our own isolate and the previously unidentified 0034 strain are both identical to the abalone pathogen Halioticida noduliformans. The genus shares morphological similarities...
Experimental Parasitology, 2012
Philasterides dicentrarchi is a histophagous scuticociliate infecting Korean olive flounder farms in Jeju Island, South Korea, where it causes significant economic losses. However, the route of entry of these parasites in olive flounder is currently unknown. In the present study, we attempted experimental infection with different doses (concentrations) of P. dicentrarchi by intraperitoneal (IP) injection; maximum cumulative mortality of 95% was recorded on the administration of 2.1 Â 10 8 ciliates/ml. In small size group (3 cm length, 24 ± 2 g wt) the ciliates were found in connective tissues of muscle, fins, and nervous tissue while in large size group (5 cm length, 47 ± 3 g wt), the ciliates were predominantly occurred with associated symptoms of liquefaction in the central nervous system. The major clinico-pathological manifestations were loss of scales, appearance of bleached spots that coalesced to form brownish patches, hemorrhagic, and severe dermal necrotic lesion. In addition there was degeneration of muscle fibers, necrosis of the hepatic parenchyma, and severe edema of the intestinal walls, extensive fouling, necrotic degeneration and hyperplasia in the gill bronchial epithelium. In this study, many ciliates were found in the blood vessel, brain, dorsal fins, muscle, kidney, and vertebra of infected flounder. The histopathological investigations are of significant importance in view of possible routes of entry into the host and doses of ciliates that trigger fast infection for potential utility of drugs as a strategy for the control of P. dicentrarchi in farmed olive flounder.
18th International Conference on Fisheries and Aquatic Sciences. Dubai, UAE, 2016
Lobster cultures have failed because of mortalities associated with parasitic and fungal infections. Monitoring of spawned eggs and larva of bamboo lobsters, Panulirus versicolour, and ornate lobsters, P. ornatus, in a hatchery was conducted in order to characterize fungal and parasitic diseases of eggs and larva. One species of protozoan parasite (Vorticella sp.) was identified from eggs while two species of fungi (Lagenidium sp. and Haliphthoros sp.) were found on the lobster larvae. Furthermore, adult lobsters cultured in floating net cages had burning-like diseases on their pleopod, uropod, and telson. Histopathological samples were collected for parasite identification and tissue changes. There were two parasites found to infect spiny lobsters on their external body and gill, they are Octolasmis sp. and Oodinium sp..Histopathology showed tissue changes, necrosis on the kidneys/liver/pancreas, necrosis in the gills and around the uropods and telson.