Aspects of systematics and host specificity for Gyrodactylus species in aquaculture

Of the 430+ extant species of Gyrodactylus, ectoparasitic monogenetic flukes of aquatic vertebrates, Gyrodactylus salaris Malmberg, 1957 is arguably the most well-known. Following the introduction of this species into Norway in the 1970s with consignments of infected Atlantic salmon smolts, Salmo salar L., this species has had a devastating impact on the Norwegian Atlantic salmon population, decimating wild stocks in over 40 rivers. Gyrodactylus salaris is the only OIE (Office International des Epizooties) listed parasitic pathogen of fish and has been reported from 19 countries across Europe, though many of these records require confirmation. The UK, Ireland and some selected watersheds in Finland are currently recognised as G. salaris-free states; however, the threat that this notifiable parasite poses to the salmon industry in the UK and Ireland is of national concern. Current British contingency plans are based on the assumption that if G. salaris were to be introduced, the parasite would follow similar dynamics to those on salmonid stocks from across Scandinavia, i.e. that Atlantic strains of Atlantic salmon would be highly susceptible to infection, with mortalities resulting; that brown trout, Salmo trutta fario L., would be resistant and would lose their infection in a relatively short period of time; and that grayling, Thymallus thymallus (L.), would also be resistant to infection, but would carry parasites, at a low level, for up to 143 days. Two of the objectives of this study were to confirm the current distribution of G. salaris across Europe, and then, to investigate the relative susceptibility of British salmonids to G. salaris, to determine whether they would follow a similar pattern of infection to their Scandinavian counterparts or whether, given their isolation since the last glaciation and potential genetic differences, they would exhibit different responses. It has been almost six years since the distribution of G. salaris across Europe was last evaluated. Some of the European states identified as being G. salaris-positive, however, are ascribed this status based on misidentifications, on partial data resulting from either morphological or molecular tests, or according to records that have not been revisited. Additional Gyrodactylus material from selected salmonids was obtained from several countries to contribute to current understanding regarding the distribution of G. salaris across Europe. From the work conducted in the study, G. salaris is reported from Italy for the first time, alongside three other species, and appears to occur extensively throughout the central region without causing significant mortalities to their rainbow trout, Oncorhynchus mykiss (Walbaum), hosts. The analysis of archive material from G. salaris-positive farms would suggest that G. salaris has been in the country for at least 12 years. Material obtained from rainbow trout from Finland and Germany was confirmed as G. salaris supporting existing data for these countries. No specimens of G. salaris, however, were found in the additional Gyrodactylus material obtained from Portuguese and Spanish rainbow trout, only Gyrodactylus teuchis Lautraite, Blanc, Thiery, Daniel et Vigneulle, 1999, a morphologically similar species was found. Gyrodactylus salaris is now reported from 23 out of ~50 recognised states throughout Europe, only 17 of these however, have been confirmed by either morphology or by an appropriate molecular test, and only ten of these records have been confirmed by a combination of both methods. To assess the susceptibility of English and Welsh salmonids to G. salaris, a number of salmonid stocks of wild origin, were flown to the Norwegian Veterinary Institute (NVI) in Oslo, where they were experimentally challenged with G. salaris. Atlantic salmon from the Welsh River Dee, S. trutta fario from the English River Tyne and T. thymallus from the English River Nidd, raised from wild stock in government hatcheries, were flown out and subsequently challenged with G. salaris haplotype A. After acclimation, each fish was infected with ~50–70 G. salaris and marked, so that parasite numbers on individual fish could be followed. The dynamics on individual fish were followed against a control (Lierelva Atlantic salmon). The experiment found that the number of G. salaris on S. salar from the River Dee continued to rise exponentially to a mean intensity (m.i.) of ~3851 G. salaris fish-1 (day 40 post-infection). These salmon were highly susceptible, more so than the Norwegian salmon control (m.i. ~1989 G. salaris fish-1 d40 post-infection) and were unable to regulate parasite numbers. The S. trutta fario and T. thymallus populations, although initially susceptible, were able to control and reduce parasite burdens after 12 (m.i. ~146 G. salaris fish-1) and 19 (m.i. ~253 G. salaris fish-1) days, respectively when peak infections were seen. Although the latter two hosts were able to limit their G. salaris numbers, both hosts carried infections for up to 110 days (i.e. when the experiment was terminated). The ability of S. trutta fario and T. thymallus to carry an infection for long periods increases the window of exposure and the potential transfer of G. salaris to other susceptible hosts. The potential role that brown trout may play in the transmission and spread of G. salaris in the event of an outbreak, needs to be considered carefully, as well as the interpretation of the term “resistant” which is commonly used when referring to brown trout’s susceptibility to G. salaris. The current British surveillance programmes for G. salaris are focused on the screening of Atlantic salmon and on the monitoring of the rainbow trout movements. The findings from this study demonstrate that G. salaris can persist on brown trout for long periods, and suggest that brown trout sites which overlap with Atlantic salmon or rainbow trout sites are also included within surveillance programmes and that the role that brown trout could play in disseminating infections needs to be factored into contingency/management plans. Throughout the course of the study, a number of parasite samples were sent to the Aquatic Parasitology Laboratory at Stirling for evaluation. Some of these samples represented Gyrodactylus material that were associated with fish mortalities, but the species of Gyrodactylus responsible appeared to be new to science. A further aspect of this study was, therefore, to investigate these Gyrodactylus related mortalities in aquaculture stock and to describe the species found in each case, which may represent emerging pathogens. The two new species, Gyrodactylus orecchiae Paladini, Cable, Fioravanti, Faria, Di Cave et Shinn, 2009 and Gyrodactylus longipes Paladini, Hansen, Fioravanti et Shinn, 2011 on farmed gilthead seabream, Sparus aurata L., were collected from several Mediterranean farms. The finding of G. orecchiae in Albania and Croatia was associated with 2–10% mortality of juvenile stock and represents the first species of Gyrodactylus to be formally described from S. aurata. Subsequently, G. longipes was found in Bosnia-Herzegovina and Italy, and at the Italian farm site, it occurred as a mixed infection with G. orecchiae, but these infections did not appear to result in any loss of stock. Unconfirmed farm reports from this latter site, however, suggest that a 5–10% mortality of juvenile S. aurata was also caused by an infection of Gyrodactylus, which is suspected to be G. longipes. Additional samples of Gyrodactylus from a gilthead seabream farm located in the north of France have been morphologically identified as G. longipes, extending the geographical distribution of this potentially pathogenic species to three countries and three different coasts. In addition to these samples, some specimens of Gyrodactylus from a Mexican population of rainbow trout were sent for evaluation. These latter specimens were later determined to be a new morphological isolate/strain of Gyrodactylus salmonis (Yin et Sproston, 1948), a notable pathogen of salmonids throughout North America. The current material was of particular interest as it extends the current geographic range of this parasite from Canada and the USA to the south-eastern region of Mexico. This new Mexican isolate was genetically identical with G. salmonis from Canada and USA, although small morphological differences were evident in the marginal hook sickle shape, which allows to discriminate between the two strains. The results from this study are important as they reflect a similar situation in Europe with G. salaris and Gyrodactylus thymalli Žitňan, 1960, two morphological different but genetically similar species. Discriminating G. salaris from other species of Gyrodactylus infecting salmonids is difficult and, according to OIE, the identification should be based on a combination of data resulting from morphological and molecular approaches. The impact of Gyrodactylus salaris in Norway currently costs £38 million p.a., including loss of revenue from tourism and angling restrictions, and also the cost of on-going surveillance programmes and river treatments. The infection in certain rivers is removed through the addition of either 100 ppb biocide rotenone, which kills all the fish that are host to the parasite, or by a 10–14 day-treatment with 100 µg L-1 aluminium sulfate, which removes the parasite but does not kill its salmon host. If G. salaris were to enter the UK, it is unlikely that either of these compounds would be used because of the human health concerns (i.e. potential links to Parkinson’s and Alzheimer’s diseases) linked to their use. There are, however, very few compounds that could be used as alternatives for the control of wild infections, and there is little research investigating possible replacements. To begin exploring alternatives, a minor component of the study was to explore the effectiveness of two compounds: bronopol (2-bromo-2-nitropropane-1,3-diol) - a broad spectrum disinfectant - and tannic acid - a natural polyphenol that is released from the breakdown of plant material. The evaluation of bronopol was conducted against two strains of G. salaris from Atlantic salmon and on a single population of Gyrodactylus arcuatus Bychowsky, 1933 from three-spined sticklebacks, Gasterosteus aculeatus aculeatus L., as a continuous exposure and for 1 hour only. The results showed that there was a significant increase in the mortality rate of G. salaris as the dose of bronopol increased, but as time progressed, the influence of dose on mortality decreased. Bronopol had a statistically significant (p<0.001) greater effect on G. salaris than it did on G. arcuatus. The analysis suggested that the 1 hour-LC50 for G. salaris was ~384 ppm bronopol, while that needed to kill 50% of G. arcuatus within a 1 hour window of exposure was ~810 ppm bronopol. The trial with tannic acid represented a preliminary assessment and its effects as a continuous exposure and as a 10 minute treatment on G. salaris only were determined. The effect of tannic acid caused the tegument of G. salaris to lift away and the 1 hour-LC50 for tannic acid was <100 ppm although lower doses administered over long periods of time (i.e. 10–14 days as is currently used for aluminium sulfate) may have greater impacts on the survival of the parasite population. While these results demonstrate that bronopol could be used to control infections of G. salaris in confined aquaria, this does not mean that this advocates its use in river systems, as there are a plethora of logistic, economic and environmental considerations to take into account. The study does, however, take important steps towards investigating alternative control agents for use in the event of an outbreak, and both these products are worthy of further evaluation

Description of Citharodactylus gagei n. gen. et n. sp. (Monogenea: Gyrodactylidae) from the moon fish, Citharinus citharus (Geoffroy Saint-Hilaire), from Lake Turkana

A new genus and species of monogenean belonging to the Gyrodactylidae, Citharodactylus gagei n. gen. et n. sp. (Plathyhelminthes, Monogenea), is described from the gills of the moon fish, Citharinus citharus (Geoffroy Saint-Hilaire), a characiform fish collected from Lake Turkana in northern Kenya. The new viviparous genus can be readily distinguished from the six other gyrodactylid genera recorded from Africa and from the other viviparous genera within the Gyrodactylidae based on the morphology of the male copulatory organ (MCO), which consists of a muscular ovate organ with an opening onto the tegument through which the narrow tapered end of a sclerotised curved cone-shaped structure protrudes. The tegumental opening of the MCO is surrounded by a collar of short spines. Sequencing of the nuclear ribosomal DNA internal transcribed spacers 1 and 2, the 5.8S and the 18S rDNA genes and a comparison with the gyrodactylid species listed in GenBank confirmed the specimens are unique and do not match with any existing entry. When phylogenies for each genomic region were conducted (i.e. 0.064 gamma-corrected pairwise genetic distance based on a alignment of 1750bp of the 1857bp long 18S rDNA gene), the most similar match was that of Afrogyrodactylus sp. [=A. girgifae (Folia Parasitol 61:529&ndash;536, 2014)] from Brycinus nurse (R&uuml;ppell). The proposed name of the new parasite is Citharodactylus n. gen. which represents the seventh gyrodactylid genus to be found in Africa and the 25th viviparous genus and the 32nd genus to be added to the Gyrodactylidae

Evidence for cryptic speciation in directly transmitted Gyrodactylid parasites of Trinidadian guppies

Cryptic species complexes are common among parasites, which tend to have large populations and are subject to rapid evolution. Such complexes may arise through host-parasite co-evolution and/or host switching. For parasites that reproduce directly on their host, there might be increased opportunities for sympatric speciation, either by exploiting different hosts or different micro-habitats within the same host. The genus Gyrodactylus is a specious group of viviparous monogeneans. These ectoparasites transfer between teleosts during social contact and cause significant host mortality. Their impact on the guppy (Poecilia reticulata), an iconic evolutionary and ecological model species, is well established and yet the population genetics and phylogenetics of these parasites remains understudied. Using mtDNA sequencing of the host and its parasites, we provide evidence of cryptic speciation in Gyrodactylus bullatarudis, G. poeciliae and G. turnbulli. For the COII gene, genetic divergence of lineages within each parasite species ranged between 5.7 and 17.2%, which is typical of the divergence observed between described species in this genus. Different lineages of G. turnbulli and G. poeciliae appear geographically isolated, which could imply allopatric speciation. In addition, for G. poeciliae, co-evolution with a different host species cannot be discarded due to its host range. This parasite was originally described on P. caucana, but for the first time here it is also recorded on the guppy. The two cryptic lineages of G. bullatarudis showed considerable geographic overlap. G. bullatarudis has a known wide host range and it can also utilize a killifish (Anablepsoides hartii) as a temporary host. This killifish is capable of migrating overland and it could act as a transmission vector between otherwise isolated populations. Additional genetic markers are needed to confirm the presence of these cryptic Gyrodactylus species complexes, potentially leading to more in-depth genetic, ecological and evolutionary analyses on this multi-host-parasite system

Calcific tendinitis of the rotator cuff: state of the art in diagnosis and treatment

Calcific tendinitis is a painful shoulder disorder characterised by either single or multiple deposits in the rotator cuff tendon. Although the disease subsides spontaneously in most cases, a subpopulation of patients continue to complain of pain and shoulder dysfunction and the deposits do not show any signs of resolution. Although several treatment options have been proposed, clinical results are controversial and often the indication for a given therapy remains a matter of clinician choice. Herein, we report on the current state of the art in the pathogenesis, diagnosis and treatment of calcific tendinitis of the rotator cuff

The description of Gyrodactylus corleonis sp. n. and G. neretum sp. n. (Platyhelminthes: Monogenea) with comments on other gyrodactylids parasitizing pipefish (Pisces: Syngnathidae)

The current work describes two new species of Gyrodactylus von Nordmann, 1832 collected from pipefish Syngnathus scovelli (Evermann et Kendall) and Syngnathus typhle L. during two separate gyrodactylosis episodes on fish held in a public aquarium located in northern Italy. The gyrodactylids collected from the skin, fins and gills of pipefish were subjected to a morphological analysis of the attachment hooks and the morphometric data were compared to the four species of Gyrodactylus previously described from syngnathid hosts, namely G. eyipayipi Vaughan, Christison, Hansen et Shinn, 2010, G. pisculentus Williams, Kritsky, Dunnigan, Lash et Klein, 2008, G. shorti Holliman, 1963 and G. syngnathi Appleby, 1996. Principal components analysis (PCA) of the morphological data indicated six clusters; two discrete groups among the specimens taken from the pipefish held in the Italian aquarium and four further groups representing G. eyipayipi, G. pisculentus, G. shorti and G. syngnathi. Molecular sequences of the ribosomal internal transcribed spacers (ITS1 and ITS2) and the 5.8S gene for the new species considered here were then compared with those available for other species in GenBank. The comparison did not reveal any identical match, supporting the morphological analysis that Gyrodactylus corleonis sp. n. from S. typhle and Gyrodactylus neretum sp. n. from S. scovelli represent distinct species. Both G. corleonis and G. neretum possess robust hamuli, marginal hook blades that curve smoothly from their sickle base to a point beyond the toe and, ventral bars with a broad median portion and a reduced membrane. Gyrodactylus corleonis, however, can be distinguished on the basis of its heart-shaped ventral bar; G. neretum has a 1:2 hamulus point:shaft ratio and a rectangular-shaped ventral bar. A redescription of the haptoral hard parts of the four species previously recorded on pipefish is also presented

Complications of calcific tendinitis of the shoulder: a concise review

Abstract: Calcific tendinitis (CT) of the rotator cuff (RC) muscles in the shoulder is a disorder which remains asymptomatic in a majority of patients. Once manifested, it can present in different ways which can have negative effects both socially and professionally for the patient. The treatment modalities can be either conservative or surgical. There is poor literature evidence on the complications of this condition with little consensus on the treatment of choice. In this review, the literature was extensively searched in order to study and compile together the complications of CT of the shoulder and present it in a clear form to ease the understanding for all the professionals involved in the management of this disorder. Essentially there are five major complications of CT: pain, adhesive capsulitis, RC tears, greater tuberosity osteolysis and ossifying tendinitis. All the above complications have been explained right from their origin to the control measures required for the relief of the patient. Level of evidence: 5

Surgical treatment of chronic acromioclavicular dislocation with biologic graft vs synthetic ligament: A prospective randomized comparative study

Background: Acromioclavicular (AC) dislocation involves complete loss of articular contact; it is defined as chronic when it follows conservative management or unsuccessful surgical treatment. Materials and methods: The study compared the clinical and radiographic outcomes of AC joint stabilization performed in 40 patients with chronic dislocation using a biological allograft (group A) or a synthetic ligament (group B). Demographic data included: M/F: 25/15; mean age: 35 ± 3.2 years; previous surgery in 11 patients, including Weaver-Dunn (3), coracoacromial ligament repair (4), stabilization with K-wires (4). Dislocation was type III in 14 (35 %) and type IV in 26 (65 %) patients. Clinical assessment was with the Constant-Murley score (pre- and postoperative) and with the modified UCLA score. Enrollment started in January 2004 and was completed in March 2008. Patients were evaluated at 1 and 4 years. Postoperative X-rays were examined to assess joint stability in the coronal and axial planes, coracoclavicular ossification, and signs of AC joint osteoarthritis and distal clavicular osteolysis. Results: The "biological" group achieved significantly better clinical scores than the "synthetic" group at both 1 and 4 years. Poor subjective satisfaction and lower clinical scores were found in the 3 patients (1 from group A and 2 from group B) who experienced complete postoperative dislocation. No significant correlations were found with other radiographic parameters. Conclusions: The biological graft afforded better clinical and radiographic outcomes than the synthetic ligament in patients with chronic AC joint instability. Fixation to the clavicle constitutes the main weakness of both approaches and needs improving. © 2012 The Author(s)

Ossifying tendinitis of the rotator cuff after arthroscopic excision of calcium deposits: report of two cases and literature review

Ossifying tendinitis (OT) is a type of heterotopic ossification, characterized by deposition of hydroxyapatite crystals in a histologic pattern of mature lamellar bone. It is usually associated with surgical intervention or trauma and is more commonly seen in Achilles or distal biceps tendons, and also in the gluteus maximus tendon. To our knowledge, there is no description of OT as a complication of calcifying tendinitis of the rotator cuff. In this report, we describe two cases in which the patients developed an OT of the supraspinatus after arthroscopic removal of calcium deposits. The related literature is reviewed

Characterisation of the intracellular protozoan MPX in Scottish mussels, Mytilus edulis Linnaeus, 1758

Ciliates have been reported as pathogens of many species of economically important bivalves. Mussel protozoan X (MPX), is an uncharacterised intracellular ciliate of mussels and has been widely reported in Mytilus spp. around the world. In order to characterise this ciliate, Mytilus edulis samples were collected from a site on the West coast of Scotland, and four different fixatives for histological examination were tested. Fresh preparations of mussel digestive glands were also examined by laser scanning confocal microscopy. Intracellular ciliates were prepared by laser capture microdissection and partial sequences of small subunit ribosomal RNA gene and of large subunit ribosomal RNA gene were generated, using Phyllopharyngea primers. Methacarn solution proved to be the best fixative for both histological and molecular characterisation. The morphological and molecular investigations confirmed that this ciliate belongs to the class Phyllopharyngea, order Rhynchodida. However, this organism does not belong to any known family, genus or species, therefore, a new description is necessary, following further morphological analyses. Most mussel samples containing MPX displayed mild to moderate infections, with no signs of necrosis or haemocytic response, although a single sample displayed a severe infection (&sim;103 ciliates per section). The localisation of this ciliate in tissues other than the digestive gland, the presence of necrosis in infected tissue of the most severely infected mussel and the binary fission of this ciliate have been observed here for the first time. We also report the first observation of the live ciliate isolated from tissue. Although MPX remains of unknown significance to the mussel industry, tools and protocols described here will be useful in further characterising these and other ciliates (subclass Rhynchodia) known as pathogens for bivalves.REF Compliant by Deposit in Stirling's Repositor

Correction to: FTIR-ATR analysis of the H-bond network of water in branched polyethyleneimine/TEMPO-oxidized cellulose nano-fiber xerogels

n/