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We provide the first documented case of whirling disease (WD) impacts to wild, self-sustaining rainbow trout (RNTR, Oncorynchus mykiss) populations in Canada. Myxobolus cerebralis (Mc), the causative agent of WD, was first confirmed in Alberta in 2016. However, evidence of disease in local fish populations was unknown. Using a weight-of-evidence approach, we examined multiple parasite life cycle stages in the Crowsnest River, Alberta. Percentage of infected Tubifex tubifex worms actively shedding triactinomyxons (TAMs) exceeded known thresholds of Mc establishment and TAM densities instream exceeded thresholds known to cause [greater than or equal to]90% declines in RNTR populations. Mc was detected at 5 of 6 study sites in water, fish, and worms. Disease severity was highest in the lower watershed where 100% of sentinel fish tested positive for Mc 7 to 14 days post-exposure; up to 85% of wild fingerling RNTR showed clinical signs of disease and yearling trout were largely absent from the river suggesting reduced survival. Our findings indicate conditions necessary for outbreak of WD exist in Alberta, highlighting the need to consider this disease as an emerging threat to wild salmonid populations. Nous faisons etat du premier cas documente d'impacts du tournis des truites sur des populations sauvages autosuffisantes de truites arc-en-ciel (Oncorynchus mykiss) au Canada. La presence de Myxobolus cerebralis (Mc), l'agent etiologique du tournis, a ete confirmee pour la premiere fois en Alberta en 2016. Aucune preuve de la presence de la maladie dans des populations locales de poissons n'avait toutefois ete rapportee a ce jour. En utilisant une approche basee sur le poids de la preuve, nous avons examine plusieurs etapes de cycles de vie de parasites dans la riviere Crowsnest (Alberta). Le pourcentage de vers de vase Tubifex tubifex infectes qui rejetaient activement des triactinomyxons (TAM) depassait les seuils connus au-dela desquels Mc peut s'etablir et la densite de TAM dans le cours d'eau depassait les seuils dont il est etabli que le depassement cause des baisses de [greater than or equal to]90% des populations de truites arc-en-ciel. Mc a ete detecte dans cinq des six sites d'etude dans l'eau, des poissons et des vers. La severite de la maladie etait la plus elevee dans le bassin inferieur, oU 100 % des poissons sentinelles ont produit un resultat positif au depistage du Mc de 7 a 14 jours apres l'exposition; jusqu'a 85 % des alevins d'un an sauvages de truite arc-en-ciel presentaient des signes cliniques de la maladie et les truites de l'annee etaient en bonne partie absentes de la riviere, ce qui indiquerait une survie reduite. Nos constatations indiquent que les conditions necessaires a des eclosions de tournis des truites existent en Alberta, ce qui souligne la necessite de considerer cette maladie comme constituant une nouvelle menace pour les populations de salmonides sauvages. [Traduit par la Redaction], 1. Introduction Aquatic invasive species are a globally significant threat to freshwater fish (Dudgeon et al. 2006; Jelks et al. 2008). Globalization has led to the increased movement of people [...]

This corrects the article DOI: 10.1038/ncomms15451.

Biomphalaria snails are instrumental in transmission of the human blood fluke Schistosoma mansoni. With the World Health Organization's goal to eliminate schistosomiasis as a global health problem by 2025, there is now renewed emphasis on snail control. Here, we characterize the genome of Biomphalaria glabrata, a lophotrochozoan protostome, and provide timely and important information on snail biology. We describe aspects of phero-perception, stress responses, immune function and regulation of gene expression that support the persistence of B. glabrata in the field and may define this species as a suitable snail host for S. mansoni. We identify several potential targets for developing novel control measures aimed at reducing snail-mediated transmission of schistosomiasis.

Gastropod molluscs, which have co-evolved with parasitic digenean trematodes for millions of years, utilize circulating heamocytes as the primary method of containing and killing these invading parasites. In order to do so, they must generate suitable amounts of haemocytes that are properly armed to kill parasitic worms. One method by which they generate the haemocytes required to initiate the appropriate cell mediated immune response is via the production and post-translational processing of granulins. Granulins are an evolutionarily conserved family of growth factors present in the majority of eukaryotic life forms. In their pro-granulin form, they can elicit cellular replication and differentiation. The pro-granulins can be further processed by elastase to generate smaller granulin fragments that have been shown to functionally differ from the pro-granulin precursor. In this study, we demonstrate that in vivo addition of Biomphalaria glabrata pro-granulin (BgGRN) can reduce Schistosoma mansoni infection success in numerous Biomphalaria sp. when challenged with different S. mansoni strains. We also demonstrate that cleavage of BgGRN into individual granulin subunits by elastase results in the stimulation of haemocytes to produce reactive oxygen species. [ABSTRACT FROM AUTHOR]

Myxobolus cerebralis is the causative agent of whirling disease in salmonid fishes. In 2016, this invasive parasite was detected in Alberta, Canada, for the first time, initiating a comprehensive 3 yr monitoring program to assess where the parasite had spread within the province. As part of this program, a qPCR-based test was developed to facilitate detection of the environmental stages of M. cerebralis and from the oligochaete host, Tubifex tubifex. During this program, ~1500 environmental samples were collected and tested over 3 yr. Fish were collected from the same watersheds over 2 yr and tested as part of the official provincial monitoring effort. Substrate testing identified sites positive for M. cerebralis in 3 of 6 watersheds that had been confirmed positive by fish-based testing and 3 novel detections where the parasite had not been detected previously. Testing of individually isolated Tubifex from each sample site was used to further confirm the presence of M. cerebralis. DNA barcoding of the cytochrome oxidase I (cox1) gene of 567 oligochaete specimens collected from 6 different watersheds yielded 158 unique sequences belonging to 21 genera and 37 putative species. Phylogenetic analyses of sequences assigned to the genus Tubifex predicted 5 species of Tubifex arising from this assessment. Based on our results, we propose that environmental and worm samples can be a valuable complement to the gold-standard fish testing and will be especially useful for monitoring in areas where fish collection is challenging or prohibitive because of site accessibility or vulnerability of the fish populations.