Reduced transmission of IHHNV to Penaeus monodon from shrimp pond wastewater filtered through a polychaete-assisted sand filter (PASF) system

A polychaete-assisted sand filter (PASF) can aid water recirculation systems for shrimp culture ponds by removing large amounts of nutrients and suspended solids and chemically treating wastewater. By ingesting and degrading organic matter, Perinereis helleri polychaetes reared in a PASF can accumulate and potentially remove infectious hypodermal and haemopoietic necrosis virus (IHHNV) present in wastewater from ponds rearing virus-infected Penaeus monodon shrimp. Reported here are data showing that filtering pond wastewater through a PASF reduces its potential to transmit IHHNV. The trial employed 3 groups of 4 tanks each containing 20 P. monodon randomly selected from a pond in which IHHNV was evident at moderate prevalence and low loads (IHHNV low-load Pond 2). Over a 2 week period, each tank group was supplied with wastewater from either the same pond (Pond 2) or Pond 1 in which IHHNV was 100% prevalent at ~104-fold higher infection loads, either directly or after being filtered through a PASF. IHHNV real-time qPCR data on total nucleic acid (TNA) extracted from pleopods of 35 P. monodon selected at random from each group identified an elevated IHHNV infection prevalence (91%) in shrimp tested from tanks supplied directly with wastewater from Pond 1. In comparison, IHHNV was detected at a much reduced prevalence and lower loads among shrimp from tanks supplied with wastewater from Pond 2 (33%) or from Pond 1 after it had been filtered through a PASF (31%). The IHHNV prevalence and load data indicate that a PASF can play a useful role in reducing the potential for shrimp pond wastewater to transmit IHHNV infection to naïve P. monodon

Polychaetes (Perinereis helleri) reared in sand beds filtering nutrients from shrimp (Penaeus monodon) culture ponds can transiently carry IHHNV

A polychaete-assisted sand filter (PASF) system has been developed to help remove nutrients from aquaculture pond wastewater whilst also producing polychaetes that are highly prized as bait by recreational anglers and as a dietary supplement to improve the fecundity of shrimp broodstock. Whilst rearing polychaetes in PASF beds offers potential to reduce impacts of sourcing them from the wild, the use of wastewater from ponds rearing shrimp such as Penaeus monodon will present a biosecurity risk of viruses being transferred to, and potentially amplified in, the worms. To assess such risks for transmitting infectious hypodermal and haematopoietic necrosis virus (IHHNV), groups of 3 or 4 PASF beds seeded with sand worm (Perinereis helleri) juveniles were supplied with wastewater from ponds of P. monodon with either high-load or low-load IHHNV infections. TaqMan real-time qPCR identified low loads of IHHNV (≤878 IHHNV DNA copies 200 ng−1 TNA) in most worms from PASF beds supplied wastewater from the high-load pond. IHHNV was either not detected or detected at the qPCR test sensitivity limits in worms from beds supplied wastewater from the low-load pond. Purging harvested worms of their gut contents in clean filtered seawater for 2 days significantly reduced IHHNV loads. Reverting PASF beds to clean seawater for 8 weeks before harvest also significantly reduced worm loads of IHHNV. Daily additions of a commercial probiotic to the sand bed surface for 4 weeks prior to clean seawater application provided no discernible benefit to IHHNV clearance. While clearly demonstrated to be capable of carrying IHHNV, the remediation measures examined suggest potential to ameliorate the infection transmission risks of P. helleri reared in PASF beds supplied with shrimp pond wastewater as a nutrient source

Feed Containing Novacq Improves Resilience of Black Tiger Shrimp, Penaeus Monodon, to Gill-associated Virus-induced Mortality

The ability of Novacq to improve resilience of black tiger shrimp, Penaeus monodon, to infection and mortality induced by gill-associated virus (GAV) was investigated. Over a 26-d period, shrimp were fed pellets with or without 10% Novacq. Following this, four replicate tanks, each containing 10 shrimp that had been fed either diet, were maintained as-is, injected with saline or injected with GAV inoculum (i.e., 40 shrimp for each of the six groups). For shrimp (n=20) in two of each group of four tanks, survival was monitored daily over 14d and a pleopod was sampled from each shrimp on Days 0 and 14. For the other two tanks, a pleopod was sampled from each shrimp on Days 0, 3, 7, 10, and 14 to track changes in GAV loads over time. Survival was significantly higher (P<0.05) from Day 7 onward among the group fed Novacq. GAV infection loads appeared to vary more between individuals in the Novacq diet cohort, but overall were not reduced significantly at any time points post-challenge compared to shrimp tested from the Control diet cohort.&nbsp

Reduced loads of pre-existing Gill-associated virus (GAV) infection in juvenile Penaeus monodon injected with single or multiple GAV-specific dsRNAs

The ability of RNA interference (RNAi) based on injected dsRNA was investigated here for its ability to reduce the severity of pre-existing subclinical Gill-associated virus (GAV) infections in farm stocks of juvenile Black Tiger shrimp (Penaeus monodon). Following tail muscle injection of single or multiple long dsRNAs targeted to sequences positioned across the GAV ORF1a/1b replicase genes, pleopods were sampled sequentially from individuals at regular intervals over a 2. week period to track changes in GAV RNA loads by quantitative real-time RT-PCR. Mean GAV RNA amounts showed statistically significant (

Ticks Associated with Macquarie Island Penguins Carry Arboviruses from Four Genera

Macquarie Island, a small subantarctic island, is home to rockhopper, royal and king penguins, which are often infested with the globally distributed seabird tick, Ixodes uriae. A flavivirus, an orbivirus, a phlebovirus, and a nairovirus were isolated from these ticks and partial sequences obtained. The flavivirus was nearly identical to Gadgets Gully virus, isolated some 30 year previously, illustrating the remarkable genetic stability of this virus. The nearest relative to the orbivirus (for which we propose the name Sandy Bay virus) was the Scottish Broadhaven virus, and provided only the second available sequences from the Great Island orbivirus serogroup. The phlebovirus (for which we propose the name Catch-me-cave virus) and the previously isolated Precarious Point virus were distinct but related, with both showing homology with the Finnish Uukuniemi virus. These penguin viruses provided the second and third available sequences for the Uukuniemi group of phleboviruses. The nairovirus (for which we propose the name Finch Creek virus) was shown to be related to the North American Tillamook virus, the Asian Hazara virus and Nairobi sheep disease virus. Macquarie Island penguins thus harbour arboviruses from at least four of the seven arbovirus-containing genera, with related viruses often found in the northern hemisphere

International genome-wide meta-analysis identifies new primary biliary cirrhosis risk loci and targetable pathogenic pathways.

Primary biliary cirrhosis (PBC) is a classical autoimmune liver disease for which effective immunomodulatory therapy is lacking. Here we perform meta-analyses of discovery data sets from genome-wide association studies of European subjects (n=2,764 cases and 10,475 controls) followed by validation genotyping in an independent cohort (n=3,716 cases and 4,261 controls). We discover and validate six previously unknown risk loci for PBC (Pcombined<5 × 10(-8)) and used pathway analysis to identify JAK-STAT/IL12/IL27 signalling and cytokine-cytokine pathways, for which relevant therapies exist

Mourilyan virus pathogenicity in kuruma shrimp (Penaeus japonicus)

The bunyavirus Mourilyan virus (MoV) occurs commonly in Black tiger (Penaeus monodon) and kuruma shrimp (Penaeus\ua0japonicus) farmed in eastern Australia. There is circumstantial evidence of MoV causing mortalities among P.\ua0japonicus moved from farm ponds to tanks for rearing as broodstock. To directly assess its pathogenic potential, independent cohorts of pond- (n\ua0=\ua024) or tank-reared juvenile (n\ua0=\ua021) P.\ua0japonicus were challenged intramuscularly with a cephalothorax tissue homogenate of P.\ua0monodon containing high loads of MoV (1.48\ua0±\ua00.28\ua0×\ua010 MoV RNA copies/µg total RNA). In each trial, mortalities accumulated gradually among the saline-injected controls. Mortality onset occurred 12–14\ua0days earlier in the pond-reared shrimp, possibly due to them possessing low-level pre-existing MoV infections. Despite the time to onset of mortality differing, Kaplan–Meier survival analyses confirmed mortality rates to be significantly higher in both the pond- (p\ua0=.017) and tank-reared shrimp (p\ua0=.031) challenged with MoV. RT-qPCR data on shrimp sampled progressively over each trial showed high loads of MoV to establish following challenge and discounted GAV and other endemic viruses from contributing to mortality. Together, the data show that acute MoV infection can adversely compromise the survival of juvenile P.\ua0japonicus

Spawning of female Black tiger shrimp (Penaeus monodon) is not impacted by muscle injection of dsRNA targeted to gill-associated virus

The ability of domesticated Penaeus monodon, Black Tiger shrimp, to spawn following tail-muscle injection of dsRNA was examined. Ablated domesticated female broodstock infected subclinically with gill-associated virus (GAV) were injected with saline or a cocktail of five-dsRNAs targeting different regions in the GAV ORF1a/1b gene. To track changes in GAV infection loads, TaqMan real-time PCR was used to quantify mean viral RNA amounts in each of three pleopod clips collected at the time of injection (Day 0) and either immediately after a female spawned or on Day 11 when the trial was terminated. Over the trial, 4 of 19 (21%) saline-injected shrimp spawned and 12 of 25 (48%) dsRNA-injected shrimp spawned, with one spawning twice. Egg numbers varied from 25\ua0600 to 459\ua0800 for the saline-injected shrimp and from 4900 to 213\ua0900 for the dsRNA-injected shrimp. Of these, one of the four egg batches hatched from saline-injected shrimp and 9 of the 13 egg batches hatched from dsRNA-injected shrimp. While variable, egg numbers and hatch rates recorded were typical of those obtained from domesticated broodstock at the commercial hatchery and particularly among females previously spawned. Mean GAV RNA amounts detected in pleopod samples increased in five of the eight saline-injected shrimp tested by 1.6–227.4-fold and decreased in 12 of the 15 ds-RNA-injected shrimp tested by −1.1 to −45.1-fold. The study demonstrated that tail-muscle injection of GAV-specific dsRNA does not adversely impact the ability of P.\ua0monodon to spawn