ISA virus detected in one fish at Benchmark salmon egg facility
Yesterday, Benchmark Genetics Salten AS, Norway, was informed by the Veterinary Institute that organ samples from one individual have been analysed as positive for the Infectious Salmon Anaemia virus. However, as all eggs and milt are routinely screened, there should be no risk of customers receiving ISAv-infected eggs.
"The current samples have very low virus levels and there have been no clinical signs of disease in the tank where the fish have been, or in the facility in general," the company stated in a press release.
"There is only one fish where a deleted virus with low virus load (high CT) has been sequenced. Analyses suggest that there was no ISA disease in this individual, as a much lower CT value (i.e., higher virus load) would have been found," said Benchmark Genetics' salmon, health and genetics leader Geir Olav Melingen in a comment to LandbasedAQ.
The tank, which has a fish group totalling 628 broodstock, is, according to the company, an isolated independent epidemiological unit with a separate water system, its own equipment for husbandry, and its own dead fish collector.
1,000 samples analysed
"About 1,000 samples from this tank have been analysed in the last month without findings and we are therefore confident that there are very few individuals in the current tank that could be carriers. In addition, we have analysed about 18,000 samples in the last half year, all coming out negative and showing no findings of virus," Melingen further stated.
The broodstock in the specific isolated tank are now quarantined and will be destroyed.
The ova from the individual that tested positive have also been routinely destroyed, Benchmark reported.
"Benchmark is actively collaborating with the Norwegian Food Safety Authority to maintain high biosecurity at the facility. There is already an established routine from January 2023 where all ova are screened for ISA virus before delivery to ensure that pathogens are not transferred to customers," the company said.
Therefore, according to the report, Benchmark Genetics Salten is conducting screening of milt, ova fluid, and organs (heart and kidney) from all broodstock that are stripped, as well as dead fish from all tanks at the site.
Strictest screening
"The screening procedure that Benchmark uses is the strictest and most sensitive available, to ensure that the facility maintains a particularly high level of biosecurity. Such a sampling regime ensures that we detect isolated incidents as early as possible, which in turn helps us to implement measures and ensure that the consequences are very limited both for our customers, our operations, and for the welfare of the fish at the facility," Benchmark said.
Melingen to LandbasedAQ: "We have invested heavily in establishing secure zones between tanks and departments specifically to handle such situations with minimal impact across fish groups. All findings show that there is no transmission between tanks, and that the measures we have implemented therefore have their expected function."
Given that all ova that have been incubated have been screened free of ISA virus through both ova fluid and organ samples, Benchmark considers it 100% safe for customers to receive roe from the facility.
"We are in ongoing dialogue with customers who have orders. We expect that the incident will not affect our ability to deliver to our customers," the aquaculture biotechnology company said.
