Experimental infection of brown trout (Salmo trutta), zebrafi sh (Danio rerio), and swan mussel (Anodonta cygnea) with infectious pancreatic necrosis virus (IPVN)

Abstract

Aim. Although more than 80 fi sh species and some invertebrate aquatic organisms are known to be susceptible to in- fectious pancreatic necrosis virus (IPNV) and aquatic birnaviruses, relatively little is known about its ability to infect brown trout (Salmo trutta), zebrafi sh (Danio rerio), and a mollusk, swan mussel (Anodonta cygnea). Therefore, the aim was to study in more detail the effects of IPNV on the said organisms. The information on the virulence of birnaviruses for aquatic organisms is important for better understanding of their transmission and for the identifi cation of suscep- tible or transient (symptomless) hosts. Methods. Cell culture method, using RTG-2 cells, was used for in vitro culti- vation of IPNV as well as virus titer assessment. The supernatants from infected RTG-2 cells were used for artifi cial inoculation to obtain experimental infection of the fi sh and mollusk. Fish and mollusk behaviour and mortality were monitored daily. The infectious titer of the virus in experimental animals was assessed by cell culture assay and reverse transcription PCR (RT-PCR). Results. This paper presents the results of IPNV experimental infection of brown trout (Salmo trutta), zebrafi sh (Danio rerio), and an aquatic invertebrate mollusk - swan mussel (Anodonta cygnea). The mortality of brown trout and zebrafi sh was 76.6 and 40 % respectively. Swan mussel was apparently resistant to the virus, but it apparently accumulated and maintained substantial levels (up to 10 -10 ID 50 /ml -1 ) of the virus for the dura- tion of the experiment (35 days). The highest infectious titer was found in brown trout (10 6 ID 50 /ml -1 ). In zebrafi sh and swan mussels, it was up to 10 4.5 ID 50 /ml -1 and 10 2 ID 50 /ml -1 respectively. Conclusions. At the end of the experiments the IPNV titers were higher than the initial viral doses in brown trout and zebrafi sh, indicating virus reproduction. In diseasesd fi sh the blackening, whirling and anorexia were observed. It was shown that swan mussel accumulates and maintains virus for at least 35 days under experimental conditions and that it may act as symptomless vector of IPNV

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): infectious pancreatic necrosis (IPN)

“…IPNV (WB strain) was shown experimentally to be able to bioaccumulate in blue mussel (Mytilus edulis) and be transmitted to naive Atlantic salmon (Salmo salar) smolts (Molloy et al, 2013). Another experiment found that swan mussel (Anodonta cygnea) was resistant to IPNV, but able to accumulate and maintain substantial levels of the virus for 35 days (Rud et al, 2020). The following is a list of fish families where aquatic birnaviruses were isolated as a naturally occurring infection (McAllister, 2007) Parameter 6 -Domestic/farmed reservoir species (or family/orders) Farmed fish are an important reservoir of IPNV in aquatic environments, where the virus can be shed from farm waters into surroundings.…”

“…IPNV (WB strain) was shown experimentally to be able to bioaccumulate in blue mussel ( Mytilus edulis ) and be transmitted to naive Atlantic salmon ( Salmo salar ) smolts (Molloy et al., 2013 ). Another experiment found that swan mussel ( Anodonta cygnea ) was resistant to IPNV, but able to accumulate and maintain substantial levels of the virus for 35 days (Rud et al., 2020 ). The following is a list of fish families where aquatic birnaviruses were isolated as a naturally occurring infection (McAllister, 2007 ), but it was not clarified in the publication if the virus described was IPNV: Acipenseridae , Amiidae , Anguillidae , Atherinidae , Bothidae , Carangidae , Catostomidae , Centrarchidae , Cichlidae , Channidae , Clupeidae , Cobitidae , Coregonidae , Cottidae , Cyprinidae , Cyprinodontidae , Embiotocidae , Esocidae , Gadidae , Gasterosteidae , Gobiidae , Hiodontidae , Ictaluridae , Lepisosteidae , Moronidae , Paralichthyidae , Percichthyidae , Percidae , Petromyzontidae , Pleuronectidae , Poeciliidae , Polyodontidae , Salmonidae , Sciaenidae , Soleidae , Thymallidae , Triglidae , Umbridae .…”

Antiviral vaccines for fish (a review)

“…to more than 700 million USD, and most likely every year financial investments in biotechnological developments of a preventive nature will grow in direct proportion to the intensive development of aquaculture [74,100,101].…”

“…може становити понад 700 млн доларів США, і, найімовірніше, щороку фінансові інвестиції в біотехнологічні розробки профілактичного характеру зростатимуть прямопропорційно до інтенсивного розвитку аквакультури [74,100,101].…”

Study of in vitro reproduction of infectious pancreatic necrosis virus (IPNV)

“…В Україні захворювання інфекційний панкреатичний некроз зустрічається у палії (Salvelinus fontinalis), струмкової форелі (Salmo trutta) та райдужної форелі (Oncorhynchus mykiss) [2][3][4]. Через значний економічний вплив вірусу на галузь аквакультури, великі зусилля в усьому світі приділяють контролю захворювання за допомогою різних підходів: рання діагностика та оцінка біологічних ризиків, контроль торгівлі об'єктами аквакультури, скринінг природних популяцій та вивчення генотипів вірусу і розробка вакцин [1].…”