Detection of Herpesvirus anguillae (AngHV-1) in European eel Anguilla anguilla (L.) originating from northern Poland-assessment of suitability of selected diagnostic methods

Complete Genome Sequence of Anguillid Herpesvirus 1 Isolated from Imported Anguilla rostrata (American Eel) from Canada

We report the full-length genome sequence (compared to reference sequences) of a variant strain of Anguillid herpesvirus 1 (AngHV-1) isolated from imported Anguilla rostrata (American eel) from Canada. This should help to further identify such viruses in the North America.

Anguilla sp. diseases diagnoses and treatments: The ideal methods at the crossroads of conservation and aquaculture purposes

Anguilla anguilla, A. japonica and A. rostrata are the most fished and consumed eel species. However, these species are Critically Endangered, Endangered and Endangered, respectively. A combination of factors is thought to be responsible for their decline including fisheries, climate change, habitat destruction, barriers to migration, pollution and pathogens. Among them, viruses, bacteria and parasites are causing weakening of wild eels and serious economic losses for fishermen and eel farmers. Early detection of pathogens is essential to provide appropriate responses both for conservation reasons and to limit economic losses. Classic diagnosis approaches are time consuming and invasive and usual treatments, for example, antipathogenic substances are becoming obsolete because of pathogen resistance and environmental impact problems. The need for early and non-invasive diagnostic methods as well as effective and environmentally friendly treatments has increased. Vaccine development and diet supplementation have known a growing interest since their use could allow prevention of diseases. In this review, we summarize the main pathogens-viruses, bacteria and parasites-of the three northern temperate eel species, the methods used to detect these pathogens and the different treatments used. We discussed and highlighted the need for non-invasive, rapid and efficient detection methods, as well as effective and environmentally friendly treatments for both conservation and aquaculture purposes.

First detection of Herpesvirus anguillae (AngHV-1) associated with mortalities in farmed giant mottled eel (Anguilla marmorata) in Vietnam

Giant mottled eel (Anguilla marmorata) farming in Vietnam is a multistage process starting from wild harvest of glass eels through the so-called "hatcheries" and distribution centres from which individuals are transferred to rearing farms and subsequently sold by one eel farm to another every 3-5 months. The information on viral agents spread and persistence in the Vietnamese eel aquaculture is scarce. Therefore, the mortality of A. marmorata at the Van Xuan Farm was the prerequisite to identify the possible aetiologic agent and additionally to formulate first recommendations for viral disease screening in the Vietnamese eel aquaculture. Juvenile giant mottled eels with haemorrhagic lesions in the skin and liver, and hyperaemia of the gut were tested with qPCR and end-point PCR for AngHV-1 presence. Here, we report the first detection of AngHV-1 associated with mortality in giant mottled eel in winter and spring seasons. On the basis of the obtained results, we recommend to test eel seeds in "hatcheries," since tropical eel farms operate in interconnected scheme and monitoring of AngHV-1 prevalence requires well-implemented measures. Disease screening in the rearing centres and on-growing facilities should be based on everyday health checks, including by-catch fish used as a base of the feeding programmes at eel farms in Vietnam.

First examination of the Lough Neagh European eel (Anguilla anguilla) population for eel virus European, eel virus European X and Anguillid Herpesvirus-1 infection by employing novel molecular techniques

Lough Neagh is home to the largest wild-caught European eel (Anguilla anguilla) commercial fishery in the EU, producing 14% of the EU catch and worth £3.2 million to the local economy. Viral infections have been suggested to play a contributory role in the decline of the worldwide eel stock, but previous studies of the Lough Neagh European eel population had not observed either acute or chronic viral signs. Eel virus European (EVE), Eel virus European X (EVEX) and Anguillid herpesvirus-1 (HVA) have been detected throughout Europe and as the Lough Neagh eel fishery is supplemented by re-stocking of eels from France, Spain and the United Kingdom and these viral infections may be asymptomatic, it is vital that the viral pathogen prevalence in the Lough is accurately determined. This study aimed to ascertain the presence of these viruses in the Lough Neagh European eel population by employing novel molecular techniques testing specifically for the presence of EVE, EVEX and HVA. No evidence was found of HVA infection, whereas EVE and EVEX were found, albeit at a very low prevalence.