46 MARCH 2023 • WORLD AQUACULTURE • WWW.WAS.ORG Manager Aquaculture at Virbac in Bangkok, Thailand. His previous experiences since 2013 have been with salmon, trout, sea bream, sea bass, tilapia and barramundi on three continents. What are the main pathogens in shrimp culture and what are the present solutions to mitigate their impacts? There are more than ten identified and named shrimp viruses as possible pathogens for cultured shrimp as well as several bacteria, especially Vibrio, that are affecting shrimp farming in many countries and regions, and last but not least parasites, like EHP (Enterocytozoon hepatopenaei), which is currently strongly affecting shrimp aquaculture in most Asian countries. The first precaution would be avoiding the spreading of pathogens from one zone to another, which explains the benefits of using Specific Pathogen Free (SPF) strains to be shipped and transferred to regions where specific pathogens are not reported and considered to be absent. Nevertheless, using only SPF shrimp does not always prevent any epizootics to occur in a particular country. Specific Pathogen Resistant (SPR) or Specific Pathogen Tolerant (SPT) selected strains makes the difference in regions where specific pathogens are present or endemic. The “opposition” or “competition” between SPF and SPR is from the past. A shrimp strain can be both SPF and SPR, meaning that the shrimp are resistant to a specific pathogen without carrying it. The distinction is important because, in some cases, SPR are not really SPR but are SPT. These shrimp may express a certain level of resistance, but still carry a chronically small amount of the pathogen, which does not affect the carrier, but may affect SPF-naïve individuals. Some preliminary observations in some cases leads us to think that resistance to a specific pathogen may induce resistance to some other pathogens, but it is not a fixed rule. Quite a lot of work is required to confirm or reject this hypothesis. The recent discovery This article is a summary of a debate about disease management in aquaculture in the presence of pathogens. The debate was held at the closing of a Special Session organized as an international tribute to Alain Michel at World Aquaculture Singapore 2022 on 1 December 2022. Alain Michel was a world-renowned aquaculturist with a long career in marine and freshwater shrimp and fish farming, who passed away last year. The Chair of the session was Alain’s colleague, Régis Bador, who invited three international experts in shrimp and fish pathology for a 90min debate and question-andanswer session. More than 50 participants from five continents participated until the end. The three experts in the debate were Marc Le Groumellec, Luis Fernando Aranguren and Roberto Cascione. Marc Le Groumellec is a Veterinarian from Ecole Nationale Vétérinaire in Nantes, France. He has a Ph.D. in Aquaculture and Pathology and has worked with the Pasteur Institute in Paris, Ifremer and the University of Arizona. Since 1999, he has been Manager of Domestication, Genetics, Pathology and Biosecurity at Aqualma / Unima in Madagascar, and since 2014, he has been an Ad Hoc Expert on Aquatic Animal Health and Biosecurity at the World Organization for Animal Health (WOAH/OIE) and FAO. Luis Fernando Aranguren is a Marine Biologist from The Universidad Jorge Tadeo Lozano in Colombia, with an M.Sc. and Ph.D. in Microbiology and Shrimp Pathobiology from the University of Arizona. He was a Research Scientist and later an Assistant Research Professor at the University of Arizona. He has been designated by the WOAH as an expert on the crustacean pathogen Hepatobacter penaei. Roberto Cascione is a Veterinarian from Università degli Studi di Bari in Italy. He earned an M.Sc. in Aquatic Veterinary Studies from the University of Stirling, specializing in Fish Veterinary Studies. Since 2002, he has been the Key Account Disease Management in Aquaculture in the Presence of Pathogens: A Debate Summary Régis Bador, Marc Le Groumellec, Luis F. Aranguren and Roberto Cascione Régis Bador (left), with three invited aquatic animal disease specialists: Marc Le Groumellec, Roberto Cascione and Luis Fernando Aranguren (left to right) at the debate at World Aquaculture 2022 in Singapore. Attendees at a Special Session on aquatic animal diseases in honor of Alain Michel at World Aquaculture 2022 in Singapore.
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