EFSA Journal (Aug 2023)

Species which may act as vectors or reservoirs of diseases covered by the Animal Health Law: Listed pathogens of molluscs

  • EFSA Panel on Animal Health and Welfare (AHAW),
  • Søren Saxmose Nielsen,
  • Julio Alvarez,
  • Dominique Bicout,
  • Paolo Calistri,
  • Elisabetta Canali,
  • Julian Ashley Drewe,
  • Bruno Garin‐Bastuji,
  • José Louis Gonzales Rojas,
  • Christian Gortazar Smith,
  • Mette Herskin,
  • Virginie Michel,
  • Miguel Angel Miranda Chueca,
  • Barbara Padalino,
  • Helen Roberts,
  • Hans Spoolder,
  • Karl Ståhl,
  • Antonio Velarde,
  • Arvo Viltrop,
  • Christoph Winckler,
  • Isabelle Arzul,
  • Shetty Dharmaveer,
  • Niels Jørgen Olesen,
  • Morten Schiøtt,
  • Hilde Sindre,
  • David Stone,
  • Niccoló Vendramin,
  • Sotiria‐Eleni Antoniou,
  • Sofie Dhollander,
  • Anna Eleonora Karagianni,
  • Linnea Lindgren Kero,
  • Marzia Gnocchi,
  • Inma Aznar,
  • Fulvio Barizzone,
  • Irene Pilar Munoz Guajardo,
  • Helen Roberts

DOI
https://doi.org/10.2903/j.efsa.2023.8173
Journal volume & issue
Vol. 21, no. 8
pp. n/a – n/a

Abstract

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Abstract Vector or reservoir species of five mollusc diseases listed in the Animal Health Law were identified, based on evidence generated through an extensive literature review, to support a possible updating of Regulation (EU) 2018/1882. Mollusc species on or in which Mikrocytos mackini, Perkinsus marinus, Bonamia exitiosa, Bonamia ostreae and Marteilia refringens were detected, in the field or during experiments, were classified as reservoir species with different levels of certainty depending on the diagnostic tests used. Where experimental evidence indicated transmission of the pathogen from a studied species to another known susceptible species, this studied species was classified as a vector species. Although the quantification of the risk of spread of the pathogens by the vectors or reservoir species was not part of the terms of reference, such risks do exist for the vector species, since transmission from infected vector species to susceptible species was proven. Where evidence for transmission from infected molluscs was not found, these were defined as reservoir. Nonetheless, the risk of the spread of the pathogens from infected reservoir species cannot be excluded. Evidence identifying conditions that may prevent transmission by vectors or reservoir mollusc species during transport was collected from scientific literature. It was concluded that it is very likely to almost certain (90–100%) that M. mackini, P. marinus, B. exitiosa B. ostreae and M. refringens will remain infective at any possible transport condition. Therefore, vector or reservoir species that may have been exposed to these pathogens in an affected area in the wild or at aquaculture establishments or through contaminated water supply can possibly transmit these pathogens. For transmission of M. refringens, the presence of an intermediate host, a copepod, is necessary.

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