711
© Springer International Publishing Switzerland 2016
B. Austin, D.A. Austin, Bacterial Fish Pathogens,
DOI 10.1007/978-3-319-32674-0_15
Chapter 15
Conclusions
Abstract There are ongoing developments in the understanding of bacterial fi sh
pathogens. New and emerging diseases are regularly recognised especially in aquaculture. Great emphasis is placed on better diagnoses, pathogenicity mechanisms,
and disease control especially by immunoprophylaxis (vaccines, nonspecifi c immunostimulants, probiotics and natural plant products). There is an interaction between
some pollutants and occurrence of fi sh diseases. Some fi sh pathogens may also
cause disease of humans, including Edw. tarda, Myc. fortuitum, Myc. marinum, Ph.
damselae, Ps. fl uorescens, Str. iniae and V. vulnifi cus.
Keywords Zoonosis • Co-infection • Developments • Pollution • New diseases
Over the last three decades since the fi rst edition of Bacterial Fish Pathogens ,
there has been a continual increase in the list of fi sh pathogens described in the
scientifi c literature. Inevitably with improvements in taxonomy, there has been the
description of new species, e.g. Fr. noatunensis, and a reclassifi cation of others, e.g.
V. salmonicida to Ali. salmonicida. With the widespread use of 16S rRNA sequencing these taxonomic changes should be more reliable than the previous reliance on
phenotypic and serological methods. Over a similar timeframe, molecular methods
have come to dominate the development of diagnostic procedures, vaccine development and the study of pathogenic mechanisms. Diagnostics has progressed from a
culture-dependent mentality to a culture-independent approach, although a positive
result for the presence of antigens or DNA does not necessarily infer that intact and
viable bacterial cells are present in the host, and causing/contributing to the disease
process. However, scientists still tend to study single isolates that differ from laboratory to laboratory, and make inter-laboratory comparisons diffi cult. These cultures
may have been kept in the laboratory for many years, and have a dubious relationship to their counterparts in a diseased animal. Yet such cultures may be used to
develop diagnostic procedures, and determine pathogenicity mechanisms. Another
concern is that there has been a move away from “good” microbiology techniques
as other scientifi c disciplines, e.g. molecular biology, occupy centre stage. Reading
many publications, it is apparent that all too often scientists do not confi rm the
authenticity of the cultures with which they have been working. Consequently, it is
often questionable whether a publication describing some biological aspect of a
© Springer International Publishing Switzerland 2016
B. Austin, D.A. Austin, Bacterial Fish Pathogens,
DOI 10.1007/978-3-319-32674-0_15
Chapter 15
Conclusions
Abstract There are ongoing developments in the understanding of bacterial fi sh
pathogens. New and emerging diseases are regularly recognised especially in aquaculture. Great emphasis is placed on better diagnoses, pathogenicity mechanisms,
and disease control especially by immunoprophylaxis (vaccines, nonspecifi c immunostimulants, probiotics and natural plant products). There is an interaction between
some pollutants and occurrence of fi sh diseases. Some fi sh pathogens may also
cause disease of humans, including Edw. tarda, Myc. fortuitum, Myc. marinum, Ph.
damselae, Ps. fl uorescens, Str. iniae and V. vulnifi cus.
Keywords Zoonosis • Co-infection • Developments • Pollution • New diseases
Over the last three decades since the fi rst edition of Bacterial Fish Pathogens ,
there has been a continual increase in the list of fi sh pathogens described in the
scientifi c literature. Inevitably with improvements in taxonomy, there has been the
description of new species, e.g. Fr. noatunensis, and a reclassifi cation of others, e.g.
V. salmonicida to Ali. salmonicida. With the widespread use of 16S rRNA sequencing these taxonomic changes should be more reliable than the previous reliance on
phenotypic and serological methods. Over a similar timeframe, molecular methods
have come to dominate the development of diagnostic procedures, vaccine development and the study of pathogenic mechanisms. Diagnostics has progressed from a
culture-dependent mentality to a culture-independent approach, although a positive
result for the presence of antigens or DNA does not necessarily infer that intact and
viable bacterial cells are present in the host, and causing/contributing to the disease
process. However, scientists still tend to study single isolates that differ from laboratory to laboratory, and make inter-laboratory comparisons diffi cult. These cultures
may have been kept in the laboratory for many years, and have a dubious relationship to their counterparts in a diseased animal. Yet such cultures may be used to
develop diagnostic procedures, and determine pathogenicity mechanisms. Another
concern is that there has been a move away from “good” microbiology techniques
as other scientifi c disciplines, e.g. molecular biology, occupy centre stage. Reading
many publications, it is apparent that all too often scientists do not confi rm the
authenticity of the cultures with which they have been working. Consequently, it is
often questionable whether a publication describing some biological aspect of a