Diseases Caused by Amoebae in Fish: An Overview

Area of Science:

• Aquatic microbiology
• Fish pathology
• Parasitology

Background:

• Parasitic and amphizoic amoebae are widespread, affecting numerous hosts including fish.
• The host-amoeba relationship in fish is categorized into ectocommensalism, ectoparasitism, endocommensalism, and endoparasitism.
• While distinctions can be blurred, these interactions significantly impact fish health and aquaculture.

Purpose of the Study:

• To review the diverse roles and impacts of parasitic and amphizoic amoebae in fish.
• To highlight key amoebic species and the diseases they cause in both wild and farmed fish populations.
• To underscore the importance of understanding these interactions for fish health management and aquaculture.

Main Methods:

• Literature review of scientific publications on amoebae in fish.
• Analysis of host-amoeba interactions, disease mechanisms, and causative agents.
• Identification of significant amoebic species and their associated pathologies in various fish species.

Main Results:

• Neoparamoeba perurans identified as a major pathogen causing amoebic gill disease in farmed salmon.
• Nodular gill disease in freshwater fish linked to unidentified amoebae.
• Species of Naegleria and Acanthamoeba, also human pathogens, found in freshwater fish.
• Entamoebae species found as endocommensals in fish digestive tracts.
• Endolimax nana implicated in systemic infections in farmed Solea senegalensis.

Conclusions:

• Amoebic infections pose a significant threat to fish health, affecting both wild and farmed populations.
• Specific amoebic species, such as N. perurans, cause economically important diseases in aquaculture.
• Further research is needed to identify causative agents of diseases like nodular gill disease and to understand the full spectrum of amoebic infections in fish.