Determine Characteristics of Concurrent Infections in Disease Processes and Evaluate Immunodiagnostic Assays for the Fish Pathogens
Aquatic Animal Health Research
2013 Annual Report
1a.Objectives (from AD-416):
Determine effects of parasitism by Ichthyophthirius or Gyrodactylus on fish susceptibility to Edwardsiella ictaluri and Flavobacterium columnare and develop diagnostic assays for detection of fish pathogen in cultured fish and farm water.
1b.Approach (from AD-416):
Catfish and tilapia will be used to evaluate the effect of parasitism by Ichthyophthirius multifiliis or Gyrodactylus on fish susceptibility to Edwardsiella ictaluri and Flavobacterium columnare; and determine if parasites can harbor and subsequently vector the bacterial pathogens using histology, fluorescent and molecular techniques. Rapid molecular and immunological detection assay will be developed and tested for their effectiveness in the detection of bacterial and parasite pathogens.
One of the goals is to evaluate effects of parasitism on fish susceptibility to pathogenic bacteria. ARS scientists at Auburn, Alabama, used a protozoan parasite Ichthyophthirius multifiliis (Ich) and Edwardsiella ictaluri (a gram negative bacterium) to study the interaction between the parasite, the bacteria and the fish host. The study demonstrated that parasites can transmit pathogenic bacteria to fish. The information can help fish farmers to prevent the introduction of pathogenic bacteria from wild fish or other farm fish infected with parasites.