My major research interests center on infectious diseases of farm-raised channel catfish, in particular, enteric septicemia of catfish caused by Edwardsiella ictaluri and columnaris disease caused by Flavobacterium columnare. We have studied the pathogenesis of enteric septicemia and have isolated and characterized various components of the outer membrane of the bacterium. Knowledge of the outer membrane proteins, lipopolysaccharide, flagella, etc. of E. ictaluri will allow us to define the virulence mechanisms of the organism. We have also carried out experiments to identify and characterize the antigens of E. ictaluri that are immunogenic to catfish. These antigens might prove useful as immunogens in subunit vaccines to protect catfish from infection by E. ictaluri. Characterization of the metalloprotease(s) of Flavobacterium columnare is also an ongoing research interest. Columnaris disease is an important disease in most food fish raised in freshwater and in freshwater aquarium fish. The metalloprotease(s) are believed to play important roles in the pathogenesis of columnaris disease.
We are also working with Pythium insidiosum, an oomycete that causes equine and canine pythiosis. We have developed an ELISA test that is useful in diagnosing the disease in dogs and horses and have also worked to develop immunotherapeutic agents for equine pythiosis.