Development and Evaluation of an Experimental Model of Cutaneous Columnaris Disease in Koi Cyprinus Carpio

Abstract

Abstract.A reproducible, experimental model of columnaris disease was developed to study the pathogenesis of cutaneous disease associated with Flavobacterium columnare infection in koi (Cyprinus carpio). In experimental infections, lesions were usually restricted to skin and fins; gill necrosis was not a consistent finding. Cytologic and histopathologic examinations provided a presumptive diagnosis of columnaris disease. Specific detection of F. columnare was done using the polymerase chain reaction and DNA in situ hybridization (ISH). Polymerase chain reaction allowed the detection of F. columnare in fresh biological material and in formalinfixed, paraffin-embedded tissues. The DNA ISH technique allowed the identification and localization of F. columnare in formalin-fixed, paraffin-embedded tissues. Using these molecular techniques, F. columnare was readily detected in skin specimens from infected fish; however, the bacterium was infrequently detected in specimens of liver, kidney, and spleen. These observations suggest that columnaris disease generally presents as a cutaneous disease that is unassociated with systemic infection in koi. Hematologic studies indicated that most infected koi developed microcytic, normochromic, nonregenerative anemia and leukopenia characterized by lymphopenia, mild neutrophilia, and monocytosis. Biochemical changes in diseased fish included significant hyperglycemia, hyponatremia, and hypochloridemia.

An Overview of the Immunological Defenses in Fish Skin

“…After infection, the bacteria were readily detected in skin specimens from infected fishes; however, the bacterium was infrequently detected in liver, kidney, and spleen of affected specimens. These observations suggest that columnaris disease generally presents itself as a cutaneous disease that is unassociated with systemic infection in koi [268]. In other words, different pathogenic microorganisms are able to produce severe alterations to fishes only by affecting the mucosal surface.…”

“…For example, infection by the bacterium Flavobacterium columnare (columnaris disease agent) causes a chronic, ulcerative, necrotic infection of the body surface and gills, often resulting in 100% mortality over a few days [268], and infection by Ichthyophthirius multifiliis, a protozoan parasite that infects the skin and gills of freshwater fishes, is frequently fatal [224]. Furthermore, a reproducible, experimental model of columnaris disease (a serious condition affecting numerous freshwater fish species all over the world) was developed to study the pathogenesis of cutaneous disease associated with F. columnare infection in koi (Cyprinus carpio).…”

Endosymbiotic Bacteria in the Parasitic Ciliate Ichthyophthirius multifiliis

“…The other 10 clones had highly similar sequences and showed 97 to 99% identity with F. columnare 16S rRNA gene sequences (data not shown). F. columnare colonizes the skin of fish (29). The potential for contamination of I. multifiliis DNA preparations with F. columnare, or other bacteria from fish skin or aquarium water, was anticipated, but not to the extent found.…”

Produção de micropartículas de alginato contendo Flavobacterium columnare inativada pelo método de emulsão para vacinação de peixes por via oral

“…Destaca-se, neste sentido, a espécie Flavobacterium columnare, que é considerada um patógeno de ocorrência mundial capaz de causar doenças em praticamente todos os tipos de peixes de água doce. 1,2 Atualmente, o tratamento da doença é realizado através de banhos com substâncias desinfetantes e antibioticoterapia oral. 3 No entanto, o uso de antibióticos em sistemas de cultivo de peixes é bastante problemático, uma vez que o uso repetitivo destes pode levar ao desenvolvimento de microorganismos resistentes no ambiente e na microbiota dos animais.…”