Establishing bacterial infectivity models in striped Catfish Pangasianodon hypophthalmus (Sauvage) with Edwardsiella ictaluri

Citation

Ngoc Phuoc N, Richards R & Crumlish M (2020) Establishing bacterial infectivity models in striped Catfish Pangasianodon hypophthalmus (Sauvage) with Edwardsiella ictaluri. Journal of Fish Diseases, 43 (3), pp. 371-378. https://doi.org/10.1111/jfd.13135

Abstract
A bacterial infectivity challenge model of Edwardsiella ictaluri in striped catfish was developed. All experiments were conducted using a bacterial isolate of E. ictaluri that had been recovered during a natural outbreak of bacillary necrosis of Pangasianodon (BNP) in farmed striped catfish Pangasianodon hypophthalmus in Vietnam. Time of immersion in 107 CFU.ml−1 had a significant effect on mortality. The immersion bacterial dose of 107 CFU/ml for 30 s resulted in a cumulative percentage mortality of 63%. Three to four days post‐bacterial challenge, fish showed gross clinical signs of natural BNP and E. ictaluri was recovered and identified from these fish. Moreover, a cohabitation challenge was evaluated as an alternative challenge method, although the mortalities among the infected fish were lower at around 15%–40%. This study confirmed the horizontal transmission of E. ictaluri in striped catfish and elucidated that cohabitation challenge could be used in reproducing the disease under controlled conditions.

Keywords
bacillary necrosis of Pangasianodon; cohabitation challenge; Edwardsiella ictaluri; immersion challenge; Pangasianodon hypophthalmus

Journal
Journal of Fish Diseases: Volume 43, Issue 3