First detection of Edwardsiella ictaluri (Proteobacteria: Enterobacteriaceae) in wild Australian catfish

The bacterium Edwardsiella ictaluri is considered to be one of the most significant pathogens of farmed catfish in the United States of America and has also caused mortalities in farmed and wild fishes in many other parts of the world. E. ictaluri is not believed to be present in wild fish populations in Australia, although it has previously been detected in imported ornamental fishes held in quarantine facilities. In an attempt to confirm freedom from the bacterium in Australian native fishes, we undertook a risk-based survey of wild catfishes from 15 sites across northern Australia. E. ictaluri was detected by selective culturing, followed by DNA testing, in Wet Tropics tandan (Tandanus tropicanus) from the Tully River, at a prevalence of 0.40 (95% CI 0.21–0.61). The bacterium was not found in fishes sampled from any of the other 14 sites. This is the first report of E. ictaluri in wild fishes in Australia

Plasma lipid profiles discriminate bacterial from viral infection in febrile children

Fever is the most common reason that children present to Emergency Departments. Clinical signs and symptoms suggestive of bacterial infection ar

Corrigendum to “Genetic diversity of Australian isolates of Photobacterium damselae subsp. damselae is associated with virulence to yellowtail kingfish (Seriola lalandi)” [Aquaculture 538 (2021) 736552]

The authors regret that the printed version of the above article contained an error in our documentation of ethics approval for challenge infection of fish. The correct and final version follows. The authors would like to apologise for any inconvenience caused. Our experiment was conducted using methodology approved by the Animal Ethics Committee of the Department of Primary Industries and Regional Development (Permit number: 19-4-14), which follows the principles and guidelines of Australian Animal Care

Genetic diversity of Australian isolates of Photobacterium damselae subsp. damselae is associated with virulence to yellowtail kingfish (Seriola lalandi)

Photobacterium damselae subsp. damselae is an emerging pathogen which recently has been found with increasing frequency globally, in both wild and cultured fishes. The aim of this study was to characterize 16 isolates of Photobacterium damselae damselae from cultured fish in Australia and to investigate their pathogenicity to yellowtail kingfish. Considerable differences in phenotypic and genotypic traits occurred between bacterial isolates, indicating that different clonal lineages can co-exist in the same geographical area. Phylogenetic analysis did not support a monophyletic origin for P. damselae damselae, distinct from the other recognized subspecies, P. damselae piscicida. Of note was the significant relationship between the toxR genetic distance among isolates of P. damselae damselae and differences in their phenotypic profiles, enzyme activities and strength of haemolysis on blood agar plates. Isolates containing the pPHDD1 plasmid, and its associated haemolysin genes, showed a significantly larger haemolytic zone than did plasmid-free isolates containing only chromosome-I encoded virulence genes. An infection trial demonstrated that presence of the pPHDD1 plasmid is not essential for pathogenicity, although the plasmid does increase virulence towards Seriola lalandi. Understanding the intraspecific variability in virulence of Australian isolates of P. damselae damselae will assist the aquaculture industry, in particular the yellowtail kingfish industry, to develop more targeted treatment and control methods for infections with this pathogen

Observations on the health of Tandanus tropicanus (Teleostei: Plotosidae) from an Australian river system

Wild Wet Tropics tandan Tandanus tropicanus were collected from the Bloomfield River, Queensland, for examination by histopathology and bacteriology. This provided an opportunity to establish baseline information on the general health and parasite fauna of native freshwater catfish in a pristine river. Histology of gill tissue revealed epitheliocystis in one fish. This is the first report of epitheliocystis in T. tropicanus. Bacterial culture showed light growth of bacteria from the kidney of only two fish, and these were identified as Aeromonas veronii, A. jandaei and Bacillus/Lactobacillus spp. An unidentified monogenean infection was observed in the gills of four fish, and trematode metacercariae were observed in the extra-ocular tissue of four fish. Nematodes were observed in the tissues of nine fish, and sequence and preliminary phylogenetic analysis of PCR products using an ITS primer suggest that these parasites may be a previously unreported Contracaecum species