Francisca Samsing

The University of Sydney · Sydney School of Veterinary Science

The development, progression, and dissemination of antimicrobial resistance (AMR) is determined by interlinked human, animal, and environmental drivers, posing severe risks to human health. Conjugative plasmid transfer drives the rapid dissemination of AMR among bacteria. Besides antibiotic judicious use and implementation of antibiotic stewardship...

Fish meal (FM) replacement is essential for the sustainable expansion of aquaculture. This study focussed on the feasibility of replacing FM with a single‐cell protein (SCP) derived from methanotrophic bacteria ( Methylococcus capsulatus , Bath) in barramundi fry ( Lates calcarifer ). Three isonitrogenous and isoenergetic diets were formulated with...

The aquaculture sector is currently experiencing a global disease crisis. Emerging bacterial diseases—often opportunistic or syndromic—have collapsed production in nations across the world. Losses in the shrimp industry associated with opportunistic Vibrio spp. exceed 40% of global capacity. This paper reviews potential drivers of syndromic disease...

Most diseases in aquaculture are caused by opportunistic pathogens. One of them, Vibrio harveyi, is a widespread Gram-negative bacterium that has become an important pathogen of aquatic species in marine environments. Here, we propose the use of the causal pie model as a framework to conceptualize the causation of vibriosis in juvenile barramundi (...

In salmon aquaculture, the sustainable management of salmon lice (Lepeophtheirus salmonis) is limited by the adaptive capacity of the parasite. This is evident in the repeated evolution of pesticide resistance in the salmon louse population. To better prepare for resistance, we constructed a numerical metapopulation model that predicts the evolutio...

Disease and parasitism cause major welfare, environmental and economic concerns for global aquaculture. In this review, we examine the status and potential of technologies that exploit genetic variation in host resistance to tackle this problem. We argue that there is an urgent need to improve understanding of the genetic mechanisms involved, leadi...

One of the most intriguing discoveries of the genomic era is that only a small fraction of the genome is dedicated to protein coding. The remaining fraction of the genome contains, amongst other elements, a number of non-coding transcripts that regulate the transcription of protein coding genes. Here we used transcriptome sequencing data to explore...

Salmonid aquaculture, producing nearly 3 million tons per year, has expanded across temperate seascapes around the globe in recent decades. Cage technologies used to farm salmonids are thought to have changed in both size and location in coastal environments, yet remarkably little data exists to explain these major developments. Using satellite ima...

Chloramine-T (Cl-T) is a disinfectant and sanitizer widely applied to treat bacterial infections on the gill and skin of Atlantic salmon during freshwater culture. It is typically applied as static or flush treatments during periods of disease risk or in response to pathogen detection or gross disease signs. While the efficacy of CI-T to reduce spe...

Pilchard orthomyxovirus (POMV) is a virus of concern to the Atlantic salmon aquaculture industry in Tasmania. First isolated from wild pilchards in southern Australia in 1998, the virus is now a recognised pathogen of farmed Atlantic salmon (Salmo salar) in Tasmania. While the current real-time PCR for POMV targets segment 5 of the viral genome, re...

Due to its significant impacts on the environment and their overabundance in multiple waterways, common carp (Cyprinus carpio) has long been a target for control in southeastern Australia. Local eradication and site-based actions have had limited impacts, instigating national efforts to examine alternatives for effective long-term control, includin...

Tenacibaculosis remains a major health issue for a number of important aquaculture species globally. On the west coast of Canada, yellow mouth (YM) disease is responsible for significant economic loss to the Atlantic salmon industry. While Tenacibaculum maritimum is considered to be the primary agent of clinical YM, the impact of YM on the resident...

Pilchard orthomyxovirus (POMV) is an emerging pathogen of concern to the salmon industry in Australia. To explore the molecular events that underpin POMV infection, we challenged Atlantic salmon (Salmo salar) post-smolts in seawater via cohabitation. Tissue samples of the head kidney and liver were collected from moribund and surviving individuals...

The Tasmanian salmon industry had remained relatively free of major viral diseases until the emergence of pilchard orthomyxovirus (POMV). Originally isolated from wild pilchards, POMV is of concern to the industry as it can cause high mortality in farmed salmon (Salmo salar). Field observations suggest the virus can spread from pen to pen and betwe...

Amoebic gill disease (AGD), caused by Neoparamoeba perurans, is a major health challenge for Atlantic salmon aquaculture globally. While freshwater bathing for 2 hr is effective in reducing infection severity, there is need for more rapid and lower cost alternatives. To this end, a combination of sodium percarbonate (SPC) in freshwater was examined...

The Tasmanian Atlantic salmon (Salmo salar) aquaculture industry had remained relatively free of major viral diseases until the recent emergence of pilchard orthomyxovirus (POMV). The virus originally isolated from wild pilchards in Southern Australia is of great concern to the industry as it can cause high mortality. Despite its classification in...

An orthomyxo-like virus was first isolated in 1998 as an incidental discovery from pilchards Sardinops sagax collected from waters off the South Australian coast. In the following 2 decades, orthomyxo-like viruses have been isolated from healthy pilchards in South Australia and Tasmania. In 2006, an orthomyxo-like virus was also isolated from farme...

Hydrogen peroxide (H2O2) is a commonly used treatment for a range of parasitic diseases of marine finfish, including amoebic gill disease (AGD). While this treatment is partially effective at reducing parasite load, H2O2 can have detrimental effects on the host under certain conditions. Treatment temperature and dose concentration are two factors t...

In trying to deal with the problematic salmon louse Lepeophtheirus salmonis in salmon aquaculture, strategies to better prevent infestations are gaining traction. Successful prevention requires an accurate understanding of the environmental influences that alter the distribution of the planktonic stages of lice in the water column in space and time...

Marine ecosystems are beset by disease outbreaks, and efficient strategies to control dispersal of pathogens are scarce. We tested whether introducing no-farming areas or ‘firebreaks’ could disconnect dispersal networks of a parasitic disease affecting the world's largest marine fish farming industry (∼1000 farms). Larval salmon lice (Lepeophtheiru...

Altered behaviour is believed to be the first form of defence against parasite infection, through reducing opportunity for infection or deflecting parasites to sub‐optimal sites on hosts. To determine whether the suite of behaviours fish exhibit deter or deflect infection, we tested for differences in salmon louse ( Lepeophtheirus salmonis ) infect...

When salmon lice, Lepeophtheirus salmonis, infect Atlantic salmon, they are typically removed by chemical or mechanical treatments. Delousing side effects can lead to poor welfare outcomes for fish, however reducing lice abundance in farms is crucial to reduce their ecological impacts. To determine which delousing treatments causes the highest salm...

Background: Hydrogen peroxide (H2 O2 ) baths are widely used to reduce salmon lice on farmed Atlantic salmon. Fish mortalities often occur after baths, with warmer temperatures increasing lethality. We tested if mortality could be reduced and lice removal efficacy maintained by lowering bath temperatures relative to ambient temperatures. Post-smol...

ContextSea lice are the most significant parasitic problem affecting wild and farmed salmon. Larval lice released from infected fish in salmon farms and their transport by water masses results in inter-farm networks of lice dispersal. Understanding this parasite connectivity is key to its control and effective management. Objectives Quantify the sp...

The cover image, by Frode Oppedal et al., is based on the Research Article Sea lice infestation levels decrease with deeper ‘snorkel’ barriers in Atlantic salmon sea‐cages, DOI: 10.1002/ps.4560.

Background: Salmon lice (Lepeophtheirus salmonis) are the most important parasite of farmed salmon. Infective larvae position themselves in the upper part of the water column to increase encounter probabilities with potential hosts. Previous studies have shown that a 'snorkel' sea-cage technology protects salmon from infection in surface waters. W...

Creation of a mismatch between Lepeophtheirus salmonis larvae and farmed salmon reduces infestations. The snorkel cage comprises a net roof keeping salmon below the surface layer where infestative lice larvae are most abundant, but with a tarpaulin lined channel above that enables salmon to access surface air to refill their swim bladders. “Proof o...

Salmon lice are one of the major parasitic problems affecting wild and farmed salmonid species. The planktonic larval stages of these marine parasites can survive for extended periods without a host and are transported long distances by water masses. Salmon lice larvae have limited swimming capacity, but can influence their horizontal transport by...

Temperatures regulate metabolism of marine ectotherms and thereby influence development, reproduction, and, as a consequence, dispersal. Despite the importance of water temperatures in the epidemiology of marine diseases, for the parasitic copepod Lepeophtheirus salmonis, the effect of high and low temperatures has not been methodically investigate...

Salmon lice are one of the major parasitic problems affecting wild and farmed salmonid species. The planktonic larval stages of these marine parasites can survive for extended periods without a host and are transported long distances by water masses. Salmon lice larvae have limited swimming capacity, but can influence their horizontal transport by...

Host-parasite interactions are moderated by the environmental conditions of the interaction medium (e.g. air or water). Encounter rate and the time available for a parasite to make physical contact with a host are both influenced by fluid dynamics, yet how they interact is poorly known. Here, we tested whether current velocities altered the initial...

Host density likely plays a key role in host−parasite interactions, but empirical evidence in marine ecosystems remains limited. Classical models predict a positive relationship between host density and parasite infection parameters, but this depends on the parasite transmission mode. Evidence from systems where mobile parasites actively seek hosts...

Currently, fish farms in marine waters are beset by parasites. For the most widely produced marine fish, salmon, parasitic sea lice are the most significant problem. These external parasites cause high environmental and economic impacts. Conventional lice-treatments are partially effective because of drug resistance, and they negatively impact fish...

This research presents a model to estimate the total concentration or CTotal of dioxins (PCDD), furans (PCDF) and dioxin-like polychlorinated biphenyls (DL-PCBs) in pork. The model was applied considering the categories of raw materials that make up two reference diets for pig production in Chile. Samples of such raw materials were analyzed to dete...

This study assessed the contribution of various feed ingredients used in swine feeding as a source of dioxins, furans and dioxin like polychlorinated biphenyls (DL-PCBs) contamination in pork, considering the dietary changes during breeding, raising and fattening. Raw materials or feed ingredients were separated into different categories, developin...

The EROD bioassay with H4IIE cell line was applied in this study to determine the equivalence of the results for chicken meat between the ERODH4IIE Bioassay in pg TCDD-EQ/g of tissue, and the results of the gas chromatography coupled to high resolution spectrometry (HRGC/HRMS) in pg WHO-TEQ/g of fat of TEQs. 41 compound samples of chicken drumstick...

The EROD bioassay with H4IIE cell line was applied in this study to determine the equivalence of the results for chicken meat between the ERODH4IIE Bioassay in pg TCDD-EQ/g of tissue, and the results of the gas chromatography coupled to high resolution spectrometry (HRGC/HRMS) in pgWHO-TEQ/g of fat of TEQs. 41 compound samples of chicken drumsticks...

This study assessed the contribution of various feed ingredients used in swine feeding as a source of dioxins, furans and dioxin like polychlorinated biphenyls (DL-PCBs) contamination in pork, considering the dietary changes during breeding, raising and fattening. Raw materials or feed ingredients were separated into different categories, developin...

Flame retardants have wide industrial applications and are incorporated into articles found in automobiles and home environments, including seat cushions. These compounds differ widely chemically and in their toxic potential. We report here two cases involving dogs following ingestion of car seat cushions impregnated with organophosphate ester fire...