Ian A Gardner

Ian A Gardner
University of Prince Edward Island | UPEI · Department of Health Management

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379
Publications
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15,259
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Publications

Publications (379)
Article
Full-text available
Real-time PCR (qPCR) testing is an essential component of early detection surveillance systems for Piscirickettsia salmonis infection in Atlantic salmon farms in Chile. Currently, all 11 laboratories in the authorised diagnostic laboratory network use assays based on published protocols. Compared with other P. salmonis qPCR assays, these assays hav...
Article
Full-text available
Piscirickettsiosis (SRS), caused by Piscirickettsia salmonis, is the main infectious disease that affects farmed Atlantic salmon in Chile. Currently, the official surveillance and control plan for SRS in Chile is based only on the detection of P. salmonis, but neither of its genogroups (LF-89-like and EM-90-like) are included. Surveillance at the g...
Article
Full-text available
Chronic subclinical infection with the aetiological agent of bacterial kidney disease (BKD), Renibacterium salmoninarum, presents challenges for the clinical management of disease in farmed salmonids and for prevalence estimation. Harvested salmon sampled at processing plants provide the opportunity to describe subclinical outcomes of BKD using gro...
Article
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Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) allows rapid and reliable identification of microorganisms. The accuracy of bacterial identification using MALDI-TOF MS depends on main spectral profiles (MSPs) provided in a quality-assured commercial reference library, which requires ongoing improvement. T...
Article
An incursion of infectious salmon anaemia virus (ISAV) was detected in 2020 in south-ern Newfoundland, Canada. This resulted in an outbreak affecting four marine farms stocking Atlantic salmon (Salmo salar L.) vaccinated against ISAV. This study provides the first description of epidemiologic characteristics of an ISAV outbreak in 2020 and 2021, an...
Article
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Bacterial infection and antimicrobial resistance are important constraints in the production and sustainability of farmed salmonids. This retrospective study aimed to describe the frequency of bacterial isolates and antimicrobial resistance profiles in salmonid aquaculture in Atlantic Canada. Bacterial isolates and antimicrobial susceptibility test...
Article
Infectious hematopoietic necrosis (IHN) virus is a rhabdovirus of significant concern to the salmon aquaculture industry in British Columbia (BC). IHN epidemic events in BC have historically resulted in high mortalities and economic losses among farmed salmon populations. A viral disease management plan (VDMP) was developed by salmon companies in B...
Article
Simulation models are useful tools to predict and elucidate the effects of factors influencing the occurrence and spread of epidemics in animal populations, evaluate the effectiveness of different control strategies and ultimately inform decision-makers about mitigations to reduce risk. There is a paucity of simulation models to study waterborne tr...
Article
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Proper sample size must be considered when designing infectious-agent prevalence studies for mixed-stock fisheries, because bias and uncertainty complicate interpretation of apparent (test)-prevalence estimates. Sample size varies between stocks and are often smaller than expected during wild-salmonid surveys. Our case example of 2010–2016 survey o...
Article
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Costs of diagnostic testing including sample collection, sampling frequency and sample size are an important consideration in the evaluation of the economic feasibility of alternative surveillance strategies for detection of infectious diseases in aquatic animals. In Chile, Piscirickettsia salmonis is the primary reason for antibiotic treatments in...
Article
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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...
Article
Full-text available
Early detection of piscirickettsiosis is an important purpose of government‐ and industry‐based surveillance for the disease in Atlantic salmon farms in Chile. Real‐time qPCRs are currently used for surveillance because bacterial isolation is inadequately sensitive or rapid enough for routine use. Since no perfect tests exist, we used Bayesian late...
Article
Aquaculture is currently the primary source of fish for human consumption. However, the sustainability of this industry has been under scrutiny. In Chile, the main concern is the use of antibiotics to control piscirickettsiosis, and farmers have identified timely detection as a critical issue. Using data provided by the Fisheries and Aquaculture au...
Article
Evaluation of the diagnostic sensitivity (DSe) and specificity (DSp) of tests for infectious diseases in wild animals is challenging, and some of the limitations may affect compliance with the OIE-recommended test validation pathway. We conducted a methodologic review of test validation studies for OIE-listed diseases in wild mammals published betw...
Article
Wild Pacific salmonids (WPS) are economically and culturally important to the Pacific North region. Most recently, some populations of WPS have been in decline. Of hypothesized factors contributing to the decline, infectious agents have been postulated to increase the risk of mortality in Pacific salmon. We present a literature review of both publi...
Article
Bayesian mixture models, often termed latent class models, allow users to estimate the diagnostic accuracy of tests and true prevalence in one or more populations when the positive and/or negative reference standards are imperfect. Moreover, they allow the data analyst to show the superiority of a novel test over an old test, even if this old test...
Article
Infection with Streptococcus agalactiae causes mortality and major economic losses in Nile tilapia (Oreochromis niloticus) farming worldwide. In Brazil, serotype strains Ia, Ib and III have been isolated in streptococcosis outbreaks, but serotype Ib is the most prevalent. Vaccination is considered an effective method to prevent economically-importa...
Article
Renibacterium salmoninarum infection causes bacterial kidney disease (BKD) in salmonid freshwater and saltwater life stages, with potentially severe financial loss for the aquaculture industry. Preventing vertical transmission, from infected broodstock to eggs, is key to disease management. As there is no perfect reference standard for detecting R....
Article
Fish aquaculture is rapidly growing in Brazil. Nile tilapia is the most cultivated species, mainly through an intensive production system carried out in floating cages installed in large reservoirs. However, fish pathogens pose a major challenge to production chain sustainability, and tilapia farmers may have limited knowledge of prevailing health...
Article
The purpose of the study was to describe spatial and time-at-sea patterns of endemic and new infectious agents and histopathologically-identified lesions in dead-and-dying farmed non-native Atlantic (AS) and native Pacific (PS) salmon in BC, between 2011 and 2013. Novel high-throughput molecular testing and blinded histopathological examination of...
Article
Full-text available
Rabies continues to pose a significant threat to human and animal health in regions of Indonesia. Indonesia has an extensive network of veterinary diagnostic laboratories and the 8 National laboratories are equipped to undertake diagnostic testing for rabies using the commercially-procured direct fluorescent antibody test (FAT), which is considered...
Data
OpenBUGS code for estimation of the diagnostic sensitivity and specificity. (DOCX)
Data
Data used for Bayesian statistical analysis. (XLSX)
Article
Limited research has been done using multivariable statistical methods to assess factors associated with fish mortality in warm-water finfish aquaculture in China. We carried out a case study to test the hypothesized association between pond-level daily mortality of farmed grass carp and predisposing environmental and husbandry factors. Based on lo...
Article
Full-text available
Fish farming in reservoirs is a growing aquaculture sector in Brazil. This study aimed to characterize Nile tilapia health and production patterns in net cages at a tropical reservoir in Brazil, to provide baseline information for future studies and policies. The study was carried out in 2015, at the Reservoir of Três Marias, Minas Gerais, and invo...
Article
Bacterial kidney disease (BKD) diagnosis is often carried out by IFAT, ELISA, and PCR because these tests yield rapid results compared with bacterial culture for the causative agent, Renibacterium salmoninarum. However, the diagnostic sensitivity (DSe) and specificity (DSp) of these tests is generally unknown, particularly in subclinically infected...
Article
Full-text available
Heart and skeletal muscle inflammation (HSMI) is an emerging disease of marine-farmed Atlantic Salmon (Salmo salar), first recognized in 1999 in Norway, and later also reported in Scotland and Chile. We undertook a longitudinal study involving health evaluation over an entire marine production cycle on one salmon farm in British Columbia (Canada)....
Data
Data extrapolated from the Department of Fisheries and Oceans—Aquaculture Management Division—Fish Health and Surveillance Audit program. The data show heart lesions identified on four farms located in the region of the farm of interest, for years 2011–2013. (XLSX)
Data
Complete sample inventory detailing the fish number, sampling date, associated metrics, histopathological and molecular results, and analysis carried out for each fish collected. (XLSX)
Data
Molecular Phylogenetic analysis of Piscine orthoreovirus segment S1 isolates from Canada, Chile, Norway and Japan by Maximum Likelihood method. Phylogenetic relationships were inferred by using the Maximum Likelihood method based on the Kimura 2-parameter model. Bootstrap analysis (1,000 replicates) was used to validate tree topology. The percentag...
Data
Ordinal logistic regression modeling the 3-category heart lesion score (HS0 = total heart score≤1, HS1 = total heart score >1 and <4, and HS2 = total heart score ≥4) from 178 fish (samples collected from Live, Moribund, or Dead fish) taken over five sampling events from one farm in British Columbia, Canada. Heart tissues from each fish were tested...
Data
List of all the infective agents tested through Fluidigm BioMark™ microfluidics-based qPCR system. (XLSX)
Data
Immunohistochemical detection of PRV using PRV Sigma-1 antibody on the brain. A) Interstitial cells of the saccus vasculosus (arrows) show presence of PRV (red—Novared). Bar scale 50 μm. B) PRV is also present in the innermost layer of cells lining the third ventricle (arrows) (red—Novared). Bar scale 100 μm. (TIF)
Article
Biosecurity has been identified as a core concept for Asian freshwater aquaculture for purposes of food safety, aquaculture sustainability, and trade. To our knowledge, no published studies have evaluated producers' knowledge of biosecurity and biosecurity practices in Chinese aquaculture. We carried out a questionnaire-based knowledge, attitudes,...
Article
The Standards for the Reporting of Diagnostic Accuracy (STARD) statement, which was recently updated to the STARD2015 statement, was developed to encourage complete and transparent reporting of test accuracy studies. Although STARD principles apply broadly, the checklist is limited to studies designed to evaluate the accuracy of tests when the dise...
Article
Historically, serological tests for finfish diseases have been underused when compared with their use in terrestrial animal health. For years the nonspecific immune response in fish was judged to make serology unreliable and inferior to the direct measurement of agent analytes. We conducted a systematic review of peer-reviewed publications that rep...
Article
Full-text available
The global distribution of bluetongue virus (BTV) has been changing recently, perhaps as a result of climate change. To evaluate the risk of BTV infection and transmission in a BTV-endemic region of California, sentinel dairy cows were evaluated for BTV infection, and populations of Culicoides vectors were collected at different sites using carbon...
Data
Fitted seasonal pattern for relative abundance of Culicoides sonorensis per CO2-baited trap-night. (TIF)
Article
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Freshwater aquaculture in China is expanding and intensifying as this country experiences rapid economic growth, and understanding farm-level profitability is necessary if farmers are to make reasonable decisions about their production plans. We conducted a survey of yellow catfish farmers in 2014 in Guangdong and Zhejiang provinces in order to est...
Article
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Customers of finfish in China place a high priority on healthy fish at the point of sale but factors that increase the risk of morbidity and mortality during transportation have had limited study. We designed a case study to investigate variation of mortalities claimed by customers receiving fish at markets with above-normal mortalities. We used da...
Technical Report
Full-text available
microbe surveillance research was undertaken. Forty-seven assays to 46 microbes suspected or known to cause disease in salmon worldwide were developed or derived from the literature, and appropriate controls obtained. The evaluation completed stage-1 of the OIE pathway, ascertaining the analytical sensitivity, analytical specificity, and repeatabil...
Article
The area under the receiver operating characteristic (ROC) curve (AUC) is used as a performance metric for quantitative tests. Although multiple biomarkers may be available for diagnostic or screening purposes, diagnostic accuracy is often assessed individually rather than in combination. In this paper, we consider the interesting problem of combin...
Article
In biosecurity-related activities in aquaculture, diagnostic tests are commonly used to (1) demonstrate freedom from infection in a facility, (2) screen aquatic animals prior to introduction to the receiving facility, (3) detect infected animals as early as possible during a quarantine period, and (4) confirm suspicious or clinical case(s). The int...
Article
The objective of this cohort study was to evaluate whether rearing dairy heifers at different premises than the dairy of origin (off-site) reduced the risk of Mycobacterium avium ssp. paratuberculosis (MAP) infection more effectively than rearing on the dairy of origin (on-site). From 2003 to 2005, 3 cohorts of Jersey heifers were born on a single...
Article
Full-text available
Complete and transparent reporting of key elements of diagnostic accuracy studies for infectious diseases in cultured and wild aquatic animals benefits end-users of these tests, enabling the rational design of surveillance programs, the assessment of test results from clinical cases and comparisons of diagnostic test performance. Based on deficienc...
Article
Indices of test accuracy, such as diagnostic sensitivity and specificity, are important considerations in test selection for a defined purpose (e.g., screening or confirmation) and affect the interpretation of test results. Many biomedical journals recommend that authors clearly and transparently report test accuracy studies following the Standards...
Article
Reasons for performing studyKnowledge of the site distribution of ligamentous injuries facilitates clinical diagnosis of suspensory apparatus conditions.Objective To determine if lesions within the suspensory ligament (SL) and distal ligaments of the proximal sesamoid bones (DSLs) were associated with suspensory apparatus failure or metacarpal late...
Article
Full-text available
Bluetongue virus (BTV) is the cause of an economically important arboviral disease of domestic and wild ruminants. The occurrence of BTV infection of livestock is distinctly seasonal in temperate regions of the world, thus we determined the dynamics of BTV infection (using BTV-specific real time reverse transcriptase polymerase chain reaction) amon...
Article
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Background Aleutian mink disease virus (AMDV) is the cause of a chronic immune complex disease, Aleutian disease (AD), which is common in mink-producing countries. In 2005, implementation of an AMDV eradication programme in Finland created a need for an automated high-throughput assay. The aim of this study was to validate an AMDV-VP2 -recombinant...
Article
African horse sickness (AHS) is typically a highly fatal disease in susceptible horses and vaccination is currently used to prevent the occurrence of disease in endemic areas. Similarly, vaccination has been central to the control of incursions of African horse sickness virus (AHSV) into previously unaffected areas and will likely play a significan...
Article
Objective —To evaluate associations between Mycobacterium avium subsp paratuberculosis (MAP) and caudal fold tuberculin (CFT) test results in cattle. Design —Longitudinal and cross-sectional evaluations. Animals —1 California (approx 3,600 cows) and 3 Colorado (approx 640, 1,190, and 1,480 cows) dairy herds considered free of Mycobacterium bovis in...
Article
Full-text available
The Sacramento (northern Central) Valley of California (CA) has a hot Mediterranean climate and a diverse ecological landscape that is impacted extensively by human activities, which include the intensive farming of crops and livestock. Waste-water ponds, marshes, and irrigated fields associated with these agricultural activities provide abundant l...
Article
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In this paper, we develop a class of semi-parametric statistical models that can be used for the important problem of analyzing longitudinal biomarker data with the purpose of quantifying their diagnostic capabilities, as a function of time from infection. We focus on the complicated problem where there is no gold standard assessment of the actual...
Article
Weaning, particularly the widespread practice of abrupt separation of the mare and foal, has been shown to be a stressful event for horses. Physiological changes in foals measured after weaning include increased blood cortisol concentrations and a subsequent decrease in cell-mediated immune responses. In the randomized, double-blinded, placebo-cont...
Article
Objective: To estimate the prevalence of radiographic abnormalities (lesions) in Thoroughbred racehorses at 2-year-old in-training sales and determine whether these lesions and 1-furlong presale workout times were associated with subsequent racing performance. Design: Retrospective cohort study. Animals: 953 Thoroughbreds. Procedures: Reposi...
Article
Objective: To define scintigraphic, physical examination, and scapular ultrasonographic findings consistent with bone fragility syndrome (BFS) in horses; develop indices of BFS severity; and assess accuracy of physical examination, scapular ultrasonography, and serum biomarkers for BFS diagnosis. Design: Prospective case-control study. Animals:...
Article
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Objective: To estimate likelihood ratios (LRs) of correctly identifying internal Corynebacterium pseudotuberculosis infection in horses by measurement of antibody titers via serum synergistic hemolysis inhibition (SHI) testing. Design: Retrospective case-control study. Animals: 170 horses (171 records; 92 cases of C pseudotuberculosis infectio...
Article
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Cheetahs (Acinonyx jubatus) are a highly threatened species because of habitat loss, human conflict, and high prevalence of disease in captivity. An epidemic of feline infectious peritonitis and concern for spread of infectious disease resulted in decreased movement of cheetahs between U.S. zoological facilities for managed captive breeding. Identi...
Article
Identification of risk factors for subclinical intramammary infections (IMI) in dairy goats should contribute to improved udder health. Intramammary infection may be diagnosed by bacteriological culture or by somatic cell count (SCC) of a milk sample. Both bacteriological culture and SCC are imperfect tests, particularly lacking sensitivity, which...
Article
Reasons for performing study: African horse sickness is an insect-transmitted, noncontagious disease of equids caused by African horse sickness virus (AHSV). Mortality can exceed 90% in fully susceptible horse populations. A live-attenuated (modified live) cell-culture-adapted (MLV) polyvalent AHSV vaccine is widely used to control African horse s...
Article
Testing of composite fecal (environmental) samples from high traffic areas in dairy herds has been shown to be a cost-effective and sensitive method for classification of herd status for Mycobacterium avium subsp. paratuberculosis (MAP). In the National Animal Health Monitoring System's (NAHMS) Dairy 2007 study, the apparent herd-level prevalence o...
Article
Reasons for performing study: Identification of exercise history patterns that are related to catastrophic scapular fracture will facilitate prevention of racehorse fatalities. Objectives: To determine if exercise patterns are associated with scapular fracture in Thoroughbred (TB) and Quarter Horse (QH) racehorses. Methods: High-speed exercise...
Article
Full-text available
Diagnostic strategies to detect Mycobacterium avium subsp. paratuberculosis (MAP) super-shedder cows in dairy herds have been minimally studied. The objective of the current study was to compare the cost-effectiveness of strategies for identification of MAP super-shedders on a California dairy herd of 3,577 cows housed in free-stall pens. Eleven st...
Article
To develop a better system for classification of herd infection status for paratuberculosis (Johne's disease [JD]) in US cattle herds on the basis of the risk of potential transmission of Mycobacterium avium subsp paratubeculosis. Simulated data for herd size and within-herd prevalence; sensitivity and specificity for test methods obtained from con...
Article
The objectives of the current study were to estimate the sensitivity and specificity of three real-time polymerase chain reaction (PCR) tests for diagnosis of feline immunodeficiency virus (FIV) infection in domestic cats, both individually and when interpreted in series with one of two serological tests, separately in populations of cats at low an...
Article
Bluetongue is an economically important arboviral disease of ruminants that is transmitted by hematophagous Culicoides midges. In light of dramatic recent changes in the global distribution of bluetongue virus (BTV), the goals of this study were to re-evaluate the prevalence of BTV infection of cattle and abundance of Culicoides midges on individua...
Article
West Nile virus (WNV) was first documented in North America in New York City in 1999. Several deaths attributable to WNV have been reported in captive thick-billed parrots (Rhynchopsitta pachyrhyncha), an endangered psittacine native to North America. The serologic responses in 12 captive adult thick-billed parrots after a series of three initial W...
Article
The Standards for Reporting of Diagnostic Accuracy (STARD) statement (www.stard-statement.org) was developed to encourage complete and transparent reporting of key elements of test accuracy studies in human medicine. The statement was motivated by widespread evidence of bias in test accuracy studies and the finding that incomplete or absent reporti...
Article
Full-text available
Bluetongue is a vector-borne viral disease that affects domestic and wild ruminants. The epidemiology of this disease has recently changed, with occurrence in new geographic areas. Various real-time quantitative reverse transcription polymerase chain reaction (real-time qRT-PCR) assays are used to detect Bluetongue virus (BTV); however, the impact...
Article
Full-text available
Many animal health, welfare and food safety databases include data on clinical and test-based disease diagnoses. However, the circumstances and constraints for establishing the diagnoses vary considerably among databases. Therefore results based on different databases are difficult to compare and compilation of data in order to perform meta-analysi...
Article
Diagnostic test evaluations (DTEs) for chronic infections are challenging because a protracted incubation period has to be considered in the design of the DTE, and the adverse effects of infection may be widespread and progressive over an animal's entire life. Frequently, the specific purpose of the test is not formally considered when a test is ev...
Article
To improve the understanding of exercise related sudden death in Thoroughbred racehorses. To describe the post mortem findings in cases of sudden death associated with exercise in 268 Thoroughbred racehorses. Gross and histological post mortem findings of 268 cases of sudden death were collated and reviewed. Cases originated from 6 racing jurisdict...
Article
Over a 2-yr study period, we investigated possible endogenous transplacental transmission of Neospora hughesi in 74 mare and foal pairs following the diagnosis of neuronal neosporosis in a weanling foal. Presuckle and postsuckle serum of each foal, serum and colostrum of each periparturient mare, and serum of each mare and foal pair, collected at 3...