Browsing by Author "Mardones, Fernando O."

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    50 years of cetacean strandings reveal a concerning rise in Chilean patagonia
    (2020) Alvarado-Rybak, Mario; Toro, Frederick; Escobar-Dodero, Joaquín; Kinsley, Amy C.; Sepúlveda, Maximiliano A.; Capella, Juan; Azat, Claudio; Cortés Hinojosa, Galaxia Andrea; Zimin Veselkoff, Natalia; Mardones, Fernando O.
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    An assessment of the owned canine and feline demographics in Chile: registration, sterilization, and unsupervised roaming indicators
    (2024) Atero Fredericksen, Nicolhole Alejandra; Córdova Bührle, Francisca; Salgado Caxito, Marília; Benavides, Julio A.; Fernández, Miriam; Diethelm Varela, Benjamín; Ramos, Romina; Sapiente Aguirre, Claudia; Trujillo, Florencia; Dürr, Salome; Mardones, Fernando O.
    The global rise in companion animal populations, particularly dogs and cats, is driven by emotional and social benefits for owners, and their population management is becoming critically important to avoid a plethora of adverse effects on themselves, humans, and wildlife. We estimated the size and density of the owned canine and feline population in Chile and evaluated the status of microchipping, registration, sterilization rates, and the proportion of owned animals that roam unsupervised. A cross-sectional household survey in 36 districts was conducted and standard inferential statistics was employed to analyze differences between cats and dogs, sexes within each species, and between rural and urban areas. Additionally, two negative binomial models with mixed effects were developed to predict the number of dogs and cats per households. Two methods were used to compare population size estimates at the country level, multiplying: (1) the estimated mean number of companion animals per household by the estimated number of households at the country level, and (2) the estimated human:dog and human:cat ratios by the total human population. The study involved 6333 respondents, of which 76% (74% urban; 83% rural) owned companion animals (dogs and/or cats). Individuals in rural multi-person households increase the probability of owning dogs and/or cats. Additionally, women exhibit a greater inclination towards cat and dog ownership compared to men, while those over 30 years old demonstrate lower rates of companion animal ownership in contrast to the 18–30 age group for both species. The overall human:dog and human:cat ratios estimated were 2.7:1, and 6.2:1, respectively. The estimated total number of owned dogs and cats in Chile ranged from 9.6 to 10.7 million, depending on the methodological approach, while national median density of companion animals was 12 dogs per km2 (ranging from 0.02 to 7232) and 5 cats per km2 (ranging from 0.01 to 3242). This nationwide study showed one of the highest percentages of households with companion animals in Latin America and relatively low registration and sterilization rates, highlighting the need to strength long-term public policies to control populations of companion animals and promote responsibility in pet ownership.
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    Bayesian estimation of diagnostic sensitivity and specificity of a qPCR and a bacteriological culture method forPiscirickettsia salmonisin farmed Atlantic salmon (Salmo salarL.) in Chile
    (WILEY, 2020) Laurin, Emilie; Gardner, Ian A.; Pena, Andrea; Rozas Serri, Marco; Gayosa, Jorge; Heise, Joaquin Neumann; Mardones, Fernando O.
    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 latent class models to estimate diagnostic sensitivity (DSe) and specificity (DSp) of qPCR and culture using separate two-test, single-population models for three farms (n = 148, 151, 44). Informative priors were used forDSp(culture (beta(999,1); qPCR (beta(98,2)), and flat priors (beta 1,1) forDSeand prevalence. Models were run for liver and kidney tissues combined and separately, based on the presence of selected gross-pathological signs. Across all models, qPCRDSewas 5- to 30-fold greater than for culture. Combined-tissue qPCR medianDSewas highest in Farm 3 (sampled duringP. salmonisoutbreak (DSe = 97.6%)) versus Farm 1 (DSe = 85.6%) or Farm 2 (DSe = 83.5%), both sampled before clinical disease. MedianDSeof qPCR was similar for liver and kidney, but higher when gross-pathological signs were evident at necropsy. HighDSeandDSpand rapid turnaround-time indicate that the qPCR is fit for surveillance programmes and diagnosis during an outbreak. Targeted testing of salmon with gross-pathological signs can enhanceDSe.
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    Bioclimatic and anthropogenic variables shape the occurrence of Batrachochytrium dendrobatidis over a large latitudinal gradient
    (NATURE PORTFOLIO, 2021) Alvarado Rybak, Mario; Lepe Lopez, Manuel; Penafiel Ricaurte, Alexandra; Valenzuela Sanchez, Andres; Valdivia, Catalina; Mardones, Fernando O.; Bacigalupe, Leonardo D.; Puschendorf, Robert; Cunningham, Andrew A.; Azat, Claudio
    Amphibian chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has caused the greatest known loss of biodiversity due to an infectious disease. We used Bd infection data from quantitative real-time PCR (qPCR) assays of amphibian skin swabs collected across Chile during 2008-2018 to model Bd occurrence with the aim to determine bioclimatic and anthropogenic variables associated with Bd infection. Also, we used Bd presence/absence records to identify geographical Bd high-risk areas and compare Bd prevalence and infection loads between amphibian families, ecoregions, and host ecology. Data comprised 4155 Bd-specific qPCR assays from 162 locations across a latitudinal gradient of 3700 km (18 degrees to 51 degrees S). Results showed a significant clustering of Bd associated with urban centres and anthropogenically highly disturbed ecosystems in central-south Chile. Both Bd prevalence and Bd infection loads were higher in aquatic than terrestrial amphibian species. Our model indicated positive associations of Bd prevalence with altitude, temperature, precipitation and human-modified landscapes. Also, we found that macroscale drivers, such as land use change and climate, shape the occurrence of Bd at the landscape level. Our study provides with new evidence that can improve the effectiveness of strategies to mitigate biodiversity loss due to amphibian chytridiomycosis.
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    Canine olfactory detection of SARS-CoV-2-infected humans—a systematic review
    (Elsevier Inc., 2023) Meller, Sebastián; Caraguel, Charles; Twele, Friederike; Charalambous, Marios; Schoneberg, Clara; Chaber, Anne-Lise; Desquilbet, Loïc; Grandjean, Dominique; Mardones, Fernando O.; Kreienbrock, Lothar de la Rocque; de la Rocque, Stéphane; Volk, Holger
    To complement conventional testing methods for severe acute respiratory syndrome coronavirus type 2 infections, dogs’ olfactory capability for true real-time detection has been investigated worldwide. Diseases produce specific scents in affected individuals via volatile organic compounds. This systematic review evaluates the current evidence for canine olfaction as a reliable coronavirus disease 2019 screening tool. Methods: Two independent study quality assessment tools were used: the QUADAS-2 tool for the evaluation of laboratory tests’ diagnostic accuracy, designed for systematic reviews, and a general evaluation tool for canine detection studies, adapted to medical detection. Various study design, sample, dog, and olfactory training features were considered as potential confounding factors. Results: Twenty-seven studies from 15 countries were evaluated. Respectively, four and six studies had a low risk of bias and high quality: the four QUADAS-2 nonbiased studies resulted in ranges of 81%–97% sensitivity and 91%–100% specificity. The six high-quality studies, according to the general evaluation system, revealed ranges of 82%–97% sensitivity and 83%–100% specificity. The other studies contained high bias risks and applicability and/or quality concerns. Conclusions: Standardization and certification procedures as used for canine explosives detection are needed for medical detection dogs for the optimal and structured usage of their undoubtful potential.
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    Cost-effectiveness of longitudinal surveillance for Piscirickettsia salmonis using qPCR in Atlantic salmon farms (Salmo salar) in Chile
    (2020) Delphino, M. K. V. C.; Mardones, Fernando O.; Neumann Heise, J.; Gallardo, A.; Jimenez, D.; Peña, A.; Rozas Serri, M.; Gardner, I. A.
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    Epidemiological Factors Associated With Caligus rogercresseyi Infection, Abundance, and Spatial Distribution in Southern Chile
    (FRONTIERS MEDIA SA, 2021) Lepe Lopez, Manuel; Escobar Dodero, Joaquin; Rubio, Daniel; Alvarez, Julio; Zimin Veselkoff, Natalia; Mardones, Fernando O.
    Sea lice (Caligus rogercresseyi) are external parasites that affect farmed salmonids in Chile, and the scale of their sanitary and economic impact cannot be overstated. Even though space-time patterns suppose parasite aggregation, specific locations related to different infestation levels, as well as their associated factors across the geographic range involved, had not been investigated as of the writing of the present article. The understanding of the effects and factors entailed by the presence of C. rogercresseyi may be deemed a key element of Integrated Pest Management (IPM). In the present study, the multivariate spatial scan statistic was used to identify geographic areas and times of C. rogercresseyi infestation and to estimate the factors associated with such patterns. We used official C. rogercresseyi monitoring data at the farm level, with a set of 13 covariates, to provide adjustment within the analyses. The analyses were carried out for a period of 5 years (2012-2016), and they included three fish species (Salmo salar, Oncorhynchus mykiss, and Oncorhynchus kisutch) in order to assess the consistency of the identified clusters. A retrospective multinomial, spatial, and temporal scan test was implemented to identify farm clusters of either of the different categories of C. rogercresseyi infested farms: baseline, medium, and high, based on the control chemical threshold established by the health authority. The baseline represents adequate farm performance against C. rogercresseyi infestation. Then, production and environmental factors of the medium and high infestation farms were compared with the baseline using regression techniques. The results revealed a total of 26 clusters (p < 0.001), of which 12 correspond to baseline, 1 to medium, and the remaining 13 to high infestation clusters. In general, baseline clusters are detected in a latitudinal gradient on estuarine areas, with increasing relative risks to complex island water systems. There is a spatial structure in specific sites, north of Los Lagos Region and central Aysen Region, with high infestation clusters and epidemic peaks during 2013. In addition, average weight, salmon species, chemotherapeutants, latitude, temperature, salinity, and year category are factors associated with these C. rogercresseyi patterns. Recommendations for an IPM plan are provided, along with a discussion that considers the involvement of stock density thresholds by salmon species and the spatial structure of the efficacy of chemical control, both intended to avoid the advance of resistance and to minimize environmental residues.
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    Epidemiological investigation of the re-emergence of infectious salmon anemia in Chile
    (2009) Mardones, Fernando O.
    Reports from surveillance activities were analyzed to determine the epidemiology of the re-emergence of infectious salmon anemia virus (ISAV) in Atlantic salmon farms in Chile. The epidemic and spatial and spatiotemporal patterns were described, taking into account commercial compartmentalization of the farms. During the 64 wk study period, 76 ISAV-infected salmon farms, representing 17 companies, were reported in 65% of the management geographic zones of the 10th region in southern Chile. Approximately 20% of the farms at risk became infected, with the incidence rate increasing slightly over time. Results from epidemic analyses and observed spatial and spatiotemporal patterns suggested an initial dispersal and subsequent clustering of cases around the index case (IC) in a propagated epidemic mode. Results suggested that delayed depopulation may have been a key factor in the spread and persistence of ISAV. Clustering of cases supported the assumption that passive transmission in seawater from ISAV-infected farms (proximity) is a critical factor in controlling disease. The re-emergence of ISAV in Chile has resulted in one of the largest ISAV epidemics reported in the world and this study generates new hypotheses and provides useful information for spatial disease control planning in salmon farming areas.
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    Epidemiological investigation of the re-emergence of infectious salmon anemia in Chile
    (2009) Mardones, Fernando O.
    Reports from surveillance activities were analyzed to determine the epidemiology of the re-emergence of infectious salmon anemia virus (ISAV) in Atlantic salmon farms in Chile. The epidemic and spatial and spatiotemporal patterns were described, taking into account commercial compartmentalization of the farms. During the 64 wk study period, 76 ISAV-infected salmon farms, representing 17 companies, were reported in 65% of the management geographic zones of the 10th region in southern Chile. Approximately 20% of the farms at risk became infected, with the incidence rate increasing slightly over time. Results from epidemic analyses and observed spatial and spatiotemporal patterns suggested an initial dispersal and subsequent clustering of cases around the index case (IC) in a propagated epidemic mode. Results suggested that delayed depopulation may have been a key factor in the spread and persistence of ISAV. Clustering of cases supported the assumption that passive transmission in seawater from ISAV-infected farms (proximity) is a critical factor in controlling disease. The re-emergence of ISAV in Chile has resulted in one of the largest ISAV epidemics reported in the world and this study generates new hypotheses and provides useful information for spatial disease control planning in salmon farming areas.
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    Hydrodynamic connectivity, water temperature, and salinity are major drivers of piscirickettsiosis prevalence and transmission among salmonid farms in Chile
    (2020) Bravo, F.; Sidhu, J. P. S.; Bernal, P.; Bustamante, R. H.; Condie, S.; Gorton, B.; Herzfeld, M.; Jimenez, D.; Mardones, Fernando O.; Rizwi, F.; Steven, A. D. L.
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    Method for lineage typing of epidemic Renibacterium salmoninarum in Chilean salmon farms
    (John Wiley and Sons Inc, 2023) Mora Salas, Patricia; Zapararte, Sebastián; Villouta, Pamela; Araya León, Henry; Avendaño Herrera, Rubén; Mardones Loyola, Fernando Otoniel; Mardones, Fernando O.
    Renibacterium salmoninarum (Rs) is the etiological agent of bacterial kidney disease (BKD), which significantly affects farmed and wild salmonids worldwide. Although the whole genome of Rs (~3.1 million nucleotides) is highly conserved, genomic epidemiology analyses have identified four sub-lineages from Chilean isolates. A total of 94 Rs genomes from the BIGSdb aquaculture database were aligned and compared using bioinformatics tools, identifying 2199 independent single-nucleotide polymorphisms (SNPs) spread along the genome. A detailed analysis of the distribution of the SNPs showed five local zones of a length in the range of 10–15 kbp that should be used to unambiguously identify a specific sub-lineage. Based on the Rs type strain DSM 20767T, we designed multiplex PCR primers that produce specific amplification products which were further sequenced by the Sanger method to obtain the genotype of the sub-lineage. For the genetic typing, we evaluated 27 Rs isolates recovered from BKD outbreaks from different fish species and regions of Chile. Based on the findings reported here, we propose the PCR approach as a valuable tool for the rapid and reliable studying of the relationships between Rs isolates and the different sub-lineages without requiring the sequencing of the entire genome.
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    Parameterization of the duration of infection stages of serotype O foot-and-mouth disease virus: an analytical review and meta-analysis with application to simulation models
    (2010) Mardones, Fernando O.
    Foot-and-mouth disease (FMD) is considered one of the most important infectious diseases of livestock because of the devastating economic consequences that it inflicts in affected regions. The value of critical parameters, such as the duration of the latency or the duration of the infectious periods, which affect the transmission rate of the FMD virus (FMDV), are believed to be influenced by characteristics of the host and the virus. Disease control and surveillance strategies, as well as FMD simulation models, will benefit from improved parameter estimation. The objective of this study was to quantify the distributions of variables associated with the duration of the latency, subclinical, incubation, and infectiousness periods of FMDV transmission. A double independent, systematic review of 19 retrieved publications reporting results from experimental trials, using 295 animals in four reference laboratories, was performed to extract individual values related to FMDV transmission. Probability density functions were fitted to data and a set of regression models were used to identify factors associated with the assessed parameters. Latent, subclinical, incubation, and infectious periods ranged from 3.1 to 4.8, 2 to 2.3, 5.5 to 6.6, and 3.3 to 5.7 days, respectively. Durations were significantly (p < 0.05) associated independently with route of exposure, type of donor, animal species, strains, characteristics of sampling, and clinical signs. These results will contribute to the improvement of disease control and surveillance strategies and stochastic models used to simulate FMD spread and, ultimately, development of cost-effective plans to prevent and control the potential spread of the disease in FMD-free regions of the world.
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    Parameterization of the duration of infection stages of serotype O foot-and-mouth disease virus: an analytical review and meta-analysis with application to simulation models
    (2010) Mardones, Fernando O.
    Foot-and-mouth disease (FMD) is considered one of the most important infectious diseases of livestock because of the devastating economic consequences that it inflicts in affected regions. The value of critical parameters, such as the duration of the latency or the duration of the infectious periods, which affect the transmission rate of the FMD virus (FMDV), are believed to be influenced by characteristics of the host and the virus. Disease control and surveillance strategies, as well as FMD simulation models, will benefit from improved parameter estimation. The objective of this study was to quantify the distributions of variables associated with the duration of the latency, subclinical, incubation, and infectiousness periods of FMDV transmission. A double independent, systematic review of 19 retrieved publications reporting results from experimental trials, using 295 animals in four reference laboratories, was performed to extract individual values related to FMDV transmission. Probability density functions were fitted to data and a set of regression models were used to identify factors associated with the assessed parameters. Latent, subclinical, incubation, and infectious periods ranged from 3.1 to 4.8, 2 to 2.3, 5.5 to 6.6, and 3.3 to 5.7 days, respectively. Durations were significantly (p < 0.05) associated independently with route of exposure, type of donor, animal species, strains, characteristics of sampling, and clinical signs. These results will contribute to the improvement of disease control and surveillance strategies and stochastic models used to simulate FMD spread and, ultimately, development of cost-effective plans to prevent and control the potential spread of the disease in FMD-free regions of the world.
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    Preventive healthcare among dogs and cats in Chile is positively associated with emotional owner-companion animal bond and socioeconomic factors
    (2023) Salgado Caxito, Marília; Benavides, Julio A.; Atero, Nicolhole; Córdova-Bürhle, Francisca; Ramos, Romina; Fernández, Miriam; Sapiente Aguirre, Claudia; Mardones, Fernando O.
    Global companion animal population has been increasing as well as the number of dogs and cats being considered as a family member. However, it is unclear whether this close relationship could be associated with higher preventive healthcare in companion animals. Using data from 7,048 questionnaires of dogs and 3,271 of cats from the First National Study on Responsible Companion Animal Ownership, we estimated the proportion of preventive healthcare in companion animals of Chile. We also conducted a general linear mixed-effect regression model to identify socioeconomic factors and indicators of the emotional owners-companion animal bond that could influence owners’ practices related to vaccination, parasite control, and veterinary visits. Based on the owner’s answers, Chile has a satisfactory overall rates of parasite control (71%) and annual veterinary visits (65%) but a low vaccination coverage of both dogs (39%) and cats (25%). ‘Purebred’, ‘live in urban areas’, ‘acquired by monetary compensation’, and ‘dog species’ were associated with a higher probability of preventive healthcare in companion animals. Conversely, this probability was lower among senior animals compared to adults, males, and those owned by the Silent Generation or Baby Boomers (i.e., owners born before 1964). ‘Sleeping inside’, ‘acquired for an emotional reason’ (e.g., companionship), and ‘considered a family member’ were positively associated with at least one of assessed preventive measures. Our findings suggest that emotional owner-companion animal bonds could positively impact the frequency and quality of preventive healthcare in dogs and cats. However, owners who totally disagreed that a companion animal is a “family member” were also associated with a higher likelihood of vaccination uptake and veterinary visits for their animals. This highlights that owner’s compliance with veterinary preventive healthcare is multifactorial. Chile has a high prevalence of infectious diseases circulating among dogs and cats and increasingly close contacts between owners and companion animals due to emotional bonds. Thus, our study calls for One Health approaches to reduce the risks of cross-species disease transmission. Specifically, increasing vaccination coverage of companion animals in Chile is the most urgent preventive measure needed, especially among cats, males, and older animals. Expand preventive healthcare among dogs and cats will promote public and animal health, including local wildlife that is susceptible to infectious diseases circulating in companion animals.
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    Qualitative Risk Assessment for Antimicrobial Resistance among Humans from Salmon Fillet Consumption Due to the High Use of Antibiotics against Bacterial Infections in Farmed Salmon
    (MDPI, 2022) Salgado-Caxito, Marilia; Zimin-Veselkoff, Natalia; Adell, Aiko D.; Olivares-Pacheco, Jorge; Mardones, Fernando O.
    Background: Worldwide, aquaculture is considered as a hotspot environment for antimicrobial resistance (AMR) due to the intense use of antibiotics in its productive systems. Chile is the second largest producer of farmed salmon worldwide, and tons of antibiotics are used to control bacterial diseases, such as Salmon Rickettsial Syndrome (SRS) and Bacterial Kidney Disease (BKD). However, studies determining the risk of consuming salmon fillets that have been treated with antibiotics during the salmon production are limited. Consulting leading experts in the field could provide a knowledge base to identify and address this question and research gaps. Methods: Multisectoral risk perception of AMR through salmon fillet consumption was evaluated by eliciting expert data obtained through discussions during a workshop and from questionnaires given to experts from academia (n = 15, 63%), the public sector (n = 5, 21%), and the salmon industry (n = 4, 17%). Results: The qualitative risk analysis suggested an overall 'low' probability of AMR acquisition by consumption of salmon fillet that had been treated during the production cycle. The risk perception varied slightly between production stages in freshwater and seawater. In consensus with all sectors, this overall 'low', but existing, risk was probably associated with bacterial infections and the use of antibiotics. Conclusions: As it is essential to reduce the use of antibiotics in the Chilean salmon industry, this intersectoral approach and consensual results could favor effective implementation of targeted initiatives for the control and prevention of major bacterial diseases.
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    Risk factors associated with Tritrichomonas foetus infection in beef herds in the Province of Buenos Aires, Argentina
    (2008) Mardones, Fernando O.
    Bovine trichomonosis (BT) is a contagious disease, characterized by reproductive failure, embryonic losses, infertility, and abortions, which directly impacts the reproductive performance of cattle. In this cross-sectional questionnaire-based study, 56 veterinarians provided information on the geographic location and on the demographic, husbandry, and sanitary characteristics of 173 beef herds located in 26 (21%) counties of the Province of Buenos Aires, Argentina. Herds rearing beef cattle (OR=2.5, 95% CI=1.0, 6.3), with low pregnancy rate in cows (
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    The COVID-19 Pandemic and Global Food Security
    (2020) Mardones, Fernando O.; Rich, K. M.; Boden, L. A.; Moreno Switt, Andrea Isabel; Caipo, M. L.; Zimin Veselkoff, Natalia; Alateeqi, A. M.; Baltenweck, I.
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    Tracing Listeria monocytogenes contamination in artisanal cheese to the processing environments in cheese producers in southern Chile
    (2020) Barría, C.; Singer, R. S.; Bueno, I.; Estrada, E.; Rivera, D.; Ulloa, S.; Fernández, J.; Mardones, Fernando O.; Moreno Switt, A. I.