Publications by authors named "Terra Kelly"

38 Publications

Early detection of wildlife morbidity and mortality through an event-based surveillance system.

Proc Biol Sci 2021 Jul 14;288(1954):20210974. Epub 2021 Jul 14.

EpiCenter for Disease Dynamics, One Health Institute, School of Veterinary Medicine, University of California, Davis, CA, USA.

The ability to rapidly detect and respond to wildlife morbidity and mortality events is critical for reducing threats to wildlife populations. Surveillance systems that use pre-diagnostic clinical data can contribute to the early detection of wildlife morbidities caused by a multitude of threats, including disease and anthropogenic disturbances. Here, we demonstrate proof of concept for use of a wildlife disease surveillance system, the 'Wildlife Morbidity and Mortality Event Alert System', that integrates pre-diagnostic clinical data in near real-time from a network of wildlife rehabilitation organizations, for early and enhanced detection of unusual wildlife morbidity and mortality events. The system classifies clinical pre-diagnostic data into relevant clinical classifications based on a natural language processing algorithm, generating alerts when more than the expected number of cases is recorded across the rehabilitation network. We demonstrated the effectiveness and efficiency of the system in alerting to events associated with both common and emerging diseases. Tapping into this readily available unconventional general surveillance data stream offers added value to existing wildlife disease surveillance programmes through a relatively efficient, low-cost strategy for the early detection of threats.
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http://dx.doi.org/10.1098/rspb.2021.0974DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8277475PMC
July 2021

Strategies to Upgrade Animal Health Delivery in Village Poultry Systems: Perspectives of Stakeholders From Northern Ghana and Central Zones in Tanzania.

Front Vet Sci 2021 7;8:611357. Epub 2021 Jun 7.

International Livestock Research Institute, Kampala, Uganda.

Village chicken production holds much potential for the alleviation of malnutrition and poverty in rural communities in Africa. Owing to their subsistence nature, however, such systems are rife with infectious poultry diseases such as Newcastle disease (ND). Strategies common for the management of ND and other poultry diseases in intensive production systems, including vaccination and biosecurity measures, have seen limited success in the village production systems. New approaches are needed that can successfully deliver animal health inputs and services for the effective management of poultry health challenges in low-input systems. Our study utilized focus group discussions with men and women farmers as well as other poultry value chain actors such as input suppliers, live bird traders and processed poultry meat retailers, to investigate potential options for delivery of animal health care to village poultry systems in northern Ghana and central Tanzania. ND was commonly reported as a major disease constraint in the study sites of the two countries, with resulting fatalities particularly impactful on men and women producers and on traders. We therefore also conducted interviews that focused specifically on the gender component of village chicken production. The key health related challenges prioritized by women and men participants included limited access to, and poor quality of, vaccines and veterinary drugs, a shortage of veterinary officers, and insufficient knowledge and training of farmers on flock management practices. Women, more than men, emphasized the difficulties of accessing poultry health services. Our assessments suggest that for poultry health care delivery in the studied communities to be effective, there is need to improve the supply of good quality drugs and vaccines in rural areas, respond to the needs of both men and women, and recognize the different incentives for farmers, traders and other value chain actors. Community-based approaches and increased use of ICT technology such as mobile phones have much to offer in this regard.
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http://dx.doi.org/10.3389/fvets.2021.611357DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8215278PMC
June 2021

Distinct transcriptomic response to Newcastle disease virus infection during heat stress in chicken tracheal epithelial tissue.

Sci Rep 2021 Apr 2;11(1):7450. Epub 2021 Apr 2.

Feed the Future Innovation Lab for Genomics to Improve Poultry, University of California, Davis, CA, 95616, USA.

Newcastle disease (ND) has a great impact on poultry health and welfare with its most virulent (velogenic) strain. In addition, issues exacerbated by the increase in global temperatures necessitates a greater understanding of the host immune response when facing a combination of biotic and abiotic stress factors in poultry production. Previous investigations have revealed that the host immune response is tissue-specific. The goal of this study was to identify genes and/or signaling pathways associated with immune response to NDV (Newcastle disease virus) in the trachea, an essential organ where NDV replicate after the infection, by profiling the tissue specific transcriptome response in two genetically distinct inbred chicken lines when exposed to both abiotic and biotic stressors. Fayoumis appear to be able to respond more effectively (lower viral titer, higher antibody levels, immune gene up-regulation) and earlier than Leghorns. Our results suggest NDV infection in Fayoumis appears to elicit proinflammatory processes, and pathways such as the inhibition of cell viability, cell proliferation of lymphocytes, and transactivation of RNA, more rapidly than in Leghorns. These differences in immune response converge at later timepoints which may indicate that Leghorns eventually regulate its immune response to infection. The profiling of the gene expression response in the trachea adds to our understanding of the chicken host response to NDV infection and heat stress on a whole genome level and provides potential candidate genes and signaling pathways for further investigation into the characterization of the time-specific and pathway specific responses in Fayoumis and Leghorns.
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http://dx.doi.org/10.1038/s41598-021-86795-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8018950PMC
April 2021

Viral Zoonoses of National Importance in Ghana: Advancements and Opportunities for Enhancing Capacities for Early Detection and Response.

J Trop Med 2021 15;2021:8938530. Epub 2021 Jan 15.

One Health Institute, University of California, Davis, 1089 Veterinary Medicine Drive, CA 95616, USA.

Zoonotic diseases have devastating impacts on human and animal health, livelihoods, and economies. Addressing the complex web of interrelated factors leading to zoonotic disease emergence and spread requires a transdisciplinary, cross-sectoral approach, One Health. The One Health approach, which considers the linkages between the health of people, animals, and their shared environment, presents opportunities to reduce these impacts through a more holistic coordinated strategy to understanding and mitigating disease risks. Understanding the linkages between animal, human, and environmental health risks and outcomes is critical for developing early detection systems and risk reduction strategies to address known and novel zoonotic disease threats. Nearly 70 countries across the world, including Ghana, have signed on to the Global Health Security Agenda (GHSA), which is facilitating multisectoral approaches to strengthen country capacities in the prevention and early detection of and respond to infectious disease threats. Currently, Ghana has not yet formalized a national One Health policy. The lack of a clearly defined multisectoral platform and limited collaboration among key Ghanaian Ministries, Departments, and Agencies has impacted the country's ability to effectively mitigate and respond to emerging and reemerging zoonoses. Many of these emerging zoonoses are caused by viruses, which, because of their diversity and evolutionary properties, are perceived to pose the greatest threat to global health security. Here, we review viral zoonoses of national importance and priority in Ghana, highlight recent advancements in One Health capacities, and discuss opportunities for implementing One Health approaches to mitigate zoonotic disease threats.
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http://dx.doi.org/10.1155/2021/8938530DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7860970PMC
January 2021

Phenotypic variability and population structure analysis of Tanzanian free-range local chickens.

BMC Vet Res 2020 Sep 29;16(1):360. Epub 2020 Sep 29.

Department of Veterinary Medicine and Public Health, Sokoine University of Agriculture, Morogoro, Tanzania.

Background: Free-range local chickens (FRLC) farming is an important activity in Tanzania, however, they have not been well-characterized. This study aimed to phenotypically characterize three Tanzanian FRLCs and to determine their population structure. A total of 389 mature breeder chickens (324 females and 65 males) from three popular Tanzanian FRLC ecotypes (Kuchi, Morogoro-medium and Ching'wekwe) were used for the phenotypic characterization. Progenies of these chickens were utilized to assess population structure. The ecotypes were collected from four geographical zones across Tanzania: Lake, Central, Northern and Coastal zones. Body weights and linear measurements were obtained from the mature breeders, including body, neck, shanks, wingspan, chest girth, and shank girth. Descriptive statistics were utilized to characterize the chickens. Correlations between the linear measurements and differences among the means of measured linear traits between ecotypes and between sexes were assessed. A total of 1399 progeny chicks were genotyped using a chicken 600 K high density single nucleotide polymorphism (SNP) panel for determination of population structure.

Results: The means for most traits were significantly higher in Kuchi relative to Ching'wekwe and Morogoro-medium. However, shank length and shank girth were similar between Kuchi and Morogoro-medium females. All traits were correlated with the exception of shank girth in Morogoro-medium. Admixture analyses revealed that Morogoro-medium and Ching'wekwe clustered together as one population, separate from Kuchi.

Conclusions: Phenotypic traits could be used to characterize FRLCs, however, there were variations in traits among individuals within ecotypes; therefore, complementary genomic methods should be considered to improve the characterization for selective breeding.
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http://dx.doi.org/10.1186/s12917-020-02541-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7523039PMC
September 2020

Liver Transcriptome Responses to Heat Stress and Newcastle Disease Virus Infection in Genetically Distinct Chicken Inbred Lines.

Genes (Basel) 2020 09 11;11(9). Epub 2020 Sep 11.

Department of Animal Science, University of California, Davis, CA 95616, USA.

Heat stress results in reduced productivity, anorexia, and mortality in chickens. The objective of the study was to identify genes and signal pathways associated with heat stress and Newcastle disease virus (NDV) infection in the liver of chickens through RNA-seq analysis, using two highly inbred chicken lines (Leghorn and Fayoumi). All birds were held in the same environment until 14 days of age. On day 14, half the birds were exposed to 38 °C with 50% relative humidity for 4 h, then 35 °C until the end of the experiment. The remaining birds were kept at 25 °C throughout the experiment. The heat-treated birds were inoculated at 21 days of age with 10 EID (One EID unit is the amount of virus that will infect 50 percent of inoculated embryos) NDV La Sota strain to investigate the effects of both heat stress and NDV infection. Physiological parameters were recorded as blood phenotypes at three stages: acute heat (AH), chronic heat (CH1), and chronic heat combined with NDV infection (CH&NDV), at 4 h, 7 days, and 10 days post-initiation of heat treatment, respectively. Our previous work revealed that the heat-resilient Fayoumi line maintained a more stable acid-base balance in their blood compared to the Leghorn line. Liver samples were harvested on both AH and CH&NDV to characterize the transcriptome profiles of these two inbred lines. Both genetic lines and treatments had large impact on the liver transcriptome. Fayoumi birds had more differentially expressed genes (DEGs) than Leghorn birds for both treatments. Metabolic and immune-related genes were on the DEG list, with Fayoumi having more immune-related DEGs than Leghorns, which was confirmed by gene functional enrichment analysis. Weighted correlation network analysis (WGCNA) indicated that the driver genes such as Solute Carrier Family genes could be very important for stabilizing the acid-base balance in Fayoumi birds during heat stress. Therefore, candidate genes such solute carrier family genes could be potential genetic targets that are regulated by Fayoumis to maintain physical hemostasis under heat stress. Differential gene expression showed that Leghorns mainly performed metabolic regulation in response to heat stress and NDV infection, while Fayoumis regulated both immune and metabolic functions. This study provides novel insights and enhances our understandings of liver response to heat stress of heat resilient and susceptible inbred chicken lines.
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http://dx.doi.org/10.3390/genes11091067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7563548PMC
September 2020

Transcriptome Analysis Reveals Inhibitory Effects of Lentogenic Newcastle Disease Virus on Cell Survival and Immune Function in Spleen of Commercial Layer Chicks.

Genes (Basel) 2020 08 26;11(9). Epub 2020 Aug 26.

Department of Animal Science, Iowa State University, Ames, IA 50011, USA.

As a major infectious disease in chickens, Newcastle disease virus (NDV) causes considerable economic losses in the poultry industry, especially in developing countries where there is limited access to effective vaccination. Therefore, enhancing resistance to the virus in commercial chickens through breeding is a promising way to promote poultry production. In this study, we investigated gene expression changes at 2 and 6 days post inoculation (dpi) at day 21 with a lentogenic NDV in a commercial egg-laying chicken hybrid using RNA sequencing analysis. By comparing NDV-challenged and non-challenged groups, 526 differentially expressed genes (DEGs) (false discovery rate (FDR) < 0.05) were identified at 2 dpi, and only 36 at 6 dpi. For the DEGs at 2 dpi, Ingenuity Pathway Analysis predicted inhibition of multiple signaling pathways in response to NDV that regulate immune cell development and activity, neurogenesis, and angiogenesis. Up-regulation of interferon induced protein with tetratricopeptide repeats 5 () in response to NDV was consistent between the current and most previous studies. Sprouty RTK signaling antagonist 1 (), a DEG in the current study, is in a significant quantitative trait locus associated with virus load at 6 dpi in the same population. These identified pathways and DEGs provide potential targets to further study breeding strategy to enhance NDV resistance in chickens.
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http://dx.doi.org/10.3390/genes11091003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7565929PMC
August 2020

Genetic Basis of Response of Ghanaian Local Chickens to Infection With a Lentogenic Newcastle Disease Virus.

Front Genet 2020 28;11:739. Epub 2020 Jul 28.

Department of Animal Science, Iowa State University, Ames, IA, United States.

Newcastle disease (ND) is a global threat to domestic poultry, especially in rural areas of Africa and Asia, where the loss of entire backyard local chicken flocks often threatens household food security and income. To investigate the genetics of Ghanaian local chicken ecotypes to Newcastle disease virus (NDV), in this study, three popular Ghanaian chicken ecotypes (regional populations) were challenged with a lentogenic NDV strain at 28 days of age. This study was conducted in parallel with a similar study that used three popular Tanzanian local chicken ecotypes and after two companion studies in the United States, using Hy-line Brown commercial laying birds. In addition to growth rate, NDV response traits were measured following infection, including anti-NDV antibody levels [pre-infection and 10 days post-infection (dpi)], and viral load (2 and 6 dpi). Genetic parameters were estimated, and two genome-wide association study analysis methods were used on data from 1,440 Ghanaian chickens that were genotyped on a chicken 600K Single Nucleotide Polymorphism (SNP) chip. Both Ghana and Tanzania NDV challenge studies revealed moderate to high (0.18 - 0.55) estimates of heritability for all traits, except viral clearance where the heritability estimate was not different from zero for the Tanzanian ecotypes. For the Ghana study, 12 quantitative trait loci (QTL) for growth and/or response to NDV from single-SNP analyses and 20 genomic regions that explained more than 1% of genetic variance using the Bayes B method were identified. Seven of these windows were also identified as having at least one significant SNP in the single SNP analyses for growth rate, anti-NDV antibody levels, and viral load at 2 and 6 dpi. An important gene for growth during stress, CHORDC1 associated with post-infection growth rate was identified as a positional candidate gene, as well as other immune related genes, including VAV2, IL12B, DUSP1, and IL17B. The QTL identified in the Ghana study did not overlap with those identified in the Tanzania study. However, both studies revealed QTL with genes vital for growth and immune response during NDV challenge. The Tanzania parallel study revealed an overlapping QTL on chromosome 24 for viral load at 6 dpi with the US NDV study in which birds were challenged with NDV under heat stress. This QTL region includes genes related to immune response, including TIRAP, ETS1, and KIRREL3. The moderate to high estimates of heritability and the identified QTL suggest that host response to NDV of local African chicken ecotypes can be improved through selective breeding to enhance increased NDV resistance and vaccine efficacy.
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http://dx.doi.org/10.3389/fgene.2020.00739DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7402339PMC
July 2020

Molecular Characterization of Newcastle Disease Viruses Isolated from Chickens in Tanzania and Ghana.

Viruses 2020 08 20;12(9). Epub 2020 Aug 20.

Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, CA 95616, USA.

Newcastle disease (ND) is one of the most challenging infectious diseases affecting poultry production in Africa, causing major economic losses. To date, Newcastle disease virus isolates from several African countries have been grouped into class II NDV genotypes I, IV, V, VI, VII, XI, XIII, XIV, XVII, XVIII and XXI. Although ND is endemic in many African countries, information on circulating genotypes is still scarce. In Tanzania, outbreaks with genotypes V and XIII have been reported. In West and Central Africa, genotypes XIV, XVII, and XVIII are the most predominant. To investigate other genotypes circulating in Tanzania and Ghana, we performed molecular genotyping on isolates from Tanzania and Ghana using the MinION, a third-generation portable sequencing device from Oxford Nanopore Technologies. Using the MinION, we successfully sequenced the NDV F gene hypervariable region of 24 isolates from Tanzania and four samples from Ghana. In Tanzania, genotypes V, VII and XIII were detected. All isolates from Ghana belonged to genotype XVIII. The data obtained in this study reflect the genetic diversity of NDV in Africa and highlight the importance of surveillance for monitoring the distribution of NDV genotypes and viral evolution.
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http://dx.doi.org/10.3390/v12090916DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7551648PMC
August 2020

Implementing One Health approaches to confront emerging and re-emerging zoonotic disease threats: lessons from PREDICT.

One Health Outlook 2020 10;2. Epub 2020 Jan 10.

One Health Institute, University of California, Davis, CA USA.

Recurring outbreaks of emerging and re-emerging zoonoses, such as Ebola virus disease, avian influenza, and Nipah virus, serve as a reminder that the health of humans, animals, and the environment are interconnected and that early response to emerging zoonotic pathogens requires a coordinated, interdisciplinary, cross-sectoral approach. As our world becomes increasingly connected, emerging diseases pose a greater threat, requiring coordination at local, regional, and global levels. One Health is a multisectoral, transdisciplinary, and collaborative approach promoted to more effectively address these complex health threats. Despite strong advocacy for One Health, challenges for practical implementation remain. Here we discuss the value of the One Health approach for addressing global health challenges. We also share strategies applied to achieve successful outcomes through the USAID Emerging Pandemic Threats Program PREDICT project, which serve as useful case studies for implementing One Health approaches. Lastly, we explore methods for promoting more formal One Health implementation to capitalize on the added value of shared knowledge and leveraged resources.
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http://dx.doi.org/10.1186/s42522-019-0007-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7149069PMC
January 2020

Genetic Analyses of Tanzanian Local Chicken Ecotypes Challenged with Newcastle Disease Virus.

Genes (Basel) 2019 07 17;10(7). Epub 2019 Jul 17.

Department of Animal Science, Iowa State University, 2255 Kildee Hall, Ames, IA 50011, USA.

Newcastle Disease (ND) is a continuing global threat to domestic poultry, especially in developing countries, where severe outbreaks of velogenic ND virus (NDV) often cause major economic losses to households. Local chickens are of great importance to rural family livelihoods through provision of high-quality protein. To investigate the genetic basis of host response to NDV, three popular Tanzanian chicken ecotypes (regional populations) were challenged with a lentogenic (vaccine) strain of NDV at 28 days of age. Various host response phenotypes, including anti-NDV antibody levels (pre-infection and 10 days post-infection, dpi), and viral load (2 and 6 dpi) were measured, in addition to growth rate. We estimated genetic parameters and conducted genome-wide association study analyses by genotyping 1399 chickens using the Affymetrix 600K chicken SNP chip. Estimates of heritability of the evaluated traits were moderate (0.18-0.35). Five quantitative trait loci (QTL) associated with growth and/or response to NDV were identified by single-SNP analyses, with some regions explaining ≥1% of genetic variance based on the Bayes-B method. Immune related genes, such as ETS1, TIRAP, and KIRREL3, were located in regions associated with viral load at 6 dpi. The moderate estimates of heritability and identified QTL indicate that NDV response traits may be improved through selective breeding of chickens to enhance increased NDV resistance and vaccine efficacy in Tanzanian local ecotypes.
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http://dx.doi.org/10.3390/genes10070546DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6678660PMC
July 2019

Genetics and Genomic Regions Affecting Response to Newcastle Disease Virus Infection under Heat Stress in Layer Chickens.

Genes (Basel) 2019 01 18;10(1). Epub 2019 Jan 18.

Genomics to Improve Poultry Innovation Lab, University of California, Davis, CA 95616, USA.

Newcastle disease virus (NDV) is a highly contagious avian pathogen that poses a tremendous threat to poultry producers in endemic zones due to its epidemic potential. To investigate host genetic resistance to NDV while under the effects of heat stress, a genome-wide association study (GWAS) was performed on Hy-Line Brown layer chickens that were challenged with NDV while under high ambient temperature to identify regions associated with host viral titer, circulating anti-NDV antibody titer, and body weight change. A single nucleotide polymorphism (SNP) on chromosome 1 was associated with viral titer at two days post-infection (dpi), while 30 SNPs spanning a quantitative trait loci (QTL) on chromosome 24 were associated with viral titer at 6 dpi. Immune related genes, such as CAMK1d and CCDC3 on chromosome 1, associated with viral titer at 2 dpi, and TIRAP, ETS1, and KIRREL3, associated with viral titer at 6 dpi, were located in two QTL regions for viral titer that were identified in this study. This study identified genomic regions and candidate genes that are associated with response to NDV during heat stress in Hy-Line Brown layer chickens. Regions identified for viral titer on chromosome 1 and 24, at 2 and 6 dpi, respectively, included several genes that have key roles in regulating the immune response.
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http://dx.doi.org/10.3390/genes10010061DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6356198PMC
January 2019

Integrated Proteomic and Transcriptomic Analysis of Differential Expression of Chicken Lung Tissue in Response to NDV Infection during Heat Stress.

Genes (Basel) 2018 Nov 27;9(12). Epub 2018 Nov 27.

Genomics to Improve Poultry Innovation Lab, University of California, Davis, CA 95616, USA.

Newcastle disease virus (NDV) is a devastating worldwide poultry pathogen with major implications for global food security. In this study, two highly inbred and genetically distinct chicken lines, Fayoumis and Leghorns, were exposed to a lentogenic strain of NDV, while under the effects of heat stress, in order to understand the genetic mechanisms of resistance during high ambient temperatures. Fayoumis, which are relatively more resistant to pathogens than Leghorns, had larger numbers of differentially expressed genes (DEGs) during the early stages of infection when compared to Leghorns and subsequently down-regulated their immune response at the latter stages to return to homeostasis. Leghorns had very few DEGs across all observed time points, with the majority of DEGs involved with metabolic and glucose-related functions. Proteomic analysis corroborates findings made within Leghorns, while also identifying interesting candidate genes missed by expression profiling. Poor correlation between changes observed in the proteomic and transcriptomic datasets highlights the potential importance of integrative approaches to understand the mechanisms of disease response. Overall, this study provides novel insights into global protein and expression profiles of these two genetic lines, and provides potential genetic targets involved with NDV resistance during heat stress in poultry.
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http://dx.doi.org/10.3390/genes9120579DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6316021PMC
November 2018

Association of Candidate Genes with Response to Heat and Newcastle Disease Virus.

Genes (Basel) 2018 Nov 19;9(11). Epub 2018 Nov 19.

Department of Animal Science, Iowa State University, Ames, IA 50011, USA.

Newcastle disease is considered the number one disease constraint to poultry production in low and middle-income countries, however poultry that is raised in resource-poor areas often experience multiple environmental challenges. Heat stress has a negative impact on production, and immune response to pathogens can be negatively modulated by heat stress. Candidate genes and regions chosen for this study were based on previously reported associations with response to immune stimulants, pathogens, or heat, including: , , , MHC-B (major histocompatibility complex, gene complex), , , , , , , , , , and . Chickens of a commercial egg-laying line were infected with a lentogenic strain of NDV (Newcastle disease virus); half the birds were maintained at thermoneutral temperature and the other half were exposed to high ambient temperature before the NDV challenge and throughout the remainder of the study. Phenotypic responses to heat, to NDV, or to heat + NDV were measured. Selected SNPs (single nucleotide polymorphisms) within 14 target genes or regions were genotyped; and genotype effects on phenotypic responses to NDV or heat + NDV were tested in each individual treatment group and the combined groups. Seventeen significant haplotype effects, among seven genes and seven phenotypes, were detected for response to NDV or heat or NDV + heat. These findings identify specific genetic variants that are associated with response to heat and/or NDV which may be useful in the genetic improvement of chickens to perform favorably when faced with pathogens and heat stress.
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http://dx.doi.org/10.3390/genes9110560DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6267452PMC
November 2018

Sarcocystis calchasi Outbreak in Feral Rock Pigeons ( Columba livia) in California.

Vet Pathol 2019 Mar 16;56(2):317-321. Epub 2018 Sep 16.

1 California Animal Health and Food Safety Laboratory, UC Davis, Davis, CA, USA.

Twenty-two feral rock pigeons ( Columba livia) from 10 counties in California with ataxia, torticollis, and difficulty standing and flying were admitted to rehabilitation centers in late winter and spring of 2017 and died or were euthanized. Common necropsy findings included thin body condition, generalized deep red discoloration of organs, and hemorrhagic subcutaneous neck tissues. Meningoencephalitis was observed microscopically in 16 pigeons, and 3 also had protozoal schizonts in the brain. The most consistently affected regions of the brain were cerebellum and brainstem. Skeletal muscles, and less frequently the heart, contained large intrasarcoplasmic bradyzoites typically without inflammation. Fifteen of the 22 birds tested positive using pan- Sarcocystis polymerase chain reaction. The sequence of the amplicon was most closely related to S. calchasi, and the 8 subtyped sequences had 100% homology with S. calchasi. This investigation demonstrated the transcontinental and North American spread of S. calchasi causing a disease outbreak in free-ranging rock pigeons, thus warranting increased surveillance in susceptible native columbids.
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http://dx.doi.org/10.1177/0300985818794262DOI Listing
March 2019

Novel insights into the host immune response of chicken Harderian gland tissue during Newcastle disease virus infection and heat treatment.

BMC Vet Res 2018 Sep 12;14(1):280. Epub 2018 Sep 12.

Genomics to Improve Poultry Innovation Lab, University of California, Davis, CA, 95616, USA.

Background: Newcastle disease virus, in its most pathogenic form, threatens the livelihood of rural poultry farmers where there is a limited infrastructure and service for vaccinations to prevent outbreaks of the virus. Previously reported studies on the host response to Newcastle disease in chickens have not examined the disease under abiotic stressors, such as heat, which commonly experienced by chickens in regions such as Africa. The objective of this study was to elucidate the underlying biological mechanisms that contribute to disease resistance in chickens to the Newcastle disease virus while under the effects of heat stress.

Results: Differential gene expression analysis identified genes differentially expressed between treated and non-treated birds across three time points (2, 6, and 10 days post-infection) in Fayoumi and Leghorn birds. Across the three time points, Fayoumi had very few genes differentially expressed between treated and non-treated groups at 2 and 6 days post-infection. However, 202 genes were differentially expressed at 10 days post-infection. Alternatively, Leghorn had very few genes differentially expressed at 2 and 10 days post-infection but had 167 differentially expressed genes at 6 days post-infection. Very few differentially expressed genes were shared between the two genetic lines, and pathway analysis found unique signaling pathways specific to each genetic line. Fayoumi had significantly lower viral load, higher viral clearance, higher anti-NDV antibody levels, and fewer viral transcripts detected compared to Leghorns. Fayoumis activated immune related pathways including SAPK/JNK and p38 MAPK signaling pathways at earlier time points, while Leghorn would activate these same pathways at a later time. Further analysis revealed activation of the GP6 signaling pathway that may be responsible for the susceptible Leghorn response.

Conclusions: The findings in this study confirmed our hypothesis that the Fayoumi line was more resistant to Newcastle disease virus infection compared to the Leghorn line. Within line and interaction analysis demonstrated substantial differences in response patterns between the two genetic lines that was not observed from the within line contrasts. This study has provided novel insights into the transcriptome response of the Harderian gland tissue during Newcastle disease virus infection while under heat stress utilizing a unique resistant and susceptible model.
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http://dx.doi.org/10.1186/s12917-018-1583-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6134752PMC
September 2018

Genetic Analysis of a Commercial Egg Laying Line Challenged With Newcastle Disease Virus.

Front Genet 2018 20;9:326. Epub 2018 Aug 20.

Department of Animal Science, Iowa State University, Ames, IA, United States.

In low income countries, chickens play a vital role in daily life. They provide a critical source of protein through egg production and meat. Newcastle disease, caused by avian paramyxovirus type 1, has been ranked as the most devastating disease for scavenging chickens in Africa and Asia. High mortality among flocks infected with velogenic strains leads to a devastating loss of dietary protein and buying power for rural households. Improving the genetic resistance of chickens to Newcastle Disease virus (NDV), in addition to vaccination, is a practical target for improvement of poultry production in low income countries. Because response to NDV has a component of genetic control, it can be influenced through selective breeding. Adding genomic information to a breeding program can increase the amount of genetic progress per generation. In this study, we challenged a commercial egg-laying line with a lentogenic strain of NDV, measured phenotypic responses, collected genotypes, and associated genotypes with phenotypes. Collected phenotypes included viral load at 2 and 6 days post-infection (dpi), antibody levels pre-challenge and 10 dpi, and growth rates pre- and post-challenge. Six suggestive QTL associated with response to NDV and/or growth were identified, including novel and known QTL confirming previously reported associations with related traits. Additionally, previous RNA-seq analysis provided support for several of the genes located in or near the identified QTL. Considering the trend of negative genetic correlation between antibody and Newcastle Disease tolerance (growth under disease) and estimates of moderate to high heritability, we provide evidence that these NDV response traits can be influenced through selective breeding. Producing chickens that perform favorably in challenging environments will ultimately increase the supply of quality protein for human consumption.
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http://dx.doi.org/10.3389/fgene.2018.00326DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6110172PMC
August 2018

Awareness and Practices Relating to Zoonotic Diseases Among Smallholder Farmers in Nepal.

Ecohealth 2018 09 4;15(3):656-669. Epub 2018 Jun 4.

One Health Institute, University of California, 1089 Veterinary Medicine Drive, Davis, CA, 95616, USA.

Increasing livestock production to meet growing demands has resulted in greater interactions at the livestock-wildlife-human interface and more opportunities for zoonotic disease spread. Zoonoses impose enormous burdens on low-income countries like Nepal, where populations are largely dependent on livestock production and access to shared grazing lands, often near protected areas, due to population pressures. Several livestock-associated zoonoses have been reported in Nepal; however, little is known regarding Nepali farmers' knowledge of zoonoses and opportunities for disease management. We conducted a cross-sectional study to investigate Nepali farmers' awareness of zoonoses, assess current health challenges, and evaluate disease prevention and control practices. We found that awareness of zoonotic pathogens was limited, especially in informally educated and illiterate farmers; the majority of which were women. Further, farmers' preventive herd health, food safety, and sanitation practices were not associated with their awareness. Several farmers reported high-risk practices despite being aware of zoonotic diseases, suggesting a disconnect between the farmers' awareness and practice. Our study highlights the need for improving Nepali farmers' knowledge of zoonoses and disease prevention measures. Closing these awareness-practice gaps will require an improved understanding of risk and effective drivers of behavior change, alongside engagement of farmers in development of zoonotic disease prevention programs that encourage participation of both male and female farmers across all levels of education.
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http://dx.doi.org/10.1007/s10393-018-1343-4DOI Listing
September 2018

Novel analysis of the Harderian gland transcriptome response to Newcastle disease virus in two inbred chicken lines.

Sci Rep 2018 04 26;8(1):6558. Epub 2018 Apr 26.

Department of Animal Science, Iowa State University, Ames, Iowa, USA.

Behind each eye of the chicken resides a unique lymph tissue, the Harderian gland, for which RNA sequencing (RNA-seq) analysis is novel. We characterized the response of this tissue to Newcastle disease virus (NDV) in two inbred lines with different susceptibility to NDV across three time points. Three-week-old relatively resistant (Fayoumi) and relatively susceptible (Leghorn) birds were inoculated with a high-titered (10EID) La Sota strain of NDV via an oculonasal route. At 2, 6, and 10 days post infection (dpi) Harderian glands were collected and analyzed via RNA-seq. The Fayoumi had significantly more detectable viral transcripts in the Harderian gland at 2 dpi than the Leghorn, but cleared the virus by 6 dpi. At all three time points, few genes were declared differentially expressed (DE) between the challenged and nonchallenged birds, except for the Leghorns at 6 dpi, and these DE genes were predicted to activate an adaptive immune response. Relative to the Leghorn, the Fayoumi was predicted to activate more immune pathways in both challenged and nonchallenged birds suggesting a more elevated immune system in the Fayoumis under homeostatic conditions. Overall, this study helped characterize the function of this important tissue and its response to NDV.
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http://dx.doi.org/10.1038/s41598-018-24830-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5920083PMC
April 2018

Transcriptome Analysis in Spleen Reveals Differential Regulation of Response to Newcastle Disease Virus in Two Chicken Lines.

Sci Rep 2018 01 19;8(1):1278. Epub 2018 Jan 19.

Department of Animal Science, Iowa State University, 806 Stange Rd, 2255 Kildee Hall, Ames, IA, 50011, USA.

Enhancing genetic resistance of chickens to Newcastle Disease Virus (NDV) provides a promising way to improve poultry health, and to alleviate poverty and food insecurity in developing countries. In this study, two inbred chicken lines with different responses to NDV, Fayoumi and Leghorn, were challenged with LaSota NDV strain at 21 days of age. Through transcriptome analysis, gene expression in spleen at 2 and 6 days post-inoculation was compared between NDV-infected and control groups, as well as between chicken lines. At a false discovery rate <0.05, Fayoumi chickens, which are relatively more resistant to NDV, showed fewer differentially expressed genes (DEGs) than Leghorn chickens. Several interferon-stimulated genes were identified as important DEGs regulating immune response to NDV in chicken. Pathways predicted by IPA analysis, such as "EIF-signaling", "actin cytoskeleton organization nitric oxide production" and "coagulation system" may contribute to resistance to NDV in Fayoumi chickens. The identified DEGs and predicted pathways may contribute to differential responses to NDV between the two chicken lines and provide potential targets for breeding chickens that are more resistant to NDV.
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http://dx.doi.org/10.1038/s41598-018-19754-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5775430PMC
January 2018

Novel Mechanisms Revealed in the Trachea Transcriptome of Resistant and Susceptible Chicken Lines following Infection with Newcastle Disease Virus.

Clin Vaccine Immunol 2017 May 5;24(5). Epub 2017 May 5.

Department of Animal Science, Iowa State University, Ames, Iowa, USA

Newcastle disease virus (NDV) has a devastating impact on poultry production in developing countries. This study examined the transcriptome of tracheal epithelial cells from two inbred chicken lines that differ in NDV susceptibility after challenge with a high-titer inoculum of lentogenic NDV. The Fayoumi line had a significantly lower NDV load postchallenge than the Leghorn line, demonstrating the Fayoumi line's classification as a relatively NDV-resistant breed. Examination of the trachea transcriptome showed a large increase in immune cell infiltration in the trachea in both lines at all times postinfection. The pathways conserved across lines and at all three time points postinfection included iCOS-iCOSL signaling in T helper cells, NF-κB signaling, the role of nuclear factor of activated T cells in the regulation of the immune response, calcium-induced T lymphocyte apoptosis, phospholipase C signaling, and CD28 signaling in T helper cells. Although shared pathways were seen in the Fayoumi and Leghorn lines, each line showed unique responses as well. The downregulation of collagen and the activation of eukaryotic translation initiation factor 2 signaling in the Fayoumis relative to the Leghorns at 2 days postinfection may contribute to the resistance phenotype seen in the Fayoumis. This study provides a further understanding of host-pathogen interactions which could improve vaccine efficacy and, in combination with genome-wide association studies, has the potential to advance strategies for breeding chickens with enhanced resistance to NDV.
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http://dx.doi.org/10.1128/CVI.00027-17DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5424241PMC
May 2017

One Health proof of concept: Bringing a transdisciplinary approach to surveillance for zoonotic viruses at the human-wild animal interface.

Prev Vet Med 2017 Feb 14;137(Pt B):112-118. Epub 2016 Dec 14.

One Health Institute & Karen C. Drayer Wildlife Health Center, School of Veterinary Medicine, 1089 Veterinary Medicine Drive, University of California, Davis, CA, 95616, USA. Electronic address:

As the world continues to react and respond inefficiently to emerging infectious diseases, such as Middle Eastern Respiratory Syndrome and the Ebola and Zika viruses, a growing transdisciplinary community has called for a more proactive and holistic approach to prevention and preparedness - One Health. Such an approach presents important opportunities to reduce the impact of disease emergence events and also to mitigate future emergence through improved cross-sectoral coordination. In an attempt to provide proof of concept of the utility of the One Health approach, the US Agency for International Development's PREDICT project consortium designed and implemented a targeted, risk-based surveillance strategy based not on humans as sentinels of disease but on detecting viruses early, at their source, where intervention strategies can be implemented before there is opportunity for spillover and spread in people or food animals. Here, we share One Health approaches used by consortium members to illustrate the potential for successful One Health outcomes that can be achieved through collaborative, transdisciplinary partnerships. PREDICT's collaboration with partners around the world on strengthening local capacity to detect hundreds of viruses in wild animals, coupled with a series of cutting-edge virological and analytical activities, have significantly improved our baseline knowledge on the zoonotic pool of viruses and the risk of exposure to people. Further testament to the success of the project's One Health approach and the work of its team of dedicated One Health professionals are the resulting 90 peer-reviewed, scientific publications in under 5 years that improve our understanding of zoonoses and the factors influencing their emergence. The findings are assisting in global health improvements, including surveillance science, diagnostic technologies, understanding of viral evolution, and ecological driver identification. Through its One Health leadership and multi-disciplinary partnerships, PREDICT has forged new networks of professionals from the human, animal, and environmental health sectors to promote global health, improving our understanding of viral disease spillover from wildlife and implementing strategies for preventing and controlling emerging disease threats.
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http://dx.doi.org/10.1016/j.prevetmed.2016.11.023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7132382PMC
February 2017

Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California.

PLoS One 2015 25;10(11):e0143018. Epub 2015 Nov 25.

Wildlife Health Center, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America.

Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0143018PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4659623PMC
June 2016

Clinical pathology reference intervals for an in-water population of juvenile loggerhead sea turtles (Caretta caretta) in Core Sound, North Carolina, USA.

PLoS One 2015 4;10(3):e0115739. Epub 2015 Mar 4.

Environmental Medicine Consortium, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, United States of America; Department of Clinical Sciences, North Carolina State University, 1060 William Moore Drive, Raleigh, North Carolina 27607, United States of America; Center for Marine Sciences and Technology, 303 College Circle, Morehead City, North Carolina 27606, United States of America.

The loggerhead sea turtle (Caretta caretta) is found throughout the waters of the Atlantic, Pacific, and Indian Oceans. It is a protected species throughout much of its range due to threats such as habitat loss, fisheries interactions, hatchling predation, and marine debris. Loggerheads that occur in the southeastern U.S. are listed as "threatened" on the U.S. Endangered Species List, and receive state and federal protection. As part of an on-going population assessment conducted by the National Marine Fisheries Service, samples were collected from juvenile loggerhead sea turtles in Core Sound, North Carolina, between 2004 and 2007 to gain insight on the baseline health of the threatened Northwest Atlantic Ocean population. The aims of the current study were to establish hematologic and biochemical reference intervals for this population, and to assess variation of the hematologic and plasma biochemical analytes by season, water temperature, and sex and size of the turtles. Reference intervals for the clinical pathology parameters were estimated following Clinical Laboratory Standards Institute guidelines. Season, water temperature, sex, and size of the turtles were found to be significant factors of variation for parameter values. Seasonal variation could be attributed to physiological effects of decreasing photoperiod, cooler water temperature, and migration during the fall months. Packed cell volume, total protein, and albumin increased with increasing size of the turtles. The size-related differences in analytes documented in the present study are consistent with other reports of variation in clinical pathology parameters by size and age in sea turtles. As a component of a health assessment of juvenile loggerhead sea turtles in North Carolina, this study will serve as a baseline aiding in evaluation of trends for this population and as a diagnostic tool for assessing the health and prognosis for loggerhead sea turtles undergoing rehabilitation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0115739PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4349656PMC
January 2016

Enteric pathogens and antimicrobial resistance in turkey vultures (Cathartes aura) feeding at the wildlife-livestock interface.

J Zoo Wildl Med 2014 Dec;45(4):931-4

Free-flying turkey vultures (Cathartes aura) were sampled in California to investigate the fecal shedding prevalence and antimicrobial susceptibility of Salmonella enterica, Campylobacter spp., and Escherichia coli. Nine different serotypes of Salmonella enterica were detected in cloacal swabs from turkey vultures, and 6% of vultures were shedding Campylobacter spp.. Turkey vultures sampled at a location with range sheep were more likely to shed tetracycline-resistant E. coli, suggesting that proximity to livestock facilities could facilitate acquisition of drug-resistant bacteria in avian scavengers. These findings illustrate the importance of assessing drug-resistant pathogen transfer at the livestock-wildlife interface.
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http://dx.doi.org/10.1638/2012-0217.1DOI Listing
December 2014

Evaluation of viruses and their association with ocular lesions in pinnipeds in rehabilitation.

Vet Ophthalmol 2015 Jan 17;18 Suppl 1:148-59. Epub 2014 Nov 17.

Royal Veterinary College, University of London, London, NW1 0TU, UK; Institute of Zoology, Zoological Society of London, London, NW1 4RY, UK.

Objective: To assess whether corneal lesions in stranded pinnipeds were associated with viral infections, and to identify the potential pathogen(s) associated with the lesions.

Animals Studied: Twenty-nine California sea lions (Zalophus californianus), 18 northern elephant seals (Mirounga angustirostris), and 34 Pacific harbor seals (Phoca vitulina richardsii).

Procedure: DNA and RNA were extracted from ocular swabs, corneal tissue, and aqueous humor and screened for herpesvirus, adenovirus, poxvirus, and calicivirus families by PCR.

Results: The results indicated a high overall prevalence of viruses, with adenoviruses and herpesviruses detected in all three host species. Three novel adenoviruses (PhAdV-1, PhAdV-2, OtAdV-2) and two novel herpesviruses (PhHV-6, OtHV-4) were detected. There were no statistical differences in the prevalence of viral infection or coinfection among groups of individuals with or without corneal lesions, nor were lesion type, onset, or presence of concurrent disease significantly associated with a viral infection.

Conclusions: The results suggested that viral presence in ocular tissues was common, not significantly associated with ocular disease and thus should not preclude release of an otherwise healthy animal. We could not confirm a correlation of virus presence with lesion due to the high percentage of virus-positive, clinically normal animals. This implied that seals and sea lions can have ocular tissues infected with several viruses without having readily evident associated lesions. This difficulty in correlating viral presence, particularly herpesviruses, with ocular lesions was also a common finding in studies with terrestrial species and highlighted the difficulty of confirming a virus as a primary pathogen in ocular lesions.
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http://dx.doi.org/10.1111/vop.12235DOI Listing
January 2015

Spatiotemporal patterns and risk factors for lead exposure in endangered California condors during 15 years of reintroduction.

Conserv Biol 2014 Dec 15;28(6):1721-30. Epub 2014 Jul 15.

Wildlife Health Center, School of Veterinary Medicine, University of California-Davis, 1089 Veterinary Medicine Drive, Davis, CA, 95616, U.S.A.

Large-scale poisoning events are common to scavenging bird species that forage communally, many of which are in decline. To reduce the threat of poisoning and compensate for other persistent threats, management, including supplemental feeding, is ongoing for many reintroduced and endangered vulture populations. Through a longitudinal study of lead exposure in California condors (Gymnogyps californianus), we illustrate the conservation challenges inherent in reintroduction of an endangered species to the wild when pervasive threats have not been eliminated. We evaluated population-wide patterns in blood lead levels from 1997 to 2011 and assessed a broad range of putative demographic, behavioral, and environmental risk factors for elevated lead exposure among reintroduced California condors in California (United States). We also assessed the effectiveness of lead ammunition regulations within the condor's range in California by comparing condor blood lead levels before and after implementation of the regulations. Lead exposure was a pervasive threat to California condors despite recent regulations limiting lead ammunition use. In addition, condor lead levels significantly increased as age and independence from intensive management increased, including increasing time spent away from managed release sites, and decreasing reliance on food provisions. Greater independence among an increasing number of reintroduced condors has therefore elevated the population's risk of lead exposure and limited the effectiveness of lead reduction efforts to date. Our findings highlight the challenges of restoring endangered vulture populations as they mature and become less reliant on management actions necessary to compensate for persistent threats.
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http://dx.doi.org/10.1111/cobi.12342DOI Listing
December 2014

Causes of mortality and unintentional poisoning in predatory and scavenging birds in California.

Vet Rec Open 2014 12;1(1):e000028. Epub 2014 Nov 12.

Wildlife Health Center, School of Veterinary Medicine, University of California , Davis, California , USA.

Objectives: We documented causes of mortality in an opportunistic sample of golden eagles, turkey vultures and common ravens, and assessed exposure to several contaminants that have been found in carrion and common prey for these species.

Methods: Dead birds were submitted for testing through wildlife rehabilitation centres and a network of wildlife biologists in California from 2007 to 2009.

Results: The leading causes of mortality in this study were collision-related trauma (63 per cent), lead intoxication (17 per cent) and anticoagulant rodenticide poisoning (8 per cent). Elevated liver lead concentration (≥2 µg/g) and bone lead concentration (>6 µg/g) were detected in 25 and 49 per cent of birds tested, respectively. Approximately 84 per cent of birds tested had detectable rodenticide residues. The majority of rodenticide exposure occurred in peri-urban areas, suggesting that retail sale and use of commensal rodent baits, particularly in residential and semi-residential areas in California, may provide a pathway of exposure.

Conclusions: Monitoring anthropogenic causes of mortality in predatory and scavenging bird species provides important data needed to inform on mitigation and regulatory efforts aimed at reducing threats to these populations.
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http://dx.doi.org/10.1136/vropen-2014-000028DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4562445PMC
September 2015

Avian influenza: mixed infections and missing viruses.

Viruses 2013 Aug 5;5(8):1964-77. Epub 2013 Aug 5.

Department of Pathology, Microbiology and Immunology, University of California, One Shields Avenue, Davis, CA 95616, USA.

A high prevalence and diversity of avian influenza (AI) viruses were detected in a population of wild mallards sampled during summer 2011 in California, providing an opportunity to compare results obtained before and after virus culture. We tested cloacal swab samples prior to culture by matrix real-time PCR, and by amplifying and sequencing a 640bp portion of the hemagglutinin (HA) gene. Each sample was also inoculated into embryonated chicken eggs, and full genome sequences were determined for cultured viruses. While low matrix Ct values were a good predictor of virus isolation from eggs, samples with high or undetectable Ct values also yielded isolates. Furthermore, a single passage in eggs altered the occurrence and detection of viral strains, and mixed infections (different HA subtypes) were detected less frequently after culture. There is no gold standard or perfect reference comparison for surveillance of unknown viruses, and true negatives are difficult to distinguish from false negatives. This study showed that sequencing samples prior to culture increases the detection of mixed infections and enhances the identification of viral strains and sequences that may have changed or even disappeared during culture.
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http://dx.doi.org/10.3390/v5081964DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761236PMC
August 2013

Impact of the California lead ammunition ban on reducing lead exposure in golden eagles and turkey vultures.

PLoS One 2011 Apr 6;6(4):e17656. Epub 2011 Apr 6.

School of Veterinary Medicine, Wildlife Health Center, University of California Davis, Davis, California, United States of America.

Predatory and scavenging birds may be exposed to high levels of lead when they ingest shot or bullet fragments embedded in the tissues of animals injured or killed with lead ammunition. Lead poisoning was a contributing factor in the decline of the endangered California condor population in the 1980s, and remains one of the primary factors threatening species recovery. In response to this threat, a ban on the use of lead ammunition for most hunting activities in the range of the condor in California was implemented in 2008. Monitoring of lead exposure in predatory and scavenging birds is essential for assessing the effectiveness of the lead ammunition ban in reducing lead exposure in these species. In this study, we assessed the effectiveness of the regulation in decreasing blood lead concentration in two avian sentinels, golden eagles and turkey vultures, within the condor range in California. We compared blood lead concentration in golden eagles and turkey vultures prior to the lead ammunition ban and one year following implementation of the ban. Lead exposure in both golden eagles and turkey vultures declined significantly post-ban. Our findings provide evidence that hunter compliance with lead ammunition regulations was sufficient to reduce lead exposure in predatory and scavenging birds at our study sites.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0017656PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3071804PMC
April 2011
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