Introduction Of Pathogens Research Articles

Probabilistic risk-based model for the assessment of Phyllosticta citricarpa-infected citrus fruit and illicit plant material as pathways for pathogen introduction and establishment

Citrus Black Spot (CBS), caused by the ascomycete, Phyllosticta citricarpa, is a fruit, foliar, and twig spotting fungal disease affecting the majority of commercial cultivars of citrus. The disease causes cosmetic lesions, may cause fruit drop and P. citricarpa is considered a quarantine pathogen by some countries, impacting domestic and international trade of citrus fruit. Regulatory requirements affecting fruit trade exist even though there is no documented case of disease spread via infected fruit into previously disease-free areas. To clarify the risk of fruit as a potential pathway for the spread of CBS, we developed a quantitative, probabilistic risk assessment model. The model provides an assessment of all steps in the fruit pathway, including production, packinghouse handling, transportation, export-import distribution channels, and consumer endpoints. The model is stochastic and uses Monte Carlo simulation to assess the risk of P. citricarpa moving through all steps in the pathway. We attempted to use all available literature and information to quantitate risk at each point in the potential pathway and by sequentially linking all steps to determine the overall quantitative risk. In addition, we assessed climatological effects on incidence of diseased fruit at production sites and on fungal reproduction and infection, as well as criteria for establishment at endpoints. We examined ten case studies between exporting and importing locations/countries. Model results indicated fruit to be an epidemiologically insignificant means for CBS spread, even between producing countries where CBS occurs and CBS-free importing countries with disease-conducive climates. We created a second model to examine the introduction of infected plant material from countries where CBS occurs. This model demonstrated significant probability of introduction via such infected material. However, pathogen establishment and disease development was still restricted only to areas with conducive climatological conditions. We created a tool to quantitatively explore the viability of various potential pathways via combinations of CBS-present production sites and corresponding pathway endpoints, including environments conducive and non-conducive to CBS. The tool is provided to aid decision makers on phytosanitary risk relative to international trade of citrus fruit.

β-defensins and the inflammatory periodontal diseases: a systematic review

Relevance. The steady increase in the number of inflammatory periodontal diseases (IPD) requires the search for new methods of their diagnosis, treatment and prevention. A large number of antimicrobial peptides are expressed in the oral cavity, including β-defensins, which form the first line of defense against periodontal pathogens. A more detailed study of these proteins will help us to answer the question: why this protective barrier breaks through and may we use β-defensins as markers of IPD. The aim is to study information about the role of β-defensins in the pathogenesis of IBD and to evaluate the possibility of their use as biomarkers of these diseases.Materials and methods. Using search systems as PubMed, Google Search and eLIBRARY were found 2106 articles published between 2003 and 2020 years. According to the inclusion and non-inclusion criteria, 39 publications were selected, including in vivo, in vitro and review articles. This review presents data from the selected articles.Results. β-defensins have antimicrobial activity against periodontal pathogens, but these bacteria can change the expression of the antimicrobial peptides or can be the cause of their destruction due to virulence factors. In addition, the concentration of β-defensins may be affected by the cytokines, synthesized during inflammation in periodontal tissues. Compared with individuals without IPD the patients with chronic generalized gingivitis, aggressive and chronic generalized periodontitis most often have changes in the expression of β-defensins both up and down, which also depends on the stage of the inflammatory process.Conclusion. β-defensins play an important role in the antimicrobial protection of periodontal tissues from the introduction of periodontal pathogens and can be used as markers of IBD. However evaluating the concentration of defensins in the oral fluid, it is necessary to take into account concomitant factors: the presence of periodontal pathogens, the presence of certain cytokines, the stage of the disease, the presence of concomitant pathology and the genetic aspect.

305 Awardee Talk: Transferring a culture of biosecurity to the feedmill

Abstract A culture of on-farm biosecurity has been established and practiced by modern swine production systems for many years. The value of this has been repeatedly demonstrated through improved animal health and performance based on the prevention of disease introduction to the herd. With the introduction of Porcine Epidemic Diarrhea Virus (PEDV) to the US swine industry in 2013, we have learned that feed and feed ingredients can be vectors of disease transmission. Therefore, there is a heightened need to transfer our on-farm biosecurity culture to our feedmills and entire feed supply chain as a way to help prevent disease introduction into swine farms. Feedmills are designed to efficiently and effectively blend feed components into a homogenous batch, and the potential to distribute contaminated feed to multiple farms is significant. While feed and ingredients can be vectors of disease and pathogen transmission, our data continues to show that people are a major risk for pathogen transmission throughout the feed supply chain. Key biosecurity principles such as exclusion, prevention, isolation, mitigation, disinfection, and containment should be adopted and enforced for a strong feedmill biosecurity program. A written feedmill biosecurity plan should be developed and a training program that covers all employees as well as visitors and delivery drivers should be implemented. Continuous risk assessment and environmental monitoring should be utilized to identify new areas of risk and to assess the current status. Unfortunately, feedmills are nearly impossible to completely disinfect and therefore every effort should be made to prevent the introduction of pathogens into the mill. Research that we have conducted with PEDV and African Swine Fever Virus has demonstrated that adopting a culture of biosecurity at the feedmill will reduce risk of disease and pathogen exposure on farms.

394 Opportunities to enhance wean-to-finish pig survival

Abstract Swine productivity as measured by total pigs born, growth rate, and efficiency has improved steadily over the last few decades. However, post-weaning mortality has not improved for several years. Estimates for post-weaning mortality are 3.6% for nursery, 4.1% for grow-finish, and 5.6% of pigs entering the wean-finish phase (USDA, 2015). The first step in improving wean-to-finish survival is to understand major causes. Post-weaning mortality can be categorized into non-infectious and infectious causes. Non-infectious factors can be classified into anatomic abnormalities, toxicity, animal factors, facility factors, nutritional inadequacies, season, and management factors. Important non-infectious mortality factors identified through literature review include birth weight, preweaning management, weaning age and weight, and season. Additionally, a low incidence but high consequence cause for individual pigs is abdominal organ torsion. Sodium ion or ionophore toxicosis or dietary imbalance due to feed formulation or manufacture error are infrequent, but can be high magnitude. Infectious factors can be categorized as respiratory disease caused by swine influenza virus, porcine reproductive and respiratory syndrome virus, Mycoplasma spp., Glasserella parasuis, and others; enteric disease caused by Lawsonia intracellularis, Brachyspira spp; or systemic disease caused by Erysipelothrix rhusiopathiae, Streptococcus suis, porcine circovirus, and others. Non-infectious and infectious mortality causes both need focus to improve wean-to-finish survival. Because of their importance in affecting survival rate, producers should focus on increasing birth and weaning weight, colostrum intake, and weaning age. Strategies to reduce abdominal organ torsions and gastric ulcers also are important for producers experiencing problems with these low frequency, high magnitude problems. Elevating biosecurity to prevent introduction of pathogens can reduce mortality due to infectious agents. For pathogens already present in the herd, producers must determine if the best management strategy is control (ex. vaccination), elimination (ex. mass exposure), or depopulation. Reducing post-weaning mortality remains an opportunity area in the swine industry.

Phytophthora Introductions in Restoration Areas: Responding to Protect California Native Flora from Human-Assisted Pathogen Spread

Over the past several years, plantings of California native plant nursery stock in restoration areas have become recognized as a pathway for invasive species introductions, in particular Phytophthora pathogens, including first in the U.S. detections (Phytophthora tentaculata, Phytophthora quercina), new taxa, new hybrid species, and dozens of other soilborne species. Restoration plantings may be conducted in high-value and limited habitats to sustain or re-establish rare plant populations. Once established, Phytophthora pathogens infest the site and are very difficult to eradicate or manage—they degrade the natural resources the plantings were intended to enhance. To respond to unintended Phytophthora introductions, vegetation ecologists took a variety of measures to prevent pathogen introduction and spread, including treating infested areas by solarization, suspending plantings, switching to direct seeding, applying stringent phytosanitation requirements on contracted nursery stock, and building their own nursery for clean plant production. These individual or collective actions, loosely coordinated by the Phytophthoras in Native Habitats Work Group ensued as demands intensified for protection from the inadvertent purchase of infected plants from commercial native plant nurseries. Regulation and management of the dozens of Phytophthora species and scores of plant hosts present a challenge to the state, county, and federal agriculture officials and to the ornamental and restoration nursery industries. To rebuild confidence in the health of restoration nursery stock and prevent further Phytophthora introductions, a voluntary, statewide accreditation pilot project is underway which, upon completion of validation, is planned for statewide implementation.

Tree health in South Africa: Retrospect and prospect

South Africa is a country with very limited natural forest cover. Consequently, the timber and fibre needs of the country cannot be provided for from indigenous forest. It is largely for this reason that South Africa initially developed a highly productive plantation forest industry, which today makes a substantial contribution to the local economy. These plantations are based on non-native species of Eucalyptus, Pinus and Australian Acacia. In the early years of establishment, South African plantations were relatively free of pest and pathogen problems. But, over time, an increasing number of insects, fungi and bacteria have emerged as serious threats to the sustainability of the forestry industry. Numerous native pests and pathogens, especially insects, have adapted to these introduced tree species to cause damage or disease. The problem is compounded by the accidental introduction of non-native pests and pathogens, and this has been at a rapidly increasing rate over the past three decades. Some of these introduced pests and pathogens also threaten the fitness and even the survival of many indigenous South African tree species. Fortunately, South Africa has developed an impressive knowledge base and range of integrated management options to deal with these problems. This development was first driven by government programmes, and in more recent years by public–private partnerships between industry, universities and government. It is clear from the pattern of emergence of pests and pathogens in recent years that South Africa will deal with an increasing number of these problems and a continuously changing tree health environment. This requires robust investment in both quarantine and mitigation mechanisms to protect the country’s biodiversity as well as to ensure the sustainability of its wood and fibre industries.
 Significance:
 
 This review about tree health in South Africa was in part inspired by the 2020 International Year of Plant Health. Plant health, and particularly tree health, is an important topic in regard to the sustainability of our forestry industry and conservation of our native forests. South Africa has been a leader in the field and this review highlights some of the achievements that researchers in the country, both past and present, have attained.

European eel restocking programs based on wild-caught glass eels: Feasibility of quarantine stage compatible with implementation of prophylactic measures prior to scheduled reintroduction to the wild

The anthropogenic spread of pathogens contributes to the decline of some species. However, restocking programs implemented to counteract the decline of such populations can also contribute to the spread of pathogens, in particular for endangered species that cannot be bred in captivity, where populations used in restocking must be sourced from the wild with no control over sanitary status. A prime example of this is the endangered species European eel (Anguilla anguilla). As part of eel restocking programs, glass eels are captured in estuaries for later release further inland. In cases where release occurs immediately after capture, pre-release quarantine is important for mitigation of sanitary risks. In this study, we explored the impact of different quarantine conditions on glass eel sanitary status, morphology, behaviour and quarantine/post-quarantine survival in order to evaluate the feasibility and optimization of quarantine stages. Replicate experiments were conducted in 2017 and 2018, using glass eels of different geographical origin. The results suggest that glass eels entering estuaries are free of pathogens and so that their capture at this early stage reduces the risk of the anthropogenic introduction of pathogens through restocking programs. They support the use of a 15-day pre-release quarantine period to allow easier management of release processes and the implementation of prophylactic and therapeutic measures as part of these useful conservation programs.

Survival of viral haemorrhagic septicaemia virus and infectious haematopoietic necrosis virus in the environment and dried on stainless steel.

Viral haemorrhagic septicaemia virus (VHSV) and infectious haematopoietic necrosis virus (IHNV) are important viral pathogens posing a serious threat to salmonid fish. Survival of two isolates of IHNV and one of VHSV was assessed at temperatures ranging from 4 to 25°C: (a) after drying on stainless steel, (b) in cell culture medium, (c) in filtered river water, (d) in unfiltered river water, and (e) survival, adsorption and desorption in river sediment and five typical soil types. The viruses survived 1 hr to > 84 days depending on the conditions. Survival was inversely related to temperature and organic and inorganic content. Both viruses remained infectious after being dried on stainless steel for several weeks highlighting the risk of mechanical transmission and persistence in a dry environment. Both adsorbed to the soils from the river water inoculum, with titres between 5.56x104 and 2.58x108 TCID50/ml after 1 hr. Clay soils adsorbed the least virus but had the greatest decrease in the river water inoculum (undetectable in ≤ 1 hr), and there was no desorption. Virus desorbed from the other soils into the surrounding water at different rates dependant on soil type (longest desorption was from chalk loam and sandy soil—detected at 28 days). When desorption was no longer detectable, virus persisted, adsorbed to the soil and remained infectious (the longest adsorption was detected in clay loam for ≥ 49 days, but all the viruses adsorbed to soils were likely to have survived longer than that detected, based on their rate of decay). The long survival of the viruses, particularly at cooler temperatures, highlights the risk of survival in the environment and waterborne spread. The data presented here are highly relevant for assessing risk of pathogen introduction via fomites (stainless steel) and for deciding on best control measures in the context of disease outbreaks.

Early detection of Neophysopella tropicalis in grapevine leaves and on spore traps by qPCR

AbstractNeophysopella tropicalis, one of the causal agents of Asian grapevine leaf rust (AGLR), can cause severe epidemics in Brazil that lead to yield losses in commercial vineyards. An early detection of the pathogen by air sampling of urediniospores on spore traps or in symptomless leaves would be valuable to multiple studies, such as epidemics modelling, risk forecasting, monitoring of pathogen introductions in rust‐free areas, and predicting the beginning of epidemics. This study developed a quantitative PCR (qPCR) protocol to quantify N. tropicalis urediniospores attached to adhesive tapes and in grapevine leaves before symptom appearance. A specific primer pair was designed based on the internal transcribed spacer (ITS) sequence region of the AGLR pathogen. Standard amplification curves using genomic DNA from urediniospores of N. tropicalis and from urediniospores attached to adhesive tapes were established. Grapevine leaves inoculated with N. tropicalis were collected at 2, 5, and 7 days postinoculation (dpi). One primer pair (580F/720R) amplified a 140 bp product in all AGLR isolates but did not amplify products of other rust genera, such as Phakopsora, Puccinia, Hemileia, Tranzschelia, Cerotelium, and Coleosporium. As little as 0.1 pg DNA and 10 urediniospores of N. tropicalis attached to adhesive tapes could be detected. qPCR enabled the detection of the pathogen as early as 2 dpi, before symptom appearance. This method can be used to monitor N. tropicalis inoculum in grapevine‐growing areas and to quantify symptomless infections of the AGLR pathogen.

Principles and Mechanisms of Wildlife Population Persistence in the Face of Disease

Emerging infectious diseases can result in species declines and hamper recovery efforts for at-risk populations. Generalizing recommendations for reducing the risk of pathogen introduction and mitigating the effects of disease remains challenging and inhibits our ability to provide guidance for species recovery planning. Given the growing rates of emerging pathogens globally, we identify key principles and mechanisms for maintaining sustainable populations in the face of emerging diseases (including minimizing the risk of pathogen introductions and their future impacts on hosts). Our synthesis serves as a reference for minimizing the risk of future disease outbreaks, mitigating the deleterious effects of future disease outbreaks on species extinction risk, and a review of the theoretical and/or empirical examples supporting these recommendations.

Giardia microti in pet Microtus guentheri: Evidence of a parasite never detected in Italy.

The genus Giardia includes several species distinguished by morphological, biological and molecular features. Currently, eight species within the genus are retained as valid. In Italy no identification of Giardia species other than Giardia duodenalis has been so far reported. Fecal samples were collected from two Günther's Voles (Microtus guentheri) positive to Giardia cysts by microscopic investigation and immunofluorescence. The voles were born in Milan (Northern Italy) from two gravid females imported from the Netherlands and kept for sale in a pet shop in Varese (Northern Italy). Positive feces were subjected to a nested PCR to amplify a 18S rRNA fragment for molecular characterization. A phylogenetic analysis was conducted to compare the obtained sequence with those of all other Giardia species available in GenBank for the 18S locus, using the Maximum Likelihood (ML) method by R software. Sequence analyses unambiguously identified the isolates as belonging to G. microti, showing 99% of identity with those of its isolates available in GenBank. A well-defined cluster, supported by significant bootstrap values and corresponding to the G. microti cluster, including sequences obtained from M. guentheri, was evidenced in the ML tree, confirming species assignment. The present finding represents the first report of G. microti from pet animals in Italy.

Survey findings of disinfection strategies at selected Norwegian and North American land-based RAS facilities: A comparative insight

Disinfection is an integral component of establishing effective biosecurity, through preventing pathogen introduction and transmission within and between aquaculture facilities. Nonetheless, there is a lack of documentation on aquaculture facility disinfection practices and strategies, thereby posing a challenge to benchmarking the current status and to determining optimal approaches. To gain a contemporary insight in this area, an internet-hosted survey was conducted for selected Atlantic salmon recirculation aquaculture (RAS) facilities in Norway (NO) and North America (NA, i.e., USA and Canada). The survey focused on the disinfection of materials and equipment in a RAS facility, and did not cover water disinfection. A total of nine facilities in NO and 16 in NA participated in the survey, which was conducted between Q2 and Q4 of 2018. Most of the responding facilities had standardised disinfection protocols (NO: 6/9; NA: 15/16); however, many respondents disclosed that their protocols had not been experimentally validated. The age of disinfection protocols was between 4 and 10 years old, with the majority of respondents regularly performing protocol appraisals. More than 80% of the facilities in both regions reported a compliance rate of 90–100%. Survey results indicated that peracetic acid-based disinfectants are the most commonly used chemicals in NO, while chlorine is predominant in NA. These disinfectants are used for the tanks and pipelines, floor, and ancillary equipment. In NO, the three topmost criteria when selecting a disinfectant were efficacy against pathogens, user safety, and ease of application. While efficacy and user safety are also prioritised in NA, it was also reported that threats of toxic residuals are also highly considered. Only one facility in NO and five in NA experienced a disease outbreak in the last 5 years. The survey responses presented the current state of aquaculture disinfection of representative land-based RAS facilities in both regions, and this information will be valuable in future benchmarking to develop robust and comprehensive disinfection strategies in salmon aquaculture.

Impact of Pronase, Sodium Thiosulfate, and Methylene Blue Combinations on Development and Survival of Sodium Hypochlorite Surface-Disinfected Zebrafish (Danio rerio) Embryos.

Embryo surface disinfection is utilized in aquaculture to decrease the risk of pathogen introduction into established colonies. Zebrafish embryos are commonly disinfected with unbuffered sodium hypochlorite at 25-50 ppm for 10 min with or without concurrent treatment with chemicals, including pronase (Pron), sodium thiosulfate, and/or methylene blue; however, the impact of these chemicals on embryo survival and development has not been evaluated. In this study, AB and casper embryos were exposed to disinfection protocols that used Pron, sodium thiosulfate, and/or methylene blue (given alone, in various combinations, or all three combined) with 50 and 100 ppm sodium hypochlorite performed 6 and 24 h postfertilization (HPF). All groups were evaluated for survival, hatching, and malformations at 5 days postfertilization. Maximal survival (69%-97%) and hatching rates (66%-94%) were generally observed with sodium hypochlorite disinfection followed by exposure to both Pron and sodium thiosulfate and maintenance in standard embryo medium without methylene blue. Methylene blue had variable effects on survival and hatching. Higher survival and hatching rates were seen in AB embryos disinfected at 6 HPF and casper embryos disinfected at 24 HPF. Susceptibility to sodium hypochlorite toxicity differed by strain, emphasizing the need to test disinfection protocols on small embryo cohorts.

Intra-regional diversity of rice bacterial blight pathogen, Xanthomonas oryzae pv. oryzae, in the Andaman Islands, India: revelation by pathotyping and multilocus sequence typing.

To investigate the genetic and pathogenic variability of Xanthomonas oryzae pv. oryzae causing bacterial blight in rice on the remote Andaman Islands, India. A total of 27 yellow-pigmented bacterial isolates representing rice fields of Andaman Islands incited blight on the susceptible-rice cultivar, C14-8. Phenotypic, pathogenic traits and 16S rRNA gene sequences revealed their identity as X. oryzae pv. oryzae. Virulence profiling indicated the prevalence of seven pathotypes of X. oryzae pv. oryzae on the Islands. Pathotypes-VI and -VII were highly virulent, whereas the pathotype-I was less virulent. Multilocus sequence typing based on nucleotide sequence polymorphism in nine housekeeping genes dnaK; fyuA; gyrB (two loci): rpoD; fusA; gapA; gltA and lepA clustered 27 isolates into 17 sequence types (STs) segregated into two clonal-complexes (CC). While CC-I comprised of isolates from Andaman Island, the CC-II is a mixture of isolates representing mainland India and Andaman Island. The data revealed trans-boundary pathogen introduction and a consequent intra-regional diversification on these islands due to the deployment of different rice cultivars in different regions. Genotyping and pathotyping of sland isolates revealed seven pathotypes distributed in two clonal complexes with strong indications for trans-boundary movement and consequent diversification of the bacterial pathogen. Highly virulent pathotypes of X. oryzae pv. oryzae that could overcome combinations of R-genes, xa13+Xa21 as well as xa5+xa13 were found prevalent in the Andaman Islands SIGNIFICANCE AND IMPACT OF THE STUDY: Genetic and virulence analysis of X. oryzae pv. oryzae in the Andaman Islands revealed introduction and host-mediated regional diversification and local adaptation of X oryzae pv. oryzae. The study calls for the need of multi-gene pyramiding for durable disease resistance and establishing stringent quarantine measures for safeguarding island agricultural practices in the future.

Population Dynamics between Erwinia amylovora, Pantoea agglomerans and Bacteriophages: Exploiting Synergy and Competition to Improve Phage Cocktail Efficacy.

Bacteriophages are viruses capable of recognizing with high specificity, propagating inside of, and destroying their bacterial hosts. The phage lytic life cycle makes phages attractive as tools to selectively kill pathogenic bacteria with minimal impact on the surrounding microbiome. To effectively harness the potential of phages in therapy, it is critical to understand the phage–host dynamics and how these interactions can change in complex populations. Our model examined the interactions between the plant pathogen Erwinia amylovora, the antagonistic epiphyte Pantoea agglomerans, and the bacteriophages that infect and kill both species. P. agglomerans strains are used as a phage carrier; their role is to deliver and propagate the bacteriophages on the plant surface prior to the arrival of the pathogen. Using liquid cultures, the populations of the pathogen, carrier, and phages were tracked over time with quantitative real-time PCR. The jumbo Myoviridae phage ϕEa35-70 synergized with both the Myoviridae ϕEa21-4 and Podoviridae ϕEa46-1-A1 and was most effective in combination at reducing E. amylovora growth over 24 h. Phage ϕEa35-70, however, also reduced the growth of P. agglomerans. Phage cocktails of ϕEa21-4, ϕEa46-1-A1, and ϕEa35-70 at multiplicities of infections (MOIs) of 10, 1, and 0.01, respectively, no longer inhibited growth of P. agglomerans. When this cocktail was grown with P. agglomerans for 8 h prior to pathogen introduction, pathogen growth was reduced by over four log units over 24 h. These findings present a novel approach to study complex phage–host dynamics that can be exploited to create more effective phage-based therapies.

ОЦЕНКА ЛИНИЙ ITMI ЯРОВОЙ МЯГКОЙ ПШЕНИЦЫ НА УСТОЙЧИВОСТЬ К ТВЁРДОЙ ГОЛОВНЕ

The aim of the study is to search for new sources of resistance to stinking smut among the ITMI population lines. The article presents analysis of data on the study of reaction of spring soft wheat, which is resistant to stinking smut, to the introduction of pathogen. The experimental part of the work was carried out in 2016-2018 on an infectious background of a phyto-stage in the conditions of the forest-steppe of the Middle Volga region (Samara ARI-branch of SamRC RAS, Bezenchuk country). 77 lines of ITMI mapping population were used as objects, as well as a population of Tilletia caries pathogen collected from zoned and susceptible varieties. In the experiment, healthy seeds (control) and seeds infected with pathogen were sown. For inoculation of wheat seeds with this pathogen, the A. I. Borggardt-Anpilogov method was used. Cleaning was carried out manually, by cutting plants from the plot in the phase of full ripeness. Accounting for damage to samples of stinking smut was carried out in the phase of milk-wax stage of the grain, carefully viewing and counting all the spikes on the plot. A five-grade scale created by V. I. Krivchenko was used for classing the samples resistance to stinking smut. Weather conditions in the years of research were different, but developed mainly favorable for creating an infectious background, as well as for the growth of spring wheat plants. 4 lines had immunity (ITMI-40, 75, 90, 91). Practical stability was observed on 5 lines (damage from 4.3 to 10.0%). 8 lines were poorly susceptible (the maximum lesion was 21.0%). With an average susceptibility, 21 lines were isolated, the remaining lines were mostly affected by more than 50%. Selected samples can serve as a valuable source material for use in immunological breeding programs.

Features of control measures and prevention of foot-and-mouth disease of large horned cattle of meat breeds

A large number of breeding heifers and bull-producers of meat breeds were brought to the Russian Federation from different countries of the world. Breeding heifers were imported to individual farms. Extensive and semi-intensive systems of large horned cattle keeping are used more often in the Russian Federation. The extensive system provides for free movement of animals and selection of pasture areas and access to watering and shelter areas. Large number of beef cattle have been imported to the Russian Federation from around the world in recent years. Timely epizootic and clinical diagnostics play a primary role in the system of measures for the control and prevention of foot-and-mouth disease. The existing system of measures for the control and prevention of foot-and-mouth disease in the Russian Federation provides for the prevention of the introduction of the virus, systematic vaccination of ruminants and revaccination of young animals and control of the level of post-vaccination antibodies. The risk of introduction of pathogens in extensive system for beef cattle is significantly higher than in intensive system. The highest risk of introduction of infectious agents exist with wild and domestic cloven-hoofed animals. Contaminated air, water and pastures can be pathway for the introduction of infectious agents into beef herds. According to the OIE Code beef-breed large horned cattle must be subject to daily inspection. All personnel working with beef-breed large horned cattle should have professional training in accordance with their job responsibilities and understand the technology of housing and behavior of animals, as well as biosecurity measures and general symptoms of diseases and signs of deterioration of the physiological state. The main features of large horned cattle breeding, distinguishing it from other areas of productivity, are early maturity and high quality meat. It is believed that professional training in these matters is acquired through specialized training and practical experience in working with beef cattle. Knowing the etiology of diseases and their syndromes is important in identifying potential animal welfare issues.

Does the Introduction of Alien Species Represent a Sanitary Threat for Native Species? The Case of the Eastern Cottontail Sylvilagus floridanus in Italy.

Introduction of alien species is a well-known threat to biodiversity. Where newly introduced, alien species may pose a risk for the local ecological community by competing for resources or by introducing pathogens. Sylvilagus floridanus is an American lagomorph introduced into Europe in the second half of 20th century, for hunting. This study evaluated the structure and epidemiological characteristics of the gastrointestinal parasite community in an introduced population of S. floridanus in the Province of Alessandria (Piedmont Region—Italy). Three alien parasites were reported out of 271 animals: Obeliscoides cuniculi in the stomach, Trichostrongylus calcaratus in the small intestine, and Passarulus nonnanulatus in the large intestine. All these nematodes are commonly reported in S. floridanus in its natural range, but they represent alien species in Europe. The report of these alien parasites is an example of the unexpected consequences caused by the introduction of non-native vertebrates. The documented introduction of new pathogens may alter the parasite community of the native lagomorphs, with possible long-term effects on local ecological dynamics.

“A reference genome assembly and adaptive trait analysis of Castanea mollissima ‘Vanuxem,’ a source of resistance to chestnut blight in restoration breeding”

Forest tree species are increasingly subject to severe mortalities from exotic pests, pathogens, and invasive organisms, accelerated by climate change. Such forest health issues are threatening multiple species and ecosystem sustainability globally. One of the most extreme examples of forest ecosystem disruption is the extirpation of the American chestnut (Castanea dentata) caused by the introduction of chestnut blight and root rot pathogens from Asia. Asian species of chestnut are being employed as donors of disease resistance genes to restore native chestnut species in North America and Europe. To aid in the restoration of threatened chestnut species, we present the assembly of a reference genome for Chinese chestnut (C. mollissima) Vanuxem, one of the donors of disease resistance for American chestnut restoration. From the de novo assembly of the complete genome (725.2 Mb in 14,110 contigs), over half of the sequences have been anchored to the 12 genetic linkage groups. The anchoring is validated by genetic maps and in situ hybridization to chromosomes. We demonstrate the value of the genome as a platform for research and species restoration, including signatures of selection differentiating American chestnut from Chinese chestnut to identify important candidate genes for disease resistance, comparisons of genome organization with other woody species, and a genome-wide examination of progress in backcross breeding for blight resistance. This reference assembly should prove of great value in the understanding, improvement, and restoration of chestnut species.

Infectious disease outbreaks among forcibly displaced persons: an analysis of ProMED reports 1996\u20132016

BackgroundThe United Nations Refugee Agency (UNHCR) estimates the number of forcibly displaced people increased from 22.7 million people in 1996 to 67.7 million people in 2016. Human mobility is associated with the introduction of infectious disease pathogens. The aim of this study was to describe the range of pathogens in forcibly displaced populations over time using an informal event monitoring system.MethodsWe conducted a retrospective analysis of ProMED, a digital disease monitoring system, to identify reports of outbreak events involving forcibly displaced populations between 1996 and 2016. Number of outbreak events per year was tabulated. Each record was assessed to determine outbreak location, pathogen, origin of persons implicated in the outbreak, and suspected versus confirmed case counts.ResultsOne hundred twenty-eight independent outbreak events involving forcibly displaced populations were identified. Over 840,000 confirmed or suspected cases of infectious diseases such as measles, cholera, cutaneous leishmaniasis, dengue, and others were reported in 48 destination countries/territories. The average rate of outbreak events concerning forcibly displaced persons per total number of reports published on ProMED per year increased over time. The majority of outbreak events (63%) were due to acquisition of disease in the destination country.ConclusionThis study found that reports of outbreak events involving forcibly displaced populations have increased in ProMED. The events and outbreaks detected in this retrospective review underscore the importance of capturing displaced populations in surveillance systems for rapid detection and response.