Infectious factor diseases in domestic small animals (carnivorous and herbivorous fur animals, wool and meat rabbits

Infectious factorial diseases of domesticated small animals are infection dependent diseases, whose pathogenesis is finally activated by additional, secondary factors, that influence the multiplying and spreading of latent and clinical symptomless infective agents present in the animals. These factorial diseases are not autonomous infectious processes, but only special types and courses of diseases by secondary activated infective agents. Secondary factors may be of exogenous origin (housing, climate, feeding, managing) or may arise by endogenic processes (immunity, resistance disregulations a.o.). In fur bearing animals and rabbits infectious factorial diseases arise by activation of latent, symptomless infections of mucosal membranes in the nose and oral cavity, in the intestinal tract, in the descending urinary tract and on the external skin. The majority of infection activating secondary factors go back on wrong housing conditions, extreme climate, malnutrition and simultaneous infections, but also animal specific situations and immunosuppression may influence the activation of latent infections. - Typical factorial diseases in fur bearing animals and rabbits are: the infectious coryza (Pasteurella multocida, Bordetella bronchiseptica) in rabbits, the Coli-dysentery and the enterotoxemia in rabbits and herbivorous fur animals, the ascending infections of urinary tract, particular in young male minks, and the different types of microbial dermatitis in all small animals. - In the prevention and control of infectious factorial diseases the improvement of housing and living conditions as well as feeding the animals with species conforming and nonobjectionable food are most important and essential measures.     

Infectious disease factors in swine--pathogenesis and control

Infectious factorial diseases occur in all porcine age groups and are specially responsible for high mortality-rates in weaners and young feeder pigs affected by bronchopneumonia and enteritis. The pathogenesis of infectious factorial diseases is dominated by disease promoting factors of the pigs' environment as well as by false treatment with medicines and disinfectants. The control of infectious factorial diseases needs thorough examination as a basis for herd specific measures. Preventive measures should be completed in all pig herds by animal protective arrangements which are prescribed in the rules for prevention of cruelty to animals and contagious diseases.     

猪传染病发生原因及预防

生猪养殖属于国内畜禽养殖业中的主要项目,生猪养殖良好发展能满足市场发展的需求。近年,国内猪养殖业发展的稳定性并不明显,在猪养殖总量不断增加的条件下,猪传染病的风险也随之提高,导致猪养殖过程伴随一些影响因素,影响猪养殖业稳定发展。因此,猪养殖企业相关工作人员应在充分掌握以上情况的同时,结合猪传染病特点,采取合理的防控对策,力求在根本上防控猪传染病,促进猪养殖业稳定发展。     

Impact of nutrition on the innate immune response to infection in poultry

Viral and bacterial diseases remain a threat to the poultry industry and countermeasures to prevent and control them are needed due to production losses. With the continued threat of exotic and emerging diseases and concern over the use of antibiotics in animal production, there is a serious and urgent need to find safe and practical alternatives to prevent or control pathogens. Identification of new tools for the design of new immunological interventions or therapeutic antimicrobials to reduce microbial pathogens in poultry is now required more than ever. Immunological interventions to reduce microbial pathogens in poultry would be of great value to the poultry industry and to the consumer. We have been advocating boosting immunity and encouraging the host to utilize its innate immune system to control and clear infections. Our research has addressed the use of innate immune mechanisms and components to develop new immune modulators (prophylactic and therapeutic) and the characterization and production of antimicrobial peptides as potential immune modulators in poultry. Dietary bioactive food components that interact with the immune response have considerable potential to reduce susceptibility to infectious diseases. With this premise, this paper asks and answers a series of pertinent questions on the utilization of avian immunity for increasing resistance to a variety of potential pathogens problematic in today's commercial poultry industry. Using experimental data to provide answers to these questions, we hope to stimulate a dialog between avian immunologists and nutritionists that results in coordinating and integrating their expertise into specific practical solutions that will benefit the industry and improve the well-being of commercial poultry.     

Viral infections in pigeons

This review provides a current update on the major viral diseases of the domestic pigeon (Columba livia domestica), based on scientific reports and clinical experience. Paramyxovirus 1, adenovirus, rotavirus, herpesvirus 1, poxvirus and circovirus infections are described according to common clinical signs and target tissues. Since pigeons are sometimes treated as if they were poultry, the review also summarises the common viral infections of poultry for which pigeons are considered resistant. It is hoped that the review will provide a useful reference for veterinarians and others and offer advice on the diagnosis, treatment and prevention of the major infectious diseases of pigeons.     

Conventional and alternative housing systems for poultry--point of view of infectious disease medicine

The use of conventional battery cages for hens will be prohibited in Germany in 2007. Only few studies, however, have considered the differences between battery cages and alternative systems with regard to infectious diseases. The existing gaps in the current knowledge need to be closed by research and measures must be developed that will prevent the spread of viral, bacterial, and parasitic infections in alternative poultry housing systems.With regard to virus infections, avian influenza requires particular attention. Since wild birds, particularly anseriformes, represent a reservoir for avian influenza viruses, free-ranging poultry is much more at risk of infection than birds in closed hen-houses. Appropriate measures must prevent direct contact with wild birds and transmission via contaminated water, feed, or equipment. Several bacterial infections of poultry represent zoonoses. Salmonella and Campylobacter are considered as particularly important. To avoid a potential increase in the risk of infection for consumers due to poultry keeping systems that might favour infections with bacterial zoonotic agents, there is a special need for research in this area. With regard to parasitic infections, coccidioses may cause problems in alternative poultry housing systems, and lead to considerable economic consequences. The epidemiological situation concerning infections with Histomonas meleagridis needs to be analysed. Since all compounds that had been used for prophylactic or therapeutic purposes in the past have been banned, there is a need to develop new drugs which are safe for animals and humans.     

Housing- and management-specific effects on the health of swine

Important diseases with regard to inadequate housing and management conditions in pig production are given. Typical examples like claw lesions, cannibalism and infectious factorial diseases are described. Beside negative factors of pig housing and management which are of particular pathogenic importance some aspects of disease control and herd health are listed finally.     

中兽药在畜禽病毒性传染病中的应用及发展前景

中兽药（Tradition Chinese Veterinary Medicine）是指以天然植物、动物和矿物为原料,炮制加工而成的饮片及其制剂,并在中兽医药学理论指导下用于动物疾病防治与提高生产性能的药物。当前,我国动物疾病面临的防治形势十分严峻：旧病复发、新病又不断发生;混合感染和继发感染疾病增多,且多出现隐性临诊表现;免疫抑制性病原感染普遍。因此在西药的薄弱领域可充分发挥中兽药的优势,特别是针对畜禽疾病中占重要部分的病毒性传染病,中兽药具有多方位调节和治疗作用,可提高动物机体的免疫力和抗应激能力。同时,国家对食品安全、公共卫生安全和健康养殖理念也日趋重视。由于中兽药具有独特的天然属性、用药原则、较高的安全性和有效性,使其拥有前所未有的发展机遇。本文就中兽药在畜禽病毒性传染病中的特点和应用现状以及发展前景作一综述。     

Emergence of novel strains of avian infectious bronchitis virus in Sweden

Infectious bronchitis virus (IBV) causes avian infectious bronchitis, an important disease that produces severe economic losses in the poultry industry worldwide. Recent IBV infections in Sweden have been associated with poor growth in broilers, drop in egg production and thin egg shells in layers. The complete spike gene of selected isolates from IBV cases was amplified and sequenced using conventional RT-PCR. Nucleotide and amino acid sequence comparisons have shown that the recent isolates bear 98.97% genetic similarity with strains of the QX-like genotype. The phylogenetic analysis revealed that strains predominant in the nineties, which were of the Massachusetts type, have been replaced by D388/QX-like strains, however the evolutionary link could not be established. The homology between the two genotypes was 79 and 81%. Remarkably, a strong positive selection pressure was determined, mostly involving the S1 subunit of the S gene. This strong selective pressure resulted in recombination events, insertions and deletions in the S gene. Two new isolates generated from recombination were found with nucleotide sequence diverging 1.7-2.4% from the D388/QX-like branch, indicating the emergence of a new lineage. The study demonstrates a constant evolution of IBV that might be in relation to increased poultry farming, trade and vaccine pressure. The findings underscore the importance of continuous monitoring to control spread of infections, as well as to timely adjust diagnostic methods, molecular epidemiological studies, development and use of vaccines that are adapted to the changing disease scenario.     

Occurrence of concurrent infectious diseases in broiler chickens is a threat to commercial poultry farms in Central Ethiopia

Commercial poultry production is one of the flourishing ventures of animal production in Ethiopia. It has been providing to the demands of proteins at least to the urban population, though concurrent health constraints are hampering its intended potential. This study reports the influence of infectious diseases in commercial broiler farms in central Ethiopia. In this study, clinical signs, gross lesions, laboratory tests (serology, bacterial culture, histopathology and parasitology) and farm management data were used to identify major causes of outbreaks in an age specific manner in broiler chickens in three poultry farms in Debre Zeit, Central Ethiopia. The outbreaks detected in the farms were due to mycoplasmosis, salmonellosis, colibacillosis, coccidiosis and infectious bursal disease. It is observed that the occurrence of concurrent diseases in the farms significantly affects the productivity and health status of broilers. The risk factors that predispose birds to the various infections in the different farms studied were also recorded. In addition, recommendations were also provided.     

Mechanisms of immunosuppression.

Immunosuppresive disease is a major economic concern in domestic poultry production. Although many immunosuppressive agents have been described, mechanisms of how infectious and noninfectious agents compromise the immune system are poorly understood in avian species. Two categories, generalized and antigen-specific immunosuppression have been described in mammals. Generalized immunosuppression produces overall reduced responsiveness and increased susceptibility to a wide variety of infectious and neoplastic diseases. The best characterized immunosuppressive mechanisms are described in HIV-1 infections that lead to acquired immune deficiency syndrome (AIDS) in humans. In contrast, the antigen-specific suppression observed in human leprosy illustrates how an infecting agent selectively suppresses host responses against itself favoring bacterial spread. Both diseases have well-defined clinical staging classifications that correlate with specific immunological defects. An approach to studying immunosuppressive mechanisms in the avian suggests the need for relating pathogenesis with tests of immune responsiveness using a series of increasingly more specific immunological assays to pinpoint defects.     

Nutritional significance of amino acids,vitamins and minerals as nutraceuticals in poultry production and health – a comprehensive review

Nutraceuticals have gained immense importance in poultry science recently considering the nutritional and beneficial health effects of their constituents. Besides providing nutritional requirements to birds, nutraceuticals have beneficial pharmacological effects, for example, they help in establishing normal physiological health status, prevent diseases and thereby improve production performance. Nutraceuticals include amino acids, vitamins, minerals, enzymes, etc. which are important for preventing oxidative stress, regulating the immune response and maintaining normal physiological, biochemical and homeostatic mechanisms. Nutraceuticals help in supplying nutrients in balanced amounts for supporting the optimal growth performance in modern poultry flocks, and as a dietary supplement can reduce the use of antibiotics. The application of antibiotic growth enhancers in poultry leads to the propagation of antibiotic-resistant microbes and drug residues; therefore, they have been restricted in many countries. Thus, there is a demand for natural feed additives that lead to the same growth enhancement without affecting the health. Nutraceuticals substances have an essential role in the development of the animals’ normal physiological functions and in protecting them against infectious diseases. In this review, the uses of amino acids, vitamins and minerals as well as their mode of action in growth promotion and elevation of immune system are discussed.     

Epidemiologic characterization of Colorado backyard bird flocks

Backyard gallinaceous bird flocks may play an important role in the spread of infectious diseases within poultry populations as well as the transmission of zoonotic diseases to humans. An epidemiologic characterization was conducted of Colorado backyard flocks to gather information on general flock characteristics, human movement of birds, human-bird interaction, biosecurity practices, and flock health. Our results suggest that backyard poultry flocks in Colorado are small-sized flocks (68.6% of flocks had < 50 birds); consist primarily of layer chickens (85.49% of flocks), show chickens (32.18% of flocks), and waterfowl (34.07% of flocks); and are primarily owned for food (meat or egg) production for the family (86.44%) or as pet or hobby birds (42.27%). The backyard flock environment may promote bird-to-bird transmission as well as bird-to-human transmission of infectious disease. Birds are primarily housed with free access to the outside (96.85%), and many are moved from the home premises (46.06% within 1 yr). Human contact with backyard flocks is high, biosecurity practices are minimal, and bird health is negatively impacted by increased movement events. Increased knowledge of backyard bird characteristics and associated management practices can provide guidelines for the development of measures to decrease disease transmission between bird populations, decrease disease transmission from birds to humans, and increase the overall health of backyard birds.     

Infection-interactions in Ethiopian village chickens

Chickens raised under village production systems are exposed to a wide variety of pathogens, and current or previous infections may affect their susceptibility to further infections with another parasite, and/or can alter the manifestation of each infection. It is possible that co-infections may be as important as environmental risk factors. However, in cross-sectional studies, where the timing of infection is unknown, apparent associations between infections may be observed due to parasites sharing common risk factors. This study measured antibody titres to 3 viral (Newcastle disease, Marek's disease and infectious bursal disease) and 2 bacterial (Pasteurella multocida and Salmonella) diseases, and the infection prevalence of 3 families of endo- and ecto-parasites (Ascaridida, Eimeria and lice) in 1056 village chickens from two geographically distinct populations in Ethiopia. Samples were collected during 4 cross-sectional surveys, each approximately 6 months apart. Constrained ordination, a technique for analysis of ecological community data, was used to explore this complex dataset and enabled potential relationships to be uncovered and tested despite the different measurements used for the different parasites. It was found that only a small proportion of variation in the data could be explained by the risk factors measured. Very few birds (9/1280) were found to be seropositive to Newcastle disease. Positive relationships were identified between Pasteurella and Salmonella titres; and between Marek's disease and parasitic infections, and these two groups of diseases were correlated with females and males, respectively. This may suggest differences in the way that the immune systems of male and female chickens interact with these parasites. In conclusion, we find that a number of infectious pathogens and their interactions are likely to impact village chicken health and production. Control of these infections is likely to be of importance in future development planning.     

畜禽氧化应激与炎症及多酚的干预作用

氧化应激是畜禽体内活性氧产生与保护机制消除的失衡,可导致组织产生氧化损伤,最终诱发炎性疾病。氧化应激可激活多种转录因子,导致炎症途径相关基因的差异表达,由氧化应激引起的炎症是许多慢性疾病的病因。多酚作为植物次生代谢产物,被认为是有效的辅助治疗佐剂,在人和动物中发挥潜在的抗氧化和抗炎作用。多酚也被认为是具有应用潜力的畜禽饲料添加剂。综述了畜禽氧化应激与炎症的关系及机制、多酚对畜禽的抗氧化和抗炎作用及机制,以期为动物疾病抗氧化疗法的应用和新型抗炎药物的开发提供参考。     

Developments in international standardization

Trade in animals and animal products has reached global proportions and so too has the threat of infectious diseases of veterinary importance. The Manual of Standards for Diagnostic Tests and Vaccines, published by the Office International des Epizooties (OIE), contains chapters on infectious diseases that may cause various degrees of socio-economic, public health, and/or zoo-sanitary consequence. These chapters cover the major diseases of cattle, sheep, goats, horses, pigs, poultry, lagomorphs and bees. A number of factors are considered when qualifying animals and animal products for international trade including epidemiological, clinical and testing parameters. Of particular note and relevance is a strong international movement to standardize the test methods and reference reagents in order to promote harmonization of testing and facilitation of trade. There is message here that is directed to those of us involved in the development and application of test methods for infectious disease diagnosis. Serological test methods have been and still remain the mainstay of diagnostic methods prescribed for trade. More than ever, there is a need to observe and apply international guidelines for the development and validation of serological test methods. There is also a need to develop international standard reagents for use in the calibration of test methods and the production of national and working standards. In the future, veterinary diagnostic testing laboratories involved in trade may also require a form of international accreditation unique to their specialty. This presentation describes the current developments in international standardization of test methods and reference reagents.     

Poultry husbandry and animal health

Close interactions are existing between poultry husbandry and poultry health. The more housing systems and the environment of the animals can be controlled, the less the general risk of disorders in poultry flocks--especially of diseases which are caused by the introduction of microoganisms. Resulting deterimental effects will affect not only the animals themselves, but also pose a risk indirectly for humans via food originating from animals under production. Also, by keeping the risk of infections as low as possible, the use of therapeutics can be avoided. This will reduce the risk of residues in food of animal origin. In summary, with all probability open poultry husbandry systems, especially those including free range systems pose increased risks for poultry health and consequently for the quality of food originating from poultry production. At least, those systems require highest standards of biosecurity, defined as management, location, farm layout, cleaning and desinfection incl. pest control programs, immunization and specific veterinary monitoring concepts to prevent infections.     

Specified pathogen-free poultry flocks: the current situation

Before the implementation of strategies to establish specified pathogen-free commercial poultry flocks, the ultimate goals need to be identified: 1) consumer protection by minimizing the risk for zoonotic diseases and food-borne pathogens, and/or 2) animal health protection against primary and secondary pathogens. The success for the establishment of specific pathogen-free poultry flocks depends on the biological characteristics, the epidemiological distribution and the transmission route of each pathogen. For zoonotic pathogens such as Salmonella Typhimurium, Salmonella Enteritidis, Campylobacter jejuni or the high pathogenic avian influenza virus, eradication has to be ultimate goal. Despite tremendous control efforts in field, only partial control of these pathogens has been achieved so far. In the future it will be necessary to continue these eradication efforts by combining optimized hygiene programs at all production levels with intensive monitoring and immunoprophylaxis. For primary pathogens affecting the health condition of poultry without known zoonotic potential, such as Salmonella Gallinarum, avian Mycoplasma or leucosis virus, specified pathogen free flocks have been established on the parent and grandparent level. In order to achieve a status free of these pathogens, rigid hygiene control, especially on the hatchery level and monitoring programs combined with elimination of pathogen- and antibody-positive birds were implemented. Nevertheless, the economically most important diseases of modern poultry production are of multifactorial origin. Ubiquitous secondary pathogens in combination with insufficient management or immunosuppressive agents induce great economic losses for the poultry producers. These secondary pathogens can not be eliminated due to their ubiquitous distribution. In the future only a reduction of these factorial diseases will be possible combining hygiene management and optimization of poultry husbandry. For the establishment of specified pathogen free poultry flocks in the field, risk analysis is necessary and the structure of poultry production has to be considered before and eradication program can be carried out successfully.     

The Ins and Outs of siderophore mediated iron uptake by extra-intestinal pathogenic Escherichia coli

Extraintestinal pathogenic E. coli (ExPEC) are responsible for many infectious diseases in livestock, such as airsacculitis in poultry, acute mastitis in dairy animals and neonatal septicaemia and urinary tract infections (UTI) in pigs and cattle. In their animal hosts, ExPEC have to cope with low iron availability. By using different strategies, ExPEC strains are able to retrieve iron sequestered by host proteins. One of these strategies is the use of siderophores, which are small secreted molecules with high affinity for iron. ExPEC are known to synthesize up to four different types of siderophores: enterobactin, salmochelins, yersiniabactin and aerobactin. Steps required for iron acquisition by siderophores include (1) siderophore synthesis in the cytoplasm, (2) siderophore secretion, (3) ferri-siderophore reception, (4) ferri-siderophore internalization and (5) iron release in the cytoplasm. Each siderophore has specific properties and may be differentially regulated to provide different advantages, potentially allowing ExPEC to adapt to different environmental conditions or to overcome host innate immunity. Iron acquisition by siderophores plays a significant role in ExPEC virulence and, as it requires outer membrane receptors, it constitutes an interesting target for the development of vaccines that could be used to limit the number of infectious diseases due to ExPEC in livestock.