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PubMed2005

Multiple perineuriomas in chicken (Gallus gallus domesticus).

Intraneural perineurioma is an extremely rare condition characterized by perineurial cell proliferation within peripheral nerve (PN) sheaths. In the veterinary field, this entity has been reported only in a dog. We examined multiple enlargements of PNs in 11 chickens (Gallus gallus domesticus) (9 Japanese bantams and 2 specific pathogen-free White Leghorn), which were inoculated with an avian leukosis virus (ALV) causing so-called fowl glioma. All chickens clinically exhibited progressive leg paralysis. Lumbosacral plexus, brachial plexus, and/or spinal ganglion were commonly affected, and these nerves contained a diffuse proliferation of spindle cells arranged concentrically in characteristic onion bulb-like structures surrounded by residual axons and myelin sheaths. The spindle cells were immunohistochemically negative for S-100alpha/beta protein. Electron microscopy revealed that these cells were characterized by short bipolar cytoplasmic processes, occasional cytoplasmic pinocytotic vesicles, and discontinuous basal laminae. These features are consistent with those of intraneural perineurioma. Furthermore, the specific sequence of the ALV was detected in the PN lesions of 8/11 (73%) birds by polymerase chain reaction. These results indicate that the multiple intraneural perineuriomas of chicken may be associated with the ALV-A causing fowl glioma.

Animals↗
PubMed1995

Risk assessment related to veterinary biologicals: side-effects in target animals.

Despite established control measures, the large-scale use of veterinary biologicals may involve side-effects. The most common side-effects observed include the following: injection site reactions, systemic reactions, allergic reactions, effects on the immune system, residual pathogenicity, inadequate inactivation, genetic recombination, contamination. New technologies, new harmonised regulations, and commitment to quality will ensure a continuous supply of safe and innovative products.

Animals↗
PubMed2004

Microbial adaptation and change: avian influenza.

The evolution of influenza is a continuing process involving viral and host factors. The increasing frequency of emergence of the highly pathogenic H5N1, H7N3 and H7N7 influenza viruses and the panzootic spread of H9N2 influenza virus, all of which can be potentially transmitted to humans, are of great concern to both veterinary and human public health officials. The question is how soon the next pandemic will emerge. A convergence of factors, including the population densities of poultry, pigs and humans, are likely factors affecting the evolution of the virus. Highly concentrated poultry and pig farming, in conjunction with traditional live animal or 'wet' markets, provide optimal conditions for increased mutation, reassortment and recombination of influenza viruses. Strategies to reduce the evolution of influenza and the emergence of pandemics include the separation of species, increased biosecurity, the development of new vaccine strategies and better basic knowledge of the virus. More effective co-operation between scientists and veterinary and public health officials is required to achieve these goals.

Animals↗
PubMed1983

Pathogenicity of Campylobacter jejuni and Campylobacter coli strains in the pregnant guinea pig model.

Pathogenicity of 17 Campylobacter isolates for pregnant guinea pigs was investigated. Of 14 isolates, 12 (86%) produced rates of abortion ranging from 13% to 87%. Two isolates did not produce abortion. Reference strains of C fetus subsp venerealis produced abortion in 60% to 87% and C fetus subsp fetus produced abortion in 60% of the guinea pigs. Inoculated organisms were recovered from uterus, blood, liver, kidney, spleen, and gallbladder of the guinea pigs at rates as high as 83% for 2 ovine isolates and as low as 13% for 2 bovine and 1 human isolates. Most isolations were from the uterus. Two avian isolates were not recovered. Within the C jejuni and C coli group, the ovine and the human isolates appear to be more pathogenic. Swine, bovine, and avian isolates were less pathogenic. Seemingly, the pregnant guinea pig was a suitable and practical model for evaluating the pathogenicity of Campylobacter organisms, regardless of their host of origin.

Abortion, Veterinary↗
PubMedDate not supplied

Veterinary use of antimicrobials and emergence of resistance in zoonotic and sentinel bacteria in the EU.

Antimicrobials are essential for treatment of sick animals, but even if used correctly, may eventually lead to antimicrobial resistance. While this represents a potential hazard to humans, the great majority of resistant human pathogens, especially the more important ones, are unrelated to animal sources. A survey of informed medical opinion suggested that of the human antimicrobial resistance problem, <4% was seen as potentially linked to animal sources. This proportion related largely to zoonotic bacteria which by definition have the capacity to carry resistance between species, although the evidence for resulting harm remains limited. A recent study compared resistance among chicken, pig and cattle isolates of Salmonella spp., Campylobacter spp. and Escherichia coli from a series of EU countries. When tested against antimicrobial agents, this survey showed variation of resistance between countries, between hosts and between organisms. Such variation may give insight into preferred methods of antimicrobial administration or disease control, but it is clear that the epidemiology of antimicrobial resistance induction and dissemination in animals remains complex and is yet to be fully understood.

Animals↗
PubMed1998

New emerging zoonoses: a challenge and an opportunity for the veterinary profession.

The concept of emerging infectious diseases appeared in the late 1980s, when major outbreaks occurred around the globe and surprised many scientists who considered infectious diseases to be maladies of the past or limited to the under-developed world. Several reports identified erosion of the public health infrastructure among the factors contributing to new and re-emerging infectious diseases. As indicated by Morse, "Disease emergence often follows ecological changes caused by human activities such as agriculture or agricultural change, migration, urbanization, deforestation, or dam building". "Among these new diseases, surprisingly, most emergent viruses and many emergent bacteria are zoonotic". Several new zoonoses have been recently identified. Many of these diseases were either unknown, because we were not able to isolate the infectious agent or to distinguish them from other clinical syndromes, or discovered accidentally. Much of the recent identification of new pathogens has been based on new molecular biology tools or epidemiological studies. For all these diseases or infections, veterinarians played a key role in their identification, isolation of the causative organisms and understanding of the epidemiology of the infection. The role of the veterinary profession is very important in public health and on the rise again in the U.S.A., as it should be in many other countries. Surveillance, clinical curiosity and awareness, epidemiology and laboratory training are the essential tools and competency that the veterinary profession must use to meet the challenge of new emerging zoonoses.

Animals↗
PubMed2005

Rational monoclonal antibody development to emerging pathogens, biothreat agents and agents of foreign animal disease: The antigen scale.

Many factors influence the choice of methods used to develop antibody to infectious agents. In this paper, we review the current status of the main technologies used to produce monoclonal antibodies (mAbs) from the B cells of antigen-sensitized animals. While companies are adopting advanced high-throughput methods, the major technologies used by veterinary and medical research laboratories are classical hybridoma fusion and recombinant library selection techniques. These methods have inherent advantages and limitations but have many common aspects when using immunized rodents. Laboratories with expertise in both methods of antibody development have a distinct advantage in their ability to advance mAb technology. New and re-emerging infectious threats in today's world emphasize the need for quality immunoreagents and the need to maintain expertise in mAb development. We provide examples of some common applications for mAb reagents used to identify pathogens such as the SARS-coronavirus (SARS-CoV), Bacillus anthracis, and foot-and-mouth disease (FMD) virus. We also outline a framework for investigators to make rational decisions concerning which method to use to develop mAbs based upon characteristics of the pathogen under study and the intended downstream application. Lastly, we provide parameters for the immunisation of mice and a classification system which describes the expected outcome for mAb development strategies when using classes of immunogens to generate mAbs with desired activities.

Animal Diseases↗
PubMedDate not supplied

[Proposals of the working group "Antibiotic resistance" for the configuration of microtitre plates to be used in routine antimicrobial susceptibility testing of bacterial pathogens from infections of large food-producing animals and mastitis cases].

Two layouts for microtitre plates, which should serve for in-vitro susceptibility testing in routine diagnostics, have been set up by the working group "Antibiotic resistance" of the German Society for Veterinary Medicine. One of these layouts was designed for the testing of bacteria from cases of mastitis and the other for bacteria from infections in large food-producing animals. The choice of the antimicrobial agents and their concentrations to be included in these layouts were based on (1) the bacteria frequently associated with the respective diseases/animals, (2) the antimicrobial agents licensed for therapeutic use in these diseases/animals, (3) the currently available breakpoints, and (4) cross-resistances between the antimicrobial agerts so far known to occur in the respective bacteria.

Animals↗
PubMed1990

Poxvirus recombinant vaccines.

The poxvirus family, subfamily Chordopoxviridae, contains six genera. The basic criteria distinguishing membership in a genus is cross-neutralization and host-range predilection. Members of the genus Orthopoxvirus (vaccinia) and of the genus Avipoxvirus (fowlpox) have been genetically engineered to express genes from heterologous pathogens, thus providing a means of assessing these recombinant viruses as live recombinant vaccines. Vaccinia virus recombinants which have a broad host range can be useful vectors for both human and veterinary applications, while fowlpox virus recombinants, with a host range restricted to avian species, provide useful vectors for application to poultry diseases. Significantly, avipoxviruses have also been shown to be useful as vaccinating vectors in non-avian species. The results presented in this paper were selected to provide the reader with a sense of the extensive potential present in recombinant poxviruses as live recombinant vaccine candidates. The broad host range of vaccinia vectors and the narrower host range of avipoxvirus provide interesting applications. The surprising results obtained in non-avian species with recombinant fowlpox viruses are quite intriguing. The ability to generate a recombinant live vaccine that can readily be amplified in tissue culture, yet is non-proliferative in vivo, provides unique properties and interesting potential applications.

Animals↗
PubMed2006

HPAI surveillance programme in Cambodia: results and perspectives.

Cambodia has faced 15 confirmed highly pathogenic avian influenza (H5N1) outbreaks in different sectors of the poultry industry since January 2004. The country has very limited human and financial resources and, when the outbreak first began, the veterinary services were not equipped with the basic tools to collect accurate epidemiological information or to fight the disease. Therefore, different agencies, under the umbrella of the Food and Agriculture Organisation, are providing support to the Government to strengthen its capacity to diagnose, survey and control the avian influenza (AI) virus. Different surveillance tools are being tested, such as market monitoring and a sentinel villages' network, to offset the weakness of the national passive surveillance network. Several constraints were identified during the implementation of this programme, such as a lack of motivation among provincial staff, the limited capacity of the central team to compile and analyse the data generated, the reluctance of farmers to have their animals sampled, and weak diagnostic capacities. The sustainability of such a surveillance system once international support ends remains to be seen. Participatory epidemiology (PE) may be an appropriate complementary tool to track diseases. PE works on the principle that livestock keepers often possess detailed knowledge of animal diseases and can provide valuable diagnostics that could help in identifying AI outbreaks, particularly in remote areas.

Animals↗
PubMed1991

[Atrophic rhinitis A.D. 1991].

In the Netherlands the Central Veterinary Institute (CVI) and the Animal Health Services carried out investigations on aetiology, pathogenesis, therapy and prevention of Atrophic Rhinitis (AR) since 1970. Since the discovery of AR toxin in AR pathogenic P. multocida in SPF piglets, quicker and cheaper tests were developed e.g. the mouse test and guinea pig skin test. Today ELISA-tests with poly- and monoclonals are also available. The CVI carried out DNA probes and is developing a PCR-test. Tests to detect a natural infection were difficult to develop. The SN test by Bechmann, the skin test by Schimmelpfenning and the ELISA test by Foged give some perspectives. From investigations with B. bronchiseptica in piglets, it appears that the role of this germ is overestimated in the development of AR. On 16-week-old pigs an infection with AR toxigenic P. multocida caused conchae atrophy and septum deviation within 4 weeks. This fact has to be taken into account concerning the preventive medications in piglets. Only high maternal antibody titres against the AR toxin are able to protect the piglets for a sufficiently long period. Conchae atrophy and brachygnathia superior are indicators for suspicion of AR but do not prove the diagnosis of AR. By means of selective agars the isolation of P. multocida from nose, tonsils and lungs could be improved. The incubation period of clinical AR may last longer than two years. The AR pathogenic P. multocida is predominantly transmitted by pigs, incidentally also by rabbits, cattle, sheep, goat, poultry, dogs and cats. Humans can get infected and diseased. The AR pathogenic P. multocida has to be classified as a zoonosis. By way of stamping out and air filtering the transmission can be prevented. Vaccination cannot avoid an infection with the AR pathogenic P. multocida. The Animal Health Services developed a program to certify breeding herds 'free of AR pathogenic P. multocida'.

Animals↗
PubMed1986

Anaerobic bacterial infections and response to treatment in dogs and cats: 36 cases (1983-1985).

Anaerobic bacteria have been increasingly implicated as important pathogens in animals. To determine the prevalence of anaerobic bacterial infection, the results of anaerobic bacteriologic culture of 599 specimens obtained from dogs and cats hospitalized at the Colorado State University Veterinary Teaching Hospital were reviewed. Obligate anaerobic bacteria were isolated from 35% of properly submitted specimens; Bacteroides spp and Fusobacterium spp were the organisms most commonly isolated. Infections most often containing anaerobes were abscesses, pleuropulmonary infections, and abdominal infections. A complication rate of 28% was observed with anaerobic bacterial infections; failure to initially treat with an effective antibiotic increased the rate of recurrence of infection.

Animals↗
PubMedDate not supplied

The application of molecular biology to the study of veterinary infectious diseases.

The practical impact that the techniques of molecular biology is having on the study of infectious diseases of veterinary importance is discussed. The areas highlighted include the development of novel diagnostic assays such as the polymerase chain reaction, the use of recombinant antigen in ELISA tests, and the potential of genetically engineered vaccines to alter radically the disease status of animals in developed and developing countries. Novel vaccine strategies such as the use of rationally attenuated viruses as has been successfully employed with pseudorabies virus, and the use of viruses such as vaccinia as vaccine vectors to carry the genes encoding potent immunogens from a range of pathogens (such as rabies and rinderpest) are described. Contributions to the study of epidemiology, mechanisms of pathogenesis and immune responses are also discussed.

Animals↗
PubMed1999

Parasites in cultured and feral fish.

Parasites, causing little apparent damage in feral fish populations, may become causative agents of diseases of great importance in farmed fish, leading to pathological changes, decrease of fitness or reduction of the market value of fish. Despite considerable progress in fish parasitology in the last decades, major gaps still exist in the knowledge of taxonomy, biology, epizootiology and control of fish parasites, including such 'evergreens' as the ciliate Ichthyophthirius multifiliis, a causative agent of white spot disease, or proliferative kidney disease (PKD), one of the most economically damaging diseases in the rainbow trout industry which causative agent remain enigmatic. Besides long-recognized parasites, other potentially severe pathogens have appeared quite recently such as amphizoic amoebae, causative agents of amoebic gill disease (AGD), the monogenean Gyrodactylus salaris which has destroyed salmon populations in Norway, or sea lice, in particular Lepeophtheirus salmonis that endanger marine salmonids in some areas. Recent spreading of some parasites throughout the world (e.g. the cestode Bothriocephalus acheilognathi) has been facilitated through insufficient veterinary control during import of fish. Control of many important parasitic diseases is still far from being satisfactory and further research is needed. Use of chemotherapy has limitations and new effective, but environmentally safe drugs should be developed. A very promising area of future research seems to be studies on immunity in parasitic infections, use of molecular technology in diagnostics and development of new vaccines against the most pathogenic parasites.

Amebiasis↗