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Rational antibiotic therapy for respiratory disorders in dogs and cats.

Therapy of respiratory tract infections presents some unique challenges to the veterinary practitioner. These infections often involve underlying disease processes that have predisposed the patient to secondary bacterial infection and may complicate the response to therapy. Because of the diversity of microbial organisms that may colonize and invade the respiratory tract, treatment targeted at the infecting pathogens is best accomplished with bacterial culture and susceptibility testing. When these data are unavailable, rational antibiotic treatment should be based on familiarity with historical data and clinical experience. Optimal drug selection is based on predicted microbial susceptibility, drug distribution in the respiratory tract, and safety of the patient. Instituting the appropriate dosage regimen and duration of therapy maximizes the opportunity for a successful resolution of bacterial infections.

Animals↗

Coxiella burnetii infection is associated with placentitis in cases of bovine abortion.

A positive score on a modified acid-fast (MAF)-stained smear test of fresh placenta was used to identify a group of bovine abortion submissions believed to be infected with Coxiella burnetii. Immunohistochemical (IHC) testing for Coxiella and Chlamydia antigens was performed on 14 MAF smear-positive cases as well as 29 MAF smear-negative cases received during the study period. Nine MAF smear-positive cases as well as 1 MAF smear-negative case were Coxiella-positive via the IHC test. No placentas were positive for Chlamydia antigen. Various histopathologic features were categorized for all placentas and the presence or absence of selected risk categories was also graded for each case. The results between Coxiella IHC-positive cases and Coxiella IHC-negative/MAF-negative cases were compared using Fisher's exact test (P value at 95% confidence). Significant associations were found between Coxiella IHC-positive cases and the presence of placental inflammation (P = 0.0027), placental necrosis (P = 0.012), fetal pneumonia (P = 0.0152), and the visibility of Coxiella-like organisms within trophoblasts on hematoxylin and eosin-stained sections (P < 0.0001). Histopathologic features of Coxiella IHC-positive placentas included infiltration of the chorionic stroma by mononuclear cells, necrosis of chorionic trophoblasts, and focal exudation of fibrin and neutrophils. The results indicate that MAF smears are a good screening tool for the presence of Coxiella in placentas from bovine abortion cases and that the detection of this pathogen in aborted placentas via traditional staining or IHC methods is usually associated with placentitis.

Abortion, Veterinary↗

Comparison of the pathogenesis of acute equine herpesvirus 1 (EHV-1) infection in the horse and the mouse model: a review.

The mouse models of the respiratory and abortion forms of equine herpesvirus 1 (EHV-1) infection have been used to investigate the vaccine potential of various EHV-1 immunogens, the effect of antiviral agents on EHV-1 infection and the pathogenicity of EHV-1 strain variants and deletion or insertional mutants. This review examines the similarities and differences in the pathogenesis of primary EHV-1 infection in the natural host, the horse, and in the mouse by comparing tissue tropism, clinical signs of infection, the effects of EHV-1 on pregnancy, haematological changes following infection, viral clearance, histopathology and latency. The evidence suggests that the mouse model provides a valid method for investigation of virological and histopathological aspects of EHV-1-induced disease in the horse. However, the extent to which useful and valid comparisons and extrapolations can be made of immunological parameters from mouse to horse is yet to be determined.

Abortion, Veterinary↗

Whole-genome analysis of Leptospira interrogans to identify potential vaccine candidates against leptospirosis.

Leptospirosis is an important global human and veterinary health problem. Humans can be infected by exposure to chronically infected animals and their environment. An important focus of the current leptospiral research is the identification of outer membrane proteins (OMPs). Due to their location, leptospiral OMPs are likely to be relevant in host-pathogen interactions, hence their potential ability to stimulate heterologous immunity. The existing whole-genome sequence of Leptospira interrogans serovar Copenhageni offers a unique opportunity to search for cell surface proteins. Predicted genes encoding potential surface proteins were amplified from genomic DNA by PCR methodology and cloned into an Escherichia coli expression system. The partially purified recombinant proteins were probed by Western blotting with sera from human patients diagnosed with leptospirosis. Sixteen proteins, out of a hundred tested, were recognized by antibodies present in human sera. Four of these proteins were conserved among eight serovars of L. interrogans and absent in the non-pathogenic Leptospira biflexa. These proteins might be useful for the diagnosis of the disease as well as potential vaccine candidates.

Antigens, Bacterial↗

Diagnosis of Mycoplasma hyopneumoniae.

Mycoplasma hyopneumoniae, the cause of enzootic pneumonia, remains an important pathogen in the swine industry. This small, complex organism colonizes the ciliated cells of the respiratory tract, resulting in little exposure to the immune system. Confirming the presence of M. hyopneumoniae, as well as identifying its role in respiratory disease and pneumonia, remains challenging to the veterinary profession. While culture of the organism remains the gold standard for identification, the use of serology, the polymerase chain reaction and various assays to detect the presence of M. hyopneumoniae in tissue is common in diagnostic laboratories. Because of the role M. hyopneumoniae plays in increasing the severity of pneumonia associated with concurrent bacterial and viral infections, understanding the pathogenesis and diagnostic assays available is critical for developing effective intervention strategies to control respiratory disease on a herd basis.

Animals↗

Evaluation of cardiac lesions and risk factors associated with myocarditis and dilated cardiomyopathy in southern sea otters (Enhydra lutris nereis).

OBJECTIVE: To describe cardiac lesions and identify risk factors associated with myocarditis and dilated cardiomyopathy (DCM) in beach-cast southern sea otters. ANIMALS: Free-ranging southern sea otters. PROCEDURE: Sea otters were necropsied at the Marine Wildlife Veterinary Care and Research Center from 1998 through 2001. Microscopic and gross necropsy findings were used to classify sea otters as myocarditis or DCM case otters or control otters. Univariate, multivariate, and spatial analytical techniques were used to evaluate associations among myocarditis; DCM; common sea otter pathogens; and potential infectious, toxic, and nutritional causes. RESULTS: Clusters of sea otters with myocarditis and DCM were identified in the southern aspect of the sea otter range from May to November 2000. Risk factors for myocarditis included age, good body condition, and exposure to domoic acid and Sarcocystis neurona. Myocarditis associated with domoic acid occurred predominantly in the southern part of the range, whereas myocarditis associated with S. neurona occurred in the northern part of the range. Age and suspected previous exposure to domoic acid were identified as major risk factors for DCM. A sample of otters with DCM had significantly lower concentrations of myocardial L-carnitine than control and myocarditis case otters. CONCLUSIONS AND CLINICAL RELEVANCE: Cardiac disease is an important cause of death in southern sea otters. Domoic acid toxicosis and infection with S. neurona are likely to be 2 important causes of myocarditis in sea otters. Domoic acid-induced myocarditis appears to progress to DCM, and depletion of myocardial L-carnitine may play a key role in this pathogenesis.

Animals↗

[Uncommon mycobacterial infections in domestic and zoo animals: four cases with special emphasis on pathology].

Infections caused by classical tubercle bacilli are rare during the last years. Nevertheless, diseases caused by other mycobacteria have to be considered clinically and in diagnostic pathology especially in cases of immunosuppression and due to their potential zoonosis risk. An infection by mycobacteria was diagnosed in four animals (Mayotte Maki, Blue-headed Parrot, Patagonian sealion, Beagle) necropsied between 1995 and 2002 in the Institute of Veterinary-Pathology of the University of Leipzig. The Maki, the blue-headed parrot and the dog showed a disseminated character of the disease caused by Mycobacterium genavense (monkey and bird) resp. Mycobacterium avium (dog), while an open chronical tuberculosis of the lungs due to a pathogenic member of Mycobacterium tuberculosis complex was observed in the seal. All these bacteria are potential causes of zoonoses. So, if granulomatous or disseminated histiocytic alterations are detected in diagnostic pathology, mycobacterial infections should always be included in differential diagnoses and require careful aetiological investigations by histopathological and bacteriological methods.

Animals↗

Rhesus macaque (Macaca mulatta) group formation and housing: wounding and reproduction in a specific pathogen free (SPF) colony.

In the present report, we examined the effects of group formation strategy and corral design on wounding and reproduction rates in rhesus macaques. Specifically, we examined group formation using a staged strategy, in which small groups of animals were introduced incrementally over a period of weeks, and a rapid formation strategy, in which all animals were introduced in 1 day. We also examined group formation using a divided corral design that facilitated visual and social separation of individuals, and an undivided corral design that did not facilitate visual or social separation. Dependent measures were wounding and reproductive rates over each of the 2 years that followed group formation. Results indicate that incrementally releasing subgroups of animals, and using a corral design that provides for visual and social separation of individuals, are effective strategies for reducing rates of traumatic wounding when forming multimale-multifemale rhesus macaque breeding groups. However, it must be noted that differences in formation strategy and corral design did not lead to higher reproductive rates. We conclude that incrementally releasing animals in hierarchical subgroups, and using a divided vs. undivided housing design, reduced intra-group wounding and associated demands on veterinary and animal management resources following formation of rhesus macaque breeding groups.

Animals↗

Antibody induction after combined application of an adjuvanted recombinant FeLV vaccine and a multivalent modified live virus vaccine with a chlamydial component.

The compatibility, safety and interaction on antibody induction of a combined vaccine application were assessed. Specific pathogen-free cats were vaccinated with either a modified live virus vaccine containing feline calici- (FCV), herpes- (FHV-1), parvovirus (FPV) and Chlamydophila felis (C. felis), an adjuvanted recombinant feline leukaemia virus (FeLV) vaccine or both vaccines in one syringe. After combined application, FeLV ELISA antibody titres were unaltered, However antibody production based on indirect immunofluorescence assay was remarkably enhanced for FCV and was at selected time points also enhanced for FHV-1 and C. felis but diminished for FPV. The use of these vaccines in combination was safe and will simplify vaccination schedules in veterinary practice.

Adjuvants, Immunologic↗

Lesions in aborted bovine fetuses and placenta associated with bovine viral diarrhoea virus infection.

Abortions in dairy cattle were investigated on 55 dairy farms sited in North West England, using a multi-level diagnostic technique. After pathological examination of fetal and placental tissues collected at the time of abortion, possible causes for these abortions could be identified, supported by bacteriological and serological laboratory findings. Of 150 abortions investigated, Bovine Viral Diarrhoea (BVD) virus infection was related to 40 episodes (27% of the total), often accompanied by evidence of concurrent infections. Lesions associated with BVD abortions were found in fetal eyelid, lung, and occasionally myocardium. Lesions in the lung were most consistent, characterized by mononuclear inflammatory cell infiltration of peribronchiolar and inter-alveolar tissues. Placental lesions were non-specific. It is concluded that the lesions observed are insufficient to be the primary cause of abortion. However, the pathological changes associated with BVD infection in the placenta may allow secondary opportunist pathogens to cross the feto-maternal barrier, thereby threatening the health of the fetus and the physiological and endocrinological functions of the placenta which maintain pregnancy.

Abortion, Veterinary↗

Leptospira interrogans serovar pomona associated with abortion in cattle: isolation methods and laboratory animal histopathology.

Leptospira interrogans serovar pomona was successfully isolated from cattle urine in the western Transvaal after an abortion storm had occurred. Direct inoculation of EMJH medium proved the most successful method. The selective agent, 5-fluorouracil, was most effective in controlling contamination when used at the 0,4 mg/ml level. The strain isolated was pathogenic in hamsters, but specific lesions and the leptospirae were seen only where overwhelming infection occurred.

Abortion, Veterinary↗

Chronic pulmonary disease with radiographic interstitial opacity (interstitial pneumonia) in foals.

Twelve foals, age 3-9 months, examined at The Ohio State University Veterinary Teaching Hospital between 1995 and 2000 were diagnosed with chronic pulmonary disease associated with marked interstitial opacity on radiographic examination. The most characteristic features were a history of respiratory disease of 1-3 months duration, marked clinical signs of respiratory disease, failure to yield a consistent pathogen from tracheobronchial aspirates and a predominantly interstitial pattern on thoracic radiographs. We attributed these signs to chronic interstitial pneumonia. Foals were treated with broad spectrum antimicrobial and corticosteroid drugs. All 12 foals were discharged alive from hospital and, of the 10 available for follow-up, all were disease-free and performing to expectation 5 months to 5 years after discharge. We conclude that chronic interstitial pneumonia, occuring in foals, is associated with a good prognosis and that corticosteroid therapy may be useful in its treatment.

Adrenal Cortex Hormones↗

[Residues in products of animal origin (author's transl)].

Products of animal origin may contain a variety of substances regarded as 'residues': traces of veterinary drugs and their metabolites, environmental contaminants, traces of compounds having injurious effects, which have their origin in the manufacturing process, and mycotoxins. Some of these substances are carcinogenic, others may impair the functions of organs or cause disturbances of hormonal balance. Antibacterial substances may induce resistance of pathogenic agents and, finally, a number of substances give rise to sensitivity reactions. Standards for permissible amounts are required in several cases; a number of substances should be completely omitted so that their use should be prohibited; adopting the concept of 'zero tolerance', however, may present problems. Extensive analysis is only practicable so far in a few cases. Rapid screening procedures will have to be developed in the future, in which immunochemical methods may play a particularly important role.

Animals↗

[Physiopathology of protozoan infections].

The pathophysiology of diseases produced by protozoal infections is caused not only by a direct effect of the parasites on their host (e.g. host cell lysis or parasite adherence), but also by indirect effects, where molecules of parasite origin exert an effect on host cells, which in turn produces a cascade of events (including the secretion of inflammatory cytokines, prostaglandins and nitric oxide) responsible for the symptomatology observed. The role of the host itself in the pathogenic events is not negligeable and its genetic background, nutritional and immunological status will influence the outcome of the infection (which will result in asymptomatic infections in some individuals and severe disease in others). The general and specific features of a variety of protozoal infections of medical and veterinary importance (including malaria, babesiosis, trypanosomiasis, toxoplasmosis, cryptosporidiosis, amoebiasis, giardiasis and trichomoniasis) are discussed in this review and a number of common patterns are identified.

Animals↗

Serologic and molecular characterization of an abortigenic strain of equine arteritis virus isolated from infective frozen semen and an aborted equine fetus.

A virus isolated from an aborted equine fetus was determined to be antigenically distinct from several other strains of equine arteritis virus (EAV) by use of a neutralization assay with a large panel of neutralizing monoclonal antibodies. The virus was readily neutralized by polyclonal equine anti-EAV serum. Comparative nucleotide and amino acid sequence analyses indicated that the virus (WA97) isolated from the aborted fetus was virtually identical to a virus (S1971) isolated from imported semen used to inseminate another mare on the farm. Phylogenetic analysis indicated that the WA97/S1971 virus was more related to European than to North American strains of EAV. These sensitive molecular procedures may be useful for epidemiologic investigations of EAV infections. Screening and certification of stallions and frozen equine semen would prevent dissemination of pathogenic strains of EAV.

Abortion, Veterinary↗

Evaluation of the effects of footwear hygiene protocols on nonspecific bacterial contamination of floor surfaces in an equine hospital.

OBJECTIVE: To evaluate the effects of footwear hygiene protocols on bacterial contamination of floor surfaces in an equine hospital. DESIGN: Field trial. PROCEDURES: Footwear hygiene protocols evaluated included use of rubber overboots with footbaths and footmats containing a quaternary ammonium disinfectant, rubber overboots with footbaths and footmats containing a peroxygen disinfectant, and no restrictions on footwear type but mandatory use of footbaths and footmats containing a peroxygen disinfectant. Nonspecific aerobic bacterial counts were determined via 2 procedures for sample collection and bacterial enumeration (contact plates vs swabbing combined with use of spread plates), and the effects of each footwear hygiene protocol were compared. RESULTS: There were no consistent findings suggesting that any of the protocols were associated with differences in numbers of bacteria recovered from floor surfaces. Although there were detectable differences in numbers of bacteria recovered in association with different footwear hygiene protocols, differences in least square mean bacterial counts did not appear to be clinically relevant (ie, were < 1 log10). CONCLUSIONS AND CLINICAL RELEVANCE: Although cleaning and disinfection of footwear are important aids in reducing the risk of nosocomial transmission of infectious agents in veterinary hospitals, the numbers of aerobic bacteria recovered from floor surfaces were not affected by use of rubber overboots or the types of disinfectant used in this study. Further study is warranted to evaluate the usefulness of footwear hygiene practices relative to their efficacy for reducing transmission of specific pathogens or decreasing nosocomial disease risk.

Animals↗

Medication of production animals--cure of malfunctioning animals or production systems?

Medication is used in all intensive animal productions. However, the increasing problems with resistant bacteria in all animal productions and in humans are supported by a number of reports. Special attention is given to the risk for transmitting food-borne (multi) resistant zoonotic agents to humans due to failure in antibiotic treatment resulting in lower cure rates or higher case fatality rates. The use of medication in humans per se is capable of selecting for resistance in human pathogens. Nevertheless, the amount of used medication/antimicrobials in treatment of Danish production animals goes far beyond the amount used for human consumption. The increase in consumption has not been followed by a similarly increased mortality, e.g. illustrated by the number of rendered animals, increased use of injection medicine for veterinary treatments of diseased animals, or increased number of remarks on the carcasses from the slaughterhouses. Medication in animal production is facing its limits and relevant economic alternatives have to be developed. The strategy for the future must concentrate on using medication only for clinically diseased animals and not as a strategic treatment of the whole herd in order to maximise growth and camouflage of suboptimal production systems and insufficient management.

Animal Husbandry↗

New outlook on the biology of cowpox virus.

Analysis of cowpox outbreaks revealed an extremely wide range of virus pathogenicity including 9 orders of mammals. Recent serological and virological data support the hypothesis that wild rodents may be a natural reservoir of cowpox virus. Cowpox infection of humans occurring without any contact with infected cattle (registered in the U. K. and Poland) is especially interesting for medical and veterinary virology. Surveillance seems justified of the possible virus dissemination beyond its natural reservoir resulting in further infection of man and animals.

Animals↗