Outpacing the resistance tsunami: Antimicrobial stewardship in equine medicine,an overview

Antimicrobial stewardship (AMS) is the term increasingly used to describe the multiple approaches needed to sustain the efficacy of antimicrobial drugs in the face of the increasing development and spread of antimicrobial resistance in bacterial pathogens, and the global crisis in medicine that it is engendering. The concept and the practices associated with AMS continue to evolve but the general approach is a dynamic and multifaceted one of continuous improvement based on reducing, improving, monitoring and evaluating the use of antimicrobials so as to preserve their future efficacy and to protect human and animal health. Using many equine examples, this basic overview discusses the multiple and interacting elements of AMS: Practice guidelines, infection control and prevention, clinical microbiology, resistance and use surveillance, dosage, pharmacokinetics and pharmacodynamics, regulation, education and owner compliance, leadership, coordination and measurement. There have been impressive advances in recent years in reporting and analysis of AMR in horses, in the scrutiny and assessment of how antimicrobial drugs are used in horses and in identification of areas for improvement including dosing, surgical prophylaxis, infection control, development of practice standards and the use of clinical microbiology. Antimicrobial stewardship is taking shape as we start to see the emergence of evidence-based recommendations but far more is required. Containing and even rolling back AMR will need the continued engagement of practitioners, equine national and international practitioner organisations, researchers and educators in the academic community, horse owners, regulators and others.     

BVD diagnosis: an overview

The first step and a crucial condition for the success of a control or eradication program for BVD (bovine viral diarrhea) is the identification and elimination of animals persistently infected with the virus. For this, besides detailed knowledge of the epidemiology, efficient diagnostic tests are necessary. This review summarizes the presently available diagnostic tests for detection of antibodies against the virus or for detection of viral components. Their performance and their applicability in eradication programs is discussed.     

Caliciviruses: an overview.

Several caliciviruses are known to cause diseases in animal and man. Amongst them are vesicular exanthema virus of swine (VESV), feline calicivirus, rabbit hemorrhagic disease virus (RHDV), and Norwalk and Sapporo-like viruses; the latter viruses cause gastroenteritis in man. In this paper, an overview of caliciviruses is presented, with particular emphasis on the molecular aspects. The unique properties as compared to other related families of positive-stranded RNA viruses will be discussed. Many findings about the molecular biology of caliciviruses came from systems that are difficult to work with, such as RHDV, which can thus far only be propagated either in animals or in primary rabbit hepatocyte cultures. Therefore, the review will concentrate on RHDV.     

Q fever: an overview

Q fever, a zoonosis caused by the gram-negative bacterium Coxiella burnetii, occurs worldwide and affects both humans and animals. Ruminants are considered to be the main source of infection of humans, with the main route of infection being through inhalation of the organism of fine-particle aerosols. Abortion is the main clinical sign in ruminants. During and after abortion, large quantities of the bacterium are shed via the placenta and other vaginal secretions. The bacterium may also be present in faeces and milk. The bacterium can survive for a long time in the environment after shedding and can be spread over long distances. Seroprevalence among cattle is rather high in the Netherlands and in many other countries. Infection is diagnosed by detecting antibodies against the bacterium or the bacterium itself by means of a PCR method. The efficacy of using antibiotics or vaccines for treatment or prevention of the disease in cattle is still unclear and there are currently no effective disease control programmes.     

Canine histiocytic neoplasia: an overview

Canine histiocytic neoplasms include cutaneous histiocytoma, as well as localized and disseminated histiocytic sarcoma. These tumors have variable biologic behavior, although the malignant disorders often have a poor prognosis. Immunohistochemistry plays an essential role in differentiating histiocytic tumors from other neoplasias that may have similar histological appearances. This allows a definitive diagnosis to be established and provides a more accurate prediction of prognosis. This article reviews the biologic behavior, diagnosis, and treatment of histiocytic tumors in the dog.     

Equine cardiovascular pathology: an overview

The few data collections that evaluate the involvement of organ systems in horse diseases are in agreement that the locomotor, gastrointestinal and nervous systems are the sites of primary disease in the vast majority of sick horses. When compared with diseases of these organ systems, equine cardiovascular diseases occur infrequently. The most detailed and comprehensive survey of equine cardiac pathology was reported in 1972 by Else and Holmes, who summarized the gross and microscopic cardiac findings from 1500 abattoir horses. This paper reviews the pathology of the cardiovascular diseases typically encountered in horses. Most of the pathological examples are from the files of the Veterinary Medical Teaching Hospital at the University of Florida, encompassing 24 years (1978-2002) and some 6000 equine necropsy cases. Preceding the specific topics are principles of the anatomy and function of the normal equine heart. Pathological entities include equine congenital cardiovascular diseases, acquired diseases of the pericardium, myocardium, endocardium and valves, cardiac neoplasms, and common equine vascular diseases and vascular neoplasms. Extensive use is made of photographs to illustrate the features of individual case examples.     

Swine vesicular disease: an overview

Swine vesicular disease (SVD) is a notifiable viral disease of pigs included on the Office International des Epizooties List A. The first outbreak of the disease was recognized in Italy in 1966. Subsequently, the disease has been reported in many European and Asian countries. The causative agent of the disease is SVD virus which is currently classified as a porcine variant of human coxsackievirus B5 and a member of the genus enterovirus in the family picornaviridae. From a clinical point of view, SVD is relatively unimportant, rarely causing deaths and usually only a minor setback to finishing schedules. However, the clinical signs which it produces are indistinguishable from those caused by foot-and-mouth disease, and its presence prevents international trade in pigs and pig products. This article reviews recent findings on all aspects of the virus and the disease which it causes.     

Antibiotic resistance of mycoplasmas from cell cultures

Investigations were conducted on 36 mycoplasma isolates to elucidate their resistance behaviours to kanamycin, gentamycin, neomycin, tylosin, oxytetracycline, chloramphenicol, and tiamulin. Only the latter proved to be highly effective, whereas all 36 strains were absolutely resistant to kanamycin, gentamycin, and neomycin, while 16 strains were resistant to all of the above antibiotics but tiamulin. Comparison of resistograms was found to provide some limited way of comparing strains and possibilities for detection of sources of contamination. Tiamulin may be used for improvement of cell cultures on account of its good cellular compatibility and high effectiveness on mycoplasmas.