The future of radiotherapy in small animals – should the fractions be coarse or fine?

Radiation therapy has been used to treat animal cancers for more than 100 years. Clinical experiences and experimental results have been widely published and provide a basis for the recognition of radiation therapy as an integral component of multimodal cancer management in veterinary oncology. As the expectations of pet owners and the demand for treatment of companion animals with cancer have increased, veterinary oncology itself has undergone dramatic advances in the past several decades both in terms of improved diagnostics and treatments, including increased accessibility of radiation therapy. Synchronous with development of the specialism of veterinary radiation oncology, confusion and controversy have arisen with regard to distinguishing between different types of radiotherapy and methods of treatment delivery. Importantly, the confusion extends beyond semantics, and includes opinionated debate about defining which forms of therapy (if any at all) are optimal for a given patient. This exemplifies how, despite marks of maturity including age and a robust publication history, the field of veterinary radiation oncology is in some ways still in its infancy. The purpose of this article is to review the evidence base for daily (fine) fractionation versus weekly (coarse) hypofractionation in veterinary oncology, using selected tumour types as examples.     

Postoperative management of the exotic animal patient.

Careful postoperative management is crucial for the success of any orthopedic surgical repair. The special needs of the exotic animal must be met during the immediate postoperative period and during hospitalization. Many exotic animals require a quiet, stress-free environment and careful attention to housing parameters, such as perching, temperature, and visual security. To provide adequate pain relief in these patients, analgesia should be given before, during, and after surgery. The drugs most often used for pain relief are NSAIDs and opioid analgesics. After surgery, monitor the healing process carefully with regular examinations and radiographs while remaining vigilant for potential problems such as osteomyelitis or nonunion. Physical therapy prevents the development of fracture disease, which includes joint or ligament contracture and bone or muscle mass loss. Because physical therapy affords the patient full use of the affected limb, it is considered a helpful practice in all patients. Physical therapy, however, is critical for free-ranging exotic animals that will be released back into the wild, such as birds of prey.     

Advances in Exotic Mammal Clinical Therapeutics

It is imperative that the veterinarian treating exotic companion mammals stay abreast of the latest developments relating to medications and drug delivery approaches for safety and efficacy. Sustained-release formulations of commonly used drugs, as well as newer routes for administration of therapeutic agents, allow the veterinarian treating exotic companion mammals to reduce the stress associated with drug administration. Interactions can occur between vehicle and drugs when formulations are compounded; therefore, research studies are warranted regarding potential problems associated with these formulations. However, newer studies have been published that provide the basis for exploring the use of different vehicles, frequency of dosing, and drug delivery techniques for various classes of drugs in exotic mammals. The goals of this review are to not only evaluate new medications or uses for medications in companion exotic mammal patients but also review new methods of drug delivery that might be useful to the veterinarian who treats these animals.     

Travel medicine of parasitic diseases in the dog

Companion animals are increasingly brought along by their owners to foreign countries. Thus, small animal travel medicine is becoming more important. The field includes both prophylaxis and metaphylaxis against various infectious diseases, as well as their diagnosis and treatment. Dogs returning from Southern Europe, but also from more tropical regions, may be infected with exotic pathogens. In addition, imported pedigree or working dogs, and especially stray dogs imported through welfare organisations, are at high risk.The present overview summarises the clinical and practical aspects of exotic parasitic diseases that may affect such dogs, and the risk of such diseases becoming autochthonously transmitted in Switzerland. Furthermore, the zoonotic potential of these infections will be considered.     

INVITED REVIEW—IMAGE REGISTRATION IN VETERINARY RADIATION ONCOLOGY: INDICATIONS,IMPLICATIONS, AND FUTURE ADVANCES

The field of veterinary radiation therapy (RT) has gained substantial momentum in recent decades with significant advances in conformal treatment planning, image‐guided radiation therapy (IGRT), and intensity‐modulated (IMRT) techniques. At the root of these advancements lie improvements in tumor imaging, image alignment (registration), target volume delineation, and identification of critical structures. Image registration has been widely used to combine information from multimodality images such as computerized tomography (CT), magnetic resonance imaging (MRI), and positron emission tomography (PET) to improve the accuracy of radiation delivery and reliably identify tumor‐bearing areas. Many different techniques have been applied in image registration. This review provides an overview of medical image registration in RT and its applications in veterinary oncology. A summary of the most commonly used approaches in human and veterinary medicine is presented along with their current use in IGRT and adaptive radiation therapy (ART). It is important to realize that registration does not guarantee that target volumes, such as the gross tumor volume (GTV), are correctly identified on the image being registered, as limitations unique to registration algorithms exist. Research involving novel registration frameworks for automatic segmentation of tumor volumes is ongoing and comparative oncology programs offer a unique opportunity to test the efficacy of proposed algorithms.     

Principles and applications of radiation therapy

Radiation therapy is emerging as a beneficial and increasingly accessible treatment option for companion animals with cancer. Various types of radiation are available with different properties that may make one more suitable than another for treating a specific tumor type. Radiation therapy can be used as the sole treatment or as part of a multimodality treatment course to result in local or locoregional tumor control, or as palliative therapy for pain control. When radiation is a potential treatment option, it should be considered early in the decision-making process to ensure that the appropriate diagnostics and other treatment modalities are considered to provide the best potential outcome. This article is intended to provide an overview of the types of radiation therapy that are available, the indications, and the potential acute and late radiation side effects.     

Clinical Technique: Digital Radiography in Exotic Pets—Important Practical Differences Compared with Traditional Radiography

The future of radiography will be digital. In exotic pet radiography, where some of the animals have a very low body weight and anatomic structures can be small, detail rendition plays an important feature in image quality. Veterinarians should be familiar with the technical principles, image quality criteria, and radiation exposure issues associated with the various types of digital systems currently available. This article discusses basic principles of digital radiography, technical solutions, and selected parameters characterizing detectors, processing, and monitors. An overview of reported experiences is given, and results from experimental clinical studies are reviewed to evaluate the current options and limitations in applying digital radiography to exotic pet medicine.     

Chlorambucil-induced myoclonus in a cat with lymphoma

Chlorambucil is an alkylating agent commonly used in veterinary oncology for conditions including lymphoma. Chlorambucil neurotoxicity has been well recognized in human patients. Onsets of central nervous system signs, such as myoclonus, tremors, muscular twitching, agitation, and tonic-clonic seizures, have been reported in humans and laboratory animals treated with chlorambucil. This case of a cat with intestinal lymphoma represents the first veterinary patient reported to have chlorambucil-induced neurotoxicity. Neurotoxicity should be considered a potential side effect of chlorambucil therapy in veterinary patients.     

Diagnostic testing for fungal diseases.

Fungal infections can be challenging to diagnose, and accurate interpretation of laboratory data is important to ensure the most appropriate treatment for the patient. An overview of the nonspecific diagnostic aids and specific fungal diagnostics is presented. Additionally, a brief summary of the role of free-living saprophytes and pathogenic dimorphic fungi is discussed in relation to exotic animals seen in veterinary practice. The important fungal diseases are reviewed with reported prevalence, hosts and with specific diagnostic testing recommendations.     

Ten things I wish I'd learned at university.

To many veterinarians, it may seem that university did not equip or prepare them adequately to deal with exotic animals. In fact, the opposite is true--graduate veterinarians have been trained as problem-solvers and doers. By applying the knowledge and skills learned at University, most veterinarians are more than capable of providing quality medical services to exotic pet owners. Veterinarians wishing to take this further need to accept that they have some learning to do and experience to gain. Those with a true love and affinity for exotic animals will be able to develop their skills and achieve proficiency and competency in one of the most exciting and fast-growing fields of veterinary medicine today.     

Skin diseases of rodents and small exotic mammals.

Small exotic mammals and rodents are becoming popular pets in the United States. Like most other exotics, the popularity of these animals has vastly preceded the accumulation of practical husbandry and veterinary information available about them. Several dermatologic conditions have been described in most rodents and small exotic mammals; however, the practitioner can assume that more exist that have not yet been diagnosed or documented. It is not unreasonable to assume that rodents and small exotic mammals could be affected by many of the same dermatologic conditions well described in other animals. Veterinarians are encouraged always to apply the same diagnostic protocols used to work up skin problems in dogs and cats when presented with an exotic pet with a dermatologic disease.     

Zoonotic poxviruses

Poxviruses compromise a group of long known important pathogens including some zoonotic members affecting lifestock animals and humans. While whole genome sequence analysis started to shed light into the molecular mechanisms underlying host cell infection, viral replication as well as virulence, our understanding of poxvirus maintenance in nature and their transmission to humans is still poor. During the last two decades, reports on emerging human monkeypox outbreaks in Africa and North America, the increasing number of cowpox virus infections in cats, exotic animals and humans and cases of vaccinia virus infections in humans in South America and India reminded us that – beside the eradicated smallpox virus – there are other poxviruses that can cause harm to men. We start to learn that the host range of some poxviruses is way broader than initially thought and that mainly rodents seem to function as virus reservoir. The following review is aiming to provide an up-to-date overview on the epidemiology of zoonotic poxviruses, emphasizing orthopoxviruses. By outlining the current knowledge of poxvirus transmission, we hope to raise the awareness about modes of acquisition of infections and their proper diagnosis.     

Telomeres and telomerase: Biological and clinical importance in dogs

In recent years in human oncology the enzyme telomerase has emerged as an ideal target for cancer therapy. This has led to the assessment of telomerase in cancers in companion animals, mainly dogs and these studies confirm that in dogs, like humans, telomere maintenance by telomerase is the primary mechanism by which cancer cells overcome their mortality and extend their lifespan. This review aims to provide an introduction to the biology of telomeres and telomerase and to discuss some of the telomere/telomerase directed therapeutic methodologies currently under development which may be of benefit to the canine cancer patient.     

Emergency care and managing toxicoses in the exotic animal patient.

The poisoned exotic veterinary patient remains a significant challenge to the clinician. A patient presenting with the history of exposure to a toxin or poison should be considered to have a potentially life-threatening problem. This article details the ABCs of emergency medicine including fluid therapy and discusses the principles of neurologic management. The last part of the article provides the clinician with guidelines for decontamination and critical care management of some of the more common toxicoses in exotic animals.     

Beyond BSE: Transmissible spongiform encephalopathies in other animal species

There are several other diseases besides BSE which belong to the group of transmissible spongiform encephalopathies (TSE). Although most mammals can be experimentally infected with the agent of these diseases, generally only single representatives of the orders Artiodactyla (cloven-hoofed animals), Carnivora (carnivores) and Primates (humans and monkeys) are naturally infected in the field. An overview of the current state of knowledge on TSE in several species like exotic ruminants, deer, mink and cats is presented. Etiological, clinical, anatomic-pathological and epidemiological aspects are described.     

Transfusion medicine in exotic pets

The decision to transfuse a patient should always be based on the packed cell volume and clinical status of the patient. This article discusses indications for transfusion and blood substitutes in exotic animal patients. The administration of blood products requires careful donor selection, knowledge of blood groups, cross-matching, and use of anticoagulants. Collection sites, volume, and administration techniques are given for different species of animals including birds, rabbits, and ferrets. Blood-transfusion therapy is not without risk. The frequency with which transfusion reactions occur in exotic pets is unknown. The most common transfusion reactions seen in small animals, along with suggested treatment, are discussed. The availability of blood products is limited in exotic pet medicine; therefore, the use of blood substitutes (Oxyglobin) has the advantage of long storage potential, no need for cross-matching, and no potential for disease transmission. General principles of blood substitutes and administration techniques will be discussed.     

Atherosclerosis: Comparative Pathogenesis,Lipoprotein Metabolism,and Avian and Exotic Companion Mammal Models

Atherosclerosis is a chronic inflammatory disease of the arterial wall where the accumulation of foam cells, lipids, calcium, and cellular debris leads to large fibrofatty atheromatous plaques narrowing the arterial lumen. As the principal cause of human deaths in the world, the pathogenesis of atherosclerosis has been extensively studied, as well as lipid and lipoprotein metabolism, across species. Important aspects of the disease were first investigated experimentally in a wide array of animal models, including laboratory avian and mammalian species also kept as companion pets. Although the disease is primarily a significant clinical entity in avian patients, the wealth of information obtained from companion exotic mammals is of interest to understand the complex comparative pathogenesis of atherosclerotic lesions. This review presents the current concepts of atherogenesis and lipoprotein metabolism followed by a brief overview of species peculiarities as it relates to the experimental reproduction of the disease. This overview should provide interesting insight on atherosclerosis, which spontaneously or experimentally affects many zoological companion species commonly seen by veterinarians.     

Companion Animals Symposium: Environmental enrichment for companion, exotic, and laboratory animals

Animal scientists have an extraordinary burden to promote the health and well-being of all animals in their care. Promoting species- or breed-appropriate behaviors through proper training and enrichment, regardless of animal housing, should be a paramount concern for all animal scientists working with exotic animals, laboratory animals, shelter animals, or privately owned pet animals. Developing ideal training and enrichment programs for any species begins with understanding basic behavior patterns and emotional systems of animals. The basic emotional systems in mammals have been extensively mapped; however, most of these studies are in the neuroscience literature and seldom read by animal science professionals. The emotional circuits for fear have been well documented through studies demonstrating that lesions to the amygdala will block both conditioned and unconditioned fear behaviors. Additionally, other core emotional systems including seeking (i.e., approaching a novel stimulus), rage, panic (e.g., separation stress), play, lust (i.e., sex drive), and care (e.g., mother-young nurturing behavior) have been identified. More recent neuroscience research has discovered the subcortical brain regions that drive different types of seeking behaviors. Research to increase the understanding of the emotional systems that drive both abnormal and normal animal behaviors could greatly improve animal welfare by making it possible to provide more effective environmental enrichment programs. Enrichment devices and methods could be specifically designed to enable the expression of highly motivated behaviors that are driven by emotional circuits in the brain. The objective of this paper is to increase awareness of animal scientists to the field of neuroscience studying animal emotions and the application of that science to improve the welfare of captive exotic animals, laboratory animals, and pets with environmental enrichment.     

Veterinary radiation therapy: review and current state of the art

Veterinary radiation oncology became a recognized specialty in 1994. Radiation therapy is an important component of a multimodality approach to treating cancer in companion animals. It is important to understand the many aspects of radiation, including the equipment used in external beam radiation therapy, the basic mechanism of action of ionizing radiation, the results of irradiating various histopathological types of tumors, as well as the associated potential acute and late side effects of radiation. A comprehensive review of radiation therapy is timely and provides information for clients on cancers that may benefit from external beam radiation therapy.     

Emergency Presentations of the Exotic Small Mammalian Herbivore Trauma Patient

Trauma is a common complaint by owners of small exotic mammalian herbivores (e.g., rabbits, rodents) presented to veterinary hospitals. The term “trauma” is a broad disease category applied to patients with physical debilitation associated with injury often classified as “blunt,” “penetrating,” or “burn” in origin. Because many small exotic mammalian herbivores are prey animals, clinical signs of trauma may be masked until the effects of the injury outweigh the innate nature to survive. Small exotic mammalian herbivores are disproportionately sensitive to stress; thus, pain management and supportive care are extremely important during the initial stages of trauma management. Small exotic mammals differ slightly from other companion animals (e.g., dogs, cats) in regard to common trauma presentations. However, with a few therapeutic modifications (e.g., antibiotic selection, avoidance of corticosteroids, preventing self-trauma), treatment of small exotic mammalian herbivore trauma cases follows the same conventional guidelines used for other companion animals.