Toxicology of selected pesticides, drugs, and chemicals. Pyrethrin and pyrethroid insecticides

Pyrethroids have a wide spectrum of insecticidal potency, vertebrate toxicity, and environmental stability. The exceptionally high selectivity ratios of pyrethrins and pyrethroids have resulted in their use for insect control in numerous formulations. A primary effect of pyrethroids is to slow the closing of the sodium activation gate in nerve cells. All pyrethroids have essentially the same basic mechanism of action on voltage-dependent sodium channels but differ in the magnitude of effect. Based on clinical signs, electrophysiologic responses, and chemical structure, pyrethroids can be classified as Type I or Type II. Inhibition of the GABAA receptor appears to be an additional mechanism of Type II pyrethroids. Clinical signs in small animals during a pyrethroid toxicosis vary but are generally attributable to neural dysfunction. Treatment consists of decontamination procedures and application of appropriate symptomatic care, including control of seizures if necessary.     

Animal poisoning in Europe. Part 2: Companion animals

This is the second in a series of three review articles on animal poisoning in Europe and focuses on cases in pet animals and horses in five European countries (Belgium, France, Greece, Italy and Spain) reported over the last decade. In the participating countries, dogs were the most commonly poisoned species, particularly younger animals. The majority of cases in companion animals resulted from exposure to insecticides, although rodenticides (especially anticoagulants and strychnine) posed a significant risk. In all five countries, horses and cats appeared to be more susceptible to plant toxins. Intoxications with herbicides, metals, household products and drugs for veterinary and human use were reported sporadically. The review demonstrates the importance of increased awareness so as to minimise poisoning episodes and emphasises the need to establish a European system for the recording of poisoning data.     

Modern veterinary vaccines and the Shaman's apprentice

This paper is an overview and assessment of new, commercially available veterinary vaccines placed in a historical context. The authors critically evaluate the current state of the field of veterinary vaccines in both food and companion animals and the promises for future vaccine development. The authors maintain that there is considerable variability in safety and sustained efficacy among veterinary vaccines, especially those developed for companion animals. It is proposed that establishment of an international vaccine advisory committee be supported which would function to apprise the veterinary profession of the current status of vaccines and their use.     

Medical Management of Recurrent Seizures in Dogs and Cats

The problem of recurrent seizures is a common and challenging one in veterinary medical practice. The pathophysiology and pharmacologic suppression of focal seizure activity have been studied extensively in basic research settings, yet little is known of the genesis, modulation, and termination of generalized seizures, the most common form of seizures noted to occur in companion animals. Knowledge concerning the pharmacokinetic fate of anticonvulsant drugs currently used in veterinary medicine is adequate, though prospective clinical studies of the efficacy of these drugs in the treatment of various types of seizures are lacking. This study will review the available literature regarding the pharmacology, use, and side effects of anticonvulsant drugs currently available for control of recurrent seizures in companion animals. Alternative anticonvulsant drugs will also be described.     

Ammonia Metabolism and the Urea Cycle: Function and Clinical Implications

Disposal of waste products accumulated during metabolic processes is integral to the health of any living organism. Disposal of excess nitrogen and ammonia is no exception. Although nitrogen is essential for growth and maintenance in animals, an excess of some nitrogenous compounds can quickly lead to toxicity and death. Because of the correlation between ammonia accumulation and clinical disease, it is important for veterinary clinicians to understand the physiological mechanisms used to dispose of nitrogen and ammonia. Therefore, the purposes of this article are to review ammonia metabolism, the urea cycle, and the clinical implications of urea cycle dysfunction in diseases of companion animals.     

The current state of veterinary vaccines: is there hope for the future?

This article is an overview and assessment of available veterinary vaccines, placed in a historical context. A more complete presentation of the main tenets of the symposium talk at Agenda for Action: Veterinary Medicine's Role in Biodefense and Public Health is published elsewhere.' The symposium presentation contained a critical evaluation of the current state of the field of veterinary vaccines for both food and companion animals and of promises for future vaccine development. There is considerable variability in safety and sustained efficacy among veterinary vaccines, especially those developed for companion animals. Standardization of vaccines and vaccinal strains and detailed knowledge of their safety, efficacy, and potency and of the duration of immunity are needed before rational recommendations can truly be made. It is proposed that the establishment of an international vaccine advisory committee be supported, which would function to apprise the veterinary profession of the current status of vaccines and their use, and that a system for reporting vaccine adverse events, similar to that for humans, should be established.     

Antimicrobial use in food and companion animals

The vast literature on antimicrobial drug use in animals has expanded considerably recently as the antimicrobial resistance (AMR) crisis in human medicine leads to questions about all usage of antimicrobial drugs, including long-term usage in intensively managed food animals for growth promotion and disease prevention. Attention is also increasingly focusing on antimicrobial use and on bacterial resistance in companion animals, which are in intimate contact with the human population. They may share resistant bacteria with their owners, amplify resistant bacteria acquired from their owners, and act as a reservoir for human infection. Considerable effort is being made to describe the basis of AMR in bacterial pathogens of animals. Documentation of many aspects of use of antimicrobials in animals is, however, generally less developed and only a few countries can describe quantities of drugs used in animals to kg levels annually. In recent years, many national veterinary associations have produced 'prudent use guidelines' to try to improve antimicrobial drug use and decrease resistance, but the impact of guidelines is unknown. Within the evolving global movement for 'antimicrobial stewardship', there is considerable scope to improve many aspects of antimicrobial use in animals, including infection control and reduction of use, with a view to reducing resistance and its spread, and to preserving antimicrobial drugs for the future.     

Antimicrobial resistance.

Development of antimicrobial resistance is an inevitable consequence of exposure of microorganisms to antimicrobial agents. Although emergence of resistance cannot be prevented, it can be retarded by minimizing use of antimicrobial agents and avoiding selection of relatively resistant pathogenic and nonpathogenic strains caused by exposure to tissue concentrations that confer a competitive advantage. Most attention in veterinary medicine has focused on the emergence of resistance in food-borne pathogens, with relatively little attention being devoted to small companion animals, despite the frequent use of antimicrobial agents in these animals, evidence that resistance is emerging, and potential for transfer of resistance between companion animals and people. To retard further emergence of resistance in small companion animals, it is imperative that surveillance programs be instituted to monitor development of resistance.     

Escherichia coli and selected veterinary and zoonotic pathogens isolated from environmental sites in companion animal veterinary hospitals in southern Ontario

Hospital-based infection control in veterinary medicine is emerging and the role of the environment in hospital-acquired infections (HAI) in veterinary hospitals is largely unknown. This study was initiated to determine the recovery of Escherichia coli and selected veterinary and zoonotic pathogens from the environments of 101 community veterinary hospitals. The proportion of hospitals with positive environmental swabs were: E. coli--92%, Clostridium difficile--58%, methicillin-resistant Staphylococcus aureus (MRSA)--9%, CMY-2 producing E. coli--9%, methicillin-resistant Staphylococcus pseudintermedius--7%, and Salmonella--2%. Vancomycin-resistant Enterococcus spp., canine parvovirus, and feline calicivirus were not isolated. Prevalence of antimicrobial resistance in E. coli isolates was low. Important potential veterinary and human pathogens were recovered including Canadian epidemic strains MRSA-2 and MRSA-5, and C. difficile ribotype 027. There is an environmental reservoir of pathogens in veterinary hospitals; therefore, additional studies are required to characterize risk factors associated with HAI in companion animals, including the role of the environment.     

Animal poisoning in Italy: 10 years of epidemiological data from the Poison Control Centre of Milan

From 2000 to 2010, the Poison Control Centre of Milan (CAV), in collaboration with the University of Milan, Faculty of Veterinary Medicine, Department of Veterinary Sciences and Technologies for Food Safety, Toxicology Section, collected epidemiological information related to animal poisoning and classified it in an organised and computerised data bank. Data recorded were predominantly related to small animals and to some extent to horses, ruminants and other food-production animals. Few calls were registered involving exotics and no information was recorded on wildlife. The dog was reported to be the most common species involved in animal poisoning, and pesticides constituted the primary group of toxicants. In the case of pets, 'drugs' including veterinary parasiticide and drugs for human use constituted the second class of toxicants responsible for poisoning followed by household products, plants, zootoxins and metals. With regard to horses and farm animals, the second group consisted of phytotoxins, even if only episodically. In Italy, published data on this subject are scarce but this information is crucial for better management of the poisoning of domestic animals in an effort to reduce mortality.     

The incidence and seasonal characteristics of veterinary toxicoses in Saskatchewan

The species incidence and seasonal occurrence of veterinary toxicoses identified in the diagnostic toxicology laboratory at the Western College of Veterinary Medicine were tabulated during the period from 1968 to 1982. A toxicological diagnosis was indicated in 990 animals during this period of time. Lead (340 cases) and strychnine (284 cases) poisoning were the predominant toxicoses encountered. Other metal, pesticide and feed-related toxicoses were reported at a much lower incidence. A statistically significant seasonal incidence of toxicity was seen with lead, chlorinated hydrocarbon and strychnine poisoning. Strychnine (261/284 cases) and metaldehyde (12/12 cases) poisoning were seen primarily in the canine. In the bovine, a high degree of species specificity was associated with lead (294/340 cases), dicoumarol (36/36 cases) and nitrite (8/10 cases) poisoning. Copper toxicity was primarily a problem in the ovine (21/24 cases). The species specificity reflects in many instances species-specific husbandry practices, local agricultural methods or biochemical and physiological differences between species.     

"Concepts in animal welfare": a syllabus in animal welfare science and ethics for veterinary schools

Public attitudes toward animal welfare have improved with growing social affluence, and veterinarians are increasingly expected to be informed about animal welfare in a broader sense than health alone. However, animal welfare has not been a traditional component of the veterinary curriculum. To help address this lack, the World Society for the Protection of Animals(WSPA) and the University of Bristol School of Veterinary Science launched the 'Concepts in Animal Welfare' syllabus in 2003. This comprehensive syllabus comprises seven core and 23 elective modules and covers a range of animal welfare issues, including farm and companion animal welfare, wildlife, and the use of animals in experiments. There are also modules on ethics and animal legislation. The syllabus is interactive, promotes critical analysis of issues from different angles, and may be adapted for use in any veterinary curriculum. WSPA provides training and workshops in developing countries and assists with the implementation of the syllabus.     

Work conditions, job preparation, and placement strategies for food-animal veterinarians

This study examines the responses of 1,047 human-resources personnel who recruit veterinarians for positions in their organizations. Work conditions in the organization, lifestyle and time-management issues, job benefits, job expectations, supervisor relations, and the physical demands of veterinary work are studied. Comparisons are made between four different occupational areas: food animals, mixed animals, companion animals, and industry positions in veterinary medicine. The findings portray a career in food animal medicine as very positive. Recruiters also make recommendations to colleges of veterinary medicine for strategies to improve the preparation and placement of their graduates.     

Conduct,Oversight, and Ethical Considerations of Clinical Trials in Companion Animals with Cancer: Report of a Workshop on Best Practice Recommendations

Development of effective and safe treatments for companion animals with cancer requires the collaboration of numerous animal health professionals and the full engagement of animal owners. Establishing ‘Best Practice Recommendations’ for clinical trials in veterinary oncology represents an important step toward meeting the goal of rigorous clinical trial design and conduct that is required to establish valid evidence. Likewise, optimizing patient welfare and owner education and advocacy is crucial to meet the unique ethical obligations to both owners and animals enrolled in these clinical trials and to ensure trust in the team conducting the research. To date, ‘Best Practice Recommendations’ for clinical trial conduct have not been reported for veterinary oncology. This document summarizes the consensus of a workshop held in November, 2014 to identify relevant ethical principles and to ensure responsible conduct of clinical research in companion animals with cancer. It is intended as a working document that will be updated as advances in science and ethical considerations require. To the extent possible, existing guidelines for the conduct and oversight of clinical trials in humans have been adapted for veterinary trials to avoid duplicative effort and to facilitate integration of clinical trials such that translational research with benefits for both companion animals and humans are encouraged.     

伴侣动物用细胞毒类抗肿瘤药临床试验设计及评价要点

肿瘤已经逐渐发展成为老年伴侣动物最为常见的疾病，而目前国内并无伴侣动物专用的抗肿瘤药。细胞毒类抗肿瘤药是治疗恶性肿瘤的主要手段之一，目前有许多兽药企业致力于此类抗肿瘤药的研发。本文以EMA和FDA发布的伴侣动物抗肿瘤药指导原则为依据，结合国家药品监督管理局药品审评中心(CDE)发布的抗肿瘤药物临床试验技术指导原则对比分析，对伴侣动物使用的细胞毒类抗肿瘤药研发过程中的临床试验设计关键技术要点进行了分析，旨在为伴侣动物用细胞毒类抗肿瘤药临床评价提供参考。     

Pesticides and domestic animals.

Domestic animals are quite often poisoned by pesticides despite the considerable effort made through legislation and Ministry recommendations to provide adequate safeguards for the use of agricultural chemicals. All pesticides have to be registered and recommendations and restrictions for use are printed on the labels. But a number of cases involving the misuse of certain poisons as bait for vermin has caused concern recently to both Government and industry. Special problems face the veterinary surgeon who has to treat a pet animal with suspected esticide poisoning. This paper provides possible sources of information from which the veterinary surgeon may obtain help with diagnosis, advice on treatment and laboratory aid.     

Use of intralipid emulsion therapy to treat suspected oleander toxicosis in a domestic goose (Anser anser domesticus)

Ingestion of toxic substances is a common event in companion animals and livestock, especially in waterfowl. Oleander (Nerium oleander) toxicosis is rarely reported in avian species, with symptoms including cardiac, neurological and gastrointestinal manifestations. A 6-month-old domestic goose (Anser anser domesticus) was presented for depression, anorexia, permanent sternal recumbency, weakness and incoordination, and the owners witnessed the ingestion of oleander leaves. Despite the absence of evident cardiac symptoms, biochemical hematological findings showed significant increase of CPK, AST, LDH, and troponin I. Therapy was set with intravenous (IV) fluid administration, antibiotic and anti-inflammatory, oral activated charcoal, and IV lipid emulsion at 15 mL/kg/h. Clinical improvement was achieved after 2 hours. The patient was discharged 3 days after admission, with complete recovery and return to normal biochemical values 10 days after initial presentation. The present work describes a suspected case of spontaneous oleander poisoning in a domestic goose, with the first use of troponin I to diagnose cardiac injury in this species, and the first report of IV lipid emulsion to successfully treat this kind of toxicosis in veterinary practice.     

Vaccine side effects: fact and fiction

The debate over adverse reactions associated with companion animal vaccination has considerably exercised the veterinary profession internationally over the past decade. A range of suspected adverse reactions to vaccines is reported including the onset of inflammatory, allergic, autoimmune or neoplastic diseases. Lack of efficacy, interference with diagnostic testing and other occasional suspected product-related issues are also reported. Available data suggest that the overall prevalence of true adverse reactions is exceedingly low and that vaccination does not significantly contribute to ill-health in companion animals. There is increasing public interest in vaccination issues with transfer of focus from publicity over human vaccine side effects to those perceived to occur in animals. We must not lose sight of the fact that vaccination is a safe procedure that has impacted significantly on infectious disease control. Reduced population uptake of vaccination leads to re-emergence of disease in both humans and animals. Nevertheless, there have recently been a series of practical recommendations produced to ensure reduced 'vaccine load' on our companion animals and vaccine manufacturers are moving towards developing non-adjuvanted products with an extended duration of immunity. These measures will further reduce the very small current risk of any adverse consequences to vaccination in our pet population.     

Attitudes of Australian and Turkish veterinary faculty toward animal welfare

The attitudes of veterinary faculty toward animal welfare were surveyed in four Australian and three Turkish veterinary schools. The former were considered to be typical of modern Western schools, with a faculty of more than 40% women and a primary focus on companion animals, whereas the latter were considered to represent more traditional veterinary teaching establishments, with a faculty of 88% men and a primary focus on livestock. A total of 116 faculty responded to the survey (42 Australian and 74 Turkish faculty members), for response rates of 30% and 33%, respectively. This survey included demographic questions as well as questions about attitudes toward animal-welfare issues. Women were more concerned than men about animal-welfare issues, especially the use of animals in experiments, zoos, entertainment, and sports and for food and clothing. Total scores demonstrated different concerns among Turkish and Australian faculty. The study demonstrates that the veterinary faculty of these two countries have different concerns for animal welfare, concerns that should be acknowledged in considering the welfare attitudes that students may adopt.