Animal Disease Prevention Research Articles

Opinión del sector ganadero sobre el rol de las vacunas en el control y eradicación de las enfermedades del ganadero en Argentina

Research by a number of international organisations indicates that world demand for red meat protein is set to increase significantly in the coming years. However, faced with the risk of infectious animal diseases and zoonoses--factors that could limit the growth of this production sector--the fight against livestock diseases must continue, especially against those that affect food safety or pose a threat to human life. The use of vaccination to prevent infectious animal diseases is of key importance, not only because it helps to control and effectively eradicate infectious livestock diseases, but also because it makes it possible to introduce new technologies for intensive or semi-intensive production, to protect the environment, to care for animal welfare and to guarantee the safety of animal-derived foodstuffs. As part of their professional culture, livestock producers have come to fully appreciate the advantages of using vaccination to prevent disease rather than curative measures, which are more costly to implement and in some cases not very effective. The control of anthrax and rabies by means of effective vaccines was a factor in the widespread development of livestock in Argentina and other parts of Latin America. Recent results in the control and eradication of foot and mouth disease have made producers even more convinced of the merits of this technology. Animal disease prevention has proven to be highly conducive to the production of healthy foodstuffs. It is the responsibility of international organisations to draw up appropriate regulations to protect trade, supply safe and healthy products and prevent the application of unjustified non-tariff measures.

Requisitos de las reglamentaciones relativas a la autorización de comercialización de vacunas

Vaccines are one of the most important tools available in the prevention and control of diseases in animals. It is therefore of the utmost importance that when vaccines are used, such use should meet with the requirements of the World Organisation for Animal Health Terrestrial Animal Health Code and must be authorised by the recognised licensing body in the country/region where the vaccines are to be used, in accordance with the three key criteria of quality, safety and efficacy. This article provides a comprehensive and comparative description of the regulatory requirements in place for veterinary vaccines in major regions of the world, highlighting the similarities and pointing out also where there are differences. Recent advances in harmonisation of such testing requirements achieved through the International Cooperation on Harmonisation of Technical Requirements for Registration of Veterinary Medicinal Products (VICH) are also described. The contents will provide a valuable guide to those engaged in the research and development of vaccines globally, and reassure those involved in the prevention and control of animal diseases that veterinary vaccines, when fully authorised and used according to the label instructions, are safe and efficacious.

A questionnaire survey of perceptions and preventive measures related to animal health amongst cattle owners of rural communities in KwaZulu-Natal, South Africa

A questionnaire survey of 315 cattle owners from the rural districts of KwaZulu-Natal was carried out. The aim of the survey was to improve our understanding of local farmers' perceptions and practices of animal disease prevention and control and to establish the extent of their relationship with veterinary services. The survey showed that many owners practice preventive measures such as deworming, tick control and vaccination. Traditional medicines were in use by over half the respondents (58.9 %). Diseases are regarded as an important management problem (56.1 %); ticks, worms and diarrhoea dominated the mentioned health problems in cattle. Veterinary services still play an important role and are a frequent source of advice to owners. The findings of the survey and their context are discussed.

Pfizer Inc

AbstractPharmaceuticals (MIC: 9.1 SIC: 2834 NAIC: 325412)Pfizer is engaged in discovering, developing, manufacturing and marketing prescription medicines for humans and animals. Co. operates in two business segments: Pharmaceutical and Animal Health. Co.'s Pharmaceutical segment develops and manufactures products that treat cardiovascular and metabolic diseases, central nervous system disorders, arthritis and pain, infectious and respiratory diseases, urogenital conditions, cancer, eye disease, endocrine disorders and allergies. Co.'s Animal Health segment discovers, develops and sells products for the prevention and treatment of diseases in livestock and companion animals.

Pfizer Inc

AbstractPharmaceuticals (MIC: 9.1 SIC: 2834 NAIC: 325412)Pfizer is a research‐based, global pharmaceutical company. Co. discovers, develops, manufactures and markets prescription medicines for humans and animals. Co. operates in two business segments: Pharmaceutical and Animal Health. Co.'s Pharmaceutical segment develops and manufactures products that treat cardiovascular and metabolic diseases, central nervous system disorders, arthritis and pain, infectious and respiratory diseases, urogenital conditions, cancer, eye disease, endocrine disorders and allergies. Co.'s Animal Health segment discovers, develops and sells products for the prevention and treatment of diseases in livestock and companion animals.

Drug-resistant NontyphoidalSalmonellaBacteremia, Thailand1

To the Editor: Despite improved public health, serious infections with nontyphoidal Salmonella enterica remain a major clinical and public health concern in Thailand and worldwide (1,2). Life-threatening Salmonella infections resistant to fluoroquinolones, extended-spectrum cephalosporins, or both, have been increasingly reported (3). Use of antimicrobial drugs for disease prevention and growth promotion in food animals has been implicated in this increase in drug resistance (4). Because of extensive global travel, such increases affect the medical community domestically and internationally (5). We report a pilot survey of drug resistance in Salmonella spp. in Thailand.

Genetics of Antimicrobial Resistance

Antimicrobial resistant strains of bacteria are an increasing threat to animal and human health. Resistance mechanisms to circumvent the toxic action of antimicrobials have been identified and described for all known antimicrobials currently available for clinical use in human and veterinary medicine. Acquired bacterial antibiotic resistance can result from the mutation of normal cellular genes, the acquisition of foreign resistance genes, or a combination of these two mechanisms. The most common resistance mechanisms employed by bacteria include enzymatic degradation or alteration of the antimicrobial, mutation in the antimicrobial target site, decreased cell wall permeability to antimicrobials, and active efflux of the antimicrobial across the cell membrane. The spread of mobile genetic elements such as plasmids, transposons, and integrons has greatly contributed to the rapid dissemination of antimicrobial resistance among several bacterial genera of human and veterinary importance. Antimicrobial resistance genes have been shown to accumulate on mobile elements, leading to a situation where multidrug resistance phenotypes can be transferred to a susceptible recipient via a single genetic event. The increasing prevalence of antimicrobial resistant bacterial pathogens has severe implications for the future treatment and prevention of infectious diseases in both animals and humans. The versatility with which bacteria adapt to their environment and exchange DNA between different genera highlights the need to implement effective antimicrobial stewardship and infection control programs in both human and veterinary medicine.

Genetically modified potato plants in nutrition and prevention of diseases in humans and animals: a review

Genetically modified organisms (GMO) become a real constituent of our lives and nowadays, they are commonly introduced into the food chain of people and animals in some states. Among higher organisms, plants are used above all for genetic modifications; potatoes are a suitable model plants for this purpose. Nowadays, a number of various genetic modifications of potato plants are available, particularly those with increased resistance to biological agents and factors of the external environment or with improved nutritional value. Plants that produce proteins of the immune system of man or animals or substances that may be used as vaccines in human or veterinary medicine are highly important. Modified potato plants that produce biomaterials for potential applications in the industry are a significant category.

Guidelines for prudent use of antimicrobials and their implications on antibiotic usage in veterinary medicine

Antibiotics are still deemed necessary for the treatment and prevention of infectious diseases in farm animals intended for food production and to protect public health from food-borne diseases. All antibiotics used in veterinary medicine are the same or closely related to antibacterials used in human medicine or may induce cross-resistance. Consumption figures of antibiotics in the European Union (EU) indicate an about 10-fold higher number of treatment days in human medicine when compared to veterinary usage with tetracyclines being the most frequently used group. However, the conditions of antibiotic use in farm animals, mainly in swine and poultry by oral treatment of a large number of animals for prolonged periods of time and risk of underdosing might favour the selection of bacterial resistance. In order to reduce the use of antibiotics and thus to minimize the development of resistance in veterinary medicine, compulsory guidelines for prudent use of antibacterials in animals were published in Germany in December 2000. These guidelines describe the minimum requirements to be followed by veterinarians when administering antibiotics to animals. Key elements of the guidelines are the use of antibiotics on the basis of an exact (preferentially microbiological) diagnosis, choice of the most suitable antibacterial substance (antibacterial spectrum as narrow as possible, margin of safety as high as possible, good tissue penetration if necessary), restricted use of antibiotics with last resort character, adherence to the label instructions (no underdosing or prolongation of dosing interval). Any deviations from the guideline recommendations must be justified and recorded. Results of monitoring of antibiotic usage as medicated feeding stuffs in pig production in the German state Sachsen-Anhalt from October 2000 until March 2002 indicate a change of the prescribing attitude of veterinarians after implementation of the guidelines. The consumption of antibiotics continuously declined from 4255 kg before the guidelines to 1145 kg in the first quarter of 2002 resulting in a reduction of the treatment days per animal from 31.6 (third quarter 2000) to 13.6 days (first quarter 2002). Simultaneously the use of chlortetracycline decreased from initially 76% of the total amount of antibiotics prescribed to 14.7% at the end of the study, respectively. These results suggest an acceptance of the guidelines for prudent antibiotic use by veterinarians as an important tool to reduce the usage of antibiotics and the consecutive development of resistance.

Strategy of production of beef from farm to table and protection of consumers

In the future value of cattle and products will be in direct relation to quality presented to consumers. Consumer demands differ depending on the culture, location and social conditions. However, since World is becoming "globally speaking" smaller consumer attitudes in regard to the definition of high quality meat is becoming uniform. In order to maintain and preserve the health of consumers huge amounts of money are spent on finding out new methods for detection and prevention of animal diseases and improvement of crop production. So, in the period 2002-2006 budget of 685 million EUR has been approved for research of the food quality and consumer safety. Average consumption of beef in EU is approx. 15 kg and is now recovering from drastic decrease because of BSE in the period 1996-2001. Total number of livestock is approx. 91-92 million heads, and production of beef is approx. 8,2 million tons. Directives in legislation relating to production of safe food date from 1960 were intensified in 1990 especially because of BSE incidence in 1994. It is considered that food will be safe if animals are healthy. Healthy doesn't relate only to their health condition but also to the natural methods of breeding of livestock. By maintaining good veterinary practice we aim to improve the general health condition of animals. Potential incidences of diseases are monitored carefully and isolated and spreading of such diseases prevented as much as possible. Projections in cattle production are made mainly as plans for twenty year period. There is a great pressure on producers relating to use of natural resources. Until 2002, it was anticipated that demand for livestock products would have been increased mainly because of increase in population. Problem occurs because increase of number of animals in rural regions and suburban city areas involves higher risk of spreading of disease. Also, there is the issue of adequate waste storage.

Evidence-Based Veterinary Dentistry: A Systematic Review of Homecare for Prevention of Periodontal Disease in Dogs and Cats

Successful treatment and prevention of periodontal disease in pet animals requires a multidimensional approach to identify and eliminate exacerbating factors, provide scheduled professional examinations and care, and plan and implement a dental homecare program. Over the years, many therapeutic and preventive interventions have been developed or advocated for periodontal disease, but evidence of efficacy or effectiveness is highly variable. Accordingly, the main objective of this systematic review is to identify and critically appraise the evidence supporting various aspects of homecare for prevention of canine and feline periodontal disease.

The Ethnobotanical and Botanical Study on Pseuderanthemum palatiferum as a New Medicinal Plant in the Mekong Delta of Vietnam

The cultivation and application of Pseuderanthemum palatiferum, a plant found in the latter half of the 1990′s in northern Vietnam, was studied at a total of 12,829 households located in the city center and suburb of Cantho city. The frequency of the households cultivating the plant, the plant′s population and age, recipients, purposes and amount of the dosages were surveyed in interviews with households. Second, growth of the plant at an experimental farm of Cantho University was observed. Only 1.1% of the total households cultivated the plant. However, more (p<0.01) households in the city center cultivated the plant than those in the suburb. More households in the city center cultivated greater populations of the plant. The city center households dosed the plant not only for treatment of human diseases, but also for the prevention and treatment of animal diseases. The frequencies of the dosage and the amount of each dose were more for treatment than for prevention, and more for human diseases than animal diseases. The dosages were more in the city center households. The results of the field study would suggest that cultivation of the plant had been spread from the city center to the suburb, and its dosage had widened from the purpose of treatment to prevention of diseases, and the recipients from human to animal diseases. The plant observed could grow very fast and bloom, in the same way as the growth in northern Vietnam. The easiness of its planting and the earliness of growth would have helped the spread of its cultivation and application in the Mekong Delta region.

Passive Immunization Through Avian Egg Antibodies

Oral administration of specific antibodies is an attractive approach to establish passive immunization against various pathogens in humans and animals. Egg yolk contains over 100 mg of IgY per egg and is considered to be a more hygienic and economical source of antibodies, than antibodies from mammalian sera. Recently, considerable research has focussed on the use of IgY as an alternative to mammalian antibodies for several applications, most notably for oral passive immunization against various bacteria and viruses. Oral administration of IgY has proven to be successful for the treatment of a variety of gastrointestinal (GI) pathogens such as bovine and human rotaviruses, bovine coronavirus, Yersinia ruckeri, enterotoxigenic Escherichia coli, Salmonella spp., Edwardsiella, Staphylococcus, and Pseudomonas. Recent advances in hybridoma technology, for the production of monoclonal IgY, also present many benefits for its universal application. IgY technology has significant future opportunities for the design of strategies for the prevention and treatment of infectious gastrointestinal diseases in humans and animals.

Benefits and barriers to the consumption of a vegetarian diet in Australia.

The aim of this study was to examine consumers' perceived benefits and barriers to the consumption of a vegetarian diet. Survey (written questionnaire) that included questions on perceived benefits and barriers to the consumption of a vegetarian diet. South Australia. Six hundred and one randomly selected South Australians. The main perceived barriers to adopting a vegetarian diet were enjoying eating meat and an unwillingness to alter eating habits. This was the case for men, women and all age groups, although there were sex and age differences present in over half of the barrier items. For example, family food preferences were a greater problem for women than for men, while the oldest group was more likely to agree that humans are 'meant' to eat meat than the younger groups. The main benefits associated with vegetarian diets were health benefits: increased fruit and vegetable intake, decreased saturated fat intake, weight control. Animal welfare-related benefits and disease prevention were also important. Age and sex differences were apparent, although age differences were more important than sex differences. The majority of respondents perceived there to be health benefits associated with the consumption of a vegetarian diet, but also, predictably, enjoyed eating meat. Given this, it is likely that interest in plant-based diets that contain some meat is higher than that in no-meat diets. An understanding of the perceived benefits and barriers of consuming a vegetarian diet will allow the implementation of strategies to influence meat and vegetarianism beliefs, dietary behaviour and, hence, public health.

Dietary cadmium inhibits spontaneous hepatocarcinogenesis in C3H/HeN mice and hepatitis in A/J mice, but not in C57BL/6 mice

Cadmium is known to be a potent carcinogenic and mutagenic metal. However, we demonstrated that dietary supplementation with 50 ppm cadmium inhibits spontaneous carcinogenesis in C3H/HeN and spontaneous hepatitis in A/J mice. We found that the frequencies of spontaneous hepatocarcinogenesis in C3H/HeN mice and of spontaneous hepatitis in A/J mice fed low-dose cadmium for 54 weeks were significantly lower than those in the respective control groups. A cadmium-induced increase in metallothionein production itself and/or metallothionein-associated increases in hepatic zinc concentrations may be involved in the observed preventive effects of cadmium. Our results suggest that low doses of cadmium in the diet or environment may play a beneficial role in the prevention of hepatic disease in humans and animals.

JOHNSON PUMP IN NEW SHARE ISSUE

Economic-welfare analysis of animal disease prevention programs frequently ignore the constraints of the agricultural policy environment. Prevention programs affect producers, consumers and the government. The policy environment to a large extent determines the magnitude as well as the distribution of benefits of the program among these groups. The Swedish hog industry has been exposed to three major policy changes during the 1990–1995 period. These scenarios involve various degrees of government intervention in the agricultural sector including internal market deregulation and EU-membership. Aujeszky's disease is a virus disease with swine as the natural infection reservoir. Piglets are the most fragile and an outbreak of the disease results in symptoms such as shaking, cramps and convulsions with an increase in the mortality rate. Slaughter hogs suffer from coughing, fever and reduce their feed consumption. During the last 20–25 years the incidence of Aujeszky's disease (AD) has been increasing in Sweden. In 1989 an eradication program was undertaken. A model is developed to analyze social benefits of an eradication program given variations in agricultural policy. The model refers to the specifics of the AD-program implemented in Sweden. The expected benefits of the program are evaluated using a welfare-economic analysis applying cost-benefit analysis. Total benefits of the program are evaluated across herd and size categories and different regions. Data concerning the frequency of the virus among various categories of herds prior to enacting the program were used (Wahlström et al., 1990). In addition, data from an agricultural insurance company were used to estimate the conditional probability of an outbreak given that the herd is infected. Biological and technical parameter values were collected from a variety of sources. The results of the analysis indicate that the program is economically viable given a social rate of discount in the range of 3–5% without considering non-monetary aspects such as animal ethics. A scenario where the Swedish agricultural sector is deregulated provides the maximum benefits of the program. Consumers obtain about 50% of the benefits excluding program costs. The deregulation scenario would correspond closely to a case where a reformed Common Agricultural Policy (CAP) is applied across member countries. In the current case where Sweden is a member of the EU, the benefits are reduced mainly due to lower prices of inputs and pork.

THE FOOD SAFETY PERSPECTIVE OF ANTIBIOTIC RESISTANCE

ABSTRACT Bacterial antimicrobial resistance in both the medical and agricultural fields has become a serious problem worldwide. Antibiotic resistant strains of bacteria are an increasing threat to animal and human health, with resistance mechanisms having been identified and described for all known antimicrobials currently available for clinical use. There is currently increased public and scientific interest regarding the administration of therapeutic and sub-therapeutic antimicrobials to animals, due primarily to the emergence and dissemination of multiple antibiotic resistant zoonotic bacterial pathogens. This issue has been the subject of heated debates for many years, however, there is still no complete consensus on the significance of antimicrobial use in animals, or resistance in bacterial isolates from animals, on the development and dissemination of antibiotic resistance among human bacterial pathogens. In fact, the debate regarding antimicrobial use in animals and subsequent human health implications has been going on for over 30 years, beginning with the release of the Swann report in the United Kingdom. The latest report released by the National Research Council (1998) confirmed that there were substantial information gaps that contribute to the difficulty of assessing potential detrimental effects of antimicrobials in food animals on human health. Regardless of the controversy, bacterial pathogens of animal and human origin are becoming increasingly resistant to most frontline antimicrobials, including expanded-spectrum cephalosporins, aminoglycosides, and even fluoroquinolones. The lion's share of these antimicrobial resistant phenotypes is gained from extra-chromosomal genes that may impart resistance to an entire antimicrobial class. In recent years, a number of these resistance genes have been associated with large, transferable, extra-chromosomal DNA elements, called plasmids, on which may be other DNA mobile elements, such as transposons and integrons. These DNA mobile elements have been shown to transmit genetic determinants for several different antimicrobial resistance mechanisms and may account for the rapid dissemination of resistance genes among different bacteria. The increasing incidence of antimicrobial resistant bacterial pathogens has severe implications for the future treatment and prevention of infectious diseases in both animals and humans. Although much scientific information is available on this subject, many aspects of the development of antimicrobial resistance still remain uncertain. The emergence and dissemination of bacterial antimicrobial resistance is the result of numerous complex interactions among antimicrobials, microorganisms, and the surrounding environments. Although research has linked the use of antibiotics in agriculture to the emergence of antibiotic-resistant foodborne pathogens, debate still continues whether this role is significant enough to merit further regulation or restriction.

Immunomodulators for Prevention and Treatment of Infectious Diseases in Food-Producing Animals

The goal of immunomodulation in food-producing animals is to regulate immunity for the benefit of the animal and production efficiency. Immunomodulators are substances that exert this control and include cytokines, pharmaceuticals, microbial products, nutraceuticals, and traditional medicinal plants. Although treatment and prevention of infectious diseases are the most common reasons to use immunomodulators, other conditions, such as amelioration of stress-induced immunosuppression, maturation of the neonate's developing immune response, and strategies to reduce the metabolic cost of eliciting an immune response also are well suited for immunomodulation. Continued discovery of new immune regulators and increased understanding of immunity in food-producing animals will ensure new opportunities for the use of immunomodulators in food-producing animals.

The Swedish experience of the 1986 year ban of antimicrobial growth promoters, with special reference to animal health, disease prevention, productivity, and usage of antimicrobials.

In Sweden the use of antimicrobial growth promoters (AMGP) was banned in 1986. The experiences gained from that ban are presented. In production of slaughter pigs, specialized beef, and turkeys, no negative clinical effects were reported as a consequence of the ban. In broiler chicken production, expected problems with necrotic enteritis were prevented by a continuous use of antibiotics, largely to the same extent during the first 2 years after the ban. Following the implementation of results from experimental activities during that period, the general usage of antimicrobials could be stopped and expected problems with outbreaks of necrotic enteritis was prevented. In piglet production, significant clinical problems emerged that created a demand for antibiotic-medicated feed at therapeutic dosages. During the subsequent 4-year period, the use of antibiotics increased, involving up to 75% of the pigs. Thereafter, the use of antibiotics decreased because of improved management, and could be halved in 1993 followed by a gradual further decrease supported by the addition of zinc oxide to the feed. In 1998, compared to 1994, the total use of zinc decreased by 90%. In 1998/1999, only 5% of weaning piglet producing herds used antibiotic medicated feed and 17% used zinc. The AMGP ban has shown that under good production conditions it is possible to reach good and competitive production results for the rearing of poultry, calves, and pigs without the continuous use of AMGP. As a result of the ban and a focus on disease prevention and correct use of antimicrobials, the total use of antibacterial drugs to animals in Sweden decreased by approximately 55% during the last 13-year period, and a relatively low prevalence of antimicrobial resistance has been maintained.

The use of bacteriophages for treatment and prevention of bacterial disease in animals and animal models of human infection

A brief history of the use of lytic bacteriophages in bacterial disease therapy is presented. After early disillusionment with the idea following poor experimental work, control of phages and field trials, studies were set up in the 1980's in the UK to study their use in farm animal infections. Work with E. coli septicaemia and diarrhoea has shown that phages can be highly effective prophylactically and therapeutically and more effective than antibiotics. There is considerable potential for their use in a limited number of infection types in both man and animals.