A review of toxoplasmosis in cattle

Worldwide reports of natural and experimentally-induced Toxoplasma gondii infections in cattle are reviewed and tabulated. Serologic tests employed in most studies in the past are of suboptimal sensitivity for the diagnosis of T. gondii infection in cattle; therefore data need to be interpreted with caution. From the evidence available it is concluded that: T. gondii is probably not important in causing abortion or clinical illness in cattle but further experimental studies are desirable; T. gondii is eliminated quickly from bovine tissues; Whether beef plays a part in the epidemiology of toxoplasmosis is unresolved; Milk from T. gondii-infected cows is of negligible importance in the epidemiology of toxoplasmosis.     

A review of toxoplasmosis in pigs

Toxoplasma gondii infection is highly prevalent in pigs in most countries, but little is known of its epizootiology. Transplacental infection appears to be less common than post-natal infection. Most pigs acquire subclinical infection. Clinical toxoplasmosis occurs mostly in young pigs. The frequency of oocyst- vs tissue cyst-acquired infections is unknown. Why clinical toxoplasmosis is more prevalent in Japan than in other countries is puzzling and needs investigation. In experimentally infected pigs, tissue cysts persist in edible organs for several months. They persist longer in the brain, heart and tongue than in other tissues.     

A review of toxoplasmosis in wild birds

Toxoplasma gondii affects most species of warm-blooded animals, including birds. There is considerable confusion regarding the identity of T. gondii-like parasites and the diagnosis of toxoplasmosis in wild birds. In this review, T. gondii-like infections in different species of wild birds are reviewed with particular reference to prevalences, clinical signs, pathology, diagnosis, and treatment. Although subclinical T. gondii infections are prevalent in many avian species, toxoplasmosis can be clinically severe in pigeons and canaries. Blindness associated with T. gondii in canaries is reviewed in detail.     

A review of toxoplasmosis of animals in the U.S.S.R

Information on the serologic and parasitologic prevalence of Toxoplasma gondii infection in domestic and wild animals of the U.S.S.R. is reviewed. Although complement-fixing antibodies to T. gondii were widely prevalent in animals, little information is available on the presence of viable T. gondii in tissues of animals. Reports of epizootics in which T. gondii was suspected to be the causative agent of toxoplasmosis are summarized. Also, the strict economic impact of toxoplasmosis on agriculture in the U.S.S.R. needs evaluation.     

Current status of food animal antidotes.

The availability of antidotes in veterinary medicine has been an issue for more than a decade. Antidotes are available for food animals through extralabel use, regulatory discretion, and compounding. There is little economic incentive for pharmaceutical companies to pursue approval of antidotes and other drug products that have a small market. In addition, human food safety concerns must be addressed when approving antidotes for use in food animals. This article provides a brief history of antidote availability, current mechanisms for procuring food animal antidotes, and availability of specific antidotes for use in food animals.     

The role of vibrissae in behavior: a status review

Vibrissae or tactile hairs are an important part of the tactile sensory apparatus of many mammals. A wide range of suggested functions found in the literature include food acquisition, prey attack, aggression and attack behavior, facial expression in intraspecies communications, dispersion of pheromones, maintaining head position in swimming, and a wide range of environmental monitoring (e.g., current detection in water, wind direction on land). There is little work done specifically on domestic animals or their feral relatives. Work on the tactile senses in general and vibrissae in particular is an open field of study. A set of general questions for study of vibrissa function in domestic animals is presented.     

Feline cutaneous toxoplasmosis: a case report

A 9-year-old female, domestic short hair cat was presented with sudden onset of polyuria/polydipsia, and hundreds of cutaneous nodules. Prior to referral, the cat had had four skin nodules that were treated with steroids. The four skin nodules then multiplied to form more than 100 ulcerated and nonulcerated nodules located all over the trunk. Clinical evaluation revealed hypothermia and respiratory distress. Cytology from both skin nodules and bronchoalveolar lavage showed macrophages and small organisms whose shape and size were indicative of Toxoplasma spp., or similar organisms. Feline immunodeficiency virus (FIV) and feline leukaemia virus (FeLV) serology results were negative. The cat was seropositive for Toxoplasma (IgG 1 : 640) and Neospora (1 : 80) infections. The cat died soon after referral. Necropsy revealed pyothorax, necrotic/purulent pneumonia, haemorrhagic spots on kidneys and mesentery. Histopathology from skin nodules showed diffuse, deep necrotic dermatitis/panniculitis, vasculitis and disseminated free and grouped protozoa. The parasites were found in lungs, spleen, kidneys and liver. Immunohistochemistry on skin tissue with anti-Toxoplasma gondii and Neospora caninum antibodies gave positive results with both. Electron microscopy showed single and grouped tachyzoites with morphological features of T. gondii, often within macrophages. Samples of cutaneous nodules and bronchoalveolar fluid were examined by a polymerase chain reaction (PCR) assay for detecting apicomplexa coccidia. PCR results were consistent only with T. gondii infection. Therefore, immunohistochemistry positivity for N. caninum was considered a cross-reaction and a diagnosis of cutaneous and visceral toxoplasmosis was made.     

Vitamin E status of cattle and sheep. 1: A background review

The role of tocopherol in animal health, and its inter-relationship with selenium and polyunsaturated fatty acids, are reviewed.     

临河市猪弓形虫病与附红细胞体病的现状分析

猪弓形虫病、猪附红细胞体病是猪的两种血液寄生虫病。临河地区 1 990年首次报道该病后 ,较长时间内 ,这两种病引起的猪只死亡使养猪业受到严重损害 ,挫伤了农民的养猪积极性。通过我站 1 990年～ 1 992年 3年的病理化验资料 ,结合近几年的临诊实践 ,我们对这两种病有了较为全面的认识 ,也从中发现了不少问题。1　流行病学猪弓形虫病的病原体是龚地第弓形虫引起的 ,猪附红细胞体病是由折光性较强的小附红细胞体引起 ,近期也偶尔能检出无折光性的大附红细胞体。两病的病原体都是血液原虫。这两种病可经子宫、胎盘垂直传播 ,也可由虱、蚤、螨…     

Vaccination of cattle against bovine schistosomosis: current status and future prospects: a review

Bovine schistosomosis, caused by Schistosoma bovis, constitutes a serious veterinary problem in many parts of the world. The vaccination approaches for the control of bovine schistosomosis include the use of irradiation-attenuated S. bovis cercarial or schistosomular vaccines, S. bovis adult worms or whole-egg antigens and defined antigen vaccine. Irradiated S. bovis cercarial or schistosomular vaccines provide partial protection against S. bovis infection. However, this type of vaccine requires live infectious cercariae or viable schistosomula for induction of protection. Unfortunately, experimental immunizations with dead schistosome antigens have been largely unsuccessful. The surge of new techniques in cellular immunology and molecular biology has made possible the development of potential candidate vaccine antigens from various species of schistosomes including S. bovis. The efficiency of these vaccines has been evaluated in experimentally infected calves. These vaccines will probably replace the irradiated S. bovis vaccines. A broad-spectrum antischistosome vaccine which can kill a variety of human and animal schistosome species is yet to be produced.     

Equine toxoplasmosis: a survey for antibodies to Toxoplasma gondii in horses.

A nationwide sample of horses was tested to determine the prevalence of toxoplasma antibodies in equine animals. Of 1,294 serum samples from horses tested by the microtitration indirect hemagglutin test, 20% were positive. Among the popular breeds of horses, the following antibody prevalences were found: Arabian, 19%; Paint, 22%; Quarter Horses, 13%; Thoroughbred, 24%; and Standardbred, 17%. The antibody prevalence increased from 2% in horses 1 year of age to 18% in 2-year-olds, and rose to 38% in horses 12 years of age. Significant differences were not evident by broad geographic locations across the United States. However, there were differences in prevalence according to premises where the horses were kept. On some ranches, there was no evidence of infection, whereas up to 67% of the horses on other premises were seropositive for toxoplasmosis.     

Serological study of ovine toxoplasmosis in Colombia: epidemiological study of a field outbreak.

A serological study, using the indirect haemagglutination test, of an outbreak of toxoplasmosis in a flock of blackface sheep is described. The serological aspects of the disease are discussed with reference to this incident, and possible sources of infection are suggested.     

Acute toxoplasmosis following renal transplantation in three cats and a dog.

Three cats and 1 dog that had undergone renal transplantation because of end-stage renal disease were examined because of complications 3 to 6 weeks after surgery. One cat died prior to treatment of the complications; Toxoplasma cysts were found in sections of the renal allograft, and Toxoplasma tachyzoites were found in other organs. The other 2 cats and the dog died despite treatment, and protozoal cysts, as well as tachyzoites, were identified in other organs but not within the allografts, suggesting that reactivation of latent infection following immunosuppression was the most likely cause of disseminated toxoplasmosis. These cases illustrate that toxoplasmosis can be a fatal complication in renal transplant recipients. We currently recommend that feline and canine donors and recipients undergo serologic testing for toxoplasmosis prior to surgery. In addition, we suggest that seropositive donors not be used for seronegative recipients and that seropositive recipients and that seropositive recipients be monitored closely after surgery for clinical signs of toxoplasmosis.     

目前我国猪瘟的流行现状及防控策略

国家对猪瘟的预防和控制一直都十分重视,尽管我国很早就研制成功了猪瘟兔化弱毒疫苗,并在预防猪瘟的发生中起到了重要作用,但由于近年来猪瘟的流行和发病特点发生了很大的变化,其流行形式从频发的大流行转变为周期性、波浪形的地区性散发性流行,出现了所谓的非典型猪瘟、温和型猪瘟和无名高热综合征等,以及在出现上述种种迹象的地区和猪场往往同时表现无法解释的免疫失败。当前,猪瘟仍是世界养猪业的一大威胁,给养猪业造成了严重的经济损失。本文主要介绍了猪瘟的传播途径、近年来猪瘟在流行时间、流行形式、流行病型的变化以及当前猪瘟的不同表现症状、病理变化及防制策略,为猪瘟的免疫监测及防控体系的建立提供参考。