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51.
The aim of this study was to investigate the effects of a porcine reproductive and respiratory syndrome virus (PRRSV) infection on the development of the immune response after pseudorabies virus (PRV) vaccination in pigs. Pigs were intranasally inoculated with the European PRRSV strain, Lelystad virus ter Huurne, and were vaccinated intramuscularly with PRV 2 weeks later (LV-PRV group). Control pigs were vaccinated with PRV only (PRV group). Eight weeks after PRV vaccination, pigs from both groups were challenged intranasally with wild-type PRV. We measured the lymphoproliferative, and the cytolytic responses to PRV of peripheral blood mononuclear cells (PBMC), isolated from blood samples. In addition, serum samples were examined for antibodies against PRV and LV. One week after PRV vaccination, PBMC proliferated abundantly to PRV in both groups. However, in the LV-PRV group the lymphoproliferative response declined after 1 week, whereas, in the PRV group, the lymphoproliferative response was high for 3 weeks and declined thereafter (P<0.05). After challenge, the lymphoproliferative response was 1 week earlier and was consistently and significantly higher in the PRV group than in the LV-PRV group. The PRV-specific killing was higher at 3 weeks after PRV vaccination and 5 weeks after PRV challenge 19+/-3 and 24+/-6%, respectively, in the PRV group, compared to 7+/-4 and 6+/-9%, respectively, in the LV-PRV group (P<0.05). However, later after vaccination and challenge the cytolytic response was identical in both groups. The antibody titre against PRV developed equally in both groups. After challenge, no PRV virus was isolated from both groups. From these results we conclude that, although PRRSV infection did cause changes in the time course of the T-lymphocyte response after PRV vaccination, PRRSV infection did not inhibit the development of vaccine-induced protection after PRV.  相似文献   
52.
Glycoproteins B (gB), gC and gD of pseudorabies virus (PRV) have been implicated as important antigens in protective immunity against PRV infection. As cell-mediated immunity plays a major role in this protective immunity, we determined the significance of these glycoproteins in the actual induction of cell-mediated immunity. We vaccinated pigs with plasmid DNA constructs coding for gB, gC or gD and challenged them with the virulent NIA-3 strain of pseudorabies virus. Vaccination with plasmid DNA coding for gB induced the strongest cell-mediated immune responses including cytotoxic T cell responses, whereas plasmid DNA coding for gD induced the strongest virus neutralising antibody responses. Interestingly, vaccination with gB-DNA reduced virus excretion early after challenge infection while vaccination with gC-DNA or gD-DNA did not.This is the first study to demonstrate that DNA vaccination induces cytotoxic T cell responses in pigs and that cell-mediated immunity induced by vaccination with gB-DNA is important for the reduction of virus excretion early after challenge infection.  相似文献   
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54.
Rectovaginal injuries can result in subsequent infertility in cows. In a retrospective study, records of 147 Holstein cows with evidence of rectovaginal injuries were reviewed to determine the odds ratio (OR) of these injuries and their related risk factors. The study was conducted in a large dairy (typical herd size 1420 cows) in Tehran between the years 1993 and 1996. Period prevalences were 0.4% fistula, 1.9% laceration (third degree), 5.7% pneumovagina, 1.5% urovagina and 0.8% mixed injuries. The highest risk occurred among first-calf heifers. Animals with dystocia, first-calf heifers and male calves were at higher risk for rectovaginal injuries. We concluded that (1) handling dystocia with care might have a substantial role in reducing rectovaginal injuries, (2) first-calf heifers are to be under close observation and care during calving, and (3) because rectovaginal injuries reoccur in the next calving, cows with the history of these injuries should be monitored at the next labor.  相似文献   
55.
An 11-year-old American Quarterhorse gelding presented for moderate periorbital swelling and exophthalmia of the left eye. The menace response, and direct and consensual pupillary light reflexes were absent in the left eye. Conjunctival hyperemia, blepharedema, a mydriatic pupil, resistance to retropulsion, and an increased intraocular pressure were present. A soft-tissue mass could be palpated in the left retrobulbar space by pressing onto the orbit over the supraorbital fossa. Incomplete surgical resection of the mass was performed and histopathologic evaluation was consistent with a fibroma. Normal pupillary light reflexes and vision returned following surgery. The mass has not recurred 14 months after surgery.  相似文献   
56.
A series of randomized, controlled, masked field studies was conducted to assess the efficacy and safety of selamectin in the treatment of flea infestations on dogs and cats, and in the prevention of heartworm infection in dogs. In addition, observations were made on the beneficial effect of selamectin treatment on dogs and cats showing signs of flea allergy dermatitis (FAD). In all studies selamectin was applied topically, once per month, in unit doses providing a minimum dosage of 6mgkg(-1). Dogs and cats with naturally occurring flea infestations, some of which also had signs associated with FAD, were assigned randomly to receive three months of topical treatment with selamectin (220 dogs, 189 cats) or a positive-control product (dogs: fenthion, n=81; cats: pyrethrins, n=66). Selamectin was administered on days 0, 30, and 60. Day 0 was defined as the day that the animal first received treatment. Flea burdens were assessed by flea comb counts and clinical evaluations of FAD were performed before treatment, and on days 14, 30, 60, and 90. On days 30, 60, and 90, mean flea counts in selamectin-treated dogs were reduced by 92.1, 99.0, and 99.8%, and mean flea counts in fenthion-treated dogs were reduced by 81.5, 86.8, and 86.1%, respectively, compared with day 0 counts. Also, on days 30, 60, and 90, mean flea counts in selamectin-treated cats were reduced by 92.5, 98.3, and 99.3%, and mean flea counts in pyrethrin-treated cats were reduced by 66.4, 73.9, and 81.3%, respectively, compared with day 0 counts. Selamectin also was beneficial in alleviating signs in dogs and cats diagnosed clinically with FAD. A total of 397 dogs free of adult heartworm infection from four heartworm-endemic areas of the USA were allocated randomly to six months of treatment with selamectin (n=298) or ivermectin (n=99). Selamectin achieved a heartworm prevention rate of 100%, with all dogs testing negative for microfilariae and adult heartworm antigen on days 180 and 300. Selamectin was administered to a total of 673 dogs and 347 cats having an age range of 6 weeks to 19 years (3954 doses). The animals included 19 purebred or crossbred Collies (Bearded, Border, and unspecified). There were no serious adverse events. Results of these studies indicated that selamectin was highly effective in the control of flea infestations in dogs and cats without the need for simultaneous treatment of the environment or of in-contact animals and also was beneficial in alleviating signs associated with FAD. Selamectin also was 100% effective in preventing the development of canine heartworms and was safe for topical use in dogs and cats.  相似文献   
57.
A series of randomized, controlled and masked field studies was conducted in veterinary patients to evaluate the efficacy of selamectin, a novel avermectin, in the treatment of naturally occurring Sarcoptes scabiei infestations on dogs and Otodectes cynotis infestations on dogs and cats. A total of 342 dogs and 237 cats participated in these studies, which were conducted at 40 veterinary practices in the USA and Europe. Animals were randomly assigned to treatment with selamectin or a positive-control product (existing approved products). Selamectin was administered as a unit dose providing a minimum of 6mgkg(-1) (range: 6-12mgkg(-1)) in a topical preparation applied to the skin in a single spot on day 0 (O. cynotis in cats, n=144), or on days 0 and 30 (O. cynotis and S. scabiei in dogs, n=83 and n=122, respectively). The presence of parasites was assessed before treatment and at 30 days (for all studies) and 60 days (for O. cynotis and S. scabiei dog studies) after first treatment. The animals were also evaluated clinically at each assessment period. Based on skin scrapings, the efficacy of selamectin against S. scabiei infestations on dogs was >95% by day 30, and 100% by day 60. Against O. cynotis, selamectin eliminated mites in 94-100% of cats by day 30, and in 90% of dogs by day 60. The positive-control products achieved similar results. Thus, selamectin was safe and effective against ear mites in dogs and cats and sarcoptic mange in dogs when used in field (veterinary patient) studies in dogs and cats of a wide variety of ages and breeds.  相似文献   
58.
A series of randomized, controlled, masked, field (veterinary patient) studies were conducted in the USA and Europe to evaluate the efficacy of selamectin, a novel macrocyclic lactone of the avermectin subclass, in the treatment of naturally acquired gastrointestinal nematode infections in cats. After confirmation of ascarid and/or hookworm infection, 298 cats of various ages and breeds were randomly assigned to treatment with selamectin (n=202) or an existing commercially approved positive-control product (n=96). Unit doses of selamectin (providing a minimum dosage of 6mgkg(-1)) were administered topically to the skin in a single spot at monthly intervals. Quantitative fecal examinations were performed on days 0 (before treatment), 30, and 60. In the selamectin-treated cats, fecal ascarid egg counts were reduced by 99.6 to 100% on day 30, and by 99.9 to 100% on day 60. Fecal hookworm egg counts were reduced by 98.3% on day 30, and by 100% on day 60 in the selamectin-treated cats. The positive-control products achieved reductions in egg counts of 96.5 to 100% (ascarids) and 98.9 to 99.9% (hookworms). These studies have shown that monthly topical administration of selamectin is safe and highly effective in the treatment of naturally acquired ascarid and hookworm infections in cats.  相似文献   
59.
Feline ocular toxoplasmosis   总被引:2,自引:0,他引:2  
Ocular infection with Toxoplasma gondii is a well-recognized and important clinical entity in many animal species. In the cat, ocular toxoplasmosis is commonly associated with systemic infection, yet its role in causing anterior uveitis in an otherwise healthy cat is unclear. The purpose of this article is to review the salient epidemiological, clinical, and histopathologic features of systemic and ocular toxoplasmosis in the cat. Additionally, pathogenesis and possible immunopathogenic mechanisms of ocular toxoplasmosis, which may account for the higher prevalence of anterior uveitis in cats seropositive for T. gondii , are discussed. Finally, diagnosis, treatment and prevention of feline toxoplasmosis are reviewed.  相似文献   
60.
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