首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 156 毫秒
1.
The purpose of the experiment was the seasonal variations investigation and drug test on coccidial infected sheep in Xinjiang Urumqi.To count infection rate and infection intention of coccidia by using the saturated solution floating method and MacMaster's method.We carried out drug test by using sulfadimidine, counted reduction ratio and negative transformation rate of oocysts and analysied the average OPG of adult sheep and lamb after sulfadimidine treatment by SPSS 17.0.The result showed that the overall prevalence of coccidial infection was 71.38%, the infection rate of summer was 65.28%, the infection rate of autumn was 78.24%, the infection rate of winter was 62.18%, the infection rate of spring was 81.58%;There was the highest infection rate of lamb;Seven species were identified by morphological analysis.The infection rate of sheep which infected by one kinds of coccidia was 42.75%, 2 to 4 kinds of coccidia was 53.94%, more than 5 kinds was 3.31%.The best effect of insecticide was high dose group, whose oocyst decrease rate and negative rate was better than the medium and low dose groups.Meanwhile, lamb using low dose could achieve obvious repellent effect.In order to treat the coccidial infected sheep in Xinjiang Urumqi, we could use the sulfadimidine to do the anthelmintic work of lamp in spring and autumn.  相似文献   

2.
试验旨在对新疆乌鲁木齐绵羊球虫感染季节动态变化进行调查及药物驱虫试验。采用饱和盐水漂浮法和麦克马斯特计数法计算感染率和感染强度,使用磺胺二甲嘧啶进行驱虫试验,计算卵囊减少率和转阴率,用SPSS 17.0软件分析成年羊和羔羊驱虫前后平均OPG。结果表明,绵羊总感染率为71.38%,夏季感染率为65.28%,秋季感染率为78.24%,冬季感染率为62.18%,春季感染率为81.58%;羔羊感染率最高;经形态学鉴定共发现7种绵羊球虫,感染单一虫种的占42.75%,感染2~4种的占53.94%,感染5种以上的占3.31%。成年羊高剂量组的卵囊减少率和转阴率最高,与中、低剂量组相比,驱虫效果较好;羔羊使用低剂量就能取得明显的驱虫效果。因此针对新疆乌鲁木齐绵羊球虫感染,今后应做好羔羊及春、秋季节的驱虫工作,使用磺胺二甲嘧啶进行驱虫,能取得较好的驱虫效果。  相似文献   

3.
The efficacy of leucocyte extract (LE) and sulphadimidine in preventing coccidiosis in naturally infected lambs on pasture was evaluated in 3 separate experiments, whereas the prophylactic effect of levamisole was studied in 1 of the experiments. LE prepared from ewes immune to coccidia (Eimeria spp.) was administered either intravenously or intraperitoneally to young lambs 7, 5, or 2 days before they were turned out on pastures contaminated with coccidia. In all experiments, LE failed to transfer protective immunity to the lambs against the first coccidial infection on pasture. The LE preparations used apparently had an immunosuppressive effect, which resulted in more severe clinical signs of coccidiosis in the recipients. The lambs given LE showed a higher incidence of diarrhoea, a poorer weight gain, a higher mortality, and a higher oocyst output than the untreated control lambs. In lambs treated with sulphadimidine at 200 mg/kg on days 12, 13, and 14 after turnout there was a reduced severity of the coccidial infections in all experiments. The sulphadimidine-treated lambs had better weight gains and passed fewer oocysts than the controls during the third and fourth week after turnout, but some of them developed diarrhoea. Lambs treated with levamisole at 2 mg/kg 2 days before turnout, at turnout, and 2 days after turnout were more severely affected by the first coccidial infection on pasture than the controls.To study the lambs’ immunity against a heavy challenge infection with coccidia as compared with their immunity against the natural reinfection on pasture, some of the lambs from the original groups (untreated, sulphadimidine-treated, LE-treated) were each inoculated with 2 mill. Eimeria spp. oocysts about 6 weeks after turnout. The oocyst counts of the challenged lambs, except the LE-treated lambs, increased to a new peak 19–20 days after challenge. The challenge infection caused a softening of the faeces and a marked depression in weight gain in all challenged groups of lambs, mainly between days 10 and 17 after challenge. The lambs were thus only partially immune to coccidia after the first coccidial infection on pasture. The lambs treated with either LE or sulphadimidine in connection with the first coccidial infection on pasture were not appreciably more susceptible to the challenge infection than the untreated lambs.  相似文献   

4.
Hybridoma antibodies (Hab) produced against sporozoites or merozoites of four species of Eimeria were tested for the ability to inhibit the invasion of cultured primary avian kidney cells by sporozoites of Eimeria. Five of 16 Hab that were tested showed inhibitory activity. All five of these Hab were produced against sporozoites and reacted with sporozoite surface antigens or surface/internal antigens. Four Hab produced against merozoites of E. acervulina cross-reacted with sporozoite surface antigens but failed to inhibit invasion. Similarly, Hab reacting with sporozoite anterior tips or refractile bodies had little effect on invasion. Collectively, the data suggest that surface antigens or surface/internal antigens that are unique to the sporozoite stage may influence or be part of the invasion process. Indirect immunofluorescent-antibody tests and ferritin (Fe) labeling combined with electron microscopy indicated differences in binding of two of the Hab to the sporozoite surface membranes. For example, after exposure to Hab 43A6 and a fluorescein-antimouse IgG conjugate, extracellular sporozoites of E. meleagrimitis fluoresced brightly but intracellular sporozoites exhibited little fluorescent label. Sporozoites labeled with Hab 43A6 plus a ferritin-antimouse IgG conjugate that were observed in the process of cell invasion had ferritin on the extracellular portion of the parasite but not on the intracellular portion. Extracellular aggregates of ferritin were observed near the site of invasion. The data suggested that antigens of the sporozoite surface that are recognized by Hab 43A6 are "scraped off" during the invasion of cells. In contrast, after exposure to Hab E5, both extracellular and intracellular sporozoites of E. tenella fluoresced. However, ferritin label was not observed on viable sporozoites, even when they were fixed immediately after the labeling procedure. The antigens recognized by Hab E5 may be associated with parasite secretory products rather than with an integral part of the sporozoite surface membrane.  相似文献   

5.
Three different hybridoma-produced monoclonal antibodies (Ab) were used to study their reactivities with in vitro developmental stages of Eimeria tenella and their effects on sporozoite penetration and intracellular development. One Ab (designated B10) was stage-specific, whereas the other 2 Ab (designated C3 and E5) reacted with various intracellular developmental stages of the coccidia. The E5 Ab interacted with the cytoplasm of cultured cells that were infected with sporozoites at 24 hours after inoculation. All 3 Ab inhibited penetration to various degrees--the one designated B10 having the greatest inhibitory effect. These 3 Ab also inhibited development of the parasite in cell culture, provided that Ab was continuously present in the cell culture medium. Removal of Ab from the medium allowed coccidial development to continue at about the same rate as in controls. A longer pretreatment time of the sporozoites with the Ab before cell inoculation increased the inhibitory effect with respect to both the penetration and the development of the parasite.  相似文献   

6.
坏死性肠炎(necrotic enteritis,NE)是家禽中最重要的肠道疫病之一,呈世界性流行,严重危害养鸡业发展。人工复制鸡坏死性肠炎病例是研究该病发病机制及筛选有效药物的重要手段,然而在实际试验过程中,通常受实验动物、感染菌株、诱导病原等多方面因素影响而难以成功复制病例。鉴于此,现综述了影响鸡坏死性肠炎病例成功复制的关键因素,包括攻毒使用的实验动物、菌株毒素、菌株培养条件、诱导病因等,同时探讨了如何通过调整这些因素来改善人工复制鸡坏死性肠炎病例的严重程度,分析了鸡坏死性肠炎病例的病变评分系统,以期为鸡坏死性肠炎的实验室研究及综合防控提供理论基础。  相似文献   

7.
Coccidiosis remains one of the most important diseases in the poultry industry and results in the annual loss of millions of US dollars by the poultry industry. In South Africa and other developing countries where a large percentage of the population is unemployed, cheap food production is necessary. If the control of the coccidian parasite could be made more economical, these savings could be passed on to the consumer. In Europe, where the economics are different, people are becoming more aware of the potential dangers of using antimicrobials in producing animal protein. A solution to both these problems could be the use of plant products that function by mechanisms other than those of chemotherapeutics, with the additional advantage of a natural origin. Antioxidant compounds could hold promise for the control of Eimeria infections due to the association of coccidial infection with lipid peroxidation of the intestinal mucosa. Four plant extracts with antioxidant activity were screened for their anticoccidial activity in vivo with toltrazuril as the positive control. Combretum woodii (160 mg/kg) proved to be extremely toxic to the birds, while treatment with Tulbaghia violacea (35 g/kg), Vitis vinifera (75 mg/kg) and Artemisia afra (150 mg/kg) resulted in feed conversion ratios similar to toltrazuril, and higher than the untreated control. T. violacea also significantly decreased the oocyst production in the birds. From this study we conclude that antioxidant-rich plant extracts have potential benefits in treating coccidial infections. The promising results obtained with T. violacea justify further studies on the potential value of the plant as a therapeutic or prophylactic anticoccidial agent.  相似文献   

8.
This study tested the hypothesis that a host mucogenic response to an intestinal coccidial infection promotes the onset of necrotic enteritis (NE). A chick NE model was used in which birds were inoculated with Eimeria acervulina and E. maxima and subsequently with Clostridium perfringens (EAM/CP). A second group of EAM/CP-infected birds was treated with the ionophore narasin (NAR/EAM/CP). These groups were compared to birds that were either non-infected (NIF), or infected only with E. acervulina and E. maxima (EAM), or C. perfringens (CP). The impact of intestinal coccidial infection and anti-coccidial treatment on host immune responses and microbial community structure were evaluated with histochemical-, cultivation- and molecular-based techniques. Barrier function was compromised in EAM/CP-infected birds as indicated by elevated CFUs for anaerobic bacteria and C. perfringens in the spleen when compared to NIF controls at day 20, with a subsequent increase in intestinal NE lesions and mortality at day 22. These results correlate positively with a host inflammatory response as evidenced by increased ileal interleukin (IL)-4, IL-10 and IFN-gamma RNA expression. Concurrent increases in chicken intestinal mucin RNA expression, and goblet cell number and theca size indicate that EAM/CP induced an intestinal mucogenic response. Correspondingly, the growth of mucolytic bacteria and C. perfringens as well as alpha toxin production was greatest in EAM/CP-infected birds. The ionophore narasin, which directly eliminates coccidia, reduced goblet cell theca size, IL-10 and IFN-gamma expression, the growth of mucolytic bacteria including C. perfringens, coccidial and NE lesions and mortality in birds that were co-infected with coccidia and C. perfringens. Collectively the data support the hypothesis that coccidial infection induces a host mucogenic response providing a growth advantage to C. perfringens, the causative agent of NE.  相似文献   

9.
通过对鸡感染柔嫩艾美耳球虫时盲肠中常见正常厌氧微生物的变化情况进行检测研究发现:鸡在感染球虫后第7、10、14天时盲肠中类杆菌(Bacteriodes)的数量显著减少(P<005),而梭状芽孢杆菌(Clostridium)则显著增多;在球虫感染后的第7、10天时,盲肠中的消化球菌(Peptostreptocuccus)和真杆菌(Eubacterium)呈显著下降(P<005)。上述结果从一个方面阐明了柔嫩艾美耳球虫感染导致对某些其它感染抵抗力下降的机制。  相似文献   

10.
免疫调节剂与抗球虫药联合应用的抗球虫效果   总被引:4,自引:0,他引:4  
为探讨免疫调节剂对鸡球虫病的免疫反应调节作用,设计并进行了免疫调节剂与抗球虫药合用的效果的研究。试验结果以抗球虫指数的测定来判定抗球虫药与免疫调节剂合用的效果。结果表明,免疫调节剂与抗球虫药合用状态下,抗球虫指数检测显示免疫调节剂卡介苗和黄芪多糖可明显提高抗球虫指数、改善球虫感染鸡的临床症、提高增重速度等,为控制球虫病提供了新的途径。  相似文献   

11.
Eimeria gruis and Eimeria reichenowi are common coccidial parasites of a number of species of cranes. Until recently, little was known about either the site for invasion or the dynamics of early development of the crane coccidia because of the difficulty of identifying sporozoites and early developmental stages of these parasites by conventional staining methods. In the present study, monoclonal antibodies (MAbs) elicited against Eimeria spp. of chickens and turkeys were found to cross-react with sporozoites and developmental stages of E. reichenowi in the tissues of Florida sandhill cranes (Grus canadensis). With these Mabs, E. reichenowi sporozoites were found in specimens taken at 6 hr postinoculation (PI) from just proximal to Meckel's diverticulum in the jejunum to the ileocecal juncture. Fewer were found in the ceca and rectum and none in the duodenal loop. At 24 hr PI, there were markedly fewer sporozoites and their location had shifted to the duodenum. No stages were seen in intestinal cells at 5 days PI (DPI), but trophozoites had developed in the liver and spleen. At 10 DPI, sexual stages were detected in the intestine from the duodenal loop through Meckel's diverticulum but not in other organs. By 14 DPI, numerous developmental stages were detected in the intestine (ceca and jejunum), liver, and lungs but not in the heart, kidney, or brain. The number, location, and maturity of the stages in the ceca differed markedly from those in the jejunum.  相似文献   

12.
Four newborn Hereford calves were orally inoculated five times with 100 sporulated oocysts of coccidia, predominantly Eimeria zurnii. Each calf was kept isolated with its dam until weaned at the age of 13 weeks. Three other newborn calves were similarly isolated but not experimentally infected. The calves were then challenged with 300,000 sporulated oocysts at the age of five, seven and nine months. The previously unexposed calves developed marked clinical coccidiosis after the first challenge, but resisted the second and third challenge. The neonatally exposed calves were susceptible to infection at the first challenge as well as to the next two challenges at seven and nine months of age, but the clinical signs following the last two challenges were milder than those of the first challenge. These findings suggest that under conditions where calves become infected with coccidia when very young, such calves may, by shedding oocysts in large numbers for long periods, be a continuing source of coccidial infections to other animals.  相似文献   

13.
The immune response to filarial infection has been shown to be of both the Th1 and Th2 types. Studies aimed at developing immunization strategies against Dirofilaria immitis infection in dogs have shown that protection against larval challenge is of the Th2 type and that several proteins are recognized by immunized or infected animals. The bacterial endosymbiont Wolbachia, harbored by many filarial species including D. immitis, has recently been shown to interact with the host immune system. Specific antibodies to the Wolbachia recombinant surface protein (WSPr) have been observed in cats infected with D. immitis. In this work the authors have determined cytokine production and antibody response in BALB/c mice inoculated with soluble antigens from third stage larvae or from adult worms of D. immitis. Inoculated mice first produced IFN-gamma followed by a peak in IL-4. Specific antibodies to the Wolbachia protein WSPr were exclusively IgG2a, while antibodies against peptides derived from antigens of D. immitis were in the IgG1 and IgE subclasses. The cytokine response is thus similar to that reported for other filarial infection, where Th1 response shifts towards Th2. Antibody response indicates that Wolbachia may induce preferentially a Th1 response during filarial infection, while nematode antigens may be involved in Th2 response. There is thus an overall agreement with current opinions on the role of bacterial versus nematode molecules in driving the response towards the different directions.  相似文献   

14.
Cyclospora cayetanensis, a food- and waterborne coccidian parasite   总被引:3,自引:0,他引:3  
Food- and waterborne coccidia including Cryptosporidium parvum, Cyclospora cayetanensis, Sarcocystis hominis and Sarcocystis suihominis, and Isospora belli are cyst-forming apicomplexan protozoa that cause intracellular infections, predominantly in the epithelial cells of the intestine. They are transmitted by oocysts from person-to-person by the fecal-oral route or via contaminated water or food. The most common symptom of infection is diarrhea, however, asymptomatic infections occur. Infections are associated with intestinal inflammation, with pathological lesions such as villus blunting, and abnormal function such as malabsorption. Mild-to-moderate, self-limiting diarrhea is common in healthy individuals ingesting infective stages of these organisms. However, patients with immune dysfunction can have severe intestinal injury and prolonged diarrhea. Diagnosis in many cases is made by a microscopic examination of the stool, and the use of appropriate staining techniques, but more recently molecular methods for detection are used increasingly. Effective antimicrobial treatment for prolonged infection in immunocompromised patients is available for most of these infections. These gastrointestinal coccidial pathogens have important similarities in epidemiology, disease pathogenesis, clinical manifestations, diagnosis, and treatment. Although there are many other cyst-forming coccidia of public health, veterinary and/or economic importance, discussion in this chapter will be limited to C. cayetanensis, as an important example of the group. Aspects of the biology, epidemiology, diagnosis, disease, treatment and control are considered. This parasite is considered to be an emerging pathogen. From 1990 to 2000, there were 11 foodborne outbreaks of cyclosporosis in North America that affected at least 3600 people. There are many outstanding questions regarding this parasite and under-reporting is common because general diagnostic methods for intestinal parasites are inadequate for detection of Cyclospora.  相似文献   

15.
鸡球虫疫苗研究进展   总被引:43,自引:10,他引:33  
鸡球虫病是生产中严重危害养禽业的寄生虫病,长期以来以药物防治为主。目前,由于球虫耐药性的普遍存在,加上消费者对禽产品药物残留问题的关注,采用疫苗防治球虫病为人心所向。球虫活苗在实际生产中发挥了一定的作用,但由于球虫活苗存在“复壮”的可能且使用麻烦,人们将目光转向了分子疫苗。球虫基因组学研究为基因工程苗开发奠定了基础,目前已经筛选了上百个功能抗原基因。受表达系统的限制,原核表达的重组蛋白抗原性较差,虽有较多尝试,但鲜有成功。人们在探索体外真核表达(如酵母、杆状病毒表达系统等)的同时,核酸疫苗以其独特的诱发高水平细胞免疫反应的能力而倍受青睐,近几年发展较快。  相似文献   

16.
Specific antibodies were produced ex vivo from intestinal culture of Eimeria tenella infected chickens. The specificity of these intestinal antibodies was tested against different parasite stages. These antibodies were used to immunoscreen first generation schizont and sporozoite cDNA libraries permitting the identification of new E. tenella antigens. We obtained a total of 119 cDNA clones which were subjected to sequence analysis. The sequences coding for the proteins inducing local immune responses were compared with nucleotide or protein databases and with expressed sequence tags (ESTs) databases. We identified new Eimeria genes coding for heat shock proteins, a ribosomal protein, a pyruvate kinase and a pyridoxine kinase. Specific features of other sequences are discussed.  相似文献   

17.
An ELISA was developed and tested for its ability to detect antibodies against Salmonella enteritidis in chickens. Various features of the ELISA were evaluated and optimized. The outer membrane protein antigens selected by use of the protein immunoblotting method made the assay specific and sensitive. The assay was evaluated in chickens experimentally infected with S enteritidis. Blood samples collected at weekly intervals after experimental infection with S enteritidis were analyzed by ELISA. Results of the ELISA were compared with those of conventional serum plate and microagglutination tests. The ELISA was more sensitive and specific in the detection of S enteritidis infection than the other 2 conventional tests.  相似文献   

18.
Litter samples obtained from a ring-necked pheasant propagation farm in Illinois contained coccidia: 57.5% of the oocysts were Eimeria duodenalis, 24.9% were E. tetartooimia, 8.8% were E. phasiani, and 8.8% were E. pacifica. Ionophorous anticoccidial drugs were tested for efficacy against the pheasant coccidia. All three drugs reduced oocyst production and prevented mortality in young pheasants; unmedicated infected controls had a 40% mortality rate. Monensin at 120 ppm in the feed was coccidiocidal against E. duodenalis and E. tetartooimia, partly coccidiocidal against E. pacifica, and only partly coccidiostatic against E. phasiani. Salinomycin at 60 ppm in the feed was highly efficacious and coccidiocidal against all four species, but the salinomycin-medicated pheasants gained the least of all medicated birds. Lasalocid at 120 ppm in the feed was the most effective, with nearly complete coccidiocidal activity against all four coccidial species.  相似文献   

19.
以纯化的酵母重组表达的犬细小病毒VP2单位免疫BALB/C小鼠,采用B淋巴细胞杂交瘤技术,通过ELISA方法筛选,获得4株能稳定分泌抗犬细小病毒CPV结构蛋白VP2的单克隆抗体杂交瘤细胞株。4株单克隆抗体中,2株属于IgG2b亚类,2株属于IgG1亚类,其腹水效价可达到1:51200和1:204800,细胞培养上清液效价可达1:256、1:512。ELISA分析表明,这些单抗仅与CPV及其VP2发生特异性反应,而与CDV和CAV-1及CAV-2没有交叉反应;荧光免疫染色病毒检测进一步表明单克隆抗体的特异性效果好。这些特异性单抗的制备为建立有效的检测犬细小病毒感染奠定了基础。  相似文献   

20.
鸡球虫耐药性的研究进展   总被引:4,自引:1,他引:3  
长期以来,人们对鸡球虫病的防治以药物控制为主要手段,但是大量抗球虫药的长期使用,导致了鸡球虫耐药性的产生,给鸡球虫病的防治带来严重的障碍,通过对鸡球虫耐药性的产生、作用机理、主要特点、耐药性的检测方法、球虫耐药性虫株的诱导以及对耐药性虫株敏感性的恢复等方面的研究,进一步提出对鸡球虫耐药性的展望,为消除球虫的耐药性,更好地防治鸡球虫病提供科学依据。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号