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 578 毫秒
1.
本研究利用已建立的间接免疫组化方法检测鸭瘟病毒(DPV)gC基因疫苗(pcDNA-DPV-gC)免疫雏鸭后其表达蛋白在雏鸭体内的表达时相和分布规律,为DPV gC基因疫苗的进一步研究和应用提供基础数据。将不同剂量(50、100和200μg)DPV gC基因疫苗免疫3周龄天府肉鸭,于免疫后不同时间点(4h、12h、1d、3d、5d、7d、2周、4周、6周和10周)分别随机宰杀2只雏鸭,采集肝、脾、肺、肾、胰、脑、胸腺、哈氏腺、法氏囊、十二指肠、盲肠、直肠以及注射部位肌肉,应用间接免疫组化方法检测pcDNA-DPV-gC在雏鸭体内的表达时相和分布规律。结果显示:①各剂量免疫组第1天在肝、十二指肠、盲肠、直肠和注射部位肌肉检测到DPV gC蛋白,其中注射部位肌肉的阳性信号最强;第2周时各组织中的抗原表达量达到高峰,随着时间推移,阳性信号以不同速度逐渐衰减;第10周时各剂量免疫组仍在肝、脑、十二指肠、盲肠和直肠发现持续表达DPV gC蛋白;而胰在所有时间点均未检出阳性信号;②pcDNA-DPV-gC在不同组织的表达量也存在差异,肝、脾、法氏囊、脑、十二指肠、盲肠和直肠是DPV gC蛋白主要的分布器官;阳性信号主要出现在肠黏膜固有层细胞、脾白髓或红髓区的淋巴细胞以及脑皮质神经胶质细胞等部位;③根据各组织的阳性信号强度和持续时间的情况,得到pcDNA-DPV-gC在雏鸭各组织的总体表达规律:十二指肠、盲肠、直肠肝脏法氏囊脾脑注射部位肌肉胸腺肺哈氏腺肾脏胰脏;④不同剂量pcDNA-DPV-gC免疫雏鸭后各组织中抗原表达量和持续时间的总体规律依次为200μg组100μg组50μg组。结果表明不同剂量pcDNA-DPV-gC免疫后1d即可在雏鸭体内发现阳性信号,持续存在10周仍可检测到DPV gC蛋白,预示pcDNA-DPV-gC免疫期可持续较长时间。  相似文献   

2.
将小鹅瘟病毒(Goose Parvovims,GPV)VP3基因疫苗(pcDNA-GPV-VP3)分别按每只6、3、1μg的剂量基因枪轰击免疫4周龄BALB/c小鼠,于免疫后不同时间采集小鼠心、肝、脾、肺、肾、肠、脑和免疫部位皮肤等组织,用原位杂交方法检测pcDNA-GPV-VF3在小鼠体内的分布规律.结果显示,pcDNA-GPV-VP3在免疫后1 h即分布于小鼠除脑外各个组织,脑组织于免疫后3 h呈阳性,各组织阳性信号随时间的推移逐渐减弱;pcDNA-GPV-VP3在不同组织中持续时间依次为肝脏>心>脾>免疫部位>肾、肠>肺>脑;pcDNA-GPV-VF3不同剂量组信号强弱和持续时间存在的总体规律依次为6μg组>3 μg组>1μg组.基因枪轰击pcDNA-GPV-VP3于免疫后能快速而广泛的分布于小鼠各个组织且持续存在达63 d.  相似文献   

3.
鹅副粘病毒的组织嗜性   总被引：2，自引：0，他引：2  
用单克隆抗体介导的免疫过氧化物酶（MC－IP）技术，对21只鹅副粘病毒病鹅体内的病毒抗原进行定位，结合组织病理学观察结果，探讨了鹅副粘病毒的组织嗜性。结果显示，除脑和心脏未检测到病毒外，在气管、肺、食道、肝脏、腺胃、胰腺、肠、哈氏腺、胸腺、脾脏、法氏囊、肾脏等器官都能检测到病毒，病毒抗原定位于上述器官的各种上皮细胞，淋巴细胞、网状细胞和巨噬细胞的胞浆内，其中以胃肠粘膜上皮细胞和法氏囊、胸腺、脾脏的淋巴细胞和网状细胞内检出率高，阳性反应强。这些结果提示，鹅副粘病毒是一种泛嗜性病毒，胃肠粘膜上皮和淋巴组织是其主要侵嗜部位。  相似文献   

4.
将100μgpcDNA-GPV-VP3基因疫苗肌肉注射4周龄BALB/c小鼠,并以生理盐水和空载体质粒pcDNA3.1(+)为对照,建立并应用寡核苷酸探针原位杂交方法检测pcDNA-GPV-VP3在免疫小鼠各组织器官(心、肝、脾、肺、肾、肠、脑、免疫部位肌肉)的动态分布规律。结果表明,所建立的原位杂交方法具有特异性强、敏感性高、定位准确等特点,能检测约13pg的同源DNA。pcDNA-GPV-VP3基因疫苗在肌注后1h可分布到除脑以外的所有组织,肌注后3h脑呈阳性,21d除脑外的其他组织仍呈阳性,105d仍能在肌注部位检测到pcDNA-GPV-VP3;pcD-NA-GPV-VP3在小鼠各组织中持续时间为肌注部位肝脾、心肾肺、肠脑。  相似文献   

5.
鸭瘟病毒弱毒株在免疫雏鸭体内的分布和排毒规律   总被引：9，自引：5，他引：9  
鸭瘟病毒(DPV)弱毒Cha株经皮下、口服和滴鼻3种途径免疫1日龄雏鸭，应用聚合酶链反应(PCR)检测了病毒在体内分布和排毒规律。Cha株免疫雏鸭后，对血液、心、肝、脾、肺、肾、十二指肠、直肠、法氏囊、胸腺、胰腺、延脑、大脑、小脑、舌、肌肉、骨髓、粪便和食道共19种组织PCR检测结果如下：(1)皮下接种雏鸭后4h，即可在心、肝、脾、肾、法氏囊、胸腺、胰腺、延脑、大脑和小脑共10种组织中检出DPV的DNA；8h后，所有采取的组织器官均可检测到DPV的DNA。(2)口服接种雏鸭后4h，可在舌和食道中检测到DPV的DNA；8h后，可在心、肝、脾、肾、胸腺、胰腺、延脑、大脑、小脑、舌、食道和血液共12种组织器官中检出DPV的DNA。(3)滴鼻接种雏鸭后4h，未能在各种组织中检出DPV的DNA；8h后，可在心、肝、脾、肾、胸腺、延脑、大脑、小脑、舌、食道和血液共11种组织中检测到DPV的DNA。(4)在3种免疫途径中，检出时间最早和检出率最高的组织器官为肝脏、脑(大脑、小脑和延脑)；3种途径免疫的鸭，从免疫后12h至21d均能从所有采集的组织中检测出DPV DNA。  相似文献   

6.
本研究以扬州鹅为试验对象,初步探讨不同比例ω-6／ω-3PUFA日粮对鹅免疫器官（胸腺、法氏囊、脾脏）生长发育的影响。选择160羽同一批出雏、体质健壮、体重接近的3周龄扬州鹅苗,随机分成四组,分别饲喂ω-6／ω-3PuFA比例为3：1、6：1、9：1、12：1的日粮,在42、56、70日龄分别进行屠宰和免疫器官的分离、称重。试验结果表明：不同比例的ω-6／ω-3PUFA日粮对扬州鹅各生长阶段免疫器官的重量和指数有不同影响,其中ω-0／ω-3PUFA比例为6：1组42目龄的胸腺指数高于其他比例组（P〈0．05）,法氏囊指数也高于其他组;56、70日龄的胸腺、法氏囊、脾脏等指数以3：1组较高;而各阶段扬州鹅的胸腺、法氏囊、脾脏等指数在9：1和12;1组间均无显著差异（P〉0．05）。结论：日粮ω-6／ω-3PUFA比例在6：1时可显著促进可显著促进42日龄前扬州鹅免疫器官的发育,而3：1的比例对42日龄后免疫器官的影响较为明显。  相似文献   

7.
鸭坦布苏病毒对雏鸭免疫系统的影响   总被引：1，自引：0，他引：1  
《中国兽医学报》2017,(2):211-217
为研究鸭坦布苏病毒(DTMUV)对雏鸭免疫系统的影响,本试验对5日龄雏鸭静脉接种DTMUV,并于接种后不同时间取雏鸭脾脏、胸腺、法氏囊进行组织病理学、抗原和凋亡检测。结果显示,DTMUV感染雏鸭的脾脏、胸腺、法氏囊均严重受损。接种DTMUV后4d,脾脏淋巴细胞减少,胸腺可见严重细胞崩解和大面积坏死区域,法氏囊滤泡轻度萎缩;接种后6d免疫器官病变最为严重,其中胸腺静脉严重栓塞,淋巴细胞变性坏死,空泡化也更加严重;接种后8d免疫器官病变均有所减轻,至16d,免疫器官结构基本恢复正常。通过免疫组织化学方法在感染雏鸭的脾脏、胸腺、法氏囊中均检测到DTMUV抗原;细胞凋亡试验显示DTMUV能够显著引起脾淋巴细胞凋亡。综上所述,DTMUV可严重损伤雏鸭免疫器官,且这种损伤常发生于感染早期,并于感染后8d出现好转。  相似文献   

8.
试验通过研究刺五加多糖(ASPS)对雏鸡免疫器官指数及组织结构发育的影响,旨在从器官和组织水平对ASPS的免疫增强作用进行评价。1日龄海兰褐公雏饲养至7日龄时选取150只,随机分为3组,每组50只:ASPS低剂量组(ASPSL组)、高剂量组(ASPSH组)和空白对照组,三组分别每天皮下注射0.2 mL的100 mg/mL和200 mg/mL ASPS以及灭菌生理盐水,连续注射3 d。注射后的第7、14、21和28天称量体重及胸腺、法氏囊、脾脏重量,计算免疫器官指数,并通过HE染色对免疫器官的组织结构变化进行观察。结果显示,胸腺、法氏囊和脾脏指数以及体重的变化趋势基本一致,除注射后7 d外,注射后14、21和28 d ASPSL组和ASPSH组胸腺、法氏囊和脾脏指数以及体重均显著高于空白对照组(P0.05),注射后21和28 d时ASPSH组的3种免疫器官指数均显著高于ASPSL组(P0.05);组织结构方面,与对照组比较,各个日龄ASPSL和ASPSH组的胸腺皮质部分明显增厚,髓质部分面积变小;法氏囊单个淋巴滤泡逐渐增大并变长,排列更加规则,而且皮质比例明显增加;脾脏中脾小体数目明显增多,动脉周围淋巴鞘面积明显增加。结果表明,ASPS能够提高胸腺、法氏囊和脾脏器官指数以及体重,并促进胸腺皮质、法氏囊淋巴滤泡和脾脏动脉周围淋巴鞘等特征性结构的发育,从而为免疫功能的增强提供了组织结构基础。  相似文献   

9.
鸭源新城疫病毒（NDV）SDFC株通过静脉注射、肌肉注射、点眼滴鼻3种途径人工感染15日龄健康雏鹅,观察试验鹅的发病情况及临床症状,于感染后不同时间剖杀,观察各组织器官的主要剖检变化,并进行病理组织学研究,同时对病毒在组织中的抗原分布进行检测。结果显示,试验鹅感染鸭源NDV后发病率达100%,静脉注射组死亡率为80%,肌肉注射组死亡率为40%,点眼滴鼻组死亡率为26.7%。病鹅表现下痢、流泪,部分出现瘫痪、扭头、角弓反张等神经症状;剖检变化表现为胰腺、脾脏有大小不等的白色坏死灶,胸腺、法氏囊萎缩,心包积液,肠道、肝脏、肺脏、肾脏出血;病理组织学变化表现为胸腺、脾脏、法氏囊等器官内淋巴细胞坏死、崩解,心脏、肺脏、肝脏、肾脏广泛性出血、变性;抗原分布检测结果显示,病毒在病鹅体内多个组织器官中分布。试验结果表明,鸭源NDV对鹅具有较强的致病性。  相似文献   

10.
为研究鸭甲肝病毒3型(DHAV-3)在雏鸭体内的动态分布情况,本研究建立了检测DHAV-3的Taqman荧光定量PCR方法,该方法在107~102范围内有良好的线性关系,相关系数0.997,检测下限为22copies/PCR。将200只2日龄雏鸭随机分为4组,依次对每组雏鸭肌肉注射0.2ELD_(50)、2ELD_(50)、20ELD50的DHAV-3(SD1201株)和生理盐水,并于感染后1、2、6、12、18、24、36、48、72、96h从各组分别随机取3只雏鸭,应用荧光定量PCR方法对其心脏、肝脏、脾脏、肾脏、胸腺、法氏囊的病毒含量进行检测。结果表明,DHAV-3于感染后1h即可在3个试验组雏鸭肝脏中检测到,病毒含量为102~103 copies/g,2h后在心脏、脾脏、肾脏、胸腺和法氏囊中均检测到该病毒。各器官中的病毒含量于感染后36~48h达到高峰期,至72h病毒含量仍维持稳定。此外,在整个感染过程中,被检器官中的病毒含量与初始感染剂量呈正相关。本研究结果有助于阐明DHAV-3的致病机理。  相似文献   

11.
试验选用96头平均体重14.82 kg左右的杜×长×大断奶仔猪,随机分成4组,每组3栏,每栏8头(公母各半)。对照组饲喂基础日粮,试验1、2、3组分别添加1%80目白术、0.2%白术多糖和1%微米白术。试验期30 d。结果表明:在生长性能方面,与对照组相比,1%微米白术添加组可显著提高日增重(P0.05)、降低饲料增重比和腹泻率,而且效果优于1%80目白术组和0.2%白术多糖组,在肠道形态和肠道微生态区系方面,与对照组相比,日粮添加1%80目白术、0.2%白术多糖、1%微米白术均可不同程度的提高十二指肠和空肠的绒毛高度,加深十二指肠和空肠的隐窝深度,并且增加肠道微生态区系的多样性,其中以1%微米白术添加组的效果最佳。  相似文献   

12.
Sissay, M.M., Uggla, A. and Waller, P.J., XXXX. Prevalence and seasonal incidence of nematode parasites and fluke infections of sheep and goats in eastern Ethiopia. Tropical Animal Health and Production, XXXX. A 2-year abattoir survey was carried out to determine the prevalence, abundance and seasonal incidence of gastro-intestinal (GI) nematodes and trematodes (flukes) of sheep and goats in the semi-arid zone of eastern Ethiopia. During May 2003 to April 2005, viscera including liver, lungs and GI tracts were collected from 655 sheep and 632 goats slaughtered at 4 abattoirs located in the towns of Haramaya, Harar, Dire Dawa and Jijiga in eastern Ethiopia. All animals were raised in the farming areas located within the community boundaries for each town. Collected materials were transported within 24 h to the parasitology laboratory of Haramaya University for immediate processing. Thirteen species belonging to 9 genera of GI nematodes (Haemonchus contortus, Trichostrongylus axei, T. colubriformis, T. vitrinus, Nematodirus filicollis, N. spathiger, Oesophagostomum columbianum, O. venulosum, Strongyloides papillosus, Bunostomum trigonocephalum, Trichuris ovis, Cooperia curticei and Chabertia ovina), and 4 species belonging to 3 genera of trematodes (Fasciola hepatica, F. gigantica, Paramphistomum {Calicohoron} microbothrium and Dicrocoelium dendriticum) were recorded in both sheep and goats. All animals in this investigation were infected with multiple species to varying degrees. The mean burdens of adult nematodes were generally moderate in both sheep and goats and showed patterns of seasonal abundance that corresponded with the bi-modal annual rainfall pattern, with highest burdens around the middle of the rainy season. In both sheep and goats there were significant differences in the mean worm burdens and abundance of the different nematode species between the four geographic locations, with worm burdens in the Haramaya and Harar areas greater than those observed in the Dire Dawa and Jijiga locations. Similar seasonal variations were also observed in the prevalence of flukes. But there were no significant differences in the prevalence of each fluke species between the four locations. Overall, the results showed that Haemonchus, Trichostrongylus, Nematodirus, Oesophagostomum, Fasciola and Paramphistomum species were the most abundant helminth parasites of sheep and goats in eastern Ethiopia.  相似文献   

13.
1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.  相似文献   

14.
Tropical Animal Health and Production -  相似文献   

15.
Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.  相似文献   

16.
Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.  相似文献   

17.
Genetic variations in chromosome Y are enabling researchers to identify paternal lineages, which are informative for introgressions and migrations. In this study, the male‐specific region markers, sex‐determining region‐Y (SRY), amelogenin (AMELY) and zinc finger (ZFY) were analysed in seven Turkish native goat breeds, Angora, Kilis, Hair, Honaml?, Norduz, Gürcü and Abaza. A SNP in the ZFY gene defined a new haplotype Y2C. All domestic haplogroups originate from Capra aegagrus, while the finding of Y1A, Y1B, Y2A and Y2C in 32, 4, 126 and 2 Turkish domestic goats, respectively, appears to indicate a predomestic origin of the major haplotypes. The occurrence of four haplotypes in the Hair goat and, in contrast, a frequency of 96% of Y1A in the Kilis breed illustrate that Y‐chromosomal variants have a more breed‐dependent distribution than mitochondrial or autosomal DNA. This probably reflects male founder effects, but a role in adaptation cannot be excluded.  相似文献   

18.
Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.  相似文献   

19.
The objective of this report was to characterize 20-year changes in proportion of calcium oxalate (CaOx) calculi and struvite calculi in dogs, and associations with breed, age, and sex. In this retrospective study, results of analysis of urinary calculi from dogs were reviewed for specimens received between July 1, 1981, and December 31, 2001. Breed, sex, age, year of submission of the specimen, and mineral type(s) were analyzed statistically. CaOx or Struvite or both were contained in 18,966 of 20,884 (91%) specimens. For both sexes, a 20-year statistically significant increase was observed in the proportion of calculus specimens that contained CaOx. The increase in this proportion was greater in females (1% to 31%) than in males (18% to 82%). From 1998 to 2001, when proportions may have plateaued, the odds of specimens containing CaOx were markedly higher in 18 breeds, markedly lower in 5 breeds, and not significantly different in 13 breeds compared with crossbreds. For both sexes, a 20-year statistically significant decrease was observed in the proportion of calculus specimens that contained struvite. This decrease in proportion was greater for males (79-16%) than for females (97-68%). From 1998 to 2001, when proportions plateaued, the odds of calculi containing struvite were markedly lower in 20 breeds, markedly higher in 1 breed, and not significantly different in 15 breeds when compared with crossbreds. Breed, age, and sex were associated statistically with CaOx or struvite urolithiasis. In conclusion, there appears to have been a long-term increase in the proportion of specimens of canine urinary calculi that contain CaOx as well as a long-term decrease in the proportion of specimens of calculi that contain struvite for both male and female dogs. The rate of change appeared to begin leveling off in the period 1998 to 2001. The recent proportion of dogs with either CaOx- or struvite-associated urolithiasis may depend on breed, age, and sex, and on interactions among these 3 factors.  相似文献   

20.
The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.  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