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1.
Specific-pathogen-free chickens orally inoculated at 4 days of age with a moderately pathogenic vaccine strain of infectious bursal disease virus (IBDV) and/or at 5 days of age with Cryptosporidium baileyi oocysts remained free of overt clinical signs throughout a 16-day period postinoculation (PI). The prepatency period for C. baileyi oocyst shedding was shorter in chickens receiving higher numbers of oocysts, but once shedding was detected, there were no obvious differences in shedding patterns among groups receiving 10(3) through 10(6) oocysts. On days 8 and 16 PI, cryptosporidia were located primarily in the bursae of Fabricius. IBDV exposure was associated with bursal follicle atrophy, whereas C. baileyi infection resulted in bursal epithelial hypertrophy and hyperplasia, mild follicle atrophy, and heterophil infiltration of the bursal mucosa. Examination of experimental groups of 30 birds each indicated that concurrent infection with both agents resulted in more severe bursal lesions, more infected birds, and greater numbers of cryptosporidia in infected tissues. At the termination of the trial, 16 days PI, Cryptosporidium infection was associated with a 6% decrease in mean body weight compared with controls. 相似文献
2.
D S Lindsay B L Blagburn C A Sundermann J A Ernest 《American journal of veterinary research》1987,48(3):354-355
Chemoprophylaxis of Cryptosporidium baileyi infections was attempted by feeding 4 groups of chicks diets containing 3 mg of halofuginone/kg of feed, 60 mg of salinomycin/kg, 75 mg of lasalocid/kg, or 110 mg of monensin/kg. Rations were fed 5 days before oral or intratracheal inoculation with oocysts and were continued for 20 days. None of the drugs prevented C baileyi infections. Clinical signs of respiratory tract disease and gross lesions of airsacculitis were observed in intratracheally inoculated birds in all treatment groups and nonmedicated controls. Orally inoculated birds did not develop clinical signs of infection. Pathogenic bacteria were not isolated from the respiratory tract systems of any chicks. Halofuginone delayed the establishment of infections of the bursa of Fabricius and cloaca, but not of the trachea. 相似文献
3.
Broiler chickens free of maternal immunity to reticuloendotheliosis virus (REV) were used in the experiment. Two groups of 25 chickens were inoculated with REV at one day of age. One of these groups and another group of 25 chickens were inoculated with Eimeria tenella sporulated oocysts at 7 days of age. Chickens inoculated with E. tenella showed bloody diarrhoea from 12 to 14 days of age. Six out of 25 chickens died (P less than 0.05) at 13 and 14 days of age in the dual infected group. At 14 days of age, when chickens were killed, the lesion score in the combined infection group, was statistically different from that in the chickens inoculated with E. tenella alone. Also the weights of the bursa of Fabricius and thymus were lower in the two REV infected groups than in the controls. Although REV infection alone adversely affected the weight gain and feed conversion, with combined infection this effect was much greater. Following REV inoculation most of the chickens showed feathering defects and all the examined chickens were viraemic at 21 days of age. At the same age, all but one chicken failed to show precipitating antigenaemia and about one-half of these chickens showed a very low serum neutralisation titre. None of these chickens showed precipitating antibodies. 相似文献
4.
Experimental Cryptosporidium infections in chickens: oocyst structure and tissue specificity 总被引：3，自引：0，他引：3
D S Lindsay B L Blagburn C A Sundermann F J Hoerr J A Ernest 《American journal of veterinary research》1986,47(4):876-879
Oocysts of an avian isolate of Cryptosporidium were used to inoculate 21 chicks orally and 7 chicks intratracheally to determine the tissue specificity of this organism. Oocysts were passed in the feces 4 to 5 days after inoculation. Oocysts (6.8 by 5.0 microns) were fully sporulated and they were passed for at least 17 days by infected chicks. The mode of inoculation did not influence the distribution of cryptosporidia within the digestive tract. Cryptosporidia were found in the cloaca (100%), bursa of Fabricius (95.7%), terminal portion of the colon (26.1%), and cecum (4.3%) of chicks that were positive for developmental stages. Of 21 chicks inoculated orally, 4 had cryptosporidia in their trachea, whereas 6 of 7 chicks inoculated intratracheally had cryptosporidia in the trachea, bronchi, and air sacs. Cryptosporidium was found in the ducts of the salivary glands and nasal turbinates of chicks inoculated intratracheally that had clinical signs of respiratory tract disease. None of the chicks died or had intestinal disease. 相似文献
5.
Ovine coccidiosis: heavy infection in young lambs increases resistance without causing disease 总被引：1，自引：0，他引：1
Seven groups of twin lambs, kept with their dams on pasture, were given single oral inoculations of 10,000 oocysts of Eimeria ovinoidalis and 10,000 E crandallis at one, two, four, seven, 14, 21 or 28 days after birth, respectively. All were then challenged with 100,000 of each species at 42 days of age. An eighth group was challenged without having received the earlier 'immunising' inoculum, and a ninth group was not inoculated at all. Bodyweights, faecal consistency, oocyst output, and serum coccidial antibody levels were monitored up to 12 weeks of age. No clinical response was detected to inoculation up to four days of age. Loosening of faeces and a slight setback in weight-gain occurred in lambs inoculated seven, 14 and 21 days after birth; inoculation 28 days after birth caused severe diarrhoea and weight loss. Challenge at 42 days caused severe coccidiosis with 50 per cent mortality in the 'unimmunised' group. In those that had received 'immunising' inoculations, the challenge at 42 days caused some diarrhoea and some weight loss, but much less than in the 'unimmunised' lambs. The later the 'immunisation', the less severe was the disease attributable to the challenge at 42 days. Serum antibody levels correlated fairly closely with resistance to the disease. It was concluded that very young lambs were resistant to the pathogenic effects of some coccidia, but were able to respond to them immunologically. 相似文献
6.
In order to evaluate the effect of in ovo vaccination on avian cryptosporidiosis, two doses (1 and 10microg) of Cryptosporidium baileyi oocyst extract (OE) were injected into the amnionic sac of embryonated, specific pathogen-free chicken eggs. After hatching these birds as well as infected controls (IC) were inoculated with 8x10(5) C. baileyi oocysts at 10 days of age. Another group of chickens remained uninfected (UC). Faecal oocyst shedding was measured every second day, and weekly ELISAs were performed to monitor seroconversion. Those chickens that received OE during embryogenesis showed dose-dependent shift in their oocyst shedding, with higher oocyst output of OE1 and OE10 birds compared to IC ones. The patency was significantly longer in the OE10 group than in IC or OE1. ELISA results showed low seroconversion of OE1 and OE10 chickens prior to homologous challenge. Challenge infection resulted in antibody levels without significant difference between IC, OE1 and OE10 groups. These data suggest that in ovo vaccination with C. baileyi oocyst extract does not promote immune response, moreover, it may impair immunity and thus delay the clearance of cryptosporidia from chickens. 相似文献
7.
Developmental stages of Cryptosporidium baileyi were observed on the epithelium of the larynx, trachea, primary and secondary bronchi, air sacs, bursa of Fabricius, and cloaca of 12 chickens inoculated intra-abdominally with oocysts. All 12 birds inoculated intra-abdominally developed clinical signs of respiratory disease and had gross lesions of airsacculitis at necropsy. Developmental stages of C. baileyi and clinical signs of disease were not observed in 12 chickens inoculated intravenously with oocysts. The response of chickens to intra-abdominal inoculation of oocysts was similar to responses recorded following intratracheal inoculation of oocysts in previous studies. 相似文献
8.
M Chandra 《American journal of veterinary research》1988,49(6):831-834
A study was conducted to compare the responses of bursectomized (Bx) and nonbursectomized (non-Bx) specific-pathogen-free male chickens to Australian T strain of infectious bronchitis virus. Four chickens from each group were killed at 3, 5, 7, 14, 21, and 28 days after conjunctival inoculation of the virus. Clinical signs and gross and microscopic lesions were more severe in Bx than in non-Bx chickens. The non-Bx chickens had linear IgG deposits along the renal tubules. Virus-neutralizing titers were log10 2.74 to 4.33 for non-Bx chickens and less than log10 1.25 for the inoculated Bx and for broth-inoculated Bx and non-Bx chickens (controls). Early in the disease, renal lesions were of the same type in all infected chickens, but were more severe in Bx chickens. Later, nephritis was chronic and active in Bx chickens and was chronic in non-Bx chickens. 相似文献
9.
J K Skeeles M Slavik J N Beasley A H Brown C F Meinecke S Maruca S Welch 《American journal of veterinary research》1980,41(9):1458-1461
Specific-pathogen-free White Leghorn chickens were inoculated with a field strain of infectious bursal disease virus. One group (A) was inoculated at 17 days after the chicks were hatched, and the other groups (C and E) were inoculated at posthatch day 42. Blood samples were obtained for determination of clotting times (whole blood recalcification, prothrombin, and activated partial thromboplastin times), virus-neutralizing antibody, and total hemolytic complement. There were significant increases in clotting times for groups C and E at 3 and 5 days after they were inoculated. There were no significant increases in clotting times at 3 days after inoculation in the group A chickens (inoculated at 17 days after hatching). There were no significant decreases in total complement activity in any of these chickens (groups A, C, and E). This study indicates that the mortality and clinical symptoms observed in chickens experimentally infected with infectious bursal disease virus may be associated with a clotting abnormality because it was noted only in chickens that developed severe clinical disease (inoculated at 42 days after hatching) and was not noted in chickens that remained clinically normal (inoculated at 17 days). 相似文献
10.
To study effects of experimental cryptosporidiosis, broiler chickens were infected per os with 5 x 10(5) oocysts of Cryptosporidium baileyi and Cryptosporidium meleagridis. In the first experiment, chickens were infected with oocysts of C. baileyi at the age of 7, 14, and 21 days. In the second experiment, chickens were infected with oocysts of C. baileyi, C. meleagridis, or both cryptosporidial species at the age of 7 days. Although clinical signs of infection were apparent, neither final live weight nor mortality was significanty influenced in chickens infected with a single Cryptosporidium species. In chickens infected with C. meleagridis, the growth retardation was observed in the 2-wk period after infection. The compensatory growth, however, started when the oocyst shedding had ceased. The number of oocysts in excreta specimens of chickens infected with C. meleagridis was two to three times lower than in excreta of chickens infected with C. baileyi. Chickens infected with both C. baileyi and C. meleagridis (5 x 10(5) oocysts of each) had significantly lower final live weight and worse feed efficiency than chickens of other groups. Concurrent infection did not influence individual C. baileyi or C. meleagridis oocyst shedding. 相似文献
11.
使用鸡新城疫-禽流感（H9N2 HP株）二联灭活疫苗分别免疫3、7、14日龄三组商品肉鸡各40羽,同时设一组空白对照组。各免疫组及对照组于3、7、14、21、28、35、42日龄采血检测新城疫、禽流感抗体,于21、28、35日龄进行禽流感病毒攻毒,对比不同日龄免疫组的抗体消涨情况及不同日龄禽流感攻毒结果。发现对照组随鸡日龄增加,新城疫与禽流感抗体逐渐下降,在42日龄时下降至0,而不同免疫组新城疫与禽流感抗体均先下降,21日龄左右开始上升,至35日龄新城疫与禽流感抗体升至6log2以上。3日龄免疫组的禽流感免疫保护效果最好,21、28、35日龄时禽流感强毒攻毒保护率均达100%;7日龄免疫组在21、35日龄时禽流感强毒攻毒保护率均达100%,28日龄时禽流感强毒攻毒保护率达70%;14日龄免疫组在28、35日龄时禽流感强毒攻毒保护率均达100%,21日龄时禽流感强毒攻毒保护率只达30%。试验表明,商品肉鸡选择3日龄免疫鸡新城疫-禽流感（H9N2 HP株）二联灭活疫苗时禽流感免疫保护效果最好,采用3日龄免疫程序可以提高新城疫与禽流感的免疫保护效果,减少养殖业的经济损失。 相似文献
12.
A S Dhillon 《Avian diseases》1986,30(1):81-86
Ten strains of adenovirus representing 10 serotypes were administered intratracheally to 3-week-old specific-pathogen-free chickens, which also received 2.5 X 10(5) colony-forming units of a pathogenic Escherichia coli intranasally. Those birds had been inoculated by eye drop at 1 day of age with a virulent infectious bursal disease virus (IBDV). Controls consisted of groups of chickens inoculated with: (a) IBDV and E. coli, (b) IBDV only, (c) E. coli only, and (d) no virus or E. coli. Gross pulmonary alterations at 5 days postinoculation (PI) included congestion and consolidation of one or both lungs of a chick inoculated with adenovirus serotype Ind-C and another inoculated with A-2. Histopathologic alterations in the lungs were those of multifocal interstitial and occasionally diffuse pneumonia. All 10 adenovirus serotypes elicited multifocal or diffuse pneumonia and bronchiolitis in one or more of the five birds per group necropsied at 5 days PI. T-8 and A-2 serotypes induced marked to serve diffuse pneumonia within 5 days; Ind-C, Stein, Tipton, 75-1A, B-3, and X-11 incited a mild diffuse pneumonia. In all groups, the pneumonic lesions were more severe 5 days PI than 12 days PI. Tracheitis was incited by Ind-C, Stein, T-8, and A-2 at 5 days PI; the lesions were minimal to marked in severity. None of the four control groups exhibited gross or histopathologic alterations except the two IBDV-infected groups, which exhibited bursal change. 相似文献
13.
El-Abasy M Motobu M Na KJ Shimura K Nakamura K Koge K Onodera T Hirota Y 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2003,65(8):865-871
The effects of oral administration of sugar cane extracts (SCE) on Eimeria tenella oocysts infection in chickens were studied with 2 different experiments. In Experiment 1, 3-week-old inbred chickens (MHC; H.B15) were inoculated into the crop with SCE (500 mg/kg/day) for 1 day or 3 consecutive days, and then challenged with E. tenella sporulated oocysts (2 x 10(4) cells/chicken). In Experiment 2, 1-week-old chickens were orally administered SCE at the same dose for 3 consecutive days, and then initially infected with E. tenella sporulated oocysts (2 x 10(3) cells/chicken). At 2 and 3 weeks of age, these chickens were immunized intravenously with the mixed antigens of sheep red blood cells (SRBC) and Brucella abortus (BA). At 4 weeks of age, chickens were challenged with E. tenella sporulated oocysts (1 x 10(5)/chicken). Challenged chickens with E. tenella oocysts showed markedly decreased body weight gain/day, severe hemorrhage and great number of shedding oocysts in feces and high lesion scores. Oral administration of SCE and initial infection with oocysts (2 x 10 (3)/chicken) resulted in a remarkable improvement in body weight gain/day, hemorrhage, the number of shedding oocysts and lesion score, compare to other infected groups. In addition, SCE-inoculated chickens with the initial infection showed a significant increase in antibody responses against SRBC and BA and also improvement in decreased relative proportions of Bu-1a(+) and CD4( )cells in cecal tonsil lymphocytes of E. tenella-challenged chickens. Cecal tissues of chickens administered SCE and initially infected with E. tenella oocysts showed lower numbers of schizonts, gametocytes and oocysts than those of infected control chickens. These results suggest that SCE have immunostimulating and protective effects against E. tenella infection in chickens. 相似文献
14.
15.
The events during the pathogenesis of chicken anemia virus (CAV) infection following intramuscular (IM) and oral inoculation were further elucidated and compared by sequential clinical, pathologic, and morphometric histopathologic evaluations, and by sequential determination of CAV genome concentrations in different organs. Specific-pathogen-free chickens were inoculated by IM or oral routes with the same dose (2 x 10(6) mean tissue culture infective dose [TCID50]) of CAV isolate 03-4876 at 1 day of age. Weights and hematocrits were obtained at 7, 10, 14, 18, 21, 25, and 28 days postinoculation (DPI). Seven birds from each group were necropsied at 7, 10, 14, and 28 DPI, and samples of thymus, Harderian gland, and cecal tonsils (CT) were obtained for histopathologic examination and CAV genome quantification by real-time polymerase chain reaction. Peak CAV genome concentrations were detected in the thymus at 10 and 14 DPI in the IM and orally infected chickens, respectively. High CAV DNA concentrations were maintained throughout the experimental period until 28 DPI, despite specific seroconversion occurring by 14 DPI in the IM-inoculated chickens. CAV was isolated from both orally and IM-infected chickens 28 DPI. Peak CAV genomes in the thymuses of IM and orally infected chickens coincided with peak lymphocyte depletion in these organs. Lymphocyte repopulation of the thymus occurred by 28 DPI in spite of the presence of the virus in the organs of both infected chicken groups. CAV genomes were detected in the CT, but histopathologic changes were not observed. Compared with the IM route of infection, orally infected chickens did not show apparent signs of illness. Clinical parameters, including reduction of weight gains and hematocrits, and gross and histopathologic changes were delayed and less severe in the orally inoculated chickens. This was concurrent with a delay in accumulation of CAV genomes in the thymus of these chickens. 相似文献
16.
为了确定柔嫩艾美耳球虫（Eimenatenella）早熟株合适的免疫剂量,本文设立7个早熟株免疫攻虫组、1个不免疫攻虫组和1个不免疫不攻虫组,免疫组的免疫剂量为孢子化卵囊100、200、400、600、800、1000和2000个／羽,经嗉囊感染,7日龄首次免疫,14日龄以同等剂量进行第二次免疫,21日龄以8×10^4个／羽的同源母株进行攻虫,28日龄结束试验,以存活率、增重、肠道病变记分、血便数量、卵囊减少率为观测指标。对免疫保护效果较好的3个免疫剂量进行重复试验,同时设置商品化球虫疫苗对照组,免疫方法、试验周期、试验指标同第一批试验。结果显示：攻虫后,不免疫攻虫组出现5％死亡,而各免疫组来出现死亡;各免疫组卵囊减少率在61．57％～69．52％;200～2000免疫组的增重与不免疫不攻虫组差异不具备显著统计学意义（P〉0．05）;600～2000免疫组的肠道病变记分和血便数量均明显少于不免疫攻虫组（P〈0．05）。用600、800和1000进行重复试验,三个免疫组攻虫期间均来出现死亡,而不免疫组和疫苗对照组均出现5％死亡;三个免疫组的增重均明显高于不免疫攻虫组和疫苗对照组（P〈0．05）;早熟株免疫组的肠道病变记分和血便数量明显低于不免疫攻虫组（P〈0．05）,而疫苗对照组与不免疫攻虫组的相当（P〉0．05）;卵囊减少率在66.30％-78．75％,高于疫苗对照组的51．82％。结果表明,该柔嫩艾美耳球虫早熟株保持了良好的免疫原性,不同免疫剂量均能诱发鸡产生免疫保护力,其中600、800和1000个／羽的免疫效果均优于疫苗对照组,可考虑以600个／羽作为该早熟株在疫苗制备中的推荐免疫剂量。 相似文献
17.
H S Lillehoj 《Avian diseases》1988,32(3):437-444
Various parasite- and host-related factors influencing disease susceptibility and development of protective immunity against Eimeria tenella infection were investigated in two inbred strains of chickens. Chickens that received a primary inoculation of 10(3), 10(4), or 10(5) oocysts showed a significant reduction in packed cell volume and produced significantly more oocysts than chickens inoculated with fewer oocysts. Younger chickens were as susceptible as older chickens to identical parasite doses. However, upon a secondary inoculation 5 weeks following primary inoculation, FP chickens 1 to 21 days old at the time of primary inoculation developed resistance to reinfection, whereas SC chickens less than 3 weeks old at the time of primary inoculation were highly susceptible to secondary infection. Flow cytometric analysis of spleen lymphocytes showed a substantial reduction in T-cell number in 1-day-old SC but not FP chickens. Furthermore, 1-week-old SC chickens showed depressed mitogenic responses to concanavalin A compared with 1-week-old FP chickens. There was no significant difference between SC and FP chickens in speen B-cell number, regardless of age. 相似文献
18.
The pathologic consequences of chicken anemia virus (CAV) oral inoculation in 4-wk-old broiler breeders of different major histocompatibility B complex (MHC) genotypes were evaluated. MHC B complex was determined by hemagglutination and sequence-based typing. Clinical signs, serology, gross lesions, histopathologic analysis, and CAV genome quantification were used to evaluate disease progression. Clinical disease was not apparent in the inoculated broilers throughout the experimental period. At 14 days postinoculation, antibodies against CAV were detected in 26.4% (29/110) of the inoculated birds. The distribution of percent positive was 34.6% (9/26) and 32.3% (10/31) of the chickens with B A9/A9 and B A9/A4 MHC genotypes, respectively, and seroconversion in six other genotypes was 19% (10/53). These differences among MHC genotypes for specific seroconversion rate were not statistically significant. CAV genomes were detected in the thymus of 87.7% (93/110) of the inoculated birds with no statistically significant differences between MHC genotypes. Mild thymic lymphocytolysis, lymphedema, and medullary hemorrhage were observed in the inoculated chickens. Histomorphometric analysis showed that cortical lymphocyte-to-parenchyma ratios did not differ between inoculated and uninoculated groups or among MHC genotypes. Similar findings have been reported previously in white-leghorn chickens of similar age, suggesting that broilers show a similar resistance to the effects of CAV infection at this age. The absence of significant clinical and pathological changes in the orally inoculated broilers at this age contrasts with CAV-associated thymus damage seen frequently in condemned commercial broilers at harvest. 相似文献
19.
Newborn Holstein male calves were purchased within 3 days after birth and were removed from the local farms to the Dixon Springs Agricultural Research Center. They were hand-fed for 7 weeks and then weaned to a prepared feed. Eight groups, each of 4 calves, were housed in separate pens. In each of 4 pens (pens 2 to 5), 1 calf was inoculated with sporulated oocysts of Eimeria bovis (and was not medicated); 1 calf was inoculated and given feed with added monensin at the dosage level of 10 g/906 kg of feed; and 2 calves were inoculated and given medicated feed with added monensin at the dosage level of 20 g/906 kg or 30 g/906 kg. In the 4 other pens (6 to 9), the calves were inoculated with E zuernii and otherwise were given feed without or with added monensin as in pens 2 through 5. Another group of 5 calves (all kept in 1 pen), served as noninoculated, nonmedicated controls. At 14 days after inoculations with E bovis, the single calves in each of the 4 pens that were given the nonmedicated feed began to show clinical signs of coccidiosis and discharged increasing numbers of oocysts. The other inoculated calves (given monensin) had fewer clinical signs and discharged fewer oocysts in the feces as the level of medication in the feed increased. The calves inoculated with E zuernii developed only moderately severe infections when compared with those inoculated with E bovis. Inoculated (with E bovis) nonmedicated calves had severe reductions in feed consumption and weight, and 3 of 4 died.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
20.
为了研究苜蓿多糖对新城疫弱毒苗免疫鸡所产生的免疫调节作用,本研究选择1日龄海兰雏鸡120羽,随机分为4组,每组30羽,7日龄每羽用鸡新城疫活疫苗（La Sota株）免疫,28日龄以相同剂量进行加强免疫。其中3个试验组从7日龄开始分别肌肉注射低、中、高剂量（10、25、50μg/mL）的苜蓿多糖,对照组注射生理盐水,1次/d,连用7 d。于14、21、28、35、42、49、56日龄,通过静脉采血,用MTT法检测外周血淋巴细胞吸光度值（OD值）;同时用微量法检测血清中新城疫病毒血凝抑制（HI）抗体效价。结果显示,苜蓿多糖能够显著提高外周血淋巴细胞OD值,中剂量组（25μg/mL）淋巴细胞OD值最大;苜蓿多糖能够显著提高血清中新城疫病毒HI抗体效价,中剂量组免疫后期抗体存在时间长,抗体高峰期持续时间也长。本试验表明合适剂量苜蓿多糖对新城疫弱毒苗的免疫效果有明显的增强作用。 相似文献