用直接凝集试验与间接荧光抗体试验检测弓形虫的比较研究

为了评价新建立的弓形虫直接凝集试验(DAT)，对DAT和常规的间接荧光抗体试验(IFA)作了比较研究。用两种方法平行检测了41份商品兔血清、76份人工感染的兔血清和271份人血清。定性和定量比较的结果显示；DAT与IFA有很高的符合率(93．4～95．9％)，DAT较IFA敏感，前者的几何平均滴度高于后者，在检测感染兔血清时，DAT远较IFA敏感。通过出较，作者认为DAT更适用于弓形虫感染的大规模筛选和血清流行病学研究。     

THE IDENTIFICATION OF BABESIA EQUI IN AUSTRALIA

A Babesia parasite, isolated from the blood of a horse at Bowral, New South Wales, was identified on the basis of its morphological features, host specificity and serological reactions, as Babesia equi (Laveran 1901). The case was originally reported by Churchill and Best (1976, Aust. vet. J. 52: 487) and is the first record of equine babesiosis in Australia. In preliminary studies, the organism produced only a mild disease in an intact horse, but caused the typical clinical syndrome of acute babesiosis in a splenectomised horse, which died 19 days after the intravenous inoculation of the parasites.     

应用ELISA间接法检测猪流行性腹泻抗体的研究

应用猪流行性腹泻病毒(PEDV)吉(J)毒株猪胎肠单层细胞培养物,以冻融法制备抗原,建立了酶联免疫吸附试验(ELISA)间接法检测PED抗体的方法。对30头份经直接免疫荧光技术证实的PED病猪群血清测定,97％为阳性;检测32头份无PED猪场猪血清,93％为阴性。对1份PED“华毒株”,1份“川毒株”以及3头份“吉毒株”PED免疫血清测定,均为阳性。对猪传染性胃肠炎血清、猪轮状病毒病血清、疑似猪血球凝集性脑脊髓炎血清、鸡传染性支气管炎血清及猪梭菌性肠炎血清共16头份检测均为阴性,证明PEDV不与TGEV等其它3种冠状病毒血清发生交叉反应。89头份疫区猪血清的区域性试验阳性率为75％(67/89);对82头份屠宰猪血清测定,53％阳性。抗原包被板保存期试验表明,包被板在-20℃可保存2个月。     

检测鸡黄病毒血清抗体间接ELISA方法的建立与应用

本研究以鸡黄病毒FQ-C1株为包被抗原,建立检测鸡黄病毒血清抗体的间接ELISA方法。经优化后确定其最佳工作条件为每孔包被抗原0.57μg,血清以1:640倍稀释,羊抗鸡IgG酶标抗体以1:3200稀释,显色10 min后读取OD450值,P/N值≥2.1的血清为阳性。本实验所建立的诊断方法敏感性高于血清中和试验。对849份来自福建的血清样品进行检测表明,鸡黄病毒的血清阳性率达33.1%,说明鸡黄病毒感染有一定的流行性。     

BOVINE BABESIOSIS: COMPARISON OF FLUORESCENT ANTIBODY AND GIEMSA STAINING IN POST-MORTEM DIAGNOSIS OF INFECTION

SUMMARY Following experimental infections of cattle, Babesia argentina was detected in smears of heart, lung and kidney, immediately, and up to 8 hours post-mortem (PM), using Giemsa staining, while smears of brain were positive for up to 28 hours after death. Direct fluorescent antibody (DFA) staining detected B. argentina in heart and lung smears for 12 hours, in kidney smears for 16 hours, and in brain smears for 28 hours after death. Following experimental infections with B. bigemina, this organism could be recognised morphologically in smears of heart, lung and kidney immediately after death, but by one hour and up to 8 hours PM, its morphology resembled B. argentina in Giemsa stained films. A few red blood cells inside and outside brain capillaries were infected with organisms resembling B. argentina up to 16 hours after death. DFA staining detected B. bigemina in heart and lung smears for 12, and in kidney smears for 16 hours after death. A few infected red blood cells inside and outside capillaries were also seen in brain smears 16 hours after death. Organ smears could be held at 22°C for 5 days and both species of Babesia detected by either Giemsa or DFA staining.B. argentina was diagnosed by Giemsa staining of organ smears from 27 field cases of babesiosis. DFA confirmed B. argentina in 22, identified B. bigemina in 3 and failed to detect parasites in the other 2 cases. B. argentha was diagnosed by Giemsa staining in 10 and B. bigemina in 1 blood film from field cases. DFA confirmed B. argentina in 4 cases and B. bigemina in the 1 case. Serum from 5 of 12 animals which died in the field from natural B. argenfina infec- tions, had fluorescent antibody titres 2 64. After an experimental primary blood infection with B. argentina and while parasites were still detectable, 18 of 72 cattle had titres 2 64. Because there was no significant statistical difference between these results, it was con- cluded that the 12 field cases were due to primary infections, not recrudescences or hetero- logous strains or variants.     

AN OUTBREAK OF SWAINSONA POISONING IN HORSES

On 6 properties in south-western Queensland an outbreak of nervous disease occurred horses due to ingestion of Swainsonia (Darling pea). Loss of condition, depression, hyperaesthesia and hyperexcitability were seen in affected horses. At autopsy of 2 horses generalised c ytoplasmic vacuolation was seen in the neurones of the central nervous system and in the liver, adrenal and thyroid. The clinical and pathological features were similar to those described in horses suffering from Swainsona poisoning in Australia and Astragalus and Oxytropis in North America.     

SCINTIGRAPHIC EVALUATION OF THE STIFLE IN NORMAL HORSES AND HORSES WITH FORELIMB LAMENESS

We tested the hypotheses that mature horses without lameness have a repeatable radiopharmaceutical uptake pattern in the stifle, which is bilaterally symmetric; immature horses have a different radiopharmaceutical uptake pattern; and forelimb lameness alters the radiopharmaceutical uptake pattern in the stifle. The objectives of the study were to describe the normal radiopharmaceutical uptake patterns using region of interest (ROI) analysis; to compare uptake patterns between left and right stifles of the same horse and between mature and immature horses; to compare radiopharmaceutical uptake in mature normal horses with those with forelimb lameness. Lateral scintigraphic images of the stifle from 51 horses aged 2-16 years were evaluated using seven ROIs and a reference site (midfemur). After subtraction of a background count, ratios between the mean counts per pixel for each ROI to the reference site were calculated. There was a repeatable radiopharmaceutical uptake pattern in mature normal horses that was bilaterally symmetrical. The caudoproximal aspect of the tibia and the patella had the highest ratios. Radiopharmaceutical uptake patterns in horses with forelimb lameness were not significantly different. Immature normal horses had a different symmetric pattern, with greatest radiopharmaceutical uptake ratios in the caudoproximal aspect of the tibia and the tibial crest. It was concluded that there are symmetric, repeatable radiopharmaceutical uptake patterns in both immature and mature horses, which are not altered by forelimb lameness.     

THE DORSOPROXIMAL-DORSODISTAL PROJECTION OF THE DISTAL CARPAL BONES IN HORSES: AN EVALUATION OF DIFFERENT BEAM-CASSETTE ANGLES

To estimate the extent of the third carpal bone (C3) visible for evaluation in the dorsoproximal-dorsodistal oblique projection of the distal row of carpal bones, 13 forelimbs collected at post mortem from 7 horses were examined radiographically. The limbs were frozen with the carpal joints flexed then radiographed using fixed beam-cassette angles of 15 degrees to 45 degrees, at 5 degree intervals. The influence of beam-cassette angle on; the depth of the proximal articular surface examined, the radiographic appearance of C3 and the assessment of subchondral sclerosis was evaluated. Beam-cassette angles of 25 degrees to 40 degrees produced subjectively acceptable radiographs and did not appear to influence assessments of sclerosis. The mean depth of the examined proximal articular surface of the C3 increased significantly with each 5 degree increase in beam-cassette angle up to 40 degrees. The use of beam-cassette angles >35 degrees is recommended for the DPr-DDiO projection.