Farmers' Perceptions of the Impacts of Tsetse and Trypanosomosis Control on Livestock Production: Evidence from Southern Burkina Faso

Interviews with all the households in the Agropastoral Zone (ZAP) of Yalé, southern Burkina Faso, were conducted in 1994 and again in 1997 to assess the impacts of a tsetse control programme implemented from 1994, using insecticide-impregnated targets and pour-on treatments of all cattle with deltamethrin 1%. In the absence of health and productivity monitoring, data were collected in single-visit surveys in order to generate quantitative estimates of relevant reproductive performance variables for cattle and to assess changes in the inputs used and outputs produced. The results indicate a 25% increase in herd size and an increase in the number of oxen from 0.1 to 1.1 per household; a reduction in mortality from 63.1% to 7.1% and reductions in the rates of abortions and stillbirth of 55.9% and 51.3%, respectively; and an increase in the rate of live births of 57.6% and in the milk yield from 0.2 to 2.2 litres/cow per day in the dry season. These results show the dramatic impacts that trypanosomosis control can have on Zebu cattle exposed to high tsetse challenge. Well-designed surveys can be a cost-effective way to obtain estimates of productivity impacts that can be used to simulate projections of herd growth and meat and milk production in herd models. While there are many confounding factors associated with farmers' perception of a gain in productivity, these estimates form a useful alternative to subjective assessments in modelling the economic benefits of tsetse and trypanosomosis control.     

A Large-scale Trial to Evaluate the Efficacy of a 1% Pour-on Formulation of Cyfluthrin (Cylence,Bayer) in Controlling Bovine Trypanosomosis in Eastern Zambia

A trial to evaluate the efficacy of a 1% cyfluthrin pour-on formulation (Cylence, Bayer) in reducing the incidence of bovine trypanosomosis was conducted in an area of ca. 2000 km2 of the Eastern Province of Zambia. The trial area was cultivated and carried a cattle population of approximately 11 animals/km2. Cattle were the main host of tsetse. Following the free of charge treatment of the adult cattle at intervals of 7 weeks and at a dosage of 15 ml/100 kg body weight, there was an increase in the average packed cell volume in the herd although the decline in the incidence of trypanosomal infections was more prolonged. The monthly incidence of trypanosomal infections started to decline substantially 8 months after the treatments were initiated. No trypanosomal infections were detected from 10 months after the start of the trial.     

以合成肽为抗原检测O型口蹄疫病毒抗体 ELISA方法的建立和评价

作者以固相法合成特异性FMDV主要保护性抗原VP1上的表位肽,将其与载体蛋白BSA偶联,作为包被抗原,制备检测抗O型口蹄疫病毒(FMDV)抗体的ELISA试剂盒,并对该试剂盒进行方法考核.结果表明该方法的敏感性为95.12%,特异性为100%.检测199份血清标本,与UBI FMD VP1试剂盒的符合率达到98.49%,与液相阻断ELISA试剂盒的符合率达到96.98%.该多肽ELISA试剂盒特异、敏感、稳定、操作简便,可用来监控口蹄疫抗体水平.     

重组N蛋白抗原检测PPRV抗体ELISA的研究——试剂盒阴阳性临界值的测定及其与OIE参考实验室试剂盒的比较

对临床上采集的244份不同背景的羊血清样本,用纯化的重组N蛋白为包被抗原建立的检测小反刍兽疫病毒(PPRV)抗体的间接ELISA进行检测,运用统计学方法摸清了检测结果的分布规律,并同时用OIE参考实验室抗体检测试剂盒进行检测,结果表明,两种检测方法的符合率为91.73%。利用TG-ROC软件分析了ELISA抗体检测临界值,该试剂盒与国外试剂盒相比,其相对特异性和敏感性分别为98.6%和85.4%。     

猪脑心肌炎病毒抗体间接ELISA方法的建立及应用

应用纯化的EMCV VP1重组蛋白建立了检测EMCV抗体的间接ELISA方法,并确定了间接ELISA的最佳工作条件。结果表明,重组蛋白抗原的最适包被浓度为0.54μg/mL;与间接免疫荧光试验比较,结果表明该方法具有良好的特异性和敏感性。此方法中VP1抗原最佳稀释度为1:100,待检血清的最佳稀释度为1:50,酶标二抗的最佳稀释度为1:800,1%明胶为封闭液,OD450时阴阳性血清的临界值为0.35。对2006年天津7个地区66个猪场295份屠宰猪的血清样本的检测结果显示,天津各地区血清EMCV抗体阳性率在41.67%～93.33%之间,平均84.75%,猪场抗体阳性率在50%～100%,平均93.94%。     

The Control of Rinderpest in Tanzania between 1997 and 1998

In January 1997, Tanzania requested international assistance against rinderpest on the grounds that the virus had probably entered the country from southern Kenya. Over the next few months, a variety of attempts were made to determine the extent of the incursion by searching for serological and clinical evidence of the whereabouts of the virus. At the clinical level, these attempts were hampered by the low virulence of the strain, and at the serological level by the lack of a baseline against which contemporary interpretations could be made. Once it became apparent that neither surveillance tool was likely to produce a rapid result, an infected area was declared on common-sense grounds and emergency vaccination was initiated. The vaccination programme had two objectives, firstly to prevent any further entry across the international border, and secondly to contain and if possible eliminate rinderpest from those districts into which it had already entered. On the few occasions that clinical rinderpest was subsequently found, it was always within this provisional infected area. Emergency vaccination campaigns within the infected area ran from January to the end of March 1997 but were halted by the onset of the long rains. At this time, seromonitoring in two districts showed that viral persistence was still theoretically possible and therefore a second round of emergency vaccination was immediately organized. Further seromonitoring then indicated a large number of villages with population antibody prevalences of over 85%. These populations were considered to have been `immunosterilized'. Although no clinical disease had been observed in them, it was decided to undertake additional vaccination in a group of districts to the south of the infected area. Serosurveillance indicated that rinderpest could have been present in a number of these districts prior to vaccination. Serosurveillance in 1998 suggested that numerous vaccinated animals had probably moved into districts outside the infected and additional vaccination areas, but did not rule out the continued presence of field infection.     

Evaluation of an ELISA for detection of antibodies to Babesia bovis in cattle in Australia and Zimbabwe

An enzyme-linked immunosorbent assay (ELISA) for antibodies to Babesia bovis was evaluated in comparison with the indirect fluorescent antibody test (IFAT) in Australia and Zimbabwe. Positive and negative threshold values for the ELISA were set using sera from cattle of known infection status. Sensitivity and specificity estimates for the ELISA based on 158 positive sera from cattle experimentally infected with Australian isolates of B. bovis and 318 negative sera collected from B. bovis-free herds in Australia were 100% and 99.4%, respectively. The specificity of the assay in Africa, based on 328 sera from B. bovis-free herds in Kenya and South Africa, was 99.7%. The ELISA was compared with the IFAT using sequential sera from 16 calves experiencing primary B. bovis infections, and a total of 777 field sera collected from B. bovis-endemic herds in Australia and Zimbabwe. In primary infections, the ELISA and IFAT detected antibodies at or about the same time. With sera from endemic herds, the performance of the ELISA was at least comparable with that of the IFAT. Two hundred and fourteen of 221 sera that were negative by IFAT, were negative by ELISA, and 428 of 439 sera that were clearly positive by IFAT were positive by ELISA. Of 117 sera that gave equivocal (suspect or weak positive) results in the IFAT, 20 were positive by ELISA, 7 were suspect and 90 were negative. We conclude that the ELISA will be useful for epidemiological studies on B. bovis in Australia and Zimbabwe, and probably elsewhere.     

产气荚膜梭菌对养牛业的危害及其防制

近年来产气荚膜梭菌对中国养牛业的危害巨大,其流行型别和致病特点较以往也在发生变化,其中C、D型菌对牛致病增多;部分病例呈现慢性型发病症状。作者参考了大量文献对牛产气荚膜梭菌病的流行病学、发病原因、临床症状、病理变化、诊断方法及防制措施进行了综述。     

Development and Evaluation of an Indirect ELISA for Detection of Porcine Epidemic Diarrhea Virus IgA in Pig Serum and Milk Captured by Monoclonal Antibody

For the rapid and accurate evaluation of the IgA antibody level of porcine epidemic diarrhea virus (PEDV) in pig serum and milk,a specific PEDV IgG monoclonal antibody (MAb) 8A3 was screened from four strains of PEDV MAb,which could capture all virus particles (inactivated virus cell culture medium) of PEDV efficiently.In this method,the coating concentration of 6.0 μg/mL showed the optimal performance of MAb 8A3,the cut-off value (D_{450 nm}) was settled as 0.34,it had no cross-reactivity with the positive serums of common porcine viruses.Compared with immune-peroxidase monolayer assay (IPMA),the concordance rates of established ELISA for positive and negative serum detection were 98.7% (152/154) and 98.0% (145/148),respectively.For positive and negative samples of colostrum and milk,the concordance rates of the established ELISA compared with IPMA were 100% (60/60) and 95.8% (23/24),respectively.IgA levels in colostrum and milk samples during lactation detected by established ELISA were highly correlated with trends in neutralizing titers (kappa=0.835).Collectively,the indirect ELISA in this study had high sensitivity and specificity,it was a rapid and objective method suitable for large-scale detection of PEDV IgA in clinical samples.     

猪瘟病毒E2蛋白主要抗原区的原核表达及其间接ELISA检测方法的建立与应用

采用RT-PCR方法扩增猪瘟病毒(CSFV)E2蛋白主要抗原区基因,克隆入原核表达载体pET32a(+),转化大肠埃希菌BL21构建重组表达菌,经SDS-PAGE和Western blot鉴定目的蛋白得到成功表达。利用纯化的重组蛋白作为包被抗原,通过反应条件优化,建立了间接ELISA抗体检测方法。ELISA抗原最适包被浓度为0.5μg/mL(0.05μg/孔),最佳封闭液为5g/L BSA,待检血清最适稀释度为1∶100,作用时间为1h,酶标抗体最适稀释度为1∶2 000,最适作用时间为45min,室温显色10min。用该方法检测牛病毒性腹泻病毒(BVDV)、猪圆环病毒2型(PCV-2)、猪繁殖与呼吸综合征病毒(PRRSV)、伪狂犬病病毒(PRV)阳性血清结果均为阴性;批内和批间重复试验变异系数分别<5%和<8%,表明本方法具有较好的特异性和重复性。应用△E2-ELISA对350份血清样品进行检测,阳性率为77.71%,高于IDEXX试剂盒检测阳性率(67.14%),与IDEXX试剂盒阳性符合率91.06%,阴性符合率50%,总符合率77.43%。表明本试验建立的间接ELISA方法适于临床CSFV血清抗体的检测。     

羊群绵羊肺炎支原体抗体间接ELISA 检测方法的建立

利用绵羊肺炎支原体国际标准株Y-98,制备全细胞抗原,作为包被抗原,建立了一种间接ELISA方法。对4个不同羊场进行了血清学调查,确定了MoP抗体阳性率各为90%、70%、83.3%和73.9%。同间接血凝试验和鼻腔拭子培养结果相比,间接ELISA方法更加特异敏感,检出率更高,从而对该病的诊断和免疫程序的制定具有重要意义。     

Comparison of the Standard AGID Test and Competitive ELISA for Detecting Bluetongue Virus Antibodies in Camels in Gujarat,India

The performance of the standard agar gel immunodiffusion (AGID) test and the competitive enzyme-linked immunosorbent assay (cELISA) for the detection of serum antibody against bluetongue virus (BTV) in clinically healthy and diseased camels in Gujarat state were compared. Out of 176 sera tested, 22 (12.5%) and 34 (19.3%) were positive for group-specific bluetongue antibodies by AGID and cELISA, respectively. Maximum seropositivities of 18.0% by AGID and 25.8% by cELISA were recorded in the Kutchhi breed, and of 6.9% and 12.6%, respectively, in the Marwari breed. The seroprevalence detected by AGID and cELISA in clinically healthy and diseased camels did not differ significantly with regard to bluetongue disease in these breeds.     

The Value of the Glutaraldehyde and Formaldehyde Tests in Evaluation of the Globulin Level in Bovine Blood

So-called liability reactions are based on the gelification of blood globulins when reacting with, i.e., glutaraldehyde or formaldehyde. Solidifying time is inversely proportional to the globulin concentration of the blood. In the present investigation glutaraldehyde and formaline-gelification tests were compared concerning their diagnostic and prognostic value in dairy cows with internal diseases.The investigation confirmed earlier results. The correlation between globulin concentration and gelification time was significant, and both tests give very good possibilities to reveal hyper-γ-globulinaemias.The 2 tests were relatively equal as regards the reliability. Even though the formol-gel reaction allows a somewhat better safety and semi-quantitative differentiation than the glutaraldehyde test, the latter has obvious practical advantages. It can be done on whole blood and with a short observation time. Thus, the blood globulin status can be evaluated during the visit on the farm.     

检测鸡球虫四价弱毒疫苗抗体应答的ELISA方法的建立及初步应用

本研究旨在建立检测鸡球虫四价弱毒疫苗(柔嫩艾美耳球虫、毒害艾美耳球虫、堆型艾美耳球虫、巨型艾美耳球虫)抗体应答的酶联免疫吸附试验(ELISA),并初步阐明鸡免疫四价弱毒疫苗及攻虫后的抗体应答。将300羽岭南黄鸡分为A(免疫攻虫组)、B(不免疫不攻虫组)、C(不免疫攻虫组)共3个组。A组雏鸡在4日龄时进行首免,11日龄时鸡开始二免,二免完成后(17日龄时)对A组及C组的鸡进行攻虫(28万个4种球虫的混合卵囊/羽),7 d后检查A、C两组鸡的存活率。在鸡二免和三免完成后,分别对A、B组进行采血,通过优化最佳抗原包被浓度、酶结合物工作浓度及最佳血清稀释度,建立了ELISA方法来检测鸡体对球虫四价弱毒疫苗的抗体应答情况。A组鸡血清抗体的平均D值为0.870和0.904,明显高于B组鸡的平均D值0.261和0.270,证明了鸡体免疫疫苗后可以刺激产生相应抗体。免疫鸡攻虫后的存活率和抗体应答的检测结果,都充分说明了此鸡球虫弱毒四价疫苗具有良好的免疫原性,所建立的ELISA方法为今后评价鸡球虫弱毒四价疫苗的免疫效力提供了有效手段。     

Evaluation of the Abbott LCx Mycobacterium Tuberculosis Assay for Direct Detection of Mycobacterium Bovis in Bovine Tissue Samples

The commercial LCx amplification assay, usually employed to detect the Myocobacterium tuberculosis complex in respiratory specimens, was evaluated by comparing the results it gave with those obtained using Löwenstein-Jensen solid medium and pathological findings on 55 lymph nodes from cattle with positive and 10 lymph nodes from cattle with negative skin tests for tuberculosis. Fifty-three cultures (51 and 2, respectively) were positive for M. bovis, while the results for the LCx assay and the histological method were positive in 48 (45, 3) and 24 (20, 4) samples, respectively. None of the samples from cattle from certified tuberculosis-free herds were positive by any of the procedures. The results obtained with the LCx assay, compared with the culture procedure, regarded as the gold standard among the diagnostic techniques, gave a specificity of 91.6% and sensitivity of 90.5%. Although the sensitivity of LCx was suboptimal, DNA of M. bovis was detected in 81.8% of the skin test-positive animals. Amplification techniques could provide a rapid and reasonably reliable tool for detecting bovine tuberculosis.     

伪狂犬病gG-ELISA鉴别诊断方法的建立及其应用

利用gG基因表达产物建立了gG-酶联免疫吸附试验(ELISA)鉴别诊断方法，以该方法检测100份猪血清，结果表明该方法可显著区分gG基因缺失疫苗免疫猪和野毒感染猪，且特异性强、敏感性高。临床应用表明，该方法结果与其它临床诊断结果符合率高。以该方法在部分使用gG基因缺失疫苗的猪场做流行病学调查，共检测842份血清，检出242份阳性，阳性率为28.74％。     

The efficacy of a commercial ELISA as an alternative to virus neutralisation test for the detection of antibodies to EAV

Infection with equine arteritis virus is a notifiable disease with sporadic occurrence in the UK. As stallions may harbour the virus after infection, horses are screened for exposure by serological testing prior to breeding. The virus neutralisation test is considered the 'gold standard' serological screening test, but it is time-consuming and labour intensive; consequently there is a move towards more rapid screening methodology. In this study, a commercially available EVA antibody ELISA is assessed. The ELISA performed poorly with a specificity [corrected] of 26% and a sensitivity [corrected] of 96% in the samples analysed. It was concluded that this ELISA would be of little value for reducing sample turnaround time. The study emphasises the need for in-house validation of commercially available kits.     

Comparison of a competitive inhibition ELISA and the card agglutination test for detection of antibodies to Anaplasma marginale and Anaplasma centrale in cattle

OBJECTIVE: To compare a recently developed recombinant MSP-5 competitive inhibition ELISA with a card agglutination test for detection of antibodies to Anaplasma marginale and Anaplasma centrale in Australian cattle. MATERIALS AND METHODS: The ELISA was compared with the card agglutination test using 208 sera from cattle in Anaplasma-free herds, 86 sera from cattle experimentally infected with A marginale or A centrale and 757 sera from cattle in areas endemic for A marginale. RESULTS: The specificity of the ELISA, based on testing 208 sera from cattle in Anaplasma-free areas, was 99.5%, and the sensitivities for detection of antibodies to A marginale and A centrale in sera from the experimentally infected cattle were 98.0% and 100%, respectively. For the same sets of sera, the specificity of the card agglutination test was 98.6% and the sensitivities for detection of antibodies to A marginale and A centrale were 98.0% and 100%, respectively. For the 757 sera collected from cattle in areas endemic for A marginale, the agreement between the ELISA and the card agglutination test depended on the positive threshold selected for the ELISA. The maximum achievable agreement was 91.5% (kappa = 0.73; 95% confidence interval 0.66, 0.79). CONCLUSION: We conclude that the competitive inhibition ELISA is a useful alternative to the card agglutination test for detection of A marginale or A centrale infection in cattle. The assay should be particularly useful for epidemiological applications such as prevalence studies and control programs.     

Evaluation of a Western Blot and ELISA for the detection of anti-Trichinella-IgG in pig sera

Human trichinellosis is a foodborne disease caused by ingestion of infective Trichinella muscle larvae via pork or meat of other food animals which are susceptible to this zoonotic parasite. There are new approaches for a risk-oriented meat inspection for Trichinella in pigs which are accompanied by monitoring programmes on herd level to control freedom from this parasite. For this purpose, testing schemes utilizing serological tests with a high sensitivity and specificity are required.This study aimed at the evaluation of an ELISA and a Western Blot (WB) for the detection of anti-Trichinella-IgG in terms of sensitivity and specificity taking results of artificial digestion as gold standard. For this purpose, 144 field sera from pigs confirmed as Trichinella-free as well as 159 sera from pigs experimentally infected with T. spiralis (123), T. britovi (19) or T. pseudospiralis (17) were examined by ELISA (excretory–secretory antigen) and WB (crude worm extract). Sera from pigs experimentally infected with four other nematode species were included to investigate the cross-reactivity of the antigen used in the WB. For all Trichinella-positive pig sera, band pattern profiles were identified in the WB and results were analysed in relation to ELISA OD% values.Testing of pig sera revealed a sensitivity of 96.8% for the ELISA and 98.1% for the WB whereas the methods showed a specificity of 97.9 and 100%, respectively. WB analysis of Trichinella-positive pig sera revealed five specific band patterns of 43, 47, 61, 66, and 102 kDa of which the 43 kDa protein was identified as the predominant antigen. The frequency of the band pattern profile was irrespective of the dose and the period of infection as well as the Trichinella species investigated.In conclusion, monitoring in swine farms for Trichinella antibodies should be based on screening pig sera by means of ELISA followed by confirmatory testing through WB analysis.