Whole Blood Agglutination Research Articles

Natural resistance of Sri Lankan village chicken to Salmonella gallinarum infection

ABSTRACT1. An experiment was conducted to compare the natural resistance of an indigenous breed of local village chickens to Salmonella gallinarum with two commercial breeds: ISA Brown and ISA White layers under experimental conditions.2. A total of 72 chickens from each of these breeds were randomly distributed to 4 pens to provide equal numbers of two replicate pens maintained as infected and control (uninfected). All chickens in infected groups were inoculated orally with 1 × 108 CFU (1 ml dose) of a field isolate of S. gallinarum, at the age of 8 and 16 weeks given over 5 consecutive days. Growth performance, clinical signs, gross pathological lesions and antibody responses were measured.3. A significantly higher mortality was observed in the brown layers compared with the white layers, and clinical signs and mortality were absent in village chickens. However, a large number of birds with gross lesions and high antibody titres were detected in village chickens, indicating that birds had the disease subclinically. Commercial breeds had a significantly higher body weight, feed intake and feed conversion efficiency.4. There was a significantly lower proportion of positive reactors in village chickens in the whole-blood agglutination test (35%) compared to brown (100%) and white (90%) layers even after the second inoculation. Uninfected birds were negative in all groups. The indirect enzyme-linked immunosorbent assay confirmed these observations.5. These results suggest that the indigenous breed had superior natural resistance to S. gallinarum than the commercial breeds.

Control of Poultry Salmonellosis - Detection of Carrier Status in Grandparent Farms in Sri Lanka -

In Sri Lanka, the control programme for Salmonellosis is carried out by Department of Animal Production and Health (DAPH), in order to keep Salmonella carrier status at a less than 1% level in poultry breeder flocks. This study was aimed at serologically verifying the Salmonella carrier status in the two Grand Parent farms during the period of 2011- 2013, by performing whole blood agglutination test. In the present study, a total of 10 batches (nA=20915) from one farm and 9 batches (nB=4651) from the other were tested for antibody detection, once the age of the birds reached 20 weeks. The results revealed the Salmonella carrier status to be below 1%, in both farms during the study period as recommended by the DAPH.

Application of microagglutination test for detection of antibodies to <i>Salmonella gallinarum</i> in commercial layer chickens<BR><BR>Application du test de microagglutination pour la detection des anticorps a <i>Salmonella gallinarum</i> chez les pondeuses commerciales

In this study a microagglutination test (MAT) was developed, evaluated and compared with a rapid whole-blood agglutination test (RWBAT) for detection of Salmonella gallinarum antibodies in commercial layer chickens in Morogoro, Tanzania. The results showed that at Kigurunyembe farm, 16 (32%) of chicken tested were RWBAT positive while 30 (60%) were MAT positive among the 50 sera tested. Results from Kilakala farm revealed 10 (20%) sera that were RWBAT positive whereas 5 (10%) were positive for MAT among the 50 sera tested. On both farms, S. gallinarum was isolated from 21 chickens. The sensitivities, specificities, positive and negative predictive values for MAT were 57, 71, 34 and 86%, respectively, and 67, 85, 54 and 82 %, respectively for RWBAT. Although MAT was slightly less sensitive and less specific than RWBAT, it revealed a higher true seroprevalence (35%) of fowl typhoid than RWBAT (26%). When the test is optimized it may be preferred because it uses less time, space and antigen while permitting more objective evaluation of antibody titers. Higher growth and seroprevalence of S. gallinarum was observed in Rhode Island Red than Black Australop chickens. Keywords : chickens, microagglutination test, Salmonella gallinarum , seroprevalence, whole blood agglutination test Bulletin of Animal Health and Production in Africa Vol. 54(2) 2006: 124-130

A diagnostic strategy involving a quantitative latex d-dimer assay reliably excludes deep venous thrombosis

Bates SM, Kearon C, Crowther M, et al(McMaster University, Hamilton, Ontario, Canada)BackgroundClinical diagnosis of deep venous thrombosis (DVT) can be inaccurate. Thus, objective testing is usually considered mandatory in patients with suspected DVT. Whether a negative finding on a quantitative latex d-dimer assay precludes further testing in patients with a low or moderate pretest probability of DVT was determined.MethodsFive hundred fifty-six consecutive outpatients with suspected first DVT seen at 3 Canadian hospitals were enrolled in the prospective study. Before d-dimer testing, patients were classified as having low, moderate, or high pretest probability of DVT. Those with low or moderate pretest probability and a negative d-dimer result did not receive further testing or anticoagulant treatment. All other patients underwent serial compression ultrasonography. Patients who did not receive a diagnosis of DVT were followed up for symptomatic venous thromboembolism.FindingsFifty-one percent of the patients had low or moderate pretest probability and a negative d-dimer test. One of these patients subsequently received a diagnosis of DVT. Overall, the negative likelihood ratio of the d-dimer test was 0.03.ConclusionsA negative finding on a quantitative latex d-dimer assay precludes additional evaluation in patients with a low or moderate pretest probability of DVT. Patients with an abnormal finding on d-dimer testing can be managed safely with serial compression ultrasonography.CommentWith the use of a latex immunoassay technique, the authors of this prospective study confirm the usefulness of d-dimer assays to exclude DVT. The latex technique appears to have a higher sensitivity than the whole-blood agglutination assay, a key parameter of a test used to exclude disease. Although bedside risk stratification is the critical starting point for determination of the likelihood of this entity, there may be some situations where the added reassurance of a negative d-dimer result may be helpful. The authors offer a model for bedside risk assessment adapted from Wells et al.1Wells PS Hirsh J Anderson DR et al.Value of assessment of pretest probability of deep-vein thrombosis in clinical management.Lancet. 1997; 350: 1795-1798Abstract Full Text Full Text PDF PubMed Scopus (977) Google Scholar Bates SM, Kearon C, Crowther M, et al (McMaster University, Hamilton, Ontario, Canada) BackgroundClinical diagnosis of deep venous thrombosis (DVT) can be inaccurate. Thus, objective testing is usually considered mandatory in patients with suspected DVT. Whether a negative finding on a quantitative latex d-dimer assay precludes further testing in patients with a low or moderate pretest probability of DVT was determined. Clinical diagnosis of deep venous thrombosis (DVT) can be inaccurate. Thus, objective testing is usually considered mandatory in patients with suspected DVT. Whether a negative finding on a quantitative latex d-dimer assay precludes further testing in patients with a low or moderate pretest probability of DVT was determined. MethodsFive hundred fifty-six consecutive outpatients with suspected first DVT seen at 3 Canadian hospitals were enrolled in the prospective study. Before d-dimer testing, patients were classified as having low, moderate, or high pretest probability of DVT. Those with low or moderate pretest probability and a negative d-dimer result did not receive further testing or anticoagulant treatment. All other patients underwent serial compression ultrasonography. Patients who did not receive a diagnosis of DVT were followed up for symptomatic venous thromboembolism. Five hundred fifty-six consecutive outpatients with suspected first DVT seen at 3 Canadian hospitals were enrolled in the prospective study. Before d-dimer testing, patients were classified as having low, moderate, or high pretest probability of DVT. Those with low or moderate pretest probability and a negative d-dimer result did not receive further testing or anticoagulant treatment. All other patients underwent serial compression ultrasonography. Patients who did not receive a diagnosis of DVT were followed up for symptomatic venous thromboembolism. FindingsFifty-one percent of the patients had low or moderate pretest probability and a negative d-dimer test. One of these patients subsequently received a diagnosis of DVT. Overall, the negative likelihood ratio of the d-dimer test was 0.03. Fifty-one percent of the patients had low or moderate pretest probability and a negative d-dimer test. One of these patients subsequently received a diagnosis of DVT. Overall, the negative likelihood ratio of the d-dimer test was 0.03. ConclusionsA negative finding on a quantitative latex d-dimer assay precludes additional evaluation in patients with a low or moderate pretest probability of DVT. Patients with an abnormal finding on d-dimer testing can be managed safely with serial compression ultrasonography. A negative finding on a quantitative latex d-dimer assay precludes additional evaluation in patients with a low or moderate pretest probability of DVT. Patients with an abnormal finding on d-dimer testing can be managed safely with serial compression ultrasonography.

Diagnosis of pulmonary embolism.

The patient with suspected pulmonary embolism presents a challenging diagnostic problem. The symptoms and signs are nonspecific, and objective testing is required to establish or exclude the presence of pulmonary embolism. Lung scanning continues to be a first-line test, but in 40% to 70% of all patients, the results do not definitively provide indication for either giving or withholding anticoagulant treatment even when combined with the clinical assessment. Pulmonary angiography is the reference standard, but it is invasive and may not be available in all clinical settings. Pulmonary embolism is strongly associated with proximal deep-vein thrombosis of the legs (popliteal, femoral, or iliac vein thrombosis). Objective testing for proximal deep-vein thrombosis is useful in patients with suspected pulmonary embolism. A positive result from such testing provides an indication for anticoagulant treatment. Serial testing for proximal deep-vein thrombosis is a safe and effective alternative to pulmonary angiography in patients with adequate cardiorespiratory reserve. The assay for plasma D-dimer using either a rapid enzyme-linked immunospecific assay technique or a bedside whole-blood agglutination technique is promising as a test for excluding venous thromboembolism. A positive result by spiral CT imaging is useful for ruling in a diagnosis of pulmonary embolism, but the safety of withholding treatment in patients with negative spiral CT results remains uncertain. Pulmonary angiography continues to have an important role in selected patients in whom it is critical to definitively confirm or exclude the presence of pulmonary embolism.

Comparison of a whole-blood agglutination test and an ELISA for the detection of the antigens ofDirofilaria immitisin dogs

To compare the usefulness of two commercial tests for detecting the antigens of Dirofilaria immitis in dogs, one based on whole-blood agglutination (WBA) and the other on ELISA, 100 stray dogs from North Taiwan were tested before necropsy. Of the 53 dogs found to contain D. immitis at necropsy, which had a mean (S.D.) burden of 8.2 (10.6) worms/dog, 45 were found to be positive by WBA and 47 by ELISA. All the false negatives were dogs with very low worm burdens. Although the ELISA was more sensitive (83.9% v. 71.7%) and specific (100% v. 85.1%) than the WBA, the latter is simpler to use and less time-consuming. In terms of their general use for diagnosis of canine heartworm, there seems little to choose between the two tests. The false negatives observed with both tests are not likely to be a problem as they represent dogs with worm burdens which are probably too low to cause significant clinical manifestations or pathology. As the positive predictive value of the WBA test declines dramatically with prevalence of infection, this test may not be suitable for detecting D. immitis in canine populations in which heartworm infection is rare.

Escherichia coli expression of a bifunctional Fab-peptide epitope reagent for the rapid diagnosis of HIV-1 and HIV-2

Background: The current format of a rapid whole-blood agglutination assay for HIV relies on a bifunctional molecule which comprises a 10 Fab fragment, with specificity for the human red blood cell surface marker (glycophorin A), chemically conjugated to a synthetic peptide that corresponds to a single immunodominant region of HIV envelope glycoprotein. In this assay erythrocyte agglutination occurs if the blood sample contains anti-HIV antibodies. Objectives: To establish whether a bacterially synthesised Fab fragment encoding several C-terminal immunodominant peptide tails can be produced in sufficient purity and yield to function in whole-blood agglutination assays. Study design: An E. coli dicistronic Fab expression cassette was constructed comprising of light and heavy chain gene fragments derived from a glycophorin specific monoclonal antibody (1C3), genetically linked with C-terminal immunoreactive peptide epitopes. Expression and purification procedures were established to enable the rapid production of I C3 Fabpeptide epitope conjugates. Results: A recombinant I C3 Fab fragment was expressed with two different immunological epitope markers, Glu-Glu-Phe (EEF) and FLAG, at the C-terminus of the Fd heavy and κ light chain, respectively. This model Fab-EEF/FLAG conjugate was detected in culture supernatant by SDS-PAGE gels and Western blots, and could be successfully used in erythrocyte agglutination assays. Furthermore, an HIV specific I C3 Fab reagent, containing immunoreactive peptide epitopes from the surface glycoproteins of HIV-1 and HIV-2, was also expressed but at lower levels and with increased sensitivity to proteolytic degradation. Nevertheless, this recombinant Fab reagent with dial diagnostic specificity performed very effectively in whole-blood diagnosis of patients infected with either HIV-1 or HIV-2. Conclusion: A recombinant 10 Fab fragment terminated by immunoreactive peptide epitopes can be expressed in E. coli in a soluble, antigen-binding form, and it can successfully mimic the commercial Fab-HIV reagents in whole-blood agglutination assays.

Some Studies of Fowl Cholera in Hong Kong

SUMMARY In Hong Kong, acute fowl cholera frequently becomes chronic and difficult to eradicate. This survey studies the development of the chronic disease on a farm originally affected by acute fowl cholera. Altogether 249 chickens, in nine groups, were examined over a period of 3 1 2 months. A blue-tetrazolium stained Pasteurella multocida whole-blood agglutination test was evaluated as an indication of infection. All birds were examined post mortem and tissues cultured for Past. multocida. Past, multocida isolates were examined for fermentation of xylose, arabinose and dulcitol. Although the majority of birds were macroscopically normal, 171 yielded Past. multocida. The lung was the most frequently infected organ. The isolates were of a number of biochemical types, and there appeared to be a constant change from type to type within the flock. The percentage of infected birds rose to 96 per cent by 9 weeks after the initial outbreak. Vaccination at this stage reduced the level of infection to 44 per cent. The whole-blood agglutination test was not accurate shortly after the initial outbreak or after vaccination. When greatest accuracy of the test was recorded so many birds were infected that the only satisfactory means of eradication would have been slaughter of the whole flock. Birds with Past. multocida bacteraemia gave falsely negative results to this test.

Comparison of Repeated Rapid Whole-Blood, Rapid Serum, and Tube Agglutination Tests for the Diagnosis of S. Pullorum Disease

Comparison of Repeated Rapid Whole-Blood, Rapid Serum, and Tube Agglutination Tests for the Diagnosis of S. Pullorum Disease