Detection Of Brucellosis Research Articles

Seroepidemiological investigation of brucellosis in sheep abortions in Kars, Turkey

This study was undertaken to investigate the seroprevalence of brucellosis in unvaccinated sheep from the flocks having previous abortion cases in Kars and around, Turkey and to compare the efficacy of each serological test used. Four hundred serum samples collected from 16 different flocks of sheep having a history of abortions in Kars and its surrounding area in Turkey were examined for the presence of antibodies raised against Brucella using Rose Bengal Plate Test (RBPT), Serum Agglutination Test (SAT), Rivanol Agglutination Test (RAT) and Complement Fixation Test (CFT). All animals were unvaccinated against Brucella. Of the serum samples tested, 147 (%36.7), 142 (%35.5), 139 (%34.75) and 135 (%33.75) were found positive by SAT, RAT, RBPT and CFT, respectively. No statistically significant difference was found between the serological tests used (p > 0.05). It is concluded from this study that brucellosis continues to be an important problem for ovine abortions and poses a risk both for human and other animals in this area. Therefore, adequate intervention measures should be implemented to control and eradicate brucellosis. In addition, if conventional serological tests are used at least two tests, RPBT for screening and CFT for the confirmation of the positive samples are preferable, should be used in parallel for detection of brucellosis effectively.

Serological Detection of Brucellosis in Cattle and Human

Serological Detection of Brucellosis in Cattle and Human

Evaluación de la prueba reacción en cadena de la polimerasa (PCR) a partir de muestras de leche y cultivos puros en el diagnóstico de la brucelosis bovina

Brucellosis is a zoonotic disease with a strong economic impact. It is also a serious public health issue. In Mexico, the official diagnosis is made by serology, using the card, rivanol, and complement fixation tests. Nevertheless, Brucella spp. isolation and characterization remain as the diagnostic gold standard. In this study the polymerase chain reaction (PCR) technique was compared with bacteriology and serology in the diagnosis of bovine brucellosis. A total of 51 blood/milk samples were collected from two herds with positive brucellosis history. Of these 51 samples 24 were negative to serological, bacteriological and PCR tests, 11 were positive to all tests, six were positive to both serology and PCR, one was positive to both serology and bacteriology, and 9 were positive to serology. From the 12 positive isolations, a sample was taken for PCR. Amplification was obtained in 100 % of these cultures. Results show that the proportional detection of positive animals by PCR was higher than isolation (P<0.05). Therefore PCR can be a very useful tool in the detection of brucellosis in milk samples. PCR from pure cultures has a 100 % sensitivity, and it can be used either in the detection of Brucella, or in discriminating between vaccine and field strains.

Epidemiology of human brucellosis in a rural area of north-western Peloponnese in Greece.

A case-control study was conducted in a rural area of Achaia in western Greece to examine the risk factors of brucellosis. The participants in the study were 414 (7.5% of the whole population of the investigated municipality). The cases (n = 140) were defined by clinical symptoms and confirmed by a positive standard agglutination test (SAT). All cases have been diagnosed between January 1997 and March 1999 either by physicians of the Local Health Center or by private practitioners. Two criteria were basic to establish the disease. The first one was clinical symptoms such as fever, fatigue, arthralgia and generalized aches and the second was a titer of SAT at least 1:160. Controls (n = 274) were matched with cases for age and gender in a 1:2 ratio. Approximately collection of controls was performed among those presented to the local Health Center for other diseases. Data were collected by the same physician via a personal interview and analyzed by logistic regression models. The overall incidence of the disease in the region was found to be 1110/100,000. Taking 'no ownership of animals' and 'no contact of animals' as the reference category, the strongest risk factor was trauma during animal delivery with an odds ratio (OR): 24.3; 95% confidence interval (CI): 8.8-67.5 following by absence of stables (OR: 14.4; 95% CI: 4.7-44.1). After application of multivariate stepwise analysis the adjusted risk factors remaining in the model were the place of residence (OR: 1.8; 95% CI: 1.1-3.1), professional occupation with animals (OR: 2.4; 95% CI: 1.2-4.8), absence of stables (OR: 9.1; 95% CI: 2.2-38.7) and trauma during animal delivery (OR: 11.2; 95% CI: 3.2-39.1). Consumption of cheese from pasteurized milk or consumption of cheese matured for over 3 months was found to be a protective factor (OR: 0.27; 95% CI: 0.11-0.67). The detection of brucellosis in animals is essential for the prevention of the disease. In addition efficient preventive measures should be established in order to eliminate the disease.

Evaluation of the currently used diagnostic procedures for the detection of Brucella melitensis in sheep

A study was conducted to determine whether the use of the enzyme-linked immunosorbent assay (ELISA) improves detection of brucellosis in individual sheep. Sera from 132 sheep that aborted due to B. melitensis were used to assess the efficacy of the ELISA to detect brucellosis in sheep. ELISA results were compared with those of the serum agglutination test (SAT), complement fixation test (CFT), Rose Bengal Plate test (RBPT) and the skin delayed-type hypersensitivity (SDTH). Sera from 11132 sheep free from brucellosis were tested with the ELISA to determine its specificity. The results show little difference in diagnostic efficacy between SAT, CFT, RBPT and the SDTH test, although the skin test indicated infection in some seronegative sheep. A combination of CFT and SAT, or CFT and RBPT, or CFT and SDTH tests indicated brucellosis in 75–88% of the infected animals, whereas the ELISA indicated infection in 97–100% of those animals. Seventeen (0.2%) from the 11132 negative sheep sera tested positive with the ELISA, indicating a 99.8% specificity. We concluded that screening sheep for brucellosis with ELISA improves Brucella diagnosis, and in areas of low prevalence it will help to maintain flocks of sheep free from brucellosis.

Field evaluation of an indirect ELISA for detection of brucellosis in lowland Bolivia.

Bovine brucellosis exists endemically at an estimated prevalence of 10% in the developing dairy industry of Santa Cruz in tropical Bolivia. This paper describes field testing of an FAO/IAEA indirect ELISA for brucellosis, as a possible replacement confirmatory test for the complement fixation test (CFT). The ELISA and CFT were compared on sera from 3 cattle populations: a non-vaccinated negative population, an S19-vaccinated negative population, and a brucellosis-positive population of unknown vaccination status. The CFT and ELISA showed excellent specificities of 100% and 98% respectively against the negative non-vaccinated group. The CFT maintained a specificity of 98% against the S19-vaccinated negative group, but ELISA specificity fell to 83% using a cut-off of 20% of positive control, and 94% using a cut-off of 40% of positive control. Against sera from the positive population, the ELISA gave many more positive reactions than the CFT, probably a combination of both higher sensitivity and lower specificity. It is concluded that as Santa Cruz is entering a phase of brucellosis control rather than eradication, the extra sensitivity of the ELISA is not valuable enough to risk a higher level of false positive reactions, especially as S19 vaccination is being increasingly used.

Comparison of serologic tests and bacteriologic culture for detection of brucellosis in swine from naturally infected herds

Objective— To compare results of 6 serologic tests with results of bacteriologic culture for Brucella suis in swine. Design— Prospective study. Animals— Two hundred twenty-one swine from 39 naturally infected herds. Procedure— Blood samples and lymph nodes were collected at slaughter. Serologic tests conducted were the particle concentration fluorescence immunoassay, the automated complement fixation assay, the card test, the buffered acidified plate antigen assay, the standard tube test, and the rivanol test. Lymph nodes were plated on Farrell's medium and serum-enriched agar for bacteriologic culture. Results— Sensitivities ranged from 57 (automated complement fixation assay) to 83% (standard tube test). Specificities ranged from 62 (standard tube test) to 95% (rivanol test). Brucella suis was isolated from 46 of the 221 (21%) pigs. For 8 of the 46 culture-positive pigs, results of all 6 tests were negative. Clinical Implications— Data illustrate the difficulty of eliminating brucellosis by means of a test-and-removal program and support the policy of slaughtering infected herds.

Chemiluminescent immunoassay (CLIA) for the detection of brucellosis and tularaemia antigens.

The detection of brucellosis and tularaemia infection agents is of particular interest for medical practice. The possibility of using enhanced chemiluminescence reactions for the determination of these agents is studied in this work. Light intensity depends on both the conjugate concentration used and the conditions at which the adsorption was performed. Optimal conditions for these test-systems were: approximately 20 micrograms/mL of Ig and 200 micrograms/mL (titre 1:20) of conjugate. As is seen from the chemiluminescent and spectrophotometric results the lowest determined concentrations are 10 and 30 ng/mL (for brucellosis) and 1 and 5 ng/mL (for tularaemia), respectively. Calibration curves in the antigen concentrations ranging from 10 to 2500 ng/mL (for brucellosis) and from 1 to 500 ng/mL (for tularaemia) are observed. Optical density depends linearly on the logarithm of the antigen concentration from 30 to 5000 ng/mL (for brucellosis) and from 5 to 250 ng/mL (for tularaemia). The results obtained permit the conclusion that the chemiluminescence method can be used in enzyme immunoanalysis for brucellosis and tularaemia antigens.

Comparison of enzyme-labeled immunosorbent assay and particle concentration fluorescence immunoassay with standard serologic methods and bacteriologic culture for detection of Brucella sp-infected cows in herds with brucellosis

Summary: Bacteriologic culture of udder secretions and card, rivanol, and complement fixation tests for detection of brucellosis were performed on samples from 828 cows vaccinated with strain 19 in herds with brucellosis. An elisa and a particle concentration fluorescence immunoassay were performed on sera from 560 and 569 cows, respectively. A field strain of Brucella abortus or strain 19 was isolated from 278 cows. The elisa and the card test had high sensitivity, but low specificity. Data suggested that there is no advantage to using primary binding assays rather than the simple buffered antigen agglutination procedures to detect cows infected with a field strain of B abortus.

Detection of brucellosis in diary herds after an outbreak of the disease using a delayed-type hypersensitivity test

A study of 14 herds was conducted to assess the skin delayed-type hypersensitivity (SDTH) test used in combination with the serum agglutination test and complement fixation test to curtail the spread of brucellosis. The tests were used to screen dairy herds suspected of brucellosis, and herds located near infected herds. The herds were tested every 5–6 weeks for 6 months. Cattle with a palpable skin swelling at the injection site of the allergen were considered as brucellosis suspects and were slaughtered. Supramammary lymph nodes of these cattle were collected and examined bacteriologically to determine their infection status. Brucellosis was detected and confirmed bacteriologically in three seronegative herds in which cattle tested positive with the SDTH test. Brucellosis was also confirmed bacteriologically in five seropositive herds in which cattle tested positive with the SDTH test. Brucellosis was not confirmed bacteriologically in one seronegative and four seropositive herds in which cattle reacted positively with the SDTH test. One herd reacted negatively in all tests. Because the SDTH test is able to detect latent carriers of Brucella organisms in seronegative herds, we recommend that the SDTH test be used in combination with serologic tests to curtail the spread of brucellosis.

Flotation of Mastitis Pathogens with Cream from Subclinically Infected Quarters. Prospects for Developing a Cream‐Rising Test for Detecting Mastitis Caused by Major Mastitis Pathogens

Bacterial isolates, originating from 36 subclinically infected quarter milk samples, were labelled with 75Se and checked for cream-rising at various temperatures in a system analogous to the ABR test ("Abortus Bang Ringprobe"; the cream-rising test based on stained brucella organisms for detection of brucellosis). Diagnostic specificity and sensitivity were analyzed in experiments where labelled bacterial isolates were mixed with a number of quarter milk samples with known bacteriological status as well as samples from healthy control quarters. Creaming at 37 degrees C resulted in specific "recognization" as the bacterial isolates showed preferential flotation in the milk samples from which they had been isolated as well as is milk samples harbouring the same bacterial species. At lower creaming temperatures, the specificity was lost since all the isolates became concentrated in the cream phase irrespective of the milk sample. When comparing the specific recognization by cream of the respective bacteria, bacterial species vary: The prospects for developing diagnostic cream-rising tests for Streptococcus agalactiae, Staphylococcus aureus and Escherichia coli seems promising, but less so for coagulase-negative staphylococci, Streptococcus dysgalactiae, and Streptococcus uberis. The mechanism behind the cream-rising of labelled bacteria at 37 degrees C seems to lie in specific fat globule membrane-bound immunity of IgA type. Therefore the milk fat globules from chronically infected quarters function as absorbents for the respective isolates. Flotation of bacteria with cream indicates an in vivo mechanism enabling bacteria to invade the upper parts of milk ducts within the udder.(ABSTRACT TRUNCATED AT 250 WORDS)

An Indirect Enzyme-Linked Immunosorbent Assay for the Detection of Antibodies to Brucella Abortus in Porcine Sera

SUMMARY An indirect enzyme-linked immunosorbent assay (ELISA) is described for the detection of brucellosis in pigs. The combination of a commercial goat antirabbit peroxidase conjugate and an experimentally-prepared rabbit anti-porcine immunoglobulin serum detected both IgM and IgG antibodies to Brucella abortus in pigs. The test gives results comparable with the Coombs’ antiglobulin test but is more rapid and uses very small volumes of reagents.

INCIDENCE OF UNDULANT FEVER

To the Editor:— In a letter to the Editor inThe Journal, May 28, 1949, Dr. Frederick Stenn reported the incidence of undulant fever among 100 patients observed in private practice from the stockyards district of Chicago. He observed only 1 person with a positive reaction to an agglutination test and 1 patient with a history of brucellosis. The agglutination test cannot be relied on as the only means for the detection of brucellosis. Several reports have been published indicating the decided variation in the results of the test obtained in different laboratories (Carpenter, C. M., and Boak, R. A.: The Significance of Brucella Abortus Agglutinins in Human Serum, J. Immunol. 17 [July] 1929. Eisele, C. W.; McCullough, N. B., and Beal, G. A.: Discrepancies in the Agglutination Test for Brucellosis as Performed with Various Antigens and as Reported from Different Laboratories, J. Lab. & Clin. Med. 32 , 7 [July]