Field Trial of the Brucellosis Fluorescence Polarization Assay

Abstract

Fluorescence polarization assay (FPA) is a homogeneous technique which was applied to the serological diagnosis of bovine brucellosis. Because of its simplicity and because it may be performed very rapidly, it was an ideal test to adapt to field use. The FPA was used to test cattle on six dairy farms in Baja California, Mexico. Anticoagulated blood, serum, and milk were collected from each animal. The anticoagulated blood was tested immediately on the farm while serum and milk were tested subsequently in the laboratory. Cattle on one farm (n = 140) were thought not to be infected with Brucella abortus and the other farms were thought to have high prevalence of the infection. The whole blood FPA (FPA(bld)) did not detect antibody in any of the cattle on the first premise. This finding was confirmed using a number of other serological tests, including the buffered antigen plate agglutination test, the complement fixation test, the indirect and competitive enzyme immunoassays, and the FPA using serum and milk. Cattle on the other premises (n = 1122) were tested in a similar fashion. The sensitivity of the FPA(bld), relative to the serum FPA (considered the definitive test), was 99.1% and the relative specificity of the FPA(bld) was 99.6%. These results compared favourably with those obtained using the other serological tests.

The value of Fluorescence Polarisation Assay in verification of problematic sera from pigs for brucellosis

“…That is why the evaluation was done on false-positive porcine sera. The earlier studies concerning pigs (Paulo et al 2000, Nielsen et al 2002 showed a high specificity of the test. Our studies showed that in pigs the method adds little as far as specificity in comparison to other methods is concerned (104 positive results out of 198).…”

“…The FPA has been validated for a number of species, including cattle, pigs and humans (Nielsen et al 2002). As the method gained the status of prescribed OIE test for international trade both for cattle and pigs the aim of the studies was to evaluate usefulness of FPA in Polish conditions and possibility of adoption of the method for routine diagnosis of brucellosis in pigs.…”

Value of Fluorescence Polarisation Assay in Comparison to Traditional Techniques in Diagnosis of Porcine Brucellosis

“…The method has been validated for a large number of species, including humans, cattle, and bisons, and is a prescribed OIE test applied for the examination of cattle and pigs during international turnover (19). The various studies concerning bovine sera showed the high sensitivity and specificity of the method (20)(21)(22). Unfortunately, there is a lack of information about the practical aspects and validation of FPA in diagnosis of porcine brucellosis (18,19).…”

“…If a molecule is labelled, the rotation can be determined by measuring polarised light intensity in vertical and horizontal planes (19). It is host species-independent method and can be performed also with whole blood or milk (9,11,(20)(21)(22). According to OIE Terrestrial Manual 2009, the FPA is recommended as a prescribed test for bovine and porcine brucellosis for determining the health status of animals (19).…”

Isolation of Yersinia Enterocolitica O:9 From Cows Positive in Serological Examination of Bovine Brucellosis

“…Taking into account the scale of investigations, costs, and ability of laboratories to perform the tests, which require an adequate accommodation, equipment, and hygienic facilities necessary to provide sufficient safety as brucellae are classified in risk group III, serological examinations play a crucial role in diagnosis of brucellosis (2,13,16,17). On the other hand, no serological method is fully reliable in diagnosing brucellosis in individual animals, and unequivocal diagnosis of Brucella infections can be only performed by the isolation and identification of the microorganisms and their molecular markers (1-4, 16, 21-23).…”