Rapid detection of contagious caprine pleuropneumonia using a Mycoplasma capricolum subsp capripneumoniae capsular polysaccharide-specific antigen detection latex agglutination test

Latex microspheres (diameter, 8 mum) were coated with anti-Mycoplasma capri colum subsp.capripneumoniae polyclonal immunoglobulin G (IgG) antiserum (an ti-F38 biotype). The coated microspheres, when used in a latex agglutinatio n test (LAT), detected M. capricolum subsp. capripneumoniae antigen in the serum of goats with contagious caprine pleuropneumoniae (CCPP). Beads also agglutinated strongly in the presence of purified M. capricolum subsp. capr ipneumoniae capsular polysaccharide (CPS). Preabsorption of CPS-specific an tibodies prior to coating of the beads removed agglutinating activity in th e presence of M. capricolum subsp.z capripneumoniae, strongly suggesting th at CPS is the likely soluble antigen recognized by the test. In addition, t he specificity of the LAT exactly mirrored that of an M. capricolum subsp. capripneumoniae CPS-specific monoclonal antibody (WM25): of the 8 other myc oplasma species tested, agglutination was observed only with bovine serogro up 7. The LAT detected all 11 strains of M. capricolum subsp. capripneumoni ae examined in this study, with a sensitivity level of 2 ng of CPS, or the equivalent of 1.7 x 10(4) CFU, in a reaction volume of 0.03 mi of serum. Wi th field sera from goats with CCPP, the results of the LAT exhibited a 67% correlation with the results of the currently used complement fixation test (CFT), with the main discrepancy in diagnosis resulting from the increased sensitivity of the LAT compared to that of CFT. This antigen-detection LAT should prove particularly useful in identifying animals in the earliest st ages of CCPP and combines sensitivity and low cost with ease of application in the field, without the need for any specialist training or equipment.