Serodiagnosis of dermatophilosis IV. antigenic selection for optimal antibody response determination in <i>Dermatophilus congolensis infected animals by counterimmunoelectrophoresis

Abstract

Four different antigenic extracts of Dermatophilus congolensis were evaluated for their suitability for   counterimmunoelectrophoresis (CIE) technique in detecting antibodies to D.congolensis. Thirty (30) sera   collected during an outbreak of dermatnphilosis in a herd of Santa Gertrudes cattle were tested. Twenty-eight (28) of the sera reacted to at least one of the antigenic extracts while 14 of them reacted to all the four  exuacis. Twent) (20) sera reacted to the two extracellular extracts (ammonium sulphate extracts, DcAS and extracellular polysaccharide, DcPS) while 18 sera reacted to the two whole cell-associated antigens (Triton X-100 extract of the cell walls, DcTX and cytoplasmic antigens, DcCP). Twenty-eight sera (93.33%) reacted to DcAS followed by 25 (83.33%) sera which reacted to DcCP, 21 (70.0%) to DcTX and lastly 20 (66.67%) to DcPS. Twenty-four 80.0% sera reacted to both DcAS and DcCP; 18 (60.0%) and 15 (50.0%) of the sera   reacted to both DcPS and DcTX antigens and DcPS and DcCP antigens respectively. Of the four extracts, only DcAS and DcCP detected multiple antibodies and these antigenic extracts \\ere found to have the highest antibody detection rates. This observation recommends the extracellular and cytoplasmic antigens for seroepidemiological studies of dermatophilosis.