Development of a Latex Slide Agglutination Test and Its Use for Serodiagnosis of Heartwater ( Cowdria Ruminantium Infection ) in Small Rum in Ants

Abstract

Heartwater is a febrile tick-borne disease of domestic and wild ruminants. The serological tests, for example, 1FAT, ELISA and nucleic acid based tests which are currently used for diagnosis of heartwater require sophisticated laboratory equipment and trained personnel to be performed and are therefore not suitable for routine field use. This means that there is need for a simple rapid and specific test that can be used in the field for routine diagnosis of heartwater. The possibility of detecting C. ruminantium antibodies and antigens circulating in sera and plasma of experimentally infected goats, using latex beads coated with crude Cowdria antigen (latex slide agglutination antibody test) and latex beads coated with anti-MAP2 immunoglobulin fraction (latex slide agglutination antigen test) was investigated. The crude Cowdria antigen was prepared from C. ruminantium organisms cultivated in bovine pulmonary artery endothelial cells (BPA). The anti- MAP2 immunoglobulin fraction was precipitated by use of 50% saturated ammonium sulphate solution from sera obtained from rabbits which had been immunised with recombinant Cowdria MAP2 antigen. Sera and plasma collected from experimentally infected goats were tested for Cowdria antibodies and antigen respectively. Four sera from goats that sutfered an acute and fatal heartwater disease tested negative for Cowdria antibodies, using latex agglutination antibody test based on whole Cowdria antigen, while 2 sera from goats that suffered a non-acute and non-fatal disease started testing positive for Cowdna antibodies during the 6**1 week after inoculation. In addition latex beads were coated with recombinant Cowdria MAP2 antigen and used to test 81 random field goat serum samples for Cowdria antibodies Of the 81 random field goat serum samples tested, 19 (23.4 %) were positive, 11 (13.6 %) weak positive (border line) and 51 were negative. It was not possible to detect Cowdria antigen in plasma of the infected goats with the Latex slide agglutination antigen test.