<prompt> Weil-Felix reaction with OXK antigen indicates infection withR. tsustsugamushiR. mooseriR. quintanaR. akari  <response>: Weil-Felix reaction:Serological diagnosis of Rickessial infection. Weil-Felix reaction is a Heterophile agglutination test. Antigens used are Nonmotile strains of Proteus vulgaris OX 19, OX 2, Proteus mirabilis OX K.Mechanism: Proteus and Rickessiae will share alkali stable carbohydrate antigen will be basis of the Weil-Felix reaction. Weil-Felix is a tube agglutination test. It is a simple and useful test for the diagnosis. The Antibody rises in 2nd week of illness and reaches the peak and get decline rapidly during the course of convalescence. 