The Weil-Felix test is primarily used to detect antibodies against which group of organisms?

- The Weil-Felix test is used to detect antibodies against Rickettsia species.
- It is based on the principle of cross-reactivity between certain Proteus bacterial antigens (OX strains) and rickettsial organisms.
- When a patient is infected with Rickettsia, their serum contains antibodies that agglutinate these Proteus antigens, producing a positive test.
- This serological test helps in the diagnosis of rickettsial infections, such as typhus and spotted fever.
- It is not used for Brucella, Leptospira, or Mycoplasma detection, as these organisms do not cross-react with Proteus antigens.