Increasing incidence of Rickettsial infection in patients of Pyrexia of Unknown Origin.

To study the incidence of rickettsial infection in pyrexia of unknown origin (PUO) patients. To promote awareness and index of suspicion among clinicians for rickettsial infection.Out of numerous patients who came to a tertiary care hospital in Delhi with fever, sera of 22 patients in whom no diagnosis could be made after basic investigations and cultures were subjected to Weil Felix (WF) test.Out of 22 patients, 14 patients tested reactive by WF test. 6 patients each were positive for OX-2 and OX-K antigens. In 3 patients, OX-2 antigen was positive with OX-19 antigen and in 3 with OX-K antigen. One patient showed a positive titer with all three Proteus antigens. All these patients responded well to standard treatment of rickettsial infections.Rickettsial diseases are one of the many causes of PUO cases. Even if advanced diagnostic facilities are not available, simple and easy to perform WF test can aid in the diagnosis of rickettsial infections.