Ocular manifestations of Rickettsia conorii in South India

Purpose: Among the major groups of rickettsiosis, the commonly reported diseases in India are: (a) Typhus group induced-scrub typhus, murine flea-borne typhus; (b) Spotted fever group induced-Indian tick typhus; and (c) Q fever. Though many scrub typhus outbreaks have been reported from India, only one outbreak of spotted fever-serologically proven Indian tick typhus (Rickettsia conorii)-has been reported. We report for the first time ocular manifestations of serologically proven R. conorii infection in a cluster of patients. Methods: In this retrospective study, case records patients with serologically proven Indian tick typhus (Rickettsia conorii) were reviewed for clinical manifestations and treatment outcomes. Results: In the months of February to April 2016, a cluster of 12 patients (23 eyes) visited us with defective vision. Examination showed multifocal retinitis; mostly bilateral; patients had a history of fever approximately 4 weeks prior to onset of symptoms. After excluding other causes of multifocal retinitis, a diagnosis of rickettsial retinitis was made after Weil-Felix test (WFT) was significantly positive, and enzyme-linked immunosorbent assay was positive for R. conorii. Course of the disease, visual outcome, and investigations are discussed. Doxycycline along with oral corticosteroids was effective in treating the condition. Conclusion: Systematic fundus examination should be part of the routine evaluation of any patient who presents with fever and/or skin rash living in or returning from a specific endemic area. Clinical clues to diagnosing ocular rickettsiosis could be multifocal retinitis predominantly involving the posterior pole and macular involvement in the form of serous macular detachment or macular hard exudates. A positive WFT still serves as a useful and cheap diagnostic tool for laboratory diagnosis of rickettsial disease. Doxycycline along with oral corticosteroids was effective in treating the condition.