Diagnosis of Rickettsioses in Clinically Suspected Cases of Rickettsial Fever by Real-Time PCR in a Tertiary Care Centre

Background: Rickettsial infections are zoonotic diseases transmitted between mites, ticks, or fleas and animals, particularly rodents.Despite being underdiagnosed, they are a significant cause of Fever of Unknown Origin (FUO) globally, including India.Timely diagnosis is crucial as untreated cases can have fatality rates as high as 30-35%, emphasizing the need for rapid diagnostic methods.This study aims to diagnose clinically suspected cases of rickettsial fever by utilizing both the traditional Weil-Felix serological test and the more advanced PanR8 real-time PCR.Methods: This cross-sectional study was conducted between December 2017 and June 2019 at Bangalore Medical College.A total of 100 blood samples were collected from clinically suspected rickettsial fever patients.Serological diagnosis using the Weil-Felix test and molecular confirmation via PanR8 real-time PCR targeting the 23S rRNA of Rickettsia species was performed.Data analysis was done using descriptive statistics to interpret prevalence and symptom correlations.Results: Out of 100 samples, 37% showed positivity for OX-19 and OX-2 antigens in the Weil-Felix test.In the real-time PCR, 7% of samples tested positive for Rickettsia species, with a p<0.05, showing a significant correlation between PCR and Weil-Felix results in high-titer cases.The majority of patients (100%) had a fever, 46% had a rash, and hepatosplenomegaly was observed in 20%. Conclusion:The study demonstrated the utility of both Weil-Felix test and PanR8 real-time PCR for diagnosing rickettsial infections.The PanR8 real-time PCR improved diagnostic accuracy and reduced turnaround time, proving valuable in clinical settings.