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Serological profile of patients suspected with non-scrub typhus rickettsioses
Chandan Kumar Thakur1, Vinayaraj E V2, Tanu Sagar2
1Department of Microbiology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India; Nepal Health Research Council (NHRC), Ramshah Path, Kathmandu, Nepal.
Background:
Rickettsial pathogens are Gram-negative, obligate intracellular bacteria. They are transmitted by arthropods and are responsible for a wide variety of disease, from minor to life-threatening, which have a global effect on human health. Limited data are available on the prevalence of rickettsial diseases from India, and the disease epidemiology is not fully described. This study aimed to diagnose non-scrub typhus rickettsioses including spotted fever and typhus group of Rickettsia in clinically suspected patients by using standard serological tests and recognition of common epidemiological conditions and clinical manifestations.
Methods:
During the study period, a total of 700 patients of all ages with acute febrile illness were enrolled. Patients were screened for rickettsial infection using IgM Enzyme-linked immunosorbent assay (ELISA) and Immunofluorescence assay (IFA) was performed to confirm the ELISA positive results. The relevant demographic, clinical, and laboratory details of patients were documented and analyzed.
Results:
Of 700 samples tested, 141 (20.2%) were found to be positive for IgM antibodies against rickettsioses using ELISA and IFA. SFGR was positive in 15 (2.2%), TGR was positive in 112 (16%) and 14 (2%) samples were positive for both groups. 20 (14.2%) patients required admission to the intensive care unit (ICU), and 24 (17%) in-hospital deaths occurred.
Conclusions:
The prevalence of rickettsioses in India appears to be underestimated; therefore, increased awareness and improved diagnostic testing could facilitate early detection of cases, pathogen-targeted appropriate treatment, and improved outcomes for patients. Despite the fact that Rickettsiae can be isolated or detected using molecular techniques in clinical specimens, serology still remains the most commonly used diagnostic method for rickettsioses around the world. Our study helps bridge the gap of limited data on Rickettsia in north India and could be useful for future epidemiological investigation of rickettsial diseases and outbreaks.
Insights
Rickettsial infections in India are more common than previously thought, with over 20% of suspected patients testing positive. Early diagnosis and treatment are crucial for better patient outcomes in rickettsioses.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Rickettsial pathogens cause significant global health issues, transmitted by arthropods.
- Data on rickettsial disease prevalence in India is limited, hindering epidemiological understanding.
- Non-scrub typhus rickettsioses, including spotted fever and typhus group Rickettsia, require further investigation in India.
Purpose of the Study:
- To diagnose non-scrub typhus rickettsioses in clinically suspected patients in India.
- To identify common epidemiological factors and clinical manifestations associated with rickettsial infections.
- To assess the prevalence of spotted fever group rickettsia (SFGR) and typhus group rickettsia (TGR) in north India.
Main Methods:
- Enrolled 700 patients with acute febrile illness.
- Screened patients for rickettsial infection using IgM Enzyme-linked immunosorbent assay (ELISA).
- Confirmed positive ELISA results with Immunofluorescence assay (IFA) and analyzed patient data.
Main Results:
- 141 out of 700 (20.2%) patients tested positive for IgM antibodies against rickettsioses.
- Spotted fever group rickettsia (SFGR) detected in 2.2%, typhus group rickettsia (TGR) in 16%, and dual infections in 2%.
- Significant patient morbidity and mortality observed, with 14.2% requiring ICU admission and 17% in-hospital deaths.
Conclusions:
- Prevalence of rickettsioses in India is likely underestimated, necessitating increased awareness and improved diagnostics.
- Serological tests remain the primary diagnostic method for rickettsioses globally.
- This study provides crucial data on Rickettsia in north India, aiding future epidemiological studies and outbreak investigations.
