Clinical Profile, Laboratory Abnormalities, and Systemic Involvement in Children with Rickettsial Infections: A Comparative Study of Scrub Typhus and Indian Tick Typhus

Alasani Manasa Reddy, N. Shivaramakrishna Babji, Vattikunta Sharath Chowdary, Mudigonda Amrusha
Author(s)
1Postgraduate, Department of Paediatrics, Kamineni Institute of Medical Sciences, Narketpally, Telangana, India
2Professor and Head, Department of Paediatrics, Kamineni Institute of Medical Sciences, Narketpally, Telangana, India
3Senior resident, Department of Paediatrics, Kamineni Institute of Medical Sciences, Narketpally, Telangana, India

Abstract

Background: Rickettsial diseases, including scrub typhus and Indian tick typhus, are significant causes of paediatric acute febrile illness. This study evaluates and compares their clinical and laboratory profiles and introduces a novel Multi-Organ Involvement Score (MOIS) to quantify systemic disease burden. Material and Methods: A hospital-based retrospective cross-sectional study evaluated 50 children (aged ≤12 years) diagnosed with ST (n=36) and ITT (n=14). Clinical manifestations and laboratory parameters were compared. Systemic involvement was quantified using the MOIS (ranging from 0–5), which assigns points for hepatomegaly, splenomegaly, breathlessness, altered sensorium, and abnormal chest radiography. Results: Rash (92%) and organomegaly were highly prevalent in both groups, but altered sensorium was observed exclusively in the Indian tick typhus cohort. Laboratory analysis revealed that children with Indian tick typhus had significantly lower platelet counts (1.09 ± 0.44 vs 1.69 ± 0.53 lakh/mm³, p=0.0003), greater C-reactive protein positivity (85.7% vs 69.4%, p<0.001), and more frequent hypoalbuminemia (50.0% vs 27.8%, p<0.001) than those with scrub typhus. Furthermore, the burden of systemic disease was significantly heavier in Indian tick typhus, reflected by a higher mean MOIS (2.86 ± 1.23) compared to scrub typhus (1.97 ± 0.88) (p=0.0158). Conclusion: While scrub typhus and Indian tick typhus share overlapping clinical presentations, paediatric Indian tick typhus exhibits a more aggressive biochemical profile and significantly higher multi-organ involvement. Implementing the MOIS aids in quantifying systemic spread, highlighting the critical need for vigilant monitoring and early targeted therapies in tick-borne rickettsiosis.

Keywords: Rickettsial infections; Scrub typhus; Indian tick typhus; Multi-Organ Involvement Score (MOIS); Acute febrile illness; Thrombocytopenia.

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