A study to assess the disease severity among scrub typhus and leptospirosis patients using clinical, immunological, and molecular tools

Scrub typhus and leptospirosis are zoonotic acute undifferentiated febrile illnesses often associated with similar clinical manifestations and risk factors. Both illnesses can range from self-limiting to severe disease and multi-organ failure. If left untreated, scrub typhus can lead to death in 30-35% of cases, while severe leptospirosis has a case fatality rate ranging from 5-20%. The confirmatory tests for scrub typhus and leptospirosis, which are IFA and MAT, are time-consuming, expensive, require experienced laboratory personnel, and are unsuitable for early detection. Due to the cross-reactivity between these tests, there may be a significant overlap and misclassification in serological tests. The association between the host immune response and disease severity might help to better understand the pathogenesis of these infections. Determining the predictors of disease severity that can be used as a biomarker to distinguish between scrub typhus and leptospirosis might help in choosing empirical antibiotics. However, no studies have explored the cytokine profile in both infections, which could serve as a prognostic marker to improve patient management in severe conditions.

The current study aims to determine the association between disease severity and laboratory, molecular, and immune profiles in scrub typhus and leptospirosis. Additionally, the study determines the novel target gene combinations with optimal sensitivity and specificity for the early diagnosis of scrub typhus disease.