Scrub Typhus Seropositivity, Clinical Manifestations, and Outcomes in Jodhpur: A Hospital-based Study.

Background: Scrub typhus is an acute febrile illness caused by the Gram-negative cocco-bacillus Orientia tsutsugamushi, accidentally transmitted to humans by the bite of mite chiggers. Its epidemiology in India remains obscure due to under-reporting of cases.

Objectives: This single-hospital study prospectively determined the seropositivity, clinical features and treatment response of scrub typhus over 5 years in the city of Jodhpur, Western Rajasthan, from where no formal seropositivity data were previously available.

Methods: All patients with acute febrile illness of more than 5 days were screened according to the Department of Health Research-Indian Council of Medical Research (DHR-ICMR) 2015 guidelines and enrolled after their signed informed consent. Serological test Orientia tsutsugamushi immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) was performed. All positives were reported to Integrated Diseases Surveillance Programme.

Results: Over the 5-year study (2019-2023), a total of 1497 patients met the DHR-ICMR criteria, and 83 (5.5%) tested Orientia tsutsugamushi IgM ELISA positive. The classical clinical features such as eschar, rash, and lymphadenopathy were less common; and others such as myalgia, headache, malaise, altered sensorium, LFT derangement, thrombocytopenia, and leukocytosis were more commonly reported. More cases occurred during winter and responded well to doxycycline or azithromycin clinically. Three died before initiation of therapy.

Discussion: This is the first study from Jodhpur to describe the occurrence of scrub typhus, by the DHR-ICMR guidelines. Despite being a reportable disease under the Integrated Disease Surveillance programme, the epidemiology of scrub typhus remains obscure in India due to low clinical suspicion, poor availability of diagnostic services and under-reporting of clinical cases.