Association of Scrub Typhus in Children with Acute Encephalitis Syndrome and Meningoencephalitis, Southern India

Scrub typhus is an established cause of acute encepha-litis syndrome (AES) in northern states of India. We sys-tematically investigated 376 children with AES in south-ern India, using a stepwise diagnostic strategy for the causative agent of scrub typhus, Orientia tsutsugamushi, including IgM and PCR testing of blood and cerebrospi-nal fluid (CSF) to grade its association with AES. We diagnosed scrub typhus in 87 (23%) children; of those, association with AES was confirmed in 16 (18%) cases, probable in 55 (63%), and possible in 16 (18%). IgM de-tection in CSF had a sensitivity of 93% and specificity of 82% compared with PCR. Our findings suggest scrub typhus as an emerging common treatable cause of AES in children in southern India and highlight the importance of routine testing for scrub typhus in diagnostic algo-rithms. Our results also suggest the potential promise of IgM screening of CSF for diagnosis of AES resulting from scrub typhus.

Automated summary

We systematically investigated 376 children with acute encephalitis syndrome (AES) in southern India and found that scrub typhus is an emerging common treatable cause of AES in this region. Diagnosing scrub typhus using IgM and PCR testing of blood and cerebrospinal fluid (CSF) showed that 16 cases were confirmed to be associated with AES, 55 cases were probable, and 16 cases were possible. Testing for IgM in CSF had a high sensitivity (93%) and specificity (82%) compared to PCR. These findings highlight the importance of routine testing for scrub typhus in diagnostic algorithms and suggest the potential promise of IgM screening of CSF for diagnosing AES caused by scrub typhus.