Scrub Typhus Pediatric Immunology Study

This is an observational study of the natural immune response to scrub typhus in patients recruited from Chiangrai Prachanukroh Hospital, N-Thailand. Febrile patients with a positive IgM rapid diagnostic test will be asked if they wish to take part in a study to improve the understanding of how the body responds to scrub typhus. Blood samples will be collected from each participant (\"STP\", n=60) at baseline (the day of presentation to hospital), 2 weeks later in hospital, 12 weeks after baseline at the clinic visit and 1 year later. Data on clinical presentation and relapses will be recorded. Control subjects are scrub typhus exposed patients from a rural village in the caption area of Prachanukroh Hospital (\"STE\", n=80; approx. 40 children and 40 adults), and healthy adults blood donors from Bangkok (\"STH\" n=30) - these subjects will be enrolled for one single blood sample. The study team will also collect eschar swab specimens from STP group and a non-invasive specimen of the dark crust on the day of enrollment. Funder: Li Ka Shing Foundation \[Grant C13004\]