Table 1.

Description of the three cohorts

Patient group	Time frame	Number of samples tested	Test/tests used	Basic demographic data
Cohort 1	October 2007 to December 2008	141	Scrub typhus IgM and IgG ELISA	Age 20.7 ± 19.6 years
				49% Female
				51% Male
Cohort 2	January 2009 to December 2009	262	Scrub typhus IgM and IgG ELISA and Spotted fever IgM and IgG ELISA	Age 20.5 ± 19.9 years
				49% Female
				51% Male
Cohort 3	January 2010 to February 2011	212	IFA--screening for group specific antibodies (Scrub typhus, Spotted fever and Typhus group)--IgM and IgG*	Age 15.1 ± 19.6
				51% Female
				49% Male

*Titre determination carried out for species shown below on screen positive samples

Scrub typhus--O.tsutsugamushi Gilliam, Karp and Kato strains

Spotted fever--R. honei, R. conorii, R.australis, R.siberica, R.rickettsii and R.akari

Typhus group--R.prowazekii and R.typhi