Risk Factors Associated with Adult Scrub Typhus Cases in a Tertiary Care Hospital - A Case Control Study

Scrub typhus is an endemic disease in some geographical regions of South and East Asia and now a re-emerging infection in India. The illness varies from being mild and self-limiting to being fatal. So, there is a need to study socioenvironmental factors associated with the disease in order to develop strategies in preventing the disease. So, this study aims to determine the environmental factors and human behaviors associated with the risk of acquiring scrub typhus among adults.

This is a hospital-based case control study, where all admitted adult scrub typhus patients who had appropriate controls were taken as cases. For each case, one geographical control and one clinical control were taken. Clinical controls include those febrile patients who were admitted to hospital and not suffering from scrub typhus, whereas geographical controls were the individuals accompanying the patients.

A total of 336 participants were studied, which included 112 cases, 112 clinical controls, and 112 geographical controls. The most common clinical sign observed was Eschar (55·4%), followed by pallor (33·9%) and hepatomegaly (24·1%). Those living near swampy areas had four times and those residing near the firewood piles had two times higher risk of developing scrub typhus. Those individuals wearing full top clothing (aOR = 0·65, CI 0·003-0·079) and fully covered bottom clothing (aOR = 0·17, CI 0·12-0·62) were found to be protective.

Environmental factors and human habits have a significant role in increasing the risk of disease.