Aetiology of acute febrile illness: a multicentre study from the province of Kerala in southern India.

Acute febrile illness with varied aetiology but similar symptoms is common in tropical countries. This prospective, multicentre study was conducted in selected centres in the province of Kerala in India principally to analyse the aetiology of acute febrile illnesses in adult patients over the course of one year. Overall, 1324 patients were included in the study. The most common cause was dengue in 576 patients (43.5%). In 396 (29.9%), the exact aetiology could not be identified. Other causes, in order, were leptospirosis, enteric fever, malaria, respiratory tract infection, urinary tract infection and typhus. When such a wide variation with a significant number of 'indeterminate' cases exists, especially in such a small area and with limited resources, the onus is on public health authorities to draw up an 'easy-to-use algorithm' to tackle epidemics of febrile illness, particularly in the monsoon season.