Common Infectious Etiologies of Acute Febrile Illness in a Remote Geographical Location: Could Scrub Typhus be the Most Common Cause?

Background: Disease burden of acute febrile illness due to infectious etiologies is under reported in various parts of India including Sikkim due to lack of laboratory confirmation. Undifferentiated febrile illnesses common in tropical areas of Asia are dengue, chikungunya, malaria, leptospirosis, enteric fever, chikungunya, rickettsia, Japanese encephalitis and scrub typhus.

Aims: This study was conducted to determine various infectious etiologies of acute febrile illness with their clinical presentations, complications and mortality with special emphasis to scrub typhus.

Setting and Design: This was a cross-sectional study and 205 patients including paediatric patients admitted with acute febrile illness were evaluated.

Materials and Methods: A detailed history was taken and complete physical examination was done in all patients. Basic laboratory tests were done in all cases along with confirmatory tests.

Results: In our study the most common cause of acute febrile illness was found to be scrub typhus 74(36.1%) followed by dengue 25(12.2%), malaria10 (4.9%) and enteric fever 10 (4.9%). Sikkim is non endemic state for filariasis and visceral leishmaniasis. Interestingly in our study we found 2 cases (0.97%) of visceral leishmaniasis and 1(0.5%) case of filariasis.

Conclusions: Scrub typhus was observed to be the common cause of acute febrile illness during the study period. Lack of diagnostic facilities makes scrub typhus an under-recognised cause of acute febrile illness in several parts of India even today. Although previously reported as occasional solitary cases from this region, this study witnessed the emergence of dengue as an outbreak in this region. Prompt recognition of acute febrile illness is important for specific treatment and better outcome in patients.