Epidemiological Investigation of a Chikungunya Fever Outbreak in a Tribal Population of Dakshin Dinajpur, West Bengal, India

Abstract

Introduction

Chikungunya is a re-emerging viral fever transmitted by the bite of infected Aedes mosquitoes. We

investigated the outbreak with the objective of finding out the cause of fever with joint pain and

recommended preventive measures.

Methods

This outbreak investigation was done at the village of Gangarampur block of Dakshin Dinajpur

district, West Bengal, India. House-to-house search for active cases was conducted at the village

during October - November 2024. The outbreak was described by time, place, and person

distribution. Epidemic curve, spot maps, and analytical tables were constructed to determine the

relation of the outbreak. Blood samples were tested for dengue, chikungunya, malaria, and scrub

typhus. Entomological surveys were also done to measure larval index.

Result

A total of 35 cases were identified, with an overall attack rate of 2.97%. Majority of the cases were

female (57.2%) and age group of 31 - 50 years (48.8%). In almost all cases, patients developed fever

with joint pain. The epidemic curve showed maximum cases in the month of November 2024.

Chikungunya, dengue & scrub typhus positivity was 51.7% (15/29), 3.4% (1/29) & 6.9% (2/29)

respectively. No such significant entomological findings were observed.

Discussion

We initiated the investigation on the presumption of a dengue outbreak, but after blood samples

reporting, it was revealed that cases were predominantly (51.7%) Chikungunya, 6.9% were Scrub

Typhus and mixed infections of Scrub Typhus with Chikungunya and 3.4% were Dengue. Without

any complications, almost all cases were managed at home. Extensive awareness generation

programmes were conducted for the prevention and transmission of fever.