A study on detection of dengue-chikungunya co-infection in and around

Introduction

Cases of simultaneous infections involving different arboviruses are becoming common in areas where they circulate concomitantly. Vector density and environmental changes, along with migration and immigration contribute to the spread of these viruses. They are endemic in the tropical and subtropical regions of the world and are the main causative agents of infectious diseases of importance in public health (S. Marinho et al., 2020).

Dengue and chikungunya are important mosquito-borne viral disease of humans. There have been a recurrent phenomenon throughout the tropics in the past decade (KP. Modi et al., 2017).

Dengue fever (DF) is a viral illness caused by a flavivirus and spreads by bite of highly anthropophilic A. aegypti mosquito (Luis FuruyaKanamori et al., 2016; Dayaraj Cecilia et al., 2014). The name dengue originated from the Swahili word for "bone-breaking fever" or the word for "the walk of a dandie" in Spanish. The spectrum of disease ranges from self-limited DF to more severe forms (Dayaraj Cecilia et al., 2014). 

CHIK fever is a viral disease caused by an alpha virus that is also spread by bite of A. aegypti mosquito (Dr. Narayan Shrihari et al., 2012). The name is derived from the Makonde word meaning that which bends up in reference to the stooped posture developed as a result of the arthritic symptoms of the disease. CHIK first established its presence during a 1952–1953 epidemic outbreak in Tanzania (Shashi sharma sudhan et al., 2017; Ms. Akanksha Tomar et al., 2017; Braira Wahida et al., 2017). In India, CHIKV was first isolated in Calcutta in 1963 (Shashi sharma sudhan et al., 2017). The virus disappeared from our country after last reports from Maharashtra in 1973. It then reemerged in 2006 after a gap of 32 years and caused an explosive outbreak affecting 13 states (Maninder Kaur et al., 2018; Isabel RodríguezBarraquer et al., 2015).

Also according to a recent investigation, patients having co-infection with the Dengue and Chikungunya viruses present a clinically severe disease with a high death rate when compared to monoinfection with these viruses. Hence, the timely diagnosis of the dual infections is essential for better patient management (Dr. Banwari Lal et al., 2020).

In India, concurrent isolation of CHIKV and DENV had been reported since 1964 from different States. In 1967, co-infections with dengue and CHIK viruses were reported from Kolkata. Subsequent serological investigations in Southern India indicated that the two viruses can co-exist in the same host. The first case report of CHIK and dengue co-infection confirmed by molecular assays was from Sri Lanka In 2010, a hospitalbased study revealed co-circulation of CHIKV and DENV in some areas of West Bengal, India with high morbidity (Dr. Karthik, R et al., 2014). The present study was planned to observe the prevalence of Dengue-Chikungunya co-infection in this region in the calendar year 2017-2018.