Molecular and Virological Investigation of a Focal Chikungunya Outbreak in Northern India

Manisha Soni,Natarajan Gopalan,Ankita Agarwal,Anil Kumar Singh,P V Lakshmana Rao,Shashi Sharma,Manmohan Parida,Paban Kumar Dash

doi:10.1155/2013/367382

Manisha Soni, Natarajan Gopalan + Show 6 more

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https://doi.org/10.1155/2013/367382

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Abstract

Chikungunya (CHIK) fever is one of the most important arboviral infections of medical significance. The objective of the present study is to identify and characterize the etiology of a focal febrile arthritis outbreak from Gwalior, northern India, during October-November 2010. A detailed virological (isolation) and molecular (end-point RT-PCR, quantitative RT-PCR, and nucleotide sequencing) investigation of this outbreak was carried out by collecting and studying 52 clinical samples and 15 mosquito pools from the affected region. The investigation revealed the presence of CHIK viral RNA in 29% of clinical samples and 13% mosquito pool by RT-PCR. The quantification of CHIK viral RNA in samples varied from 102.50 to 106.67 copies/mL, as demonstrated through quantitative RT-PCR. In addition, six CHIK viruses were isolated from RT-PCR positive samples. The nucleotide sequences of partial E1 gene of five representative CHIK viruses were deciphered, which revealed that all the viral strains from this outbreak belong to the recently emerging ECS African genotype. Identification of Chikungunya virus ECSA African genotype as the etiology of the present outbreak confirms the continued circulation of the novel genotype, since 2006, in India. The identification of CHIK virus in Aedes aegypti also confirmed it as the major vector in northern India.

Highlights

Chikungunya fever has emerged as one of the most important arboviral infection of public health significance
Chikungunya virus (CHIKV) is primarily transmitted by Aedes aegypti and Aedes albopictus mosquitoes and is maintained through a man-mosquito-man cycle in nature [3]
A total of 15 (29%) clinical samples were found to be positive for the presence of CHIKV specific ribonucleic acid (RNA), through demonstration of CHIKV specific 500 bp amplicons on agarose gel

Summary

Introduction

Chikungunya fever has emerged as one of the most important arboviral infection of public health significance. It is endemic in many parts of Africa and Asia. Chikungunya virus (CHIKV), the etiological agent, belongs to the family Togaviridae and the genus Alphavirus. Chikungunya infection in human is characterized by abrupt clinical onset, involving fever, headache, fatigue, nausea, myalgia, and severe arthralgia. This is followed by constitutional symptoms that include maculopapular rash on the trunk and limbs. During recent outbreaks, cases involving unusual manifestations and severities, including neurological complications and mortality, have been widely reported [1, 6]

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