Chikungunya Introduction

Chikungunya virus is a member of the genus Alphavirus and the family Togaviridae. 

Chikungunya is an arboviral disease carried by Aedes mosquitoes.

The virus was first isolated in 1953 in Tanzania. Chikungunya virus has been identified in over 60 countries across the world.

Known human infections in Africa have been at relatively low levels for many years, except for one short period. From 1999 through 2000 there was a large virus outbreak in the Democratic Republic of the Congo. Since then, there have been outbreaks with abnormal time breaks in-between them.

While most people associate mosquito bite-related diseases with African countries, the chikungunya virus has touched base in many countries globally.

Since 2005, India, Indonesia, Maldives, Myanmar and Thailand have reported over 1.9 million cases. In 2007 there was the transmission of the virus was reported for the first time in Europe, in a localized outbreak in north-eastern Italy.

Recently, cases have linked chikungunya to the Americas. An episode in 2015 showed infections capable of spreading in North and South America.

There have been documented surges of the disease worldwide with irregular intervals between the outbreaks.

The word “Chikungunya” is said to have come from the Makonde language where it means “that which bends up.”That may seem like a different way to describe a virus, but the name comes from a symptom. When infected with chikungunya, the illness can cause severe joint pain. That pain can cause a more stooped posture from the arthritic symptoms of the disease.

The disease generally consists of an acute illness characterised by fever, rash, and incapacitating arthralgia. The word chikungunya, used for both the virus and the disease, means “to walk bent over” in some east African languages, and refers to the effect of the joint pains that characterise this dengue-like infection. Chikungunya is a specifically equatorial disease, but it is geographically fixed and outbreaks are relatively extraordinary. It is only occasionally detected in travellers and military personnel. in which Aedes albopictus is the presumed vector. In the ongoing Indian outbreak, in which Aedes aegypti is the presumed vector, 1 400 000 cases of chikungunya were reported in 2006. The reasons for the re-emergence of chikungunya on the Indian subcontinent, and its remarkable incidence rate in the Indian Ocean region, are unclear. Reasonable explanations include increased tourism, chikungunya virus curtain-raiser into a natural population, and viral transformation.

Chikungunya outbreaks have been reported in India from the period 1963–to 1973 and from 2005–to 2019. The first CHIKF outbreak in India was noted in Kolkata (Calcutta), West Bengal, in 1963. However,retrospective serological studies have shown that chikungunya existed in India before 1963. In 1964, Chennai, Pondicherry, and Vellore reported outbreaks of chikungunya . In 1965, chikungunya outbreaks were reported from Visakhapatnam, Kakinada, Rajahmundry and Nagpur, in 1973 in Barsi in Maharashtra  and some authors have opined that lack of surveillance between 1973 and 2005 might have been the reason for lack of CHIKV reports .However, the re-emergence of the virus could be due to several other reasons . CHIKV is known to have three genotypes, namely, West African (WA), Asian and East Central South Africa (ECSA) genotypes and the circulating virus in India until the 1970s have been reported to be of the Asian genotype