In a research study that would boost efforts to develop a vaccine for chikungunya, a group of city scientists has found that the chikungunya virus, responsible for recurring outbreaks in South India except Kerala and coastal Karnataka since the 2006 epidemic, has undergone mutation

Syed Akbar
Hyderabad: In a research study that would boost efforts to
develop a vaccine for chikungunya, a group of city scientists has
found that the chikungunya virus, responsible for recurring outbreaks
in South India except Kerala and coastal Karnataka since the 2006
epidemic, has undergone mutation. It appears to have adapted to the
local vector (mosquito) diversity for wider spread.

Though there is no evidence to suggest that the virus has become more
virulent because it has acquired a change, the mutation in the gene
(E1-K211E) appears to be an “adaptive mutation” of the virus to better
suit to the local mosquito, Aedes aegypti.

Dr K Sumathy and Dr Krishna M Ella of Bharat Biotech International
Ltd, Hyderabad, studied the genetic make-up of Chikungunya virus to
find out if it had changed in this part of the world. “Our interest in
understanding the molecular epidemiology of the virus in the country
and indeed globally, is because of our ongoing efforts on development
of a novel vaccine for prophylaxis of chikungunya virus infection,” Dr
Sumathy said.

The chikungunya virus now circulating in Andhra Pradesh and other
neighbouring States is a variant. “There appears to be no distinct
serotypes of the virus that have evolved over the past few decades.
There are variants, but no distinct serotypes.” She added.

The virus strain that caused the massive 2006 epidemic in India is the
one that appears to cause recurring outbreaks in Tamil Nadu, Andhra
Pradesh and Karnataka except its coastal parts. The epidemic strain of
the virus appears to have adapted to the vector diversity in the
country for its wider dissemination. However, as of now there are no
medical implications, because the genetic diversity of the virus has
not resulted in distinct antigenic diversity or serotypes.

“Understanding the genetic diversity of the virus is important for
effective public health measures, such as control of vector population
and for developing effective medical intervention such as vaccines,
diagnostics and therapeutics that are effective against the local
strains. The genetic footprint of CHIKV and indeed any virus for that
matter provides an understanding of the local evolutionary and
transmission dynamics in the context of global epidemiological pattern
of the virus,” Dr Sumathy explained.

Chikungunya virus has two hosts, an invertebrate host (mosquito) and
the vertebrate host (human). The adaptive mutation appears to aid
adaptation of the virus to the mosquito for its propagation and wider
dissemination. However, this does not imply that the infectivity is
higher in the human population.