Wednesday, 5 July 2006
Chikungunya: Virus takes a rebirth after 40 years
July 5, 2006
By Syed Akbar
Hyderabad: As Chikungunya turns active in the country after a gap of four decades, health experts warn of severe complications if patients go in for overdose of anti-biotics and other medicines.
They advise patients to take just paracetamol and bed rest for a week. Chikungunya is self limiting febrile viral disease with no medical treatment. The disease simply gets cured on its own after a certain period. Treatment for chikungunya is symptoms-based and this often leads to overdose of anti-biotics and pain-killers. Though chikungunya as such does not cause death on its own, doctors warn of damage to
intestinal and stomach lining because of overdose of medicines. This may cause
bleeding in the digestive system often leading to death.
"What the patient needs is treatment for symptoms, paracetamol at the best, and bed
rest for a week. Overdose of anti-biotics and other medicines will complicate the matters and may lead to death, though chikungunya as such does not cause mortality. Symptomatic treatment is recommended for chikungunya after excluding other more
dangerous diseases like JE and dengue, which incidentally have similar symptoms" Sir
Ronald Ross Institute of Tropical Diseases superintendent Dr PP Prasad points out.
According to Dr Prasad, not all cases of viral fevers are chikungunya cases. People
need not worry if they get viral fevers. They should follow their doctor's advice and take rest.
That not all cases of viral fevers are of chikungunya is evident from the fact that
of the 1000 samples collected from the State by the National Institute of Virology, Pune, only 30 were declared as positive cases. Since there was no antigen in the country, the NIV has to develop it to conduct the tests.
Health experts in Andhra Pradesh are perplexed over the sudden emergence of
chikungunya in the country after a gap of nearly four decades. The chikungunya virus, that has been lying dormant in these parts since 1971, has now raised its ugly head literally sending shivers down the spine of thousands of patients.
The question now racking the brains of health experts and medical teams is, "what
has triggered the dormant chikungunya virus to become active once again"? Experts have divergent views on its spread in India and Andhra Pradesh in particular. While virologists feel that the virus might have undergone mutation after being docile to
become more powerful or Indian might have lost "herd immunity", medical doctors are
of the view that the virus might have been transmitted to local populace by a foreign tourist. Still others feel that so far we have been mistaking chikungunya for dengue as both have similar symptoms.
Going by epidemiological evidence, medical experts feel that the virus must have
passed into Andhra Pradesh through an infected tourist. Since several international conferences are held in Hyderabad, a local tiger mosquito must have transmitted the disease to healthy local persons from infected foreign tourist. There is also the possibility of the virus being transmitted by infected persons from other States visiting Hyderabad.
Says Dr S Satyavathi, Hyderabad district medical and health officer, "taking the
epidemiology into view we are now concentrating our attention on places where national expositions and international conferences are held. We are sending our teams to these places as a precautionary measure".
Togaviridae, the virus that causes chikungunya, was last noticed in Kolkata in 1971
and in Chennai in 1965.
Andhra Pradesh reported the first case of chikungunya around 1959. But since 1971
there have been no known cases of chikungunya in any part of the country including Tamil Nadu, West Bengal and Andhra Pradesh though these States have high density of the vector population - mosquito Aedes Aegyptis - for hundreds of years.
Consultant microbiologists at Apollo Hospitals Dr M Ratna Rao opines that the virus
which has been docile all these years might have become active because the "herd immunity" might have been lost. When a disease frequently occurs people develop antibodies but since there has been no known cases of chikungunya for the past
four decades this herd immunity might have been lost forcing the virus to hit back.
There is no national surveillance on viral diseases in the country and because of
this the Central or the State governments do not know what types of viral diseases or viruses are prevailing in the country or whether the known viruses have undergone mutation or turned hyperactive.
The first ever recorded case of chikungunya in human beings was in 1952 in Tanzania.
In fact, the term "chikungunya" is derived from Makonde language "Kungunyala" meaning "that which bends up", as the patient folds himself/herself up because of severe pains in joints.
Senior physician Dr Aftab Ahmed believes that chikungunya might have been prevalent
in the country all through these years but since the symptoms of chikungunya and dengue are the same, doctors might have taken it as dengue in the absence of virological tests.
"The vector (mosquito) for dengue and chikungunya is the same Aedes species. The
mosquito might have picked up the dormant virus from somewhere and spread the disease. This possibility also we cannot rule out," he points out.
Prasad says, "virus can remain dormant for several years which means an animal
(Aedes species or tiger mosquito in this case) can be carrying them for a long time without transmitting the causative agent to human beings". Tiger mosquitoes have been found in these parts for ages so the vector is not new. Only the virus which has been lying low has turned active spreading the disease after nearly four decades.
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