Thursday, October 26, 2006

Hepatitis C virus -- the new time bomb


By Syed Akbar
Published in The Asian Age/Deccan Chronicle on October 26, 2006
Hyderabad, Oct 25: As scientists and health experts rededicated themselves on World Hepatitis Day on October 1 fighting the disease, latest health data reveals that a highly asymptomatic liver disease caused by the Hepatitis C virus (HCV) is fast spreading in India.
A World Health Organisation report says that HCV, often described as a "viral time bomb", has recouped vigorously to strike at rates up to two times more than that of the human immuno-deficiency virus or HIV.
WHO lists India along with Egypt, Italy and Japan where HCV is rampant. The number of HCV patients in India equals if not exceeds the total number of HCV patients in Europe and the USA.
WHO reports that as against 5.1 million Indians suffering from HIV/AIDS, around 12 million carry HCV. About 30 per cent of HIV patients simultaneously suffer from HCV.
The Indian Journal of Gastroenterology reports that about three per cent of people in Andhra Pradesh carry the HCV. The number could be higher as the data was collected based on medical screening at laboratories.
The undetected HCV population might be large because the virus does not show symptoms straightaway.
There is no vaccine to prevent HCV unlike the other Hepatitis varieties; vaccination for other types of Hepatitis may slow or prevent HCV infection. The best way to avoid HCV infection is to follow prevention and precaution steps.
"Did you receive a blood transfusion, haemodialysis, angiogram, tatooing, prolong injections or syringes? If yes, get tested for HCV. The cure rate is high if it is detected early," says senior gastroenterologist Dr Dharmesh Kapoor.
The HCV does not spread by air. Transmission is through skin or mucous membrane and one has to be careful while sharing tooth brushes, nail cutters, razors, syringes and tattoo needles.
Those who have multiple sex partners are at high risk of contacting the disease.
The efficacy of latex condoms in preventing infection with HCV is unknown. Doctors feel that proper use of condoms may reduce the transmission risk, though it will not totally eliminate it.
According to Dr Dinesh Kini, consultant gastroenterologist of Manipal Hospital, Bangalore, "HCV has a tendency to develop into long term liver disease and can cause liver cirrhosis and even cancer of the liver. The infection has an initial phase which is often asymptomatic and lasts up to six months".
Like HIV, the HCV virus remains in the infected patients for years together. Unlike HIV, it does not invade the immune system but replicates using the liver's resource cells.
The patient does not know that he is carrying the virus; he experiences fatigue and discomfort in the upper abdominal area. HCV can remain undetected for as long as 10 years.
In up to 85 per cent cases, the virus fights the body immune system. Patients develop long term or chronic infection and transmit the disease.
About half the HCV cases do not show symptoms even though the virus is fairly active.
While 20 per cent of patients recover fully the remaining develop some form of chronicity.
Five per cent of chronic patients develop liver cell cancer and an equal number suffer from decompensated cirrhosis.
"If untreated the liver will be damaged. The only treatment then remains is to replace the damaged liver by a new one. Early detection and prompt treatment can save lives," observes Dr Samir R Shah, specialist in hepatobiliary diseases, Jaslok Hospital and Research Centre and Breach Candy Hospital, Mumbai.
"PEGylated interferon can effect a cure in a good number of patients," says gastroenterologist Dr Kapoor. PEGylation is the coupling a polyethylene glycol structure to a larger molecule, for example, a therapeutic protein. Interferons are a class of natural proteins produced by the cells of the immune systems in response to challenges by viruses, bacteria, parasites and tumour cells.
The PEGylation of the interferon slows down the body's ability to break down the interferon molecule.
The interferon gets absorbed more slowly and constant amounts of interferon are present in the body which constantly attacks the virus.
Pegylated interferon alfa-2a (40KD) suppresses the virus in more than 50 per cent of patients. Ribavirin is also found effective against this disease.
Eleven Hepatitis C virus genotypes with several distinct subtypes have been identified throughout the world.
The WHO report notes that "Although different strains have not been shown to differ dramatically in their virulence or pathogenicity, different genotypes vary in their responsiveness to interferon/ribavirin combination therapy."
"Such heterogeneity hinders the development of vaccines, since vaccine antigens from multiple serotypes will probably be necessary for global protection," the report states.

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