| Hepatitis
C - Treatment Principles - Blood Tests - Signs & Symptoms - Case Studies |
Hepatitis C
Hepatitis C is caused by a single-stranded RNA virus
from the Flaviviridae family. It was discovered in 1989 by a team of
researchers from Chiron Corporation headed by Daniel Bradley and Michael
Houghton. The nature of the virus is best characterized by a comment
Michael Houghton made in response to a question about the slow pace
of drug research to combat HCV.
He replied, "It's because it is a small, moving target". HCV is a very small virus that has no mechanism to contain mutations. Consequently worldwide there are many different strains or genotypes that vary genetically from each other, some more virulent. Scientists have also been unable to propagate cell cultures or develop a non-primate animal model, which has also slowed down effective drug development. Worldwide it has been estimated that there are 170 million people chronically infected with HCV, as well as 4-5 million in the United States.
Transmission today is primarily through needle sharing. Prior to effective screening was implemented in 1990-92 blood transfusion was a major source of this infection as was the giving of clotting factors. Currently the risk of HCV infection in receiving a blood transfusion is less than 1 in a million. The use of vaccination guns in the Vietnam era, whereby multiple men were vaccinated from the same instrument was a major source of infection. Sexual transmission is rare and the CDC does not recommend condom use in monogamous couples, when one partner is infected.
Vertical transmission from mother to fetus runs about 5% and is much higher in mothers co-infected with HIV. Breast-feeding does not appear to be a source of infection. Any blood-to-blood contact can be a risk be it tattoos, sharing straws, razors, tooth brushes, finger nail clippers. HCV is not spread through casual contact such as hugging, kissing or sharing food or water.
Currently chronic liver diseases are the 10th most
common cause of death in the USA with viral hepatitis the bulk of that
stat. Disease progression is highly variable with constitution, genotype,
toxic exposure, nutrition, drug and alcohol intake are all important
considerations.