Which of the following is an oncogenic RNA virus
Ref Robbins 8/e p315,9/e p328 Hepatitis C virus is only oncogenic RNA virus in the options.otherd mentioned are oncogenic DNA viruses Hepatitis C Virus Epidemiology and Transmission. HCV also is a major cause of liver disease. The worldwide carrier rate is esti- mated at 175 million persons (a 3% prevalence rate, ranging widely from 0.1% to 12%, depending on the country). Per- sistent chronic infection exists in 3 to 4 million persons in the United States, where the number of newly acquired HCV infections per year dropped from 180,000 in the mid- 1980s to about 19,000 in 2006. This welcome change resulted from the marked reduction in transfusion-associated hepa- titis C (as a result of screening procedures) and a decline of infections in intravenous drug abusers (related to prac- tices motivated by fear of human immunodeficiency virus infection). However, the death rate from HCV will con- tinue to climb for 20 to 25 years, because of the decades- long lag time between acute infection and liver failure. The major route of transmission is through blood inoculation, with intravenous drug use accounting for at least 60% of cases in the United States. Transmission by blood products is now for- tunately rare, accounting for only 4% of all acute HCV infections. Occupational exposure among health care workers accounts for another 4% of cases. The rates of sexual transmission and veical transmission are low. Infections of unknown origin account for 9% to 27% of cases. HCV infection has a much higher rate than HBV of pro- gression to chronic disease and eventual cirrhosis (Fig. 15-13). In fact, hepatitis C is the condition that most frequently necessitates liver transplantation in the United States. Viral Structure and Genome. HCV is a positive-sense single-stranded RNA virus belonging to the family Flavi- viridae. It contains highly conserved 5'- and 3'-terminal regions that flank a single open reading frame of nearly 9500 nucleotides that encode structural and nonstructural proteins. HCV is subclassified into six genotypes, based on the genetic sequence. Moreover, because of the poor fidel- ity of RNA replication, an infected person may carry many HCV variants, called quasispecies. The relationships between quasispecies and disease progression are being investi- gated, but it seems that high multiplicity of quasispecies is associated with worse prognosis. In addition, this variabil- ity seriously hampers effos to develop an HCV vaccine.
Hepatitis B virus
Human papilloma viruses
Epstein Barr virus
Hepatitis C virus
General anatomy