In a study published online this week in the Proceedings of the National Academy of Sciences, researchers report the use of high-throughput sequencing technology to identify a novel hepatitis C virus in domestic dogs. The new virus, named canine hepacivirus (CHV), is the first known instance of hepatitis-like infection in animals outside of humans and non-human primates. The identification and characterization of this virus gives scientists new insights into how hepatitis C in humans may have evolved and provides scientists renewed hope to develop a model system to study the disease.

Human hepatitis C virus (HCV) affects approximately 200 million people worldwide. According to the Centers for Disease Control and Prevention (CDC), 3.2 million people in the United States are chronically infected. Until recently, studies into the origin of hepatitis C and how it causes disease in humans have been limited by the absence of closely related viruses and lack of animal and cell culture models.

The study, led by researchers from the Center for Infection and Immunity at Columbia University and the University of Edinburg, began as an investigation to characterize respiratory viruses infecting domestic dogs. Using high-throughput sequencing with the GS FLX System, from 454 Life Sciences, a Roche Company, the researchers discovered an unknown hepacivirus that was more similar to HCV than any discovered to date. Further analysis determined that like HCV, CHV's genome contained Genome Scale Ordered RNA structures (GORS), secondary structures that allow viruses to chronically infect their natural hosts. Moreover, the sequence of genes that encode proteins involved in virus infection and replication were very similar between HCV and CHV.

The study findings suggest that the HCV virus may have been introduced into human populations through contact with dogs, and that it may be more widely distributed among mammalian species than previously thought.

"The identification and characterization of CHV signals the advent of a new, tractable animal model for hepatitis C," said Dr. Ian Lipkin, Director of the Center for Infection and Immunity at Columbia University. "This discovery provides new tools for understanding how this virus causes disease, and will facilitate drug and vaccine research and development.

"Using powerful genomic technologies, researchers are beginning to understand the diverse ecosystem of bacteria and viruses that live around us, on us, within us and even within our pets," explained Christopher McLeod, President and CEO of 454 Life Sciences. "This surprise finding is yet another example of how 454 Sequencing Systems offer researchers a powerful tool to detect novel viruses and pathogens in a wide range of hosts."

(1) Kapoor et al. Characterization of a canine homolog of hepatitis C virus. (2011) PNAS ePub.

Source:
Roche