Consonantal correspondence

Hepatitis A virus (HAV) is a common cause of acute hepatitis and, more rarely, fulminant and potentially fatal liver disease (Martin and Lemon, 2006). A small, nonenveloped RNA virus in the family Picornaviridae, it infects millions of people each year and remains a global public health problem despite the availability of an effective vaccine (Van Damme et al., 2003). Improve-ments in sanitation that accompany economic development have dramatically changed the epi-demiology of HAV in some regions of the world where the virus remains endemic and vaccine uti-lization is low. Under these circumstances, the mean age of HAV infection can shift from the first to the second and third decades of life. Be-cause the severity of liver disease increases with age, the disease burden caused by HAV in these societies has increased (Jacobsen and Wiersma, 2010). The age-related shift in HAV epidemiol-ogy and disease severity has highlighted a gap in our understanding of how immune responses contribute to hepatocellular injury and resolution of acute infection. Although HAV does not es-tablish a persistent infection like HCV, disease can relapse in up to 20 % of patients after normal-ization of liver transaminases and control of virus replication (Glikson et al., 1992). Mechanisms of immunity that protect against relapse, and why they occasionally fail, are also unknown