“…In many developing regions of the world where hygienic standards (i.e., clean water, sewage systems, and proper hygiene practices) may be below acceptable standards, HAV infection is endemic, with the majority of people being infected in early childhood and virtually all adults appearing to be immune; in these areas, HAV transmission occurs primarily from person to person, and outbreaks are not that common as most infections occur among children, who generally remain asymptomatic (Koopmans and Duizer, 2004;Mattison et al, 2009). In contrast, in the developed countries, where HAV endemicity is low, the majority of adults are susceptible to HAV infection, and HAV constitutes a serious and increasing public health concern (Koopmans and Duizer, 2004;Mattison et al, 2009). Viral hepatitis, which is generally an acute infection but its resolution provides life-long immune protection against future infections, is characterized by fever, jaundice, light-colored stools, darkcolored urine, abdominal pain, and occasional diarrhea (Mattison et al, 2009).…”