Both Hepatitis A and Hepatitis B are viral infections that affect the liver. They can be an acute infection that causes symptoms to develop shortly after exposure to the virus, but can also become a chronic disease in an affected person. Once infected, the virus can spread even when the infected person does not experience symptoms associated with the disease.
Both viruses are endemic in much of the developing world. Many popular travel destinations such as the Caribbean are considered risk areas for unprotected travellers.