Shingles is caused by the Varicella-zoster virus, the same virus that causes chickenpox. Anyone who's had chickenpox has the potential of developing shingles. People with weakened immune systems from HIV/AIDS, those who are receiving medical treatments, such as steroids, radiation and chemotherapy, or those who have a history of bone or lymphatic cancer are more likely to develop shingles. A person with shingles can pass the Varicella-zoster virus to anyone who hasn't had chickenpox before through direct contact with the open sores of the shingles rash.