HAV is spread primarily by unsanitary food and water. HBV is transmitted in bodily fluids and can cause chronic liver disease. HCV is perhaps the most dangerous: no vaccine is available. HDV occurs only in the presence of HBV. HEV is relatively mild and non-chronic. HFV and HGV are newly identified, their connection with liver disease is debated. Perfect teaching tool for parents, educators, health, medical and science professionals! Great gift for teachers, doctors, collectors, kids of all ages, and anyone with a healthy sense of humor!.