Avian influenza is an infectious viral disease mainly found in birds, but under certain circumstances infections can also occur in humans even though the risk is generally very low.
Syphilis is a sexually transmitted infection caused by the bacterium Treponema pallidum. It may also be transmitted mother-to-child (congenital syphilis).
HIV is a virus which attacks the immune system and causes a lifelong severe illness with a long incubation period. The end-stage of the infection, acquired immunodeficiency syndrome (AIDS), results from the destruction of the immune system.
Severe acute respiratory syndrome (SARS) is a life-threatening respiratory disease caused by a recently identified coronavirus; the SARS-associated coronavirus (SARS-CoV). This is believed to be an animal virus that recently crossed the species barrier to infect humans.
Hepatitis B is a liver disease that results from infection with the hepatitis B virus (HBV) and is spread through contact with infected body fluids or blood products.
Genital chlamydia is the leading sexually transmitted infection in Europe and the cause of considerable acute morbidity and long term reproductive health problems, particularly in young people.