What is the common in AIDS, mumps and poliomyelitis? (1) Young children get affected most readily (2) No effective vaccine has yet been developed for them (3) These are caused by viruses (4) Their germs can be transmit-ted through blood transfusions
(3) These are caused by viruses Explanation: Human immunodeficiency virus (HIV) is a lentivirus (a member of the retrovirus family) that causes acquired immunodeficiency syndrome (AIDS). Mumps (epidemic parotitis) is a viral disease of the human species, caused by the mumps virus. Poliomyelitis is an acute, viral, infectious disease spread from person top erson, primarily via the fecal-oral route.