question_answer 21)

  Diseases are broadly grouped into infectious and non-infectious diseases. In the list given below, identify the infectious diseases. I. Cancer                              II. Influenza                        III. Allergy                            IV. Smallpox (a) I and II                            (b) II and III                         (c) III and IV                        (d) II and IV

Answer:

                  (d) Influenza, commonly known as the 'flu' is an infectious disease of birds and mammals caused by influenza viruses. The most common symptoms are chill, fever, runny nose ,sore throat, muscle pain, headache, coughing, weakness/fatigue and discomfort, Cancer is defined as an uncontrolled division or proliferation of cells without any differentiation. It is a non-infectious disease caused by the agents called carcinogens .Smallpox is a serious, highly contagious and often life threatening disease characterized by a rash and (blisters) on the face, arms and legs. It is caused by the Variola virus. It get transmitted from a person to others by various means like sneeze, saliva, contaminated body fluids, etc. Allergy is the exaggerated response of the immune system to certain antigens in the environment (pollen, dust, mites, molds, clothfibres, animal hair, etc). It occurs due to the release of chemicals like histamine and serotonin from the mast cells. It isnon-infectious response.