write the names of three diseases …

Three diseases caused by virus are:
(a) Influenza (b) Hepatitis (c) AIDS

AIDS (Acquired Immuno Deficiency Syndrome).
Cause : Retro virus HIV (Human Immuno Deficiency Virus).
Mode of Communication:
(i) Blood transfusion.
(ii) Unprotected sexual contact.
(iii) Use of contaminated needles and syringes, sharing razors, piercing instruments, etc.
(iv) From mother to the developing foetus through placenta.
Symptoms:
(i) Prolonged fever.
(ii) Swollen lymph glands.
(iii) Weightloss and loss of appetite.
(iv) Unexplained bleeding.
(v) Decreased count of blood platelets causing haemorrhage.
(vi) Loss of memory and mental ability.
(vii) Patient becomes susceptible to other diseases.
Detection :
It is done by ELISA TEST and Western Blood test.
Prevention:
(i) Safe ***.
(ii) Use of disposable syringe and needles and fresh razors for shaving.
(iii) Testing the blood before transfusion.
(iv) Education of the masses through AIDS awareness programmes.
(v) Avoid pregnancy of HIV infected mother.
Treatment : There is no cure for AIDS so far.