Question

Name the disease in which the number of platelets reduces to 25,000-30,000 per cubic mm of blood. State its major symptoms.

Answer 1

Human blood consists of Plasma which is a fluid matrix and formed of elements. The plasma makes up 55% of human blood. The remaining 45% is made up of formed elements. The main function of the blood plasma is clotting of blood. The formed elements consist of Red blood cells (RBCs), white blood cells (WBCs) and platelets.

Complete answer
The normal number of platelets in human blood is 1.5 lakhs to 3.5 lakhs per mm3. However, the number of platelets decreases to 25,000-30,000 when a person suffers from dengue fever. The dengue virus causes dengue fever. The mosquitoes act as the vector of the dengue disease. The most common vector of dengue is Aedes aegypti.
The dengue virus attacks the platelets and binds to it and instructs them to make multiple copies of the virus. The infected platelets infect other platelets and harm them. This results in a significant decrease in platelet numbers in the blood. The person suffering from the disease shows symptoms in about 3-12 hours. The common symptoms that appear in a diseased person are headache, high fever, nausea, body pain especially joint pain and muscle pain, red spots on the body etc.
As the platelets help in coagulation of blood, a significant decrease in platelet count results in various clotting disorders and excessive bleeding even after a minor cut. There is a vaccine available for dengue disease. The treatment of the disease is done by giving fluids to the suffering person.

Thus the answer to the above question is dengue in which the platelet count of the blood decreases.

Note:
Platelets are formed from the special cells of the bone marrow called megakaryocytes. Thrombocytes is another name for platelets. They are short lived. They have a lifespan of 5-9 days. When their life span ends, they are removed from the bloodstream.