Public health activities
Public health activities are actions done by a community to keep all its people healthy. Examples: vaccination camps, screening (check-ups to find disease early, like blood pressure or eye tests), awareness drives (posters, street plays, school talks about hand washing or tobacco), clean water and sanitation, and mother and child care. They are run by government, local health centres, health workers and volunteers. They work best when people join in.
Prevention has levels: stop disease before it starts (vaccines, clean water), find it early (screening), and treat and support (hospitals, rehabilitation).
Blood donation
Blood cannot be made in a factory, so it must come from donors. A usual donation is about 350 to 450 mL and takes about 10 minutes (the whole visit about an hour). A blood bank splits it into red cells (carry oxygen, for accidents and anaemia), platelets (help clotting, for cancer and dengue patients) and plasma (for burns and bleeding disorders). So one donation can help up to three people.
- Who can donate: healthy people usually aged 18 to 65, weighing over 45 to 50 kg, with enough haemoglobin.
- Safety steps: health check, donation with a new sterile needle, tests for infections such as HIV and hepatitis, blood group matching, cold storage.
- Shelf life: red cells about 42 days, platelets only 5 to 7 days, so donors are needed again and again.
- Gap: the body refills fluid in a day and cells in weeks. Wait several months (often 3 or more) before the next donation.
Organ donation
When an organ such as a kidney, liver, heart or lung fails, organ transplant may be the only cure. The organ comes from a donor.
- Living donor: can give one kidney, or part of the liver, usually to a close relative, after medical tests.
- After death: if a person is declared brain-stem dead in a hospital, with the family's consent, the heart, lungs, liver, kidneys and pancreas can be given. Corneas, skin and bones can be given after ordinary death too.
- One donor can help many people: up to 8 organs and many tissues.
- Rules: consent of the donor or family is needed. Organs are matched by blood group and size and shared by a waiting list. Buying and selling organs is a crime.
Telling your family you wish to donate (and signing a pledge) makes it easier for them to say yes at a hard moment.
Social measures: why it matters
Many more patients wait for blood and organs than there are donors. Social measures are rules and campaigns that help: voluntary (unpaid) donation, donor pledge drives, safe blood banks, laws against organ trade, and school and community camps. When many people join in, more patients get help.
Try it
1) In the 3D free play, move the donor slider from 0 to 100 and count the green patients. 2) Make a poster for a health camp in your school: who, what and when. 3) Talk with your family about whether you would like to pledge eye or organ donation.
Key formulas and definitions
- Key terms: screening, vaccination camp, awareness drive, transplant, brain-stem death, consent
- One blood donation: about 350-450 mL, takes about 10 minutes, helps up to 3 patients
- Shelf life: red cells about 42 days, platelets 5-7 days
- Blood donor: healthy, 18-65 years, over 45-50 kg
Worked examples
1. A school plans a health camp. Name three activities it could include.
Vaccination, an eye and height-weight check-up (screening), and an awareness talk on hand washing or healthy food.
2. A hospital collects 4 donations. Each is split into red cells, platelets and plasma. At most how many patients can be helped?
4 donations x 3 patients each = up to 12 patients.
3. Red cells last 42 days. A donor gave blood on 1 March. About when must the red cells be used?
March has 31 days, so 42 days later is about 12 April.
4. Why do blood banks always need new donors?
Platelets last only 5 to 7 days and red cells about 42 days, and patients use blood every day. Stocks run out unless donors keep coming.
5. Using the 3D free play: at 60 donors per 100 needed, how many of 20 patients are helped?
20 x 60 / 100 = 12 patients helped, 8 still waiting.
6. A person has died in an ordinary way at home. Can they donate corneas? Can they donate the heart?
Corneas can be donated (within a few hours after death) with consent. The heart cannot, because heart donation needs brain-stem death in a hospital with the body supported.
Common mistakes
- Thinking donating blood makes you weak. A healthy donor refills fluid in a day and cells in weeks.
- Believing you can catch an infection by giving blood. A new sterile needle is used each time.
- Thinking organs can be bought or sold. This is a crime in most countries; donation must be voluntary.
- Thinking only a family member can donate. Blood can be given to anyone with a matching group.