Common Viral Diseases Revision Notes | GCSE OCR Foundation Biology

What this lesson covers

Explore three important viral diseases: measles affecting humans with fever and rash symptoms, HIV/AIDS and its impact on the immune system, and tobacco...

• Describe the symptoms and transmission methods of measles, HIV, and tobacco mosaic virus
• Explain how viral diseases affect the human body and immune system
• Compare the different ways viral diseases spread between organisms
• Evaluate the effectiveness of prevention methods for viral diseases

Key ideas to keep in view

Use this lesson to stay inside B6.3 Monitoring and maintaining health while connecting the detail back to the wider B6: Global challenges topic.

• B6: Global challenges
• B6.3 Monitoring and maintaining health
• GCSE OCR Foundation Biology

Lesson notes preview

Read the core explanations from Common Viral Diseases before testing yourself from memory.

• Viruses are microscopic parasites that can't survive on their own. They hijack your cells, turning them into virus factories that pump out thousands of copies. This cellular takeover is what makes you feel ill.
• Unlike bacteria, viruses can't be treated with antibiotics. Your immune system has to fight them off, or in some cases, antiviral drugs can slow them down. This is why prevention through vaccination is so crucial for viral diseases.
• A highly contagious viral disease that causes fever and a distinctive red skin rash, spread through airborne droplets from coughs and sneezes.
• Measles starts like a bad cold - fever, runny nose, and cough. Then comes the telltale red rash that spreads from the head downwards. What makes measles particularly dangerous is its complications: pneumonia, brain inflammation, and in severe cases, death.
• The measles virus spreads through tiny droplets when infected people cough or sneeze. These droplets can hang in the air for hours, making measles one of the most contagious diseases known. One infected person can spread it to 12-18 others in an unvaccinated population.
• Trap: Many students think measles is 'just a childhood illness'. Actually, measles can be fatal - this is why the MMR vaccine is given to young children as part of the routine vaccination programme.
• 3. HIV and AIDS - The Immune System Attack
• Human Immunodeficiency Virus - a virus that attacks and destroys the body's immune cells, eventually leading to AIDS if untreated.
• HIV is particularly cunning because it targets the very cells designed to protect you - your immune system's helper T cells. Initially, HIV causes flu-like symptoms that many people dismiss. The virus then lies dormant for years, slowly destroying immune cells.
• When the immune system becomes severely damaged, the person develops AIDS (Acquired Immune Deficiency Syndrome). At this stage, the body can't fight off infections that healthy people easily overcome, leading to life-threatening complications.

Continue through the topic

Move to the related lessons or back to the topic page when you need the wider sequence before exam-style practice.