Biology - Communicable Diseases

• Symptoms for HIV

  • Flu-like illness
  • Immune System damaged
  • Weakness in immune system leads to increase in infections and cancers
• HIV treatment

  Regular use of antiretroviral drugs which can give an almost normal life expectancy
• Measles prevention

  Vaccination of babies so they develop an immunity
• Viral diseases


  • Measles
  • HIV
  • TMV
• Measles symptoms

  High fever, runny nose, cough, rash. In worst cases, can lead to deafness and eye infections.
• Measles treatment

  There is no treatment. The body's immune system overcomes it after a couple of weeks.
• How someone becomes infected with HIV

  Sexually transmitted, from blood, from mother to child and breast milk, needle sharing and blood transfusions.
• Difference between HIV and AIDS

  AIDS is a condition while HIV is a virus. HIV leads to AIDS which is like the final stage of HIV when the immune system is very weak.
• HIV prevention

  Use condoms ,not sharing needles, screening blood of transfusions. HIV + mothers should bottle feed their children.
• Measles transmission

  through sneezes and coughs through the droplets; airborne particles inhaled by others.
• TMV


  Tobacco Mosaic Virus
• TMV transmission

  Contact between plants, and insect vectors.
• TMV symptoms

  Mosaic pattern of discolouration on leaves which reduces growth due to a lack of photosynthesis
• Why TMV reduces growth

  Discoloration is due to a reduction in chlorophyll. Reduced chlorophyll means less photosynthesis occurs, so less glucose is produced. Glucose is needed for growth (respiration), so growth is reduced.
• TMV prevention

  Selective breeding of plants with a resistance to this disease can be grown.
• Viruses reproduce by inserting its DNA into a human cell, causing it to only produce copies of the virus.
• Viruses cause illness by the human cell being killed by the mass production and release of virus copies.
• Carriers


  A person or animal that can give a disease to others but is not affected by it
• Malaria symptoms

  Symptoms resemble flu, Weakness, fever, chills, aches, diarrhoea and vomiting. High risk of birth complications
• Vectors


  An organism, generally a blood-feeding animal, that transmits infectious diseases.
• Chemoprophylaxis


  Preventative drug to combat malaria parasite
• Malaria parasite life cycle

  The parasite lives in the human, infecting the liver then red blood cells. The parasite can then be transmitted to another person via the blood consumed by mosquito vectors.
• Strategies to prevent malaria transmission

  Mosquito nets and spray, avoiding mosquito breeding grounds, rapid diagnosis and treatment.
• Malaria is caused by a Protist pathogen, Plasmodium.
• Rose Black Spot is caused by a Fungal pathogen, Diplocarpon Rosae.
• Rose Black Spot


  A disease of roses where leaves develop purple or black spots that stunts growth.
• Why Rose Black Spot stunts growth

  The loss of leaves causes a reduction in photosynthesis, and so also a reduction in glucose production. Growth uses glucose, so growth is stunted.
• Rose Black Spot treatment

  RBS can be treated with fungicide.
• Rose Black Spot transmission

  RBS transmission occurs by water moving from one leaf to another by rain or wind.
• Rose Black Spot prevention

  Removing affected leaves
• Salmonella bacteria

  Bacteria that lives on the gut of many different animals
• Where salmonella can be found

  In raw meat, poultry, eggs and egg products such as mayonnaise.
• How salmonella causes disease

  Salmonella divides/reproduces rapidly, causing toxins to be released.
• Cause of salmonella infection

  Eating undercooked food when the bacteria have not been killed or preparing food in unhygienic conditions where the food is contaminated from the salmonella bacteria from raw meat
• Salmonella symptoms

  Fever, abdominal cramps, vomiting and diarrhoea caused by the bacteria and toxins they secrete
• Who salmonella can be most fatal to

  young children and old people because of the dehydration
• Salmonella prevention in the UK

  Poultry are vaccinated against salmonella to control the spread of disease. Hygienic cooking practices.
• Salmonella treatment

  The body's immune system usually manages the disease itself, but antibiotics can be used
• Gonorrhea


  A sexually transmitted disease
• Gonorrhea spread

  unprotected sexual contact with an infected person