NCDs and CDs

• what is a pathogen?


  A pathogen is a microorganism or agent that causes disease in its host.
• how can pathogens be spread?

  Through direct contact, airborne transmission, contaminated food or water, and vectors such as mosquitoes or ticks.
• Viruses 


  in animals- HIV potentially leading to AIDS

  in plants- tobacco mosaic virus
• bacteria 


  in animals- salmonella

  in plants- agrobacterium
• fungi


  in animals- athletes foot

  in plants- rose black spot
• protists


  in animals- malaria

  in plants- downy mildew
• what are 4 ways the spread of diseases can be reduced?

  1. sterilise water to prevent cholera using chemicals or UV light kills the pathogens in unclean water
  2. hygiene (food) prevents salmonella by cooking foods thoroughly and preparing them in hygienic conditions like washing your hands and tools
  3. personal hygiene prevents athletes foot by washing surfaces with disinfectants and treating existing cases
  4. contraception prevents HIV/AIDs, using barriers stops transfer of bodily fluids
• what damage do pathogenic viruses and bacteria do to the body?

  Bacterial and viral infections can cause similar symptoms such as coughing and sneezing, fever, inflammation, vomiting, diarrhea, fatigue, and cramping -- all of which are ways the immune system tries to rid the body of infectious organisms.
• what does HIV do to the body?

  Weakens immune system and destroys the bodies T-lymphocytes
• what does AIDS do the body?

  attacks the patients immune system which makes it hard for people to fight off illnesses and infections
• what is measles. how is it transferred and what does it do to the body?

  Measles is a very infectious viral disease that is often caught by young children. It is transmitted through the air in tiny droplets after an infected person sneezes. It causes a fever and skin rash. Many children in developed countries are given vaccines against measles, but sadly this is not the case throughout the world. Infection can cause more serious effects like infertility in adults who did not catch the disease as children.
• what is tobacco mosaic virus?

  The tobacco mosaic virus infects tobacco and lots of other closely related species, such as tomatoes and peppers. It is transmitted by contact between plants, either naturally or through the hands of farmers. It infects the chloroplasts of plant leaves and changes their colour from green to yellow or white in a mosaic pattern. It can also make leaves crinkle or curl up.This reduces the plant's ability to photosynthesise and grow properly, which reduces the crop yield for farmers.
• is there a cure for tobacco mosaic virus?

  There is no cure therefore farmers must try to reduce the infection to their crops or attempt to reduce the spread of the virus.
• how can farmers prevent tobacco mosaic virus?

  wash their hands after handling infected plants. wash tools that have come into contact with infected plants in detergent or bleach. rotate the crops they grow in a contaminated field - they must not grow tobacco or tomato plants in the field for at least two years.
• explain gonorrhoea


  Gonorrhoea is a sexually transmitted disease (STD) caused by a bacterium. It is a common infection.Gonorrhoea causes a burning pain when urinating and often forms a thick yellow or green discharge, if untreated it may cause infertility.
• how can people prevent gonorrhoea?


  To prevent infection, people can abstain from having anal, oral or vaginal sex or use a barrier-type of contraception like a condom. Gonorrhoea is treated by antibiotics. Many of the antibiotics which were effective against bacterial diseases like gonorrhoea are not as effective as they used to be. This is because bacteria are evolving to become resistant to existing antibiotics. Scientists are constantly trying to find new antibiotics to treat these diseases
• explain salmonella?


  Salmonella is a genus of bacteria that causes food poisoning. This often means abdominal cramps, vomiting and diarrhoea. It is often found in unhygienic kitchens, undercooked foods such as meat, eggs and poultry, or the same foods that have not been reheated properly
• how can you prevent salmonella?

  To prevent the spread of salmonella in the UK, all poultry are vaccinated against it. Cooking food thoroughly, after preparing it in hygienic conditions, is the best way to avoid illness.
• explain rose black spot

  Rose black spot is caused by a fungus which infects roses. It infects leaves and causes black or purple spots on the leaves. The rest of the leaves often turn yellow and can drop off the plant. This reduces that plant's ability to photosynthesise and reduces growth.
• how is rose black spot transmitted?

  It can be transmitted in air or water, as well as through direct contact by gardeners.
• how is rose back spot treated?

  It is treatable using fungicides and by removing and destroying infected leaves.
• explain what malaria is

  Malaria is spread by mosquitos which carry the Plasmodium protist. These are often found in areas with higher temperatures like Africa, Asia, and South and Central America, but not the UK. Mosquitos suck blood containing the protists from an infected person. They pass the protist, to other people they suck blood from. The mosquitos do not become ill and are called 'vectors' because they transmit the disease.
• what are the symptoms of malaria?

  The symptoms of malaria include a fever, sweats and chills, headaches, vomiting and diarrhoea. Of the 200 million people infected each year, up to half die from this disease. 
• how can we control malaria?

  There is no vaccination for malaria. Infection can only be prevented by stopping individuals from being bitten. People sleep under mosquito nets and wear insect repellent to avoid bites. Antimalarial drugs are also taken, which treat the symptoms and can prevent infection.
• how does the skin prevent infection from pathogens?

  If it is cut or grazed it immediately begins to heal itself, often by forming a scab, which prevents infection as the skin acts as a physical barrier. Parts of the body that do not have skin have developed other ways to prevent infection. For example, the eyes produce tears, which contain enzymes, and these are chemical barriers.
• how does the nose prevent pathogens from entering the body?

  The nose has internal hairs, which act as a physical barrier to infection. Cells in the nose produce mucus. This traps pathogens before they can enter the lungs. When the nose is blown, mucus is removed and any pathogens are trapped within it.
• how does the trachea prevent pathogens from entering the body?

  The cells that line the trachea also have hairs called cilia, which are much smaller than those in the nose. These are called ciliated cells. The ciliated cells waft their hairs and move mucus and pathogens upwards towards the throat where it is swallowed into your stomach. Other cells called goblet cells create the mucus in order to trap pathogens. The production of mucus in your airways is a physical barrier.
• how does the stomach prevent pathogens from entering the body?

  Stomach acid is part of the body's non-specific first line of defence. It is hydrochloric acid and while it does us no harm, it is strong enough to kill any pathogens that have been caught in mucus in the airways or consumed in food or water. Stomach acid is a chemical barrier against infection.
• what is the role of the immune system?

  The role of the immune system is to prevent disease., and mainly consists of two types of white blood cell called phagocytes. and lymphocytes.White blood cells which attack pathogens by producing antibodies..
• how do white blood cells destroy pathogens?

  Phagocytes which are a white blood cells surround any pathogens in the blood and engulf them. They are attracted to pathogens and bind to them.The phagocytes membrane surrounds the pathogen and enzymes found inside the cell break down the pathogen in order to destroy it. 
• how do lymphocytes kill pathogens?

  They recognise proteins on the surface of pathogens called antigens. Lymphocytes detect that these are foreign not naturally occurring within your body and produce antibodies. This can take a few days, during which time you may feel ill. The antibodies cause pathogens to stick together and make it easier for phagocytes to engulf them
• what do lymphocytes produce?

  Some pathogens produce toxins which make you feel ill. Lymphocytes can also produce antitoxins to neutralise these toxins. Both the antibodies and antitoxins are highly specific to the antigen on the pathogen, thus the lymphocytes that produce them are called 'specific
• how are vaccines effective at population level?

  The majority of the population are vaccinated and healthy against a specific disease, a few are not vaccinated but well. A few are not vaccinated against the disease, and they are ill and contagious. The result is that the majority are protected due to the high level of vaccination. A few individuals will still become ill, but the large number of vaccinated individuals gives protection.
• how are painkillers used to kill diseases?

  Painkillers are chemicals that relieve the symptoms but do not kill the pathogens. Common examples include paracetamol and aspirin, and they can relieve a headache or a sore throat.

  As the symptoms are treated, your immune system still needs to combat the pathogen.
• what are the limitations of painkillers?


  they do not kill the pathogen forever
• how are antibiotics used to kill diseases?

  Antibiotics damage the bacterial cells but do not damage the host cells. They have the ability to cure some bacterial diseases that would have previously killed many people. Since their introduction, they have had a large influence on the world's health and death rate.
• what is the limitation of antibiotics?

  they do not cure viral diseases
• what is penicillin?


  Penicillin was the first antibiotic discovered in 1928 by Alexander Fleming. He noticed that some bacteria he had left in a Petri dishhad been killed by the naturally occurring Penicillium mould
• how can new drugs be discovered?

  plant extracts and research
• how has sources of drugs changed overtime?

  drugs used to be discovered by plants but now we can use labatories to research and discover new drugs. and example is willow bark. willow bark was used by the ancient Greeks to help cure fevers and pains. It was later discovered that the active ingredient was salicylic acid. This was modified by chemists into the substance we call aspirin, which is less irritating to the stomach than salicylic acid. Another example is the heart drug, digitalis which is extracted from foxgloves.