B3- Infection And Response Flashcards
What are pathogens?
Pathogens at microorganisms that enter the body and cause disease. They cause communicable diseases and can be spread. Both plants and animals can be infected by pathogens.
What are bacteria?
Bacteria are very small cells which can reproduce rapidly inside your body. They cause illness by providing toxins that damage your cells and tissues.
What are Viruses?
Viruses are not cells but like bacteria they can rapidly reproduce inside your body. They live inside your cells and replicate themselves using the cell’s machinery to produce many copies of themselves. The cell will usually then burst releasing the new viruses. The cell damage is what causes the illness.
What are protists?
There are multiple variations of protists but they’re all eukaryotes and most of them are single celled. Some protists are parasites.
What are parasites?
Parasites live on or inside other organisms and can cause them damage. They are often transferred to the organism b the vector which doesn’t get the disease itself.
What are fungi?
Some fungi are single celled. Others have a body which is made up of hyphae These hyphae can grow and penetrate human skin and the surface of plants causing diseases. The hyphae can produce spores which can spread to other plants and animals.
How can pathogens be spread?
Water- Some pathogens can be picked up by drinking or bathing in dirty water. E.g. cholera
Air- Pathogens can be carried in the air and can be breathed in. Some airborne pathogens are carried in the air in droplets when someone coughs or sneezes. E.g. the influenza virus that causes flu
Direct contact- Some pathogens can be picked up by touching contaminated surfaces including the skin. E.g. athlete’s foot which is spread by touching the same thing as the infected person
Explain what measles is
Measles is a viral disease which is spread by the droplets from an infected person’s cough or sneeze. People with measles develop a red skin rash and will develop a fever. Measles can be very serious or even fatal. For example measles can sometimes lead to pneumonia (lung infection) or a brain infection called encephalitis. Most people are vaccinated against measles when they’re very young.
Explain what HIV is
HIV is a viral virus spread by sexual contact or by exchanging bodily fluids such as blood. This can happen if people share needles when taking drugs. HIV initially causes flu like symptoms for a few weeks. Usually a person doesn’t then experience any symptoms for several years. During this time it can be controlled with antiretroviral drugs which stop the virus replicating in the body. The virus attacks the immune cells and if the body’s immune system is badly damaged it can’t cope with other infections or cancers. At this stage the virus becomes known as late stage HIV infection or AIDS.
Explain what tobacco mosaic virus is
Tobacco mosaic virus is a viral virus that affects many species of plants. It causes a mosaic pattern on the leaves of the plants and parts of the leaves become discoloured. The discoloration means the plant can’t carry out photosynthesis as well so the virus affects growth.
Explain what Rose black spot is
Rose black spot is a fungal disease where fungus causes purple or black spots to develop on the leaves of rose plants. The leaves can turn yellow and fall off. This means that photosynthesis can’t happen and it will affect the plant’s growth. It spreads through the environment in water or by the wind. Gardeners can treat the disease using fungicides and by stripping the plant of it’s affected leaves. These leaves then need to be destroyed so that the fungus can’t spread to other rose plants.
Explain what malaria is
Malaria is caused by a protist. Part of the malarial protist’s life happens in a mosquito. The mosquitos are vectors and pick up the malarial protists when they feed on the infected animal, it infects by inserting the protist into the animal’s blood vessels. Malaria causes repeating episodes of fever and can be fatal. The spread of malaria can be reduced by stopping the mosquitos from breeding. People can be protected by using insecticides and mosquito nets.
Explain what salmonella is
Salmonella is a type of bacteria that causes food poisoning. It is a bacterial disease. Infected people can suffer from fever, stomach cramps, vomiting and diarrhoea. These symptoms are caused by the toxins the bacteria produce. You can get salmonella food poisoning by eating food that has been contaminated with salmonella bacteria. In the UK most poultry are vaccinated against salmonella. This is to control the spread of the disease
Explain what gonorrhoea is
Gonorrhoea is a sexually transmitted disease. It is a bacterial disease and STI’s are spread by sexual contact. A person with gonorrhoea will get pain when they urinate and a thick yellow discharge from the vagina or penis. Gonorrhoea was originally treated with an antibiotic called penicillin but this has become trickier now because strains of the bacteria have become resistant. To prevent the spread of gonorrhoea people can be treated with antibiotics and should use barrier methods of contraception such as condoms.
How can the spread of disease be reduced or prevented?
Being hygienic- using simple hygienic measures can prevent the spread of disease. For example washing your hands before preparing food
Destroying vectors- By getting rid of the organisms that spread disease you can prevent the disease from being passed on. Vectors that are insects can be killed using insecticides or by destroying the habitat so they can no longer breed.
Isolating infected individuals- If you isolate someone who has a communicable disease it prevents them from passing it on to anyone else.
Vaccination- Vaccinating people and animals against communicable diseases means that they can’t develop the infection and pass it on.
