3.1 Communicable Diseases Flashcards
What are communicable diseases?
Communicable diseases are diseases that can be passes from one individual to another
What are pathogens?
Pathogens are microorganisms that cause infectious disease
What are the 4 types of pathogens?
- Viruses
- Bacteria
- Fungi
- Protists
How can pathogens spread?
Pathogens can spread by direct contact, water or air
How can the spread of pathogens be reduced?
- Isolation
- Vaccination
- Hygiene
How do viruses work?
Viruses invade host cells. They then reproduce rapidly within those cells which causes the cells to burst. The cell damage is what causes us to feel ill
Measles?
Measles is a viral disease showing symptoms of fever and a red skin rash
Why are young children vaccinated against measles?
Young children are vaccinated against measles because it can be fatal if complications arise.
How are measles spread?
Measles are spread through the inhalation of droplets from sneezes and coughs
HIV
- HIV is a virus that is initially a flu-like illness
- HIV is spread by sexual contact or exchange of body fluids
- Unless successfully controlled with antiretroviral drugs, the virus then attacks the body’s own immune cells.
- AIDS is the condition resulting from long term HIV infection, where the body’s immune system becomes so badly damaged it can no longer defend against other infections or destroy cancer cells
Explain how HIV has to be treated?
HIV has to be treated at an early stage with antiretroviral drugs
How is HIV spread?
HIV is spread by sexual contact or exchange of body fluids such as blood (e.g. when drug users share needles)
Tobacco Mosaic Virus
- Tobacco mosaic virus (TMV) is a pathogen that affects plants such as tomatoes.
- It gives a distinctive ‘mosaic’ pattern of discolouration on the leaves which affects the growth of the plant due to lack of photosynthesis
Bacteria
- Bacteria are prokaryotic cells
- divide rapidly by binary fission
- It either damages the cells directly or produces toxins that causes damage to body cells
In what conditions do bacteria reproduce?
Bacteria reproduce rapidly in warm, moist conditions with a good supply of oxygen
What is Salmonella
- Salmonella food poisoning is spread by bacteria ingested in food, or on food prepared in unhygienic conditions.
- In the UK, poultry are vaccinated against Salmonella to control the spread.
- Fever, abdominal cramps, vomiting and diarrhoea are caused by the bacteria and the toxins they secrete.
Gonnorhoea
Gonorrhoea is a sexually transmitted disease (STD) with symptoms of a thick yellow or green discharge from the vagina or penis and pain on urinating. It is caused by a bacterium and was easily treated with the antibiotic penicillin until many resistant strains appeared. Gonorrhoea
is spread by sexual contact. The spread can be controlled by treatment with antibiotics or the use of a barrier method of contraception such as a condom
How do fungi work?
- Fungi are single celled organisms that have a body made of hyphae (thread-like structures)
- They then produce spores which then spread to other organisms
Rose Black Spot
Rose black spot is a fungal disease where purple or black spots develop on leaves, which often turn yellow and drop early. It affects the growth of the plant as photosynthesis is reduced. It is spread by water or wind. Rose black spot can be treated by using fungicides and/or removing and destroying the affected leaves.
Explain how malaria functions?
- Malaria is a disease caused by protist pathogens
- The disease is carried from host to host by mosquitoes, the vector, when it infects them by biting them