Chapter 5 Communicable Diseases Flashcards

1
Q

What is health?

A

Health is the state of physical and mental well-being.

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2
Q

What are pathogens?

A

Micro-organisms which cause infectious diseases. These include viruses, bacteria, protists or fungi.

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3
Q

List 2 ways that pathogens infect plants or animals.

A

Pathogens can infect plants or animals through direct contact, water or air.

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4
Q

Give 6 ways that communicable diseases are transmitted.

A

1 - by air: pathogens can be carried in the air and then breathed in (a common example is a droplet infection, which is when sneezing, coughing or talking expels pathogens in droplets which can be breathed in)
2 - by direct contact: e.g. handshakes
3 - indirect contact: touching contaminated surfaces
4- through contaminated water: e.g. through drinking or coming into contact with dirty water
5 - spread by use of a vector: e.g. mosquitoes
6 - spread through contaminated food by eating it

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5
Q

How do pathogens make people feel ill?

A

Pathogens produce toxins or damage cells making people feel ill. They reproduce very quickly inside the body.

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6
Q

How can the spread of communicable diseases be reduced?

A

1 - Improve hygiene: hand washing, using disinfectants, isolating raw west, using tissues and handkerchiefs when sneezing
2 - Isolating/reducing contact with infected individuals
3 - Removing vectors: using pesticides and removing their habitat
4 - Vaccination: by injecting a small amount of harmless pathogen into an individual’s body, they can become immune to it so it won’t infect them - means they can’t pass it on

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7
Q

Are viruses cells?

A

No

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8
Q

What is the size of viruses?

A

Viruses are very small - 20 - 400nm

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9
Q

How do viruses make individuals feel ill?

A

Viruses replicate themselves by invading cells. They live and reproduce rapidly inside cells, causing cell damage.The cell bursts and releases new viruses into the bloodstream. The damage and destruction of the cells makes you feel ill.

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10
Q

Where do viruses reproduce?

A

Inside cells

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11
Q

Draw a diagram of a virus

A

Diagram

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12
Q

How small are bacteria?

A
  • small but larger than viruses
  • 0.2 - 2.0μm
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13
Q

How do bacteria make individuals feel ill?

A
  • they reproduce rapidly
  • may produce toxins that damage tissues that makes you feel ill
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14
Q

How do bacteria cells multiply quickly?

A

Bacteria multiply very quickly by dividing through a process called binary fission.

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15
Q

Draw a diagram of a bacterial cell.

A

Diagram

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16
Q

What is the size of a fungal cell?

A

3-4μm

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17
Q

What type of conditions are ideal for fungal growth?

A

Damp conditions

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18
Q

What happens in humans infected with fungi?

A

Fungal infections cause severe itching and damage to skin and can lead to secondary infections. The fungi produce spores which can be spread to other organisms.

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19
Q

Draw a diagram of a fungal cell.

A

Diagram

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20
Q

What size are protists?

A

10 - 100μm

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21
Q

What are protists?

A

Protists are single-celled. Some are parasitic and use humans and animals as their hosts to live on and inside, causing damage.

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22
Q

What do protists use humans or animals for?

A

Protists often use humans or others animals as hosts to complete their life cycle, and use vectors e.g. mosquitoes to reach them

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23
Q

Draw a diagram of a protist

A

Diagram

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24
Q

What is the difference between the way bacteria and viruses damage cells?

A

Bacteria damage the outside of cells so don’t need to get into cells to cause damage.
Viruses do damage inside cells so must get into host cells to cause damage.

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25
Q

What type of pathogen is measles caused by?

A

Virus

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26
Q

How is measles transmitted?

A

Measles is highly infectious and transmission is through the air by inhaling infected droplets from sneezes and coughs from an infected individual.

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27
Q

What are the symptoms of measles?

A

Symptoms initially begin with fever, swollen eyes, coughing and runny nose. After a few days, a red skin rash on the face develops before spreading across the body leading to spots, red eyes and diarrhoea.

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28
Q

What can measles lead to?

A

Measles can lead to complications in children (which can be fatal) e.g. pneumonia (lung infection), encephalitis (brain infection), blindness, lifelong brain damage, deafness, death.

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29
Q

How is the spread of measles prevented?

A

Most young children vaccinated against measles due to measles being a serious illness and being fatal if complications arise and to reduce transmission.
Infected individuals should minimise contact to avoid spreading it further.

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30
Q

What is the treatment for measles?

A

There is no specific treatment for this disease. With appropriate rest and care the individual will recover.

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31
Q

What type of pathogen is HIV caused by?

A

Virus

32
Q

What effect does HIV have on the body?

A

HIV attacks and destroys the cells of the immune system making it difficult for the body to fight infections and certain cancers.
HIV virus attacking immune systems means white blood cells can’t kill bacteria as easily.

33
Q

What are the symptoms of HIV?

A
  • initially causes flu-like illness
  • fever
  • headache
  • rash
  • rapid weight loss
  • chronic diarrhoea
34
Q

How is HIV transmitted?

A

HIV is spread through exchange of body fluids through sexual contact e.g. semen, pre-seminal fluids, rectal fluids, vaginal fluids
Exchange of body fluids also occurs when drug users exchange needles.
It can also be spread through breast milk.

35
Q

How can the spread of HIV be prevented/controlled?

A
  • use condoms
  • ensure you and any partners are STD tested
  • don’t injects drugs/share needles
  • screening blood when it is used in blood transfusions
  • mothers with HIV bottle-feeding their children instead of breastfeeding
36
Q

What is the treatment for HIV?

A

There is no cure for HIV. Antiretroviral drugs stop viruses replicating in body and to stop the development of AIDS (late stage of HIV)

37
Q

What type of pathogen is TMV (tobacco mosaic virus)?

A

Virus

38
Q

What was the 1st virus to be discovered?

A

TMV (tobacco mosaic virus)

39
Q

How is TMV transmitted?

A

TMV is transmitted by direct between diseased and healthy plants, indirect contact e.g. plants infected via plant wounds after human handling, via contaminated equipment.

40
Q

What are the symptoms of TMV?

A

A distinct ‘mosaic’ pattern of discoloration on the surface of leaves which affects growth of plants due to lack of photosynthesis. The virus doesn’t usually cause the plant to die, but can seriously stunt its growth.

41
Q

What is the treatment for TMV?

A

There is no cure or treatment for TMV.

42
Q

How can the spread of TMV be prevented/controlled?

A

The diseased plant should be dug up and burnt. Hands need to be washed thoroughly and all gardening implements disinfected after handling infected plants.

43
Q

How does TMV negatively affect the growth of a plant?

A

The discolouration on leaves caused by TMV means there is less chlorophyll made so less photosynthesis takes place. This means less glucose/starch/protein is made and growth is reduced.

44
Q

What type of pathogen is salmonella food poisoning caused by?

A

Bacteria

45
Q

How is Salmonella transmitted?

A

Salmonella is ingested in food and spread by food prepared in unhygienic conditions or through eating contaminated food that is undercooked or raw eg. poultry, eggs, meat and untreated milk and dairy products.

46
Q

What are the symptoms of Salmonella?

A

In most cases of salmonellosis are mild, however sometimes can be life-threatening
- diarrhoea
- stomach cramps
- fever
- vomiting
These symptoms are caused by the toxins produced by salmonella.

47
Q

What is the treatment for Salmonella?

A

There is no cure. In severe cases, intravenous fluids used to keep someone hydrated and antibiotics used.

48
Q

How can the spread of Salmonella be prevented/controlled?

A

-vaccinate poultry against Salmonella to control its spread
- good personal hygiene - wash hands thoroughly after using WC, before preparing food and handling raw food, before eating meals and after playing with animals
- don’t sell infected chickens
- give animals with Salmonella antibiotics
- keep Salmonella infected animals isolated from rest of animals
- cook all food thoroughly
- don’t use raw eggs in ready to eat dishes e.g. mayonnaise or mousse

49
Q

What type of pathogen is gonorrhoea caused by?

A

Bacteria

50
Q

What does gonorrhoea cause?

A

It can cause infections in genitals, rectum and throat.

51
Q

How is gonorrhoea transmitted?

A

Gonorrhoea is an STD so transmitted through sexual contact.

52
Q

What are the symptoms of gonorrhoea?

A

Symptoms include a burning sensation when urinating, thick white, yellow, or green discharge from vagina or penis.

53
Q

What is the treatment for gonorrhoea?

A

The antibiotic penicillin.

54
Q

How can the spread of gonorrhoea be controlled/prevented?

A

Use of condoms.
Abstinence

55
Q

What sort of pathogen is rose black spot caused by?

A

Fungus

56
Q

Why does rose black spot make resistant roses difficult to breed?

A

It mutates rapidly, making resistant roses difficult to breed.

57
Q

What are the symptoms of rose black spot disease?

A

Purple or black spots on leaves of rose plants which often turn yellow and drop early. It affects growth of the plant as photosynthesis is reduced, drooping leaves, small, black lesions on stems.

58
Q

How is rose black spot transmitted?

A

1 - by water - black spot fungus produces spores which are released under water conditions and are usually spread by rain splash
2 - by wind
3 - through direct or indirect contact - disease can be spread from plants to plant directly or via hands, clothing or tools

59
Q

What is the treatment for rose black spot disease?

A

Treated using fungicides

60
Q

How can the spread of rose black spot disease be prevented?

A

Collect and destroy fallen leaves in autumn.
Prune out all stem lesions in spring before leaves appear.

61
Q

What type of pathogen causes malaria?

A

Protist

62
Q

How is malaria transmitted?

A

By a vector - the vector is the mosquito, in which the protists reproduce sexually, when the mosquito punctures the skin to feed on the blood, the protists enter the human bloodstream via their saliva.

63
Q

What are the symptoms of malaria?

A

Fever, nausea, headache.

64
Q

What is the treatment for malaria?

A

There is no preventative medicine that prevents infection. The main treatment is use of antimalarial drugs over a long period of time.

65
Q

How can the spread of malaria be controlled/prevented?

A

1 - vector control - using insecticide coated nets while sleeping to avoid being bitten
2 - removing stagnant water to prevent vectors from breeding
3 - travellers taking antimalarial drugs to kill parasites that enter the blood

66
Q

What is the first line of defence against pathogens?

A

Non-specific defence systems against pathogens

67
Q

Give 4 non-specific defence systems against pathogens in humans.

A

1 - skin
2 - nose
3 - trachea and bronchi
4 - stomach

68
Q

How is skin a non-specific defence system?

A

Skin acts as a physical barrier against pathogens.

69
Q

How is the nose a non-specific human defence system?

A

The nose has hairs and mucus (sticky substance) which prevent particles from entering the lungs.

70
Q

How are the trachea and bronchi non-specific human defence systems?

A

They secrete mucus in order to trap pathogens. Cilia (hair-like structures) beat to waft mucus upwards so it can be swallowed.

71
Q

How is the stomach a non-specific human defence system?

A

The stomach produces hydrochloric acid that kills any ingested pathogens (e.g. bacteria) from mucus, food or drink

72
Q

What is the role of the immune system in the defence against diseases?

A

If a pathogen enters the body the immune system tries to destroy the pathogen. White blood cells can destroy pathogens through phagocytosis, producing antibodies or producing antitoxins.

73
Q

Describe the process of phagocytosis.

A
  1. Phagocytes are attracted to any area of the body in which an infection is present
  2. Phagocyte (type of white blood cell) moves towards a bacterium
  3. The phagocyte begins to engulf the bacterium
  4. When the phagocyte comes into contact with pathogen, it binds to it
  5. The membrane of the phagocyte then surrounds the pathogen and engulfs it with the cytoplasm of the phagocyte wrapping around the bacterium - the bacterium is engulfed into the vacuole
  6. The bacterium is now enclosed in a vacuole inside the phagocyte
  7. Digestive enzymes enter the vacuole and it is killed and digested
74
Q

Draw a diagram of the process of phagocytosis.

A

Diagram

75
Q

How can antibodies be used to defend against pathogens?

A

Antibodies bind to pathogens. This stops them from entering cells and marks them for destruction by phagocytes.

76
Q

How is producing antitoxins used to defend against pathogens?

A

Antitoxins are proteins that bind to toxins making them harmless.

77
Q

Draw a diagram to show how antibodies work.

A

Diagram