Pathogens, spread of human disease and control of infection

?
  • Created by: Owain
  • Created on: 23-04-14 20:14
What is a pathogen?
A bacterium, virus, or other organisms that can cause disease.
1 of 110
Are all micro-organisms pathogenic?
No.
2 of 110
Are micro-organisms pathogens in every area of the body
Yes
3 of 110
What is an infectious disease?
A disease that may be passed or transmitted from one individual to another.
4 of 110
What is the meaning of the term carrier?
A person that shows no symtoms when infected by a disease but can pass the disease on to another individual
5 of 110
What is the meaning of the term resevoir?
The place where a pathogen is normally found. This may be humans or another animal.
6 of 110
What is the meaning of the term endemic?
A disease which is always present at low levels in an area.
7 of 110
What is the meaning of the term epidemic?
A significant increase in the usual number of cases of a disease
8 of 110
What is the meaning of the term toxin?
A chemical produced by a micro-organisms which causes damage to its host
9 of 110
What is the meaning of the term antigen?
A substance when introduced to the body or tissues induces the formation of antibodies or reacts with them if already present
10 of 110
What is the meaning of the term antigenic type?
Organisms with the same or very similar antigens on the surface. Such types are sub groups or strains of a microbial species which may be used to trace infections. They are usually identified by using antibodies from serum.
11 of 110
What is the meaning of the term antibody?
A substance produced by lymphocytes in the presence of a specific antigen and that can combine with the antigen to neutralise, inhibit or destroy it
12 of 110
What is the meaning of the term antibiotic?
A substance produced by micro-organisms which affect the growth of micro-organsims
13 of 110
What is the meaning of the term antibiotic resistant?
A micro-organisms which should be affected by an antibiotic, is no longer susceptible to it.
14 of 110
What are the 8 things you need to know about each pothogen?
Name, Tissues afftected, symptoms, Source of infection, Mode of transmission
15 of 110
What is the name of the pathogen caused by salmonellosis
Gram negative bacterium
16 of 110
Describe the bacterium?
Rod shaped bacterium.
17 of 110
What tissues are affected by the pathogen?
Gut lining
18 of 110
What are the symtoms of salmonellosis?
Diaarrhoea and vomiting
19 of 110
Describe 2 ways that the pathogen can be transferred?
Animal slaughter, contaminated food or poor hygiene practise.
20 of 110
What can happen to this pathogen in storage?
Multiplies during storage.
21 of 110
Describe 4 ways of reducing the transfer of the pathogen?
Hygienic practices, thorough cooking, cool storage conditions and prevention of contamination from carriers
22 of 110
How can we trace the source of infection?
Analysis of antigenic types.
23 of 110
Why do doctors not use antibiotics oftento treat salmonellosis
To prevent a build up of resistance.
24 of 110
Why is there no vaccine available
There are over 2000 antigenic types.
25 of 110
What is the name of the pathogen caused by Cholera
Gram negative bacterium
26 of 110
Describe the bacterium?
Rod shaped
27 of 110
What tissues are affected by the pathogen?
Gut lining
28 of 110
What are the symtoms of cholera? What can these symptoms lead to?
Water diarrhoea leading to dehydration and frequentlt death.
29 of 110
Name one source and carrier of this pathogen
Humans act as reservoirs
30 of 110
Describe 2 ways that the pathogen can be transferred?
Contaminated water and food
31 of 110
Describe 3 ways of reducing the transfer of the pathogen?
Hygienic disposal of human faeces, treating drinking water to ensure a clean supply and hygienic preperation of food in order to prevent cross contamination and thorough cooking of food.
32 of 110
Describe 2 treatments for cholera?
Rehydration and antibiotics.
33 of 110
Is there a vaccine available, What is the disadvantage of it?
Yes it is used to give temporary protection.
34 of 110
What is the name of the pathogen that causes TB?
Bacterium
35 of 110
Why has there been an increase in the number of TB cases recently?
Due to AIDS epidemic and the build up of resistance in bacteria.
36 of 110
How is TB pathogen transferred?
Spread by airbourne droplet infection when people cough or sneeze.
37 of 110
Give an example of an environment where TB would spread very quickly?
Spread rapidly in over crowded conditions
38 of 110
What tissues are affected by the TB pathogen?
Lung and lymph nodes
39 of 110
What are the symptoms
Persistent coughing, cough up blood and chest pain.
40 of 110
How is TB treated?
Long course of antibiotics (6-12 months)
41 of 110
What is the name of the vaccine given to children
Bcg Vaccine
42 of 110
What type of pathogen causes the flu
Virus
43 of 110
Describe this type of micro-organism
Made of a central core of RNA, a protein coat and an outer lipoprotein
44 of 110
How many sub groups does this pathogen have?
3 main subgroups
45 of 110
What is different about each subgroup?
Different antigenic types
46 of 110
Which tissue is affected by this pathogen?
Lining of the upper respiratory tract
47 of 110
What are the symptoms?
Sore throat, cough and fever.
48 of 110
How is the flu transferred?
Droplet infection when sufferer coughs or sneezes
49 of 110
How can the spread be prevented?
Prevention is by quarantine and good hygiene
50 of 110
Why is it difficult to prevent this type of transfer?
Droplet infection is difficult to control
51 of 110
Why is it not possible to treat flu with antibiotics?
Because it is caused by a virus
52 of 110
What is the other treatment used?
Vaccination
53 of 110
How often does this treatment have to be given? Why?
Every year
54 of 110
Why is this treatment not entirely effective?
New types of flu emerge frequently
55 of 110
What is the name of the pathogen that causes malaria?
Parasitic protoctistan called plasmodium
56 of 110
Where is it found in endemic levels?
In tropical areas
57 of 110
Once the pathogen gain access to the body, where does it go first?
It invades the liver first.
58 of 110
Where does the pathogen multiply
Multiplies in red blood cell
59 of 110
how is the pathogen released back into the blood
The red blood cells burst releasing more of the parasites
60 of 110
What symtoms develop at this stage? why?
Severe fever caused by toxins
61 of 110
What is the vector of this pathogen
Femail mosquitoes
62 of 110
How does this vector pick up the pathogen?
By feeding on human blood
63 of 110
How does this vector transfer the pathogen to another person?
If they bite snother person they inject some saliva to stop the blood clotting, This saliva will contain plasmodium.
64 of 110
Describe 3 ways we can reduce transfer of Malaria through reducing bites?
1.Hanging nets treated with insectaside 2.wearing protective clothing e.g. long sleeves 3. using insect repellents
65 of 110
Describe 4 ways we can reduce transfer of Malaria through destroying the vector?
1. Draining swamps where mosquitos lay there eggs 2.spraying the breeding grounds with diesel oil 3.Spraying insecticides on the surface of the swamps to kill the larvae 4.Using biological control
66 of 110
Why are the problems of using drugs to treat malaria?
They have limited effectiveness and have side effects
67 of 110
What has the vaccine been difficult to develop?
Resistance is increasing and there are many antigenic types
68 of 110
Why is the vaccine not very effective?
It is only effective against the parasite when outside body cells
69 of 110
Why do bacteria have a specific shape?
Due to their rigid cell wall
70 of 110
What is the name of the chemical that makes up bacteria cell walls?
Bacteria cell walls contain murein
71 of 110
Describe the structure of this chemical?
They consist of polysaccharide cross linked by amino acid side chains
72 of 110
Why is the cell wall important for bacteria?
The cell wall protects against osmotic lysis
73 of 110
Name 2 types of antibiotics and describe them?
Gram positive and Gram negative
74 of 110
Describe the structural differences between gram positive and gram negative bacteria?
Split into 2 groups according to whether they take up a stain called crystal violet. Gram positive can take up the stain to become purple but gram negaitive do not take up the stain
75 of 110
Describe how penicillin kills bacteria?
It affects the formation of cross linkages in the bacteria cell wall. The cell walls become weakens and takes up water so it swells. The weak wall cannot withstand the pressure and break
76 of 110
Why aren't human cells or viruses affectived by antibiotics?
Human cells and viruses do not have a cell walls. Viruses do not have metabolic pathway
77 of 110
What is a parasite?
Organisms that live on/in other organisms
78 of 110
Name two groups of parasites and describe the difference?
ECTOPARASITES are specialised to a degree but live outside the body of the host. ENDOPARASITES live inside the body of the host.
79 of 110
What type of parasite is the pediculus?
Its a headlouse which is an ectoparasite
80 of 110
Where is it found?
It is found on the scalp of the host
81 of 110
What does it feed on?
Feeds by sucking blood from the scalp of the host
82 of 110
How is it transferred?
It can walk from one hair to another so it is transferred by close hair contact
83 of 110
Describe 3 adaptations of the pediculus?
The 1.eggs are called nits and are laid glued to the base of the hair 2.Produces a large number of offspring 3. The adults have claws on the end of their legs which allow them to attach themselves to the hairs on the head.
84 of 110
How is pediculis treated?
The use of insectacides and using a fine comb to remove the nits
85 of 110
What type of parasite is the blood fluke?
Endoparasitic flatworms
86 of 110
Where is the blood fluke found?
Living in the blood vessels of the intestine or bladder
87 of 110
What ilness is caused by the blood fluke?
Schistosomiosis
88 of 110
Descibe the first 3 stages of the blood flukes life cycle?
The larvae are picked up from freshwater and penetrate through the skin of a human when they go fishing or washing. They enter a vein and then pass through the body in the blood stream to the liver. In the liver they mature to adults.
89 of 110
Descibe the last 3 stages of the blood flukes life cycle?
They enter the capillary network where they feed on red blood cell. Many eggs are produced and are shed in faces or urine. These develop in the snail and the larvae are released into the water to infect human host
90 of 110
What type of parasite is the ascaris?
Endoparasitic
91 of 110
How many eggs are produced by the ascaris every day?
200,000 eggs
92 of 110
How do these eggs pass out of the body?
In the faeces
93 of 110
How do these eggs gain access to the human beings?
Children become infected after touching the mouth with hands that have been contaminated with the eggs
94 of 110
How do the eggs get into the blood?
Penetrate the intestine
95 of 110
Where do the eggs travel now?
To the lungs
96 of 110
How does the hatched larva get from he small intestine to the lungs?
Pass into blood vessels.
97 of 110
What type of parasite is the tape worm?
Endoparasitic
98 of 110
What is the primary host organisms for this parasite
Humans
99 of 110
What is the secondary host organisms for this parasite
Pigs
100 of 110
How does the secondary host organisms become infected?
As it feeds in drainage channels contaminated by human faeces
101 of 110
How does the primary host organisms become infected?
By eating undercooked pork
102 of 110
Describe 8 adaptations of the tape worm to allow it to survive?
1. It has suckers and a double row of curved hooks to attach to the gut wall
103 of 110
2.
It has body covering that protects from hosts immune respons
104 of 110
3.
It has a thick cuticle with inhibitors which stop the digestive enzymes from attacking the host
105 of 110
4
Simple exretory system and nervous system but most of the body is involved with reproducing
106 of 110
5
Very large surface are to volume ratio so it can absorb pre-digested food
107 of 110
6
Each segment contains male and female reproductive organs
108 of 110
7
Eggs have resistant coats to survive untill consumed by second host organisms
109 of 110
8
Large number of eggs produced. A mature segment can contain up to 400000 eggs
110 of 110

Other cards in this set

Card 2

Front

Are all micro-organisms pathogenic?

Back

No.

Card 3

Front

Are micro-organisms pathogens in every area of the body

Back

Preview of the front of card 3

Card 4

Front

What is an infectious disease?

Back

Preview of the front of card 4

Card 5

Front

What is the meaning of the term carrier?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Health, illness and disease resources »