Communicable diseases Year 10 Flashcards
1
Q
What are communicable diseases?
A
diseases that can be passed from one individual to another. these are caused by pathogens
2
Q
What are pathogens?
A
microorganisims that cause disease
viruses, bacteria, protists or fungi
3
Q
How do pathogens cause people to feel ill?
A
- cause damage to tissues = we feel ill
- bacteria may make** toxins** that damage tissues
- bacteria and viruses may spread rapidly throughout the body
4
Q
How are communicable diseases spread?
A
- direct contact - touching an infected person (both sexual and non sexual)
- water - pathogens entering water supply, drinking contaminated watter or food it is added to
- air - when infected person sneezes or coughs tiny droplets spray out. another person breathes them in or lands on surfaces that other people touch
5
Q
How do you reduce the spread of disease?
A
- contact - disinfecting surfaces, regular hand washing, avoided risky sexual contact, isolating sick idividuals
- water and food - sterilisation of drinking water using chemicals or UV light, cooking food, boiling water, treatment & safe disposal of sewage
- air - using a tissue when sneezing or coughing/ good ventilation
- all - vaccination for a specific disease so that people cannot pass it on
6
Q
How do viral diseases work?
A
- viruses have genetic material enclosed in a protein coat
- reproduces using host cells they infect and enter
- viral genetic material used by host cell to replicate virus
- causes damage and death of cells as new viruses burst from infected cells
7
Q
Examples of viral diseases
A
- HIV
- measles
- tobacco mosaic virus
8
Q
what are the symptoms of HIV and how would it develop if left untreated?
A
- flu like illness
- early and ongoing treatment with antiretroviral drugs keeps virus under control
- untreated = leads to AIDS
- immune system is damaged so badly that it can not defend against other infections or cancer cells
9
Q
How is HIV spread?
A
- sexual contact
- exchange of body fluids (eg blood)
10
Q
What are the symptoms of measles?
A
- fever
- red skin rash
- can kill or cause pernament damage
- young children are vaccinated against it
11
Q
How is mealses spread?
A
- in droplets when an infected person coughs or sneezes
12
Q
What are the symptoms of tobacco mosaic virus?
A
- yellow patches in a “mosaic” pattern on leaves
- reduces photosynthesis & growth of plant
13
Q
What are the symptoms of gonorrhoea?
A
- think green or yellow discharge from vagina or penis
- pain when urinating
14
Q
How is gonorrhoea spread and treated?
A
- sexually transmitted
- treated with penicillin
- antibiotic resistant strands appeared = more people with disease
15
Q
What are the symptoms of salmonella and what is it caused by?
A
- fever
- abdominal cramps
- vomiting
- diarrhoea
- bacteria invading tissues and secreting damaging toxins
16
Q
How is salmonella spread?
A
- when bacteria is in food that is eaten
- source of contamination = infected animal or person’s faeces
- more likely when food is prepared in an unhygenic way
17
Q
What kind of disease is rose black spot?
A
fungal disease
18
Q
What are the symptoms for rose black spot?
A
- leaves develop purple or black spots
- leaves turn yellow and drop off early
- less healthy leaf tissue = growth of plant is slowed
19
Q
how can rose black spot be treated?
A
- with fungicides- chemicals that specifically kill fungi (sprayed onto the leaves)
- removing and destroying the affected leaves
20
Q
how do fungi reproduce?
A
- using microscopic spores
- small enough to be carried on the wind
21
Q
What is malaria caused by?
A
- protist called plasmodium
22
Q
How is malaria spread?
A
- starts in first host mosquito
- bites first person, they get infected
- second mosquito bites infected person and becomes a vector for the disease
- second (now infected) mosquito bites second person and passes on the disease
23
Q
What are the symptoms of malaria?
A
- episodes of fever
- headache & high temperature
- could be fatal
24
Q
How is the spread of malaria controlled?
A
- preventing mosquitos from breeding by draining water from ditches and small ponds
- using insecticides to kill the larvae
- using mosquito nets to prevent people being bitten while asleep
25
What are the four non specific human defence systems?
- skin
- trachea and bronchi
- stomach
- nose
26
How does skin act as a non specific defence system?
- **physical barrier** that pathogens cannot pass through
- **glands** in skin secretes substances that have **antimicrobial properties** (kill or stops the growth of pathogens)
27
How does the stomach act as a non specific human defence system?
- cells of stomach produces **hydrochloric acid**
- kills pathogens in food
28
How does the trachea and bronchi act as a non specfic human defence system?
- cells produce sticky **mucus**
- **traps pathogens** in inhaled air
- **cilia** (hair like projections) in bronchi move backwards and forwards)
- **sweeps** the mucus and pathogens to the throat to be **swallowed**
- pathogens **die in stomach**
29
How does the nose act as a non specific human defence system?
- **nose hairs trap** pathogens that are suspended in the air or attached to dust particles
- **reduces the risk of infection** of the lungs and throat
30
What are antibiotics for?
- **kill bacteria**
- do not kill viruses
- different types are needed to treat specific bacterial diseases
- new strains of bacteria that are resistant to antibiotics
- race to develop new types of antibiotics to kill resistant strains as they develop
31
What are painkillers for?
- treating the **symptoms** of the disease
- **does not kill the pathogens**
- will not cure the disease
32
Where does digitalis originate from?
foxgloves, used to treat heart conditions
33
Where did penicillin originate from?
- discovered by **alexander fleming**
- from the mould **penicillium**
- fungus contaminated a plate of agar which killed the bacteria that he was culturing
34
Where did aspirin originate from?
- extracted from willow tree
35
what are the three stages of drug testing?
- preclinical testing
- early clinical testing
- further clinical testing
36
What happens during preclinical testing?
- tests on **cells, tissues, and live animals**
- tests for **toxicity, efficacy and dose**
- takes place in a laboratory
37
What happens during early clinical testing?
- carried out on **healthy volunteers**
- tests for **safety and toxicity**
- uses very **low concentrations** of the drug
38
What happens during further clinical testing?
- carried out on **patients with the disease**
- tests for **optimum dosage** and **efficacy**
- includes **double blind trials** in which some patients are given a **placebo**
39
What is a double blind trial?
- both doctors don't know which is the new drug or placebo to remove bias
