week beginning 27th april pathogens
TRANSCRIPT
Week beginning 27th AprilPathogens
10x1 work from Miss Start
If you have any questions or problems, please email me:
Please email me your answers to the questions at the end by 4th
May – you can type them up or take a picture of your handwritten answers
Week beginning 27th AprilPathogens
Write the date and title down in your book
In this session you will learn about: • What pathogens are• How pathogens are spread• Common infections caused by pathogens
• Wherever you see this symbol, I would like you to write the notes down in your book
What are pathogens? - A pathogen is a disease causing organism (usually a microorganism).
- Microorganisms include:
Can you think of examples of diseases caused by these microorganisms?
Bacteria Protoctista Virus Fungi
How are infectious diseases spread?
• Watch the video for a visual demonstration
• https://www.youtube.com/watch?v=e-3Li7iMqMM
How are pathogens actually spread?
How are pathogens spread?
By air Coughs or sneezes can
release millions of pathogens into the air,
which can be carried by the wind
By waterDirty water can transmit diseases – e.g. cholera can be transmitted by
drinking infected water
By animal vectorsAnimals can carry
pathogens from one place to another – e.g. mosquitos
carrying the malaria parasite
By contactDirect contact by hand,
indirect contact (e.g. a wet floor contaminated by athlete’s foot), sexual
contact, via placenta, via breastfeeding
Copy this mind map into your book
• Diseases spread in water (cholera, typhoid, dysentery) are rare in developed countries, because water is treated to kill pathogens
• Keeping things clean to remove or kill pathogens is known as good hygiene
• Outbreaks occur where hygiene is difficult – e.g. after environmental disasters
The 2014-15 Ebola outbreak became an epidemic in West Africa, because many people became infected when burying those who had died from Ebola
Diseases caused by different pathogens
Copy this table into your exercise book, and use the 7 slides that follow it to fill the table in
Feel free to add your own information by doing some extra reading!
Disease What is it caused by? What are the symptoms? Other information
Cholera
Symptoms:
Severe diarrhoea
Caused by: Vibrio cholera (bacterium)
Other facts:
- Major outbreak in Italy in 1854- Robert Koch proved in 1883 that
Vibrio cholera caused the disease- Koch showed that the bacterium
that causes cholera was always found in the diarrhoea of people
with cholera, but not in the diarrhoea of people with other
diseases.
Tuberculosis
Symptoms:
Blood specked mucus after coughing
Fever (high body temperature)
Weight loss
Lung damage
Caused by: Mycobacterium tuberculosis (bacterium) Other facts:
- Communicable disease- Infects the lungs
- Robert Koch proved that tuberculosis (TB) was
caused by the bacterium Mycobacterium
tuberculosis
Chalara ash diebackSymptoms:
Leaf loss (leaves die earlier than usual)
Dieback of top branches of the tree
Bark lesions
Caused by: fungus
Other facts:
- A disease of ash trees- First spotted in the UK
in early 2012- Woodlands are now
being closely surveyed to monitor and control
it’s spread
Malaria
Symptoms:
Fever
Weakness
Sickness
Damage to blood and liver
Caused by: Plasmodium (a protist)
Other facts:
- One of the greatest causes of human death by infection
- 124-283 million cases of malaria each year
- Up to 755,000 people die of malaria every year
- Caused by the protest Plasmodium,which multiplies inside red blood cells
and liver cells. - New protists break out of the cells to
produce symptoms
HIVSymptoms:
Most people who are infected with HIV experience a short, flu-like illness that occurs two to six weeks after infection. After this, HIV often causes no symptoms for several years.
Caused by: HIV virus (human immunodeficiency virus)
Other facts:
- HIV virus attacks and destroys white blood cells in the immune
system- People infected with HIV often
develop AIDs (Acquired Immune Deficiency Syndrome) as their immune system can’t protect
them from secondary infections- Many people die from other
infections (e.g. TB)
Stomach ulcers
Symptoms:
Pain in the stomach where bacteria have attacked the stomach lining
Caused by: Helicobacter pylori (bacteria)
Other facts:
- Many types of bacteria live in our bodies, and some are essential for
our health- Over 50% of people have
Helicobacter pylori in their stomachs
- Many people are not affected, but some people develop ulcers (sore
areas) in stomach lining
Ebola
Symptoms:
Haemorrhagic fever
Caused by: Ebola virus
Other facts:
- Causes the breakdown of blood vessels and liver and kidney cells
- This leads to internal bleeding (haemorrhaging) and fever
- This is called haemorrhagic fever
Questions
1. What is the general term for a microorganism that causes a disease?
2. Why are diseases caused by microorganisms called communicable diseases?
3. What symptoms are shown by someone infected with the TB bacterium?
4. Describe the signs of malaria
5. Describe a negative effect of H. pylori on humans
Answer these questions and e-mail your answers to me
Plenary
Challenge: describe a disease caused by a bacterium and a virus, and describe the symptoms of both.
Bonus video: how are pandemics spread?
https://www.youtube.com/watch?v=UG8YbNbdaco