Hi there, I'm Mrs. Kemp, and welcome to today's lesson all about bacterial and viral diseases in humans.

We're going to be talking about TB, cholera, Helicobacter pylori, and also Ebola.

So let's get started on the lesson then.

Our outcome for today is I can describe examples of common bacterial and viral diseases in humans, how they are spread and ways to reduce the spread.

These are some of the key terms that we're going to be using today, and if you'd like to read those in more detail, please do pause the video now.

we've got three learning cycles.

We've got pathogens, pathogenic bacteria, and pathogenic viruses.

Of course, we will begin with pathogens.

So a pathogen is a virus, bacteria, or other type of microorganism that causes a communicable disease.

A communicable disease is a type of disease that can be passed from organism to organism, so person-to-person.

They include things like viruses then, bacteria, fungi, and protists.

Not all microorganisms cause disease: only pathogens do.

And pathogens can in fact infect plants as well as animals, that you will see throughout your learning.

Pathogens are able to be spread then from one infected organism to a healthy one.

And you can see that there are different ways of passing these diseases.

In that image there, there is a person sneezing, and any way that bodily fluids can be passed from one person to another, like blood, saliva, mucus, semen, or in fact waste products including faeces or maybe vomit, they would all be able to spread communicable diseases.

We also find diseases in contaminated food and water, and also, it can be passed by touching one person and another person.

Okay, true or false? Pathogens are microorganisms that cause disease.

Is that true or false? Can you justify your answer? A: not all microorganisms cause disease, or B: all microorganisms cause disease.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay.

Did you think of true? And that is because not all microorganisms cause disease.

Excellent.

Well done.

So not all microorganisms are in fact pathogens.

Some of them live on us, in us, around us without causing any harm at all.

And in fact, we actually have millions of bacteria living in our digestive system.

They're called our gut flora, and they're actually very helpful.

So they're not pathogens; they're not causing disease down there.

They're actually doing something really important for us, and we want them to be there, okay? For example, they can help digest food that we cannot digest properly ourselves.

So they can provide some extra nutrients out of our food.

So we would like to encourage those types of microorganisms to live inside us.

We also use bacteria to make food and medicines, so things like medication that we might need to take, or even making food, so like yoghourts and cheeses, we actually use bacteria to help make those as well.

All right, which substances do bacteria help to make? A: apples, B: medicine, C: wood, or D: yoghourt? I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay.

Did you get B: medicine and D: yoghourt? Excellent.

Well done.

So onto our first task of the day then.

So if you want to get your worksheets out, you can record your answers on there.

Number one: What is a pathogen? Number two: Name two types of pathogen.

Number three: Describe some microorganisms can be useful.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay did you get a pathogen is a microorganism that causes a disease? Number two: Any two from bacteria, fungi, viruses, and protists.

Number three: Our gut flora is made up of millions of bacteria.

These can help digest food that we cannot digest by ourselves.

We also use microorganisms to produce medicine and food such as yoghourt and cheese.

Excellent.

Really well done.

Please feel free to add to your answer if you wish.

Onto our second learning cycle of the day then: pathogenic bacteria.

So bacteria are known as prokaryotes, okay, which means that they don't have a nucleus.

Here is a bacterial cell, and we can see that they have a circular loop of DNA, and that is not enclosed in a nucleus like we find in other types of cells, like plants and animals that are eukaryotes.

Bacteria are actually able to produce toxins.

When they produce those toxins then, it's that that makes people feel poorly, because that toxin can actually damage the living tissue.

Okay, what do bacteria produce that cause damage to the host? A: antibodies, B: poison, or C: toxin? I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay.

Did you get C: toxins? Excellent, well done.

So tuberculosis, or we sometimes call it TB for short, is an example of a communicable disease.

So it can be spread from organism to organism, caused by a bacterium called Mycobacterium tuberculosis.

Hence, the reason that we often shorten it to TB.

TB is a disease that mainly affects the lungs and can cause lung damage.

It is actually a very serious disease, and you have to treat it with antibiotics to make sure that it goes away.

Symptoms can include a persistent cough, a high temperature, loss of appetite.

We can see there that a doctor is listening to the back of a patient to hear their lungs, to see whether or not there could be a potential of TB.

When a person that is infected with TB coughs or sneezes, the tiny little droplets of mucus contain the bacteria, and they can spread through the air from person to person.

In order to prevent the spread of TB then, anyone at risk of getting TB infection should get a vaccination, okay? This can massively reduce the spread of TB around a community.

Okay, how can you control the spread of TB? A: eat a balanced diet, B: cook food properly, or C: get a vaccination? I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay.

Did you get vaccination? Excellent.

Really well done.

So cholera is another example of a communicable disease that's caused by bacteria.

And it is usually spread through contaminated food or water.

You probably know the example of where a water pump in London got contaminated with cholera, and it spread across London.

But actually, that was a long time ago, but we still see cholera outbreaks in other countries, especially where there have been natural disasters or some sort of war or armed conflict.

And that's because in those areas, the normal water systems actually often break down and people do not have access to clean water.

Symptoms may include things like diarrhoea, vomiting, or stomach cramps.

Vomiting and diarrhoea, although we don't think about them necessarily as being quite serious, in certain times, it can be really, really serious.

It can lead to dehydration and shock.

Shock is where you actually have a much lower blood volume, usually because of the plasma being reduced, which, remember, is the liquid part of your blood, and so therefore you haven't got enough of a supply for your tissues.

It can even lead to death.

So if a person isn't rehydrated effectively and fast enough, they can actually die.

People can be treated with oral rehydration fluids.

You can see a little packet there that will contain lots of different salts and minerals.

And you mix it with water in order for a person to become rehydrated much quicker.

Some patients may actually need antibiotics then.

And in areas where there is a high risk of cholera, we may actually provide people with a vaccine.

Helicobacter pylori is another bacterium that can also cause a noncommunicable disease.

In this case, it is a stomach ulcer.

Stomach ulcers, or sorry, the Helicobacter is actually a common infection that actually lots of people have.

And it seems to be quite harmless.

It can be transmitted or released through saliva.

For some unknown reasons then, some people, when they have this bacterium, actually are more likely to then get a stomach ulcer.

How it develops is that bacterium, we can see it in the image there, burrows into the stomach lining.

Now, the stomach lining usually has a protective layer on it, because obviously you've got hydrochloric acid in your stomach.

So when the bacteria actually burrows in, it reduces that protection against the stomach acid, and so the stomach lining then becomes irritated and inflamed, leading to an ulcer.

Ulcers can cause stomach pains, indigestion, and lack of appetite.

And you might see people losing a lot of weight, for example, when they have a stomach ulcer.

These can all worsen symptoms of stomach ulcers then that are caused by Helicobacter pylori.

So if you eat lots of spicy food, if you're very stressed, excessive alcohol consumption and all, and also smoking, all of these things can irritate that stomach ulcer more and make it feel worse.

They can use antibiotics to treat stomach ulcers, as long as it is a stomach ulcer caused by that bacteria.

The spread of the bacterium can be reduced by practising good hygiene, such as washing hands and also making sure that food is prepared in clean conditions.

So those things can help to reduce the reduce spread.

Okay, true or false? Cholera is spread when a person coughs and sneezes.

Is that true or false? Can you justify your answer? The bacteria is found in the droplets of mucus, or B: cholera is spread through contaminated water and food.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay.

Did you get false? And that is because cholera is actually spread through contaminated water and food.

Excellent.

Really well done.

Okay, onto our next task of the day then.

So if you want to open up your worksheets, you can write your answers on there.

A man has a stomach ache.

He lives in the UK, hasn't travelled out of the country in some time, and has been under a lot of stress at work.

Usually, he loves going out to eat spicy food with his friends, but recently he's not had a very good appetite and has been experiencing indigestion.

Number one: Which of the bacterial infections would you test the man for? Explain why you would test for this bacterial infection.

And number three: What treatment and advice would you give him? I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay, did you realise that you probably needed to test him for Helicobacter pylori? And that is because the man has a stomach ache, but it's unlikely to be cholera as he hasn't travelled out of the country.

He has indigestion and a loss of appetite.

He also has been under a lot of stress, which may have worsened his symptoms. Number three: If he tests positive, he should be treated with antibiotics.

The man should look for ways of reducing his stress, as this worsens the symptoms of stomach ulcers.

He should also avoid spicy food and smoky environments.

Okay, if you need to add any more into your answer, please do that now.

So onto our final learning cycle of the day: pathogenic viruses.

So viruses are not actually alive, okay? They don't carry out all seven processes of life without other cells.

So they cannot reproduce on their own, they cannot respire, these types of things that we remember from Mrs. Grenn.

And actually, that means that they have to have another host in order to be able to reproduce.

We can have a look at this image here that's showing, first of all, a virus entering the host cell.

It gets into the cell's own systems, and actually uses its own cellular functions in order to replicate a new virus.

The cell puts that virus together, and then the virus can burst out of that host cell.

This is what causes damage to the host.

Similar to the pathogens and viruses, it can actually survive for a long period of time outside of the body, okay? So if a person sneezes and that virus was in the mucus and it gets onto a surface, it can actually remain there for quite a long period of time, even after it's dried out.

They can also lay dormant in cells for long periods of time.

This can be a real problem then, because actually, the host may not realise they actually have the disease because they're not showing any signs and symptoms. But it is still hiding inside their cells, and they are probably still infectious.

Okay, two students were discussing whether viruses are alive.

Who is the best answer.

Laura: "I think viruses are alive because they are made of cells." Sofia: "I don't think viruses are alive because they cannot replicate on their own." I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay.

Did you get Sofia? "I don't think viruses are alive because they cannot replicate on their own." Excellent.

Really well done.

Okay, so a type of virus infection that we need to know about is Ebola.

It's actually very rare but really, really serious.

And it's caused by the Ebola virus.

The virus is thought to have actually passed from fruit bats.

We can see a fruit bat there in the image, okay? And that might be that people have been hunting them and eating them, for example.

The Ebola virus can be passed from human to human through bodily fluids and items that have been touched by infected persons, such as clothing; that could even be post somebody dying from the infection.

Actually, the body remains infectious for quite a long period of time.

Outbreaks have occurred in several African countries, and the symptoms include things like fever, fatigue, so feeling quite tired, pains in the joints and muscles, and also headaches.

From that then, that tends to then lead on to diarrhoea, vomiting, and then internal bleeding and viral hemorrhagic fever.

And actually, it's got a real high fatality rate.

It's actually 50% of people do end up dying if they have contracted Ebola.

That's really, really high and very serious.

There is currently no cure for Ebola.

Treatment mainly involves that oral rehydration therapy that we mentioned earlier, so where you've got salts and minerals, and you mix it with water and drinking, and that will really just help with dehydration.

To prevent the spread of Ebola, the WHO suggests, so the World Health Organisation, suggest people in infected areas should make sure that they're washing their hands regularly, they actually avoid touching the bodily fluids of other people who may have had or have Ebola, not touching the bodies of anyone that has died from Ebola, and also getting the Ebola vaccine if they are at high risk of a particular type of Ebola.

There isn't a vaccine that covers all different strains of Ebola, but if you do think that you have a risk of one of the variants that does have a vaccine, then you should get them.

Health workers are actually at really high risk of getting Ebola then in these different areas, because obviously they're being exposed to things like vomit, so actually bodily fluids of people that probably have Ebola.

And also, they are exposed to the bodies of dead people, so they're much more likely to be getting this.

So they would probably want to make sure that they are wearing protective clothing as well.

We can see that in the image there.

And also making sure that they do definitely get that vaccine.

Okay.

Which type of pathogen causes Ebola? A: bacteria B: fungi, or C: virus? I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay.

Did you realise that it's a virus? Excellent.

Well done.

So onto our final task of the day then.

This is task C.

And so you can record this on your worksheet if you wish.

Can you create an information leaflet on Ebola? You should include: 1: What causes Ebola? 2: The symptoms someone with Ebola may experience.

3: Treatment for Ebola.

And 4: Advice on how to prevent the spread.

I'll give you a moment to think about it, but if you need more time, please pause the video.

Okay.

So have you included that it is the Ebola virus? You may experience fever, fatigue, joint and muscle pain, headaches.

This can lead to diarrhoea, vomiting, internal bleeding, viral hemorrhagic fever, and potentially death.

Unfortunately, there is no current cure for Ebola, but treatment would involve oral rehydration therapy, or ORT.

Things that you can do then: Wash hands, avoid touching the bodily fluids of people who have or may have Ebola.

Do not touch the bodies of people who have died from Ebola, and also get the vaccine if you are at risk of a particular variant of Ebola.

Okay, so we're onto our summary then, and we're going to go through the key learning points from today.

So some microorganisms are pathogens and cause communicable diseases.

Some microorganisms do not cause disease, such as the ones that live in our digestive system.

Pathogenic bacteria produce toxins that damage living tissue and cause disease.

Cholera, TB, and Helicobacter pylori are all examples of bacterial infections.

Viruses invade cells to reproduce, where they cause damage to cells.

Ebola is an example of a viral infection that is spread through bodily fluids.

Okay, I'm really happy that you decided to learn with me again today, so hopefully I'll see you again soon.

Thank you very much.

Bye.