You are not currently logged in. Please create an account or log in to view the full course.
Disease and Prions
Generating Lecture Summary...
Generating Lecture Summary...
Generating Vocabulary List...
Generating Questions...
Generating Questions...
- About
- Transcript
- Cite
About the lecture
In the first mini-lecture, we introduce communicable diseases by first giving a definition for disease itself. How does disease differ from injury, especially when disease can be symptomless, cause major life-changing symptoms or even cause death? Disease, such as ischaemic heart disease, COPD, and lung cancers make up some of the leading causes of death in humans, according to WHO. Communicable diseases can be transferred between subjects through a number of different means, and in this lecture we investigate some of those ways. We introduce some of the different types of organisms that can cause disease, such as bacteria, protists, viruses and parasites, before also discussing the impact of prions, particularly in the brain.
About the lecturer
Dr Matthew Ivory is a Lecturer at Cardiff University in the School of Pharmacy and Pharmaceutical Sciences (2016-present). His key expertise is in ex vivo human skin organ culture and histology, human skin immune cell extraction and culture, flow cytometry and pharmaceutical formulation, and his research interests are in the delivery of vaccines and therapeutics into the skin. In addition to this, he is also a qualified pharmacist.
Hi, My name is Dr Mo Ivory.
00:00:05I'm a lecturer at Cardiff University, and I'm also a pharmacist.
00:00:07So my research interests include things like pharmacy practise and also diseases,
00:00:10which will be the topic of today's set of talks.
00:00:14So today we are going to be looking at communicable diseases,
00:00:17some of the major types that affect humans
00:00:20and how we can treat those different diseases.
00:00:23So starting off with the concept of disease,
00:00:27it's something that everybody has a feel for.
00:00:29But not everybody can nail down a specific definition for it.
00:00:32The word itself comes from old French, meaning a lack of ease,
00:00:36and to put a real definition on it can be quite tricky.
00:00:40So one way you might think about it is a
00:00:44condition where an organism has a reduced level of health,
00:00:48and it might be that one of its organs, one of its organ systems, are affected
00:00:52and cannot function as it normally would.
00:00:56And this is different from an injury where some event has
00:00:59caused those organs stopped working Disease normally has a causative factor,
00:01:03which may be a pathogen,
00:01:07but it might also be inherent to the organism itself.
00:01:08Diseases can sometimes be symptomless,
00:01:11so a person might have a disease and not know it because it doesn't show any symptoms.
00:01:13Or they might have mild symptoms or potentially cause major
00:01:17symptoms or even death in some in some diseases,
00:01:21so diseases can arise from intrinsic factors people
00:01:24born with genetic conditions or as people age.
00:01:28Sometimes they develop different conditions,
00:01:30such as Alzheimer's or coronary heart disease.
00:01:32They can also be caused by extrinsic factors,
00:01:35so things like pathogens can cause disease poisons.
00:01:37Or it might be a combination of the two,
00:01:40so things like cancers develop as a result of intrinsic and extrinsic factors.
00:01:42So risk factors lead to the development of cancer
00:01:46within these talks are going to be focusing on communicable diseases,
00:01:51So these are diseases that can be transmitted either
00:01:53directly between people or indirectly between two infected people.
00:01:56So if you look at things on a global scale
00:02:02and look at the disease burden across the world
00:02:05and the W. H.
00:02:08O estimates that roughly 55 million people die every year of all combined causes
00:02:09and they collect data on the various causes of death,
00:02:16that happen and they rank them to kind of determine
00:02:20where the important areas of focus are for health systems.
00:02:23So globally, three of the top 10 diseases in the world are communicable,
00:02:27so these are lower respiratory tract infections, neonatal conditions,
00:02:32so conditions that affect newborn babies
00:02:37and diarrhoeal diseases.
00:02:40So if you were to further subdivide the world into kind of higher
00:02:43income countries like Western Europe and
00:02:46developing countries turned lower income countries,
00:02:48you find that the number of deaths caused by communicable diseases increases
00:02:51from 3 to 6 of the top 10 causes of death.
00:02:55So the extra causes that go in there are malaria, tuberculosis and HIV slash AIDS.
00:02:58So these are causing a much higher death rate in
00:03:05lower income countries than they are in developed countries.
00:03:09And so that's why they're seen
00:03:11more frequently.
00:03:12The data I'm talking about is from 2019, so the W. H. O.
00:03:15Hasn't published its figures yet for 2020 and 2021.
00:03:19But with 4.4 million deaths at the time of recording from Covid,
00:03:22it's likely that this is gonna be in the global top 10
00:03:26causes of death worldwide for 2020 and potentially 2021 as well.
00:03:30So the ways that communicable diseases can be transmitted between people
00:03:34and there are a few different ways that this can happen.
00:03:39So it might be that you come into direct contact with an infected person,
00:03:41so a lot of pathogens will multiply within a person,
00:03:45and so they become a kind of pathogen factory.
00:03:48And so if you come into direct contact with them,
00:03:51then they can spread those pathogens to you.
00:03:52It might be that there are contaminated fluids,
00:03:56so some pathogens reside in saliva or in blood.
00:03:58And it might be that you come into contact with infected fluids
00:04:02and, as a result, become infected yourself.
00:04:06And this will depend on the life cycle of the pathogen that's involved.
00:04:07So some of them reside in blood, and so bloods will be the high risk fluids.
00:04:10Others in saliva.
00:04:14Another way that communicable diseases are
00:04:15transmitted is via droplet transmission,
00:04:17so things like coughs and sneezes generate aerosols.
00:04:19And these can pass pathogens from one person to another.
00:04:22And this is particularly important in winter seasons.
00:04:25When people are inside,
00:04:27got the windows closed because it's cold and that's why you
00:04:28see things like respiratory viruses in the flu a much higher,
00:04:31much more prominent during the winter months.
00:04:35It can also be that there's a third organism involved.
00:04:39So as well as a pathogen and human.
00:04:42You might have something called a vector,
00:04:43which is an animal that can transmit a disease,
00:04:45and it might be that you're just in close proximity.
00:04:48So in a lot of developing countries they
00:04:51will share kind of living space with animals.
00:04:52Or it might be that you get bitten, say, by an insect,
00:04:55which can transmit that disease to you.
00:04:57And lastly, it might be through contaminated water or food.
00:05:00So there a number of different pathogens that can multiply in water supply.
00:05:03And so if you're drinking contaminated water or you're
00:05:08not cooking food that's been washed with contaminated water,
00:05:10you may well encounter a pathogen in your kind of food and water intake,
00:05:13and that can cause disease as well.
00:05:19So proper cooking, very important.
00:05:20Proper sanitation,
00:05:23good sewage systems absolutely vital to try and
00:05:24reduce the amount of disease in areas where
00:05:26diseases that grow in water are endemic.
00:05:30So when we think about our strategies for fighting disease,
00:05:33there's two ways we can go about it.
00:05:37We can either be proactive and try and prevent disease from occurring,
00:05:38and this is a prophylactic strategy.
00:05:43Or we can wait till people get diseases and then cure those diseases. And so
00:05:45there's obviously the old saying of an ounce of prevention is worth a pound of cure.
00:05:49And that's absolutely true when it
00:05:53comes to communicable diseases that efforts that
00:05:55can prevent humans developing disease can reduce the incidences of side effects,
00:05:58reduce mortality and reduce spread of disease as well.
00:06:03So, quite often, the most effective way, both scientifically and economically,
00:06:06is to try and prevent disease from occurring or trying to limit
00:06:10outbreaks rather than trying to just treat the cases that occur.
00:06:13So one of the most established ways of doing this is through vaccines.
00:06:17Um, I do another series of talks on vaccinations,
00:06:20so if that's something you're interested in, you can give that a watch.
00:06:23And the way that vaccines benefit us is that the
00:06:26people who are vaccinated will become immune to a disease,
00:06:29but also those who aren't vaccinated or aren't able to respond properly
00:06:32to a vaccine can benefit through a process called herd immunity.
00:06:36As I said before, We can also use improved sanitation,
00:06:41so good sewage systems keeping sewage and drinking water separate.
00:06:44Good cooking technique can also limit the chance of infection as well.
00:06:48And that's one of the reasons that more developed
00:06:53higher income nations have a lower communicable disease.
00:06:55Death rate is that we have these systems in
00:06:58place that can help to prevent the diseases.
00:07:00There are also a number of treatments because, however hard you try,
00:07:04some people will still get infected with the disease.
00:07:08There will still be outbreaks and pandemics.
00:07:10And so we have a number of different
00:07:13drug treatment strategies to treat communicable diseases,
00:07:15and we'll talk through some of those in the series of short lectures.
00:07:18You can also use some drug treatments prophylactically,
00:07:23but this will vary depending on the causative agent of the disease.
00:07:25So the cost of agents we're going to talk about
00:07:31in the series of talks we'll talk about viruses.
00:07:34We'll talk about bacteria.
00:07:36We'll talk about protests and then we'll
00:07:37talk about fungi and multicellular parasites.
00:07:39And like I said,
00:07:42we'll talk about some of the diseases that are caused by these organisms.
00:07:43We'll talk about how we fight them and how we try and prevent them as well.
00:07:48But just to finish off this first talk, we'll just have a brief chat about prions.
00:07:52So prions kind of sit in a kind of near life place that they're not quite organisms.
00:07:56They lack some of the characteristics to be considered alive,
00:08:03and what they are is a pro, tenacious infectious particle.
00:08:06That's what prison is short for,
00:08:10and they are misfolded proteins.
00:08:13So obviously in your body you have lots of different proteins, enzymes,
00:08:15structural proteins.
00:08:18And most of them do the job that they are supposed to
00:08:20but spontaneously every now and then one of the proteins misfold.
00:08:22And sometimes that just means the protein doesn't do its normal function.
00:08:28So it might be that the enzyme loses its activity.
00:08:31But in some cases this misfolded protein gains
00:08:33the ability to then misfolds other proteins,
00:08:37so creating copies of itself.
00:08:39So
00:08:41in a way, it kind of semi replicates, and that creates more copies of itself.
00:08:42But it needs those existing copies of protein.
00:08:46It doesn't have any machinery there to generate copies of that protein.
00:08:48Um, it lacks any genetic material, so it's not able to replicate on its own,
00:08:52and they tend to occur in neuronal tissues.
00:08:59So what happens is the protein misfolds,
00:09:02and then these misfolded proteins tend
00:09:05to aggregate into something called amyloid.
00:09:07These amyloid build up and cause cell death.
00:09:09And so if you've got cell death going on in your nerve cells,
00:09:11then you're gonna have neuronal loss,
00:09:14and you're gonna have a breakdown of the
00:09:16nerves and lots of nerve function in patients,
00:09:18so that can lead to loss of motor function so you can't move as well.
00:09:21It can lead to neuro degeneration in the brain,
00:09:26and this can lead to memory loss and psychological symptoms In the U. K.
00:09:28One of the most common prion diseases is bovine spongiform encephalopathy,
00:09:34and this is also known as mad cow disease, um, in the tabloid newspapers.
00:09:39And so this occurred where kind of dead animal tissue was being re used to feed cows.
00:09:44And so you're having these build up of prions which were then perpetuating,
00:09:49and it was able to be transmitted to humans.
00:09:53And the problem with prion diseases is that there are no cures currently known.
00:09:55They're very poorly understood,
00:09:59and they are always fatal.
00:10:01So if someone has a prion disease diagnosed,
00:10:02you may be able to prolong their life or improve the quality,
00:10:06but unfortunately they are always fatal diseases.
00:10:09So watch the space. Hopefully, science will find some answers in the near future,
00:10:12be quite an emerging disease.
00:10:16
Cite this Lecture
APA style
Ivory, M. (2022, August 30). Module 7: Infectious Disease - Disease and Prions [Video]. MASSOLIT. https://massolit.io/options/module-7-infectious-disease?auth=0&lesson=8668&option=15854&type=lesson
MLA style
Ivory, M. "Module 7: Infectious Disease – Disease and Prions." MASSOLIT, uploaded by MASSOLIT, 30 Aug 2022, https://massolit.io/options/module-7-infectious-disease?auth=0&lesson=8668&option=15854&type=lesson