Parasitic Diseases Lectures #1: Introduction

Summary

This online course, based on the 6th edition of 'Parasitic Diseases' textbook, delves into the world of human parasites with Dr. Daniel Griffin and the course creator. They explore the life cycle, pathogenesis, clinical disease, diagnosis, treatment, and prevention of various parasitic infections. The course highlights the global impact of parasites, with a focus on malaria and geohelminths, and discusses the challenges of controlling these diseases in less developed regions.

Takeaways

• 📚 The course is based on the 6th edition of the textbook 'Parasitic Diseases', which has been in publication since 1982.
• 🌐 The course is available online and is open to anyone interested in learning about parasitic diseases.
• 🏆 The course is co-hosted by Dr. Daniel Griffin, who holds both an MD and a PhD degree.
• 🌟 The course's motto is 'Successful systems attract parasites', highlighting the prevalence of parasites in human systems.
• 📖 The book can be downloaded for free in PDF format from the 'Parasites Without Borders' website.
• 📊 The course consists of 45 episodes, each covering a different parasitic disease based on the book's content.
• 🔬 Each episode covers the introduction, history, life cycle, cellular and molecular pathogenesis, clinical disease, diagnosis, treatment, prevention, and epidemiology of a parasite.
• 🌍 Parasitic diseases are a global problem, with infections found wherever humans live.
• 🔴 Malaria is a significant tropical disease, with the highest number of cases in Africa, Pakistan, India, and the Middle East.
• 🐛 Soil-transmitted helminths are prevalent in areas with poor sanitation, affecting a large portion of the world's population.
• 🌱 Poor sanitation and contaminated water sources contribute to the spread of parasitic diseases.
• 🦟 Arthropod-borne diseases, such as those transmitted by insects, are a major health concern and can be lethal.

Q & A

What is the main theme of the book 'Parasitic Diseases'?

The main theme of the book 'Parasitic Diseases' is to educate readers about the various types of parasites that infect humans, their life cycles, how they cause disease, and the methods for diagnosing, treating, and preventing these infections.

Who are the hosts of the online course based on the book 'Parasitic Diseases'?

Dr. Daniel Griffin, who holds both an MD and a PhD degree, and Dr. Vincent, who is responsible for the production's professional look, are the hosts of the online course.

How can one access a free PDF copy of the 6th edition of 'Parasitic Diseases'?

To access a free PDF copy of the 6th edition of 'Parasitic Diseases', one can visit the website 'Parasites Without Borders', navigate to the menu option for the 6th edition, and click on the provided link to download the book.

What is the significance of the phrase 'successful systems attract parasites' in the context of this course?

The phrase 'successful systems attract parasites' signifies that as human beings have become the most successful species on Earth, we have become a prime target for parasites due to our widespread presence and the fact that we provide a suitable environment for them to thrive.

What is the format of each presentation in the online course?

Each presentation in the online course follows a format that includes an introduction to the subject, a brief history of discovery, a discussion on the life cycle, cellular and molecular pathogenesis, clinical disease aspects, diagnosis, treatment, prevention, control, and epidemiology, and finally, recommendations for further reading.

How many episodes are there in total in the online course?

There are a total of forty-five episodes in the online course.

What is the global distribution of malaria as discussed in the script?

Malaria is predominantly found in Africa, with the reddest colors on the map indicating the highest intensity of infection. It is also prevalent in parts of Pakistan, India, and throughout the Middle East, with the tropics being particularly affected.

What was the approximate number of malaria cases worldwide in 2015?

In 2015, there were approximately 212 million cases of malaria worldwide.

How are parasitic infections often transmitted in less developed regions?

In less developed regions, parasitic infections are often transmitted through contaminated water and soil, which can be contaminated with fecal matter containing stages of these infections. This can occur due to poor sanitation and the use of human waste as fertilizer.

What is the role of arthropod-borne vectors in transmitting parasitic diseases?

Arthropod-borne vectors, such as insects and arachnids, play a significant role in transmitting parasitic diseases. They can inject pathogens into humans or deposit them on the skin, leading to infections. Controlling these vectors is a strategy for preventing the spread of diseases.

What are some of the clinical presentations that might indicate a parasitic infection?

Clinical presentations that might indicate a parasitic infection include fever, rash, skin lesions, discomfort, respiratory complaints, and mental health issues. These symptoms can be clues for clinicians to consider parasitic infections in their diagnosis.

Outlines

00:00

📚 Introduction to Parasitic Diseases Course

The speaker introduces an online course based on the 6th edition of the textbook 'Parasitic Diseases', which has been in circulation since 1982. The course, open to all, is co-hosted by Dr. Daniel Griffin, who holds both an MD and a PhD. The course aims to educate about parasites that infect humans. The speaker highlights the importance of the course by referencing a phrase from Science Magazine, 'successful systems attract parasites', emphasizing humans as a successful system. The course is structured to cover the introduction, history, life cycle, cellular and molecular pathogenesis, clinical disease, diagnosis, treatment, prevention, and control of parasitic diseases. The speaker also encourages downloading a free PDF of the textbook from the 'Parasites Without Borders' website to accompany the course.

05:02

🌍 The Global Impact of Parasitic Diseases

This section discusses the prevalence of parasitic diseases worldwide, highlighting that parasites are found wherever humans live. The speaker uses malaria as an example, showing a 'heat map' of infection rates. Malaria is particularly prevalent in Africa, with over 212 million cases reported in 2015, resulting in 429,000 deaths. The speaker also addresses the issue of soil-transmitted helminths, which are common in areas with poor sanitation. These parasites are spread through fecal contamination of soil and water, and can be ingested through food. The speaker notes that the least developed countries have the highest number of infections, emphasizing the link between poverty, sanitation, and parasitic diseases.

10:04

🌱 Transmission of Parasitic Diseases

The speaker explains how parasitic diseases are transmitted, particularly in areas with poor sanitation. The use of human waste as fertilizer can lead to the spread of parasites through contaminated food. The speaker also discusses the role of arthropod vectors, such as insects, in transmitting diseases. These vectors can carry pathogens that cause serious illnesses, some of which can be lethal. The section concludes with a mention of the course format, which will include discussions on clinical disease, diagnosis, treatment, and prevention.

15:05

🩺 Clinical Presentation of Parasitic Diseases

This section focuses on how to approach clinical presentations of parasitic diseases. The speaker discusses the importance of quickly identifying whether a fever is life-threatening, such as malaria or sepsis, and whether it localizes to a specific body system. The speaker also addresses the presentation of skin problems, such as rashes, and how they can be indicative of parasitic infections. The discussion includes questions to consider when diagnosing parasitic diseases, such as the location and characteristics of symptoms and the geographical origin of the patient, which can provide clues about possible infections.

Keywords

💡Parasitic diseases

Parasitic diseases are illnesses caused by parasites, which are organisms that live in or on a host organism and derive nutrients at the host's expense. In the context of the video, parasitic diseases are the central theme, with the hosts being humans. The video aims to educate about these diseases, their impact on human health, and how they are transmitted.

💡Eukaryotic parasites

Eukaryotic parasites are organisms with complex cells containing a nucleus that can cause disease in humans. They include protozoa, helminths, and some arthropods. The video discusses these parasites, emphasizing their diversity and the various ways they infect humans, as part of the broader category of parasitic diseases.

💡Life cycle

The life cycle of a parasite refers to the series of stages a parasite goes through, from birth to maturity, often involving multiple hosts. In the video, understanding the life cycle is crucial for comprehending how parasites are transmitted and how infections can be prevented.

💡Pathogenesis

Pathogenesis is the process by which a disease develops due to the invasion and multiplication of a pathogen in the body. The video touches on cellular and molecular pathogenesis, explaining how parasites interact with their hosts at a cellular level to cause disease.

💡Clinical disease

Clinical disease refers to the observable symptoms and signs of an illness in a patient. The video discusses clinical disease in the context of parasitic infections, detailing what it's like to be a patient harboring these pathogens and the various symptoms they might experience.

💡Diagnosis

Diagnosis in the context of the video involves identifying the presence of a parasitic infection. It is a critical step in managing these diseases, as accurate diagnosis allows for appropriate treatment and can prevent the spread of the disease.

💡Treatment

Treatment refers to the medical interventions used to cure or manage parasitic diseases. The video will discuss various treatment options, which are crucial for patient recovery and are part of the comprehensive approach to dealing with these infections.

💡Prevention and control

Prevention and control are strategies aimed at stopping the spread of parasitic diseases or reducing their impact. The video mentions these strategies, emphasizing the importance of sanitation and public health measures in controlling the prevalence of these diseases.

💡Epidemiology

Epidemiology is the study of the distribution and determinants of health-related states in populations. In the video, epidemiology is used to understand the patterns of parasitic diseases, including where they are most common and the factors that contribute to their spread.

💡Sanitation

Sanitation refers to the hygienic practices and conditions that prevent the spread of disease. The video highlights sanitation as a key factor in the prevalence of parasitic diseases, particularly in less developed areas where poor sanitation can lead to higher rates of infection.

💡Vectors

Vectors are organisms that transmit infectious diseases between humans or from animals to humans. In the context of the video, vectors such as mosquitoes are discussed as they play a significant role in the transmission of diseases like malaria, which is a major focus of the course.

Highlights

Introduction to an online course on parasitic diseases based on the 6th edition textbook.

The book is available for free as a PDF download from the website 'Parasites Without Borders'.

The course will cover the life cycle, cellular and molecular pathogenesis of various parasites.

Malaria is highlighted as a significant tropical disease affecting a large proportion of the world's population.

The importance of sanitation and its impact on the spread of parasitic diseases is discussed.

A map is used to illustrate the global distribution of parasitic infections.

The concept that successful systems attract parasites is introduced as a central theme.

The course will explore the clinical aspects of parasitic diseases and patient experiences.

The necessity of understanding the diagnosis, treatment, prevention, and control of parasitic diseases.

The definition of a parasite as an organism that takes metabolic advantage of another organism.

The global impact of parasitic diseases, affecting billions of people.

The role of human evolution and settlement in the spread of parasitic diseases.

The dangers of consuming contaminated food and water as a means of parasite transmission.

The impact of poor sanitation on the transmission of geohelminths.

The potential health risks associated with consuming food from compromised sources.

The importance of controlling arthropod vectors to prevent the spread of parasitic diseases.

The course will use a clinical vignette approach to discuss diagnosis and treatment of parasitic diseases.

The approach to clinical diagnosis in cases of fever, rash, and other symptoms.

The upcoming discussion on eukaryotic parasites, including protozoans and helminths.

Transcripts

[Music]

welcome to parasitic diseases it's based

on the 6th edition of our textbook

called parasitic diseases which has been

out now since 1982 we're up to our sixth

edition and so what we've decided to do

dr. Griffin and myself is to introduce

this book as an online course it's open

to anybody who wants to take these

presentations and learn all about

parasitic diseases the kind that make

you sick

my producer dr. Vincent reckon yellow is

off screen but he's responsible for all

of the nuance that makes this production

look professional so I await a vote of

confidence and thanks for setting this

all up for us to begin with we'll take

you through the world of human parasites

that is to say these are organisms that

infect humans dr. Daniel Griffin has an

MD degree and a PhD degree and he will

be my co-host for this series so without

further ado let's start by introducing

the subject and it's very interesting

that we should introduce it by the

winner of a phrase that was solicited by

science magazine from its readership

what is the most important thing you

could say that happened over the last

100 years in terms of science and

biology

they actually limited it to biology and

the winner that they chose was a phrase

that says successful systems attract

parasites so that's our motto so we as

human beings are the world's most

successful system as we will see so

here's what our book looks like and in

fact for those that are not aware you

can actually download a free pdf copy of

this by simply going online to parasites

Without Borders

finding the head of the menu menu that

says PD 6th edition click on it and then

you will see a page that comes up and

it'll say for a free copy click here I

strongly recommend you're doing this you

can have it on your Kindle you can have

it on your cell phone you can have it on

your home computer you can look at

anytime you want it's obviously a

companion to the 6th edition hard copy

the episodes that follow there are forty

five of them all together are based on

what's present actually in the book and

we're going via that order so the format

for each presentation is as follows

there's an introduction where we sort of

introduce the subject of whatever that

is for that particular time then we

touch on the history of discovery we

won't go into the depth of that but

there of course is a large history

regarding how each one of these things

became known to the medical world we'll

talk about the life cycle next then the

cellular and molecular pathogenesis

section will cover how the host and the

parasite interact to produce disease or

to limit the infection in the host we'll

talk about the clinical disease of

course and that's where dr. Griffin will

come on and tell you about the details

of what it's like to be a patient that

harbors one of these pathogens finally

we'll discuss the diagnosis the

treatment of course the prevention and

control or epidemiology as the case may

be and then finally we'll have a

recommendation for you if you want to

really learn more about the subject that

we haven't covered because what we're

really giving you is a sort of a a

thumbnail sketch of the way this

presents in the real world we can't give

you all the details of course as we

would like to but you can learn more

about those details there either by

reading them in our textbook or

following the references that we've

listed at the end of each one of these

presentations so let's begin by asking

the basic question of course and that is

what is a parasite you can define this

any way you want

a lot of people have their own version

of that definition but

actually the one that fits the best for

all of the organisms out there that

cause illness in humans is a parasite is

any organism that takes metabolic

advantage of another organism they could

be a virus which is the smallest unit of

infection that we know of except for the

prion it could be Rickettsia which are

bacteria like organisms but not quite as

sophisticated in terms of their

biochemistry of course bacteria and all

of those taken together represent what

we would call organisms without a

nucleus or prokaryotes it's before the

nucleus arose in evolutionary history

but everything after that that I'll

discuss from protozoa helminths and a

few arthropods as well all contain

nuclei and those nuclei enable us to

categorize those organisms as eukaryotic

organisms and so parasitic diseases

covers the breadth and depth of that

subject of eukaryotic parasites so how

large a problem is the problem facing

Humanity of encountering eukaryotic

parasites so I show you in front of you

a map or a schematic map of the of the

world as far as we know all of the land

masses are shown and wherever people

live on those land masses we find

parasites which is quite amazing

actually

so will the examples that I think we're

all familiar with at least we've heard

of this before

is malaria so where would we find

malaria for instance throughout the

world and this map shows you vividly in

colors that the redder the color the

more intense the infection so it's

called a heat map so the red are the

infection

happens to be the reddest of the

continents because a lot of malaria is

found there the next most common place

we're finding that is as you can see in

Pakistan and India and throughout the

Middle East there's very little in the

Middle East because there's very little

water and because this is a

mosquito-borne infection you need water

for this to be transmitted but we see a

lot of it throughout the tropics and so

we consider malaria as a tropical

disease in 2015 there were roughly 212

million cases of malaria throughout the

world now the population of the earth is

about 7.3 billion so these are this is a

large proportion of that number that

encounter malaria virtually every year

with 429 thousand deaths it's compared

to the number of cases it has a very low

mortality rate but when you add up all

the number of cases of course it's one

of the largest reasons why a person

would die from an infectious disease

malaria is still one of those great

unsolved problems that we'll be

discussing on the other side of the

spectrum of eukaryotic parasites we have

the worms and everywhere where you see

the blue color is an endemic center for

worm transmission and these worms are

found as you can see throughout most of

the tropical and subtropical and even

temperate zone world depending upon the

level of Sanitation that we find there

these are just the ones that are

transmitted by fecal contamination of

soil so they're called geo Hellmann's

for that reason because the feces

contaminates the soil the soil then

contaminates things like water and the

food that we grow and crops we harvest

them we bring those stages of the

infection to our table and we ingest

them and that's why so many people have

these parasites most of the parasitic

infections that we'll be discussing

although not all are limited to places

considered to be less developed we have

less developed and at least developed

countries as their class of

now by the United Nations and we see of

course a preponderance of infection in

the places which are considered to be

the least developed therefore the

sanitation is rather primitive if at all

existing so therefore the people that

are forced to live in these places most

of them are forced to live in these

places encounter these parasites on a

daily basis as the result they're the

highest number of people infected

throughout the world if you want to know

where to go to find a lot of parasitic

infections just go to the least

developed countries and you'll find them

so you could ask of question of course

throughout the whole world why are there

so many parasitic infections when you

add them up it's like 2 or 3 billion

people's worth of infection and the

answer is quite simple because when

humans evolved out of Africa and spread

throughout the world they occupied

virtually every landmass that was

possible to get to and they settled

there some continued to explore of

course but others remained so as the

result we live everywhere and because we

live someplace we've got to eat and

therefore it turns out to we'll eat

anything that crawls or swims or flies

or grows and many people who live in

places which are compromised in terms of

their sanitation are forced to drink

water because we drink 2.3 liters of

water every day because of that need we

often drink contaminated water that's

contaminated with feces that has stages

of these infections as we will say that

are easily transmitted from person to

person so that's sort of the opening

salvo for parasitic diseases and here's

a good example of of how these parasites

are being transmitted from one person to

another what we see here is a typical

green garden somewhere in Asia and

because most people living in

compromised situations that is

financially compromised or politically

compromised or just because their level

of economics is low

than most of the world they are forced

to use the most common sources for

things that you and I would hardly think

of using in one case if you want to make

those plants grow you've got to

fertilize them so what do you think they

use for fertilizer but he was a

combination of urine and feces and it

turns out to be human urine and human

feces together they make a wonderful

growth medium for green plants but they

also transmit the stages of infections

that are present in those people from

person to person they end up on these

green grocers shelves they have in most

cases been washed to make them look

fresh and palatable but in reality that

could serve as a warning that you should

stay away from these because it contains

the water of that little creek that you

saw next to this green grocer Green

grower rather and it ends up again in

inducing people to eat things that

ultimately they they shouldn't have

eaten there are some places which are so

compromised that the children and young

adults are forced to eat let's say one

or two meals a day and these meals are

heavily contaminated with their

environment and you see these two

children sitting on the ground sharing a

meal Lord knows what's in that bowl but

it probably isn't something that would

make them healthier it probably would

take away from their sense of well-being

and it could very well contain the stage

of a parasite that we'll be discussing

later in this presentation so if the

soil base doesn't get you and if the

waterborne infections don't get you then

perhaps something will fly or crawl or

land on you and inject something into

you or deposit something on your skin

which could then result in an infection

we call these arthropod borne vectors so

author pods are jointed legged animals

some of them are insects some of them

are Arachne

the ones you see depicted here are

insects they have six legs

some of them fly some of them crawl it

depends on what stage they're at but all

of the ones shown here transmit what I

would consider to be major health

altering infections many of which have

proven lethal and so to concur on

controlling the vectors is a way of

controlling these infections rather than

looking at drugs or vaccines we have

lots of intervention strategies which

take advantage of the fact that we can

limit how many of these are the pods are

in our area of where we live now the

format as dr. de première was was

presenting is gonna follow really the

same format as our book so introduction

history life cycle cellular molecular

pathogenesis but then when we get to

clinical disease diagnosis and treatment

I'm gonna jump in we'll start with a

clinical vignette I will try to point

out a little bit about the features

we'll then move on to diagnosis and then

finally we're gonna finish with

treatment and then we'll return to dr.

de palma for a discussion of prevention

epidemiology and where one might go to

learn more as far as the approach to the

patient you know in most of these cases

you're gonna know you're in the chapter

you're gonna know what the what the case

is but I'm always gonna suggest that

people be thinking as I present the case

about how we how we focus how we make

the diagnosis how we're Altima league

owing to figure this out should we not

know going into it what it is and we'll

break things down into chief complaints

different presentations and a little bit

on how a clinician might approach this

now for instance fever rash skin lesion

is an affiliate I riobamba discomfort

general problems respiratory complaints

mental health issues these are different

ways that we start off and then kind of

move forward so let me just take a

couple of these to talk to you about

them one of the issues with feet so when

a patient presents with fever how do we

approach this we my

whether it's localizing we might also

ask whether it's life-threatening we

might say in the tropics first is it

malaria or sepsis we want to know do we

have time to think about this or do we

need to really start moving quickly here

second does it localize so there any

clues does this seem to be primarily a

pulmonary complaining a gastrointestinal

complaint something coming from the

urinary symptoms stiff neck may be rash

now rash as I mentioned sometimes this

is going to be something that comes in

the context of a fever sometimes it

presents all by itself sometimes the

chief diagnosis is I have a skin

complaint and in this in this context

we're gonna be asking where is the skin

problem look I have a skin problem is

said is it diffuse is it popular as a

particular is it scaly

as we'll get does it have a breathing

hole an odd question but by the end I

think you'll understand why we want to

know that is it sir pigeon is's it look

like a snake is it migratory is it

moving and sometimes with parasites that

is an unfortunately upsetting now what

about yes an affiliate us is going to

come up we're gonna talk about how we

approach that and this will be a a clue

in certain times that there are certain

pathogens that might be on our radar

should be on our radar but again yes an

affiliate we're gonna go back to some of

the same questions as we do with fever

that's it localized is this a person

with eosinophilia and pulmonary

complaints gastrointestinal complaints

urinary complaints a stiff neck a rash

and then where is this person coming to

us from where might they have acquired

this infection and what is common in

this geographical location so the next

time we're going to talk about an

introduction to eukaryotic parasites and

we'll go through the protozoans and the

helmets to show you the variety and then

the perhaps of something of their

lifestyles as well thank you for

listening

[Music]