Hello and welcome to parasites. I hope that after
watching this lecture, you'll know the definition of a parasite.
You will understand what is a zoonosis.
It's not going to the zoo.
I hope you'll be familiar with different types of
protozoan and helminthic parasites.
And I want you to have an overview of
how parasitic infections are transmitted.
Let's start by answering the question,
what is a parasite?
Parasite is an organism that takes
metabolic advantage of another organism.
So rather broad definition and as you might expect
it encompases many different organisms
including viruses, bacteria, fungi,
protozoa, helminths and arthropods.
Today we're gonna talk about protozoan and helminth parasites.
There are parasites that are arthropods like tics.
But we won't be talking about them further
except there's possible vectors of transmission.
Another important concept is that of a zoonosis
or zoonoses which is the plural form.
These are human infections that are acquired from animals.
Can be any of the variety of different animals.
Sometimes the organism causes disease in the animal,
sometimes it doesn't.
But the point is, it's acquired from animals.
It's not a human to human transmitted infection.
Many human parasite infections are zoonosis.
They're caused by agents that infect non-human animals.
Cause we're all animals.
Humans and all those other animals on the slide are all animals
but we distinguish us from others as non-human.
An example, adults may carry the beef tapeworm
in their intestine. Adults humans.
This is acquired from cattle, not from another human.
So that's a zoonosis.
Many bacterial and viral infections are also zoonosis.
When an infection is propagated solely among humans,
that is no longer a zoonotic infection.