Modes of Transmission of Diseases - Why do we fall ill, Class 9 Science

hello friends now we'll cover the topic
that is modes of transmission in modes
of transmission we'll go through what
are infectious agents how they are
transmitted and how they call the
busyness okay so for this we need to
understand first of all water pathogens
pathogens means the harmful
microorganisms which are causing various
types of diseases or the agents which
caused infectious diseases know the
infection say agents may be we have seen
they can be bacterias they can be
viruses they can be Protestants or they
can be fungi bacteria causes diseases
like cholera Vibrio cholera colony
causes cholera s-type he causes typhoid
M tuberculosis causes tuberculosis like
so all these diseases are caused by
bacteria so different bacteria causes
different types of diseases viruses
cause these type of diseases like common
cold
influenza AIDS hepatitis B all these are
examples of there are diseases which are
caused due to viruses now protozoans
as we have seen earlier Plasmodium which
causes malaria and it's vector or the
carrying agent is mosquito then again
like you can say kala-azar amoebic
dysentery sleeping sickness all these
are examples of protozoans okay next
fungi fungi causes various types of skin
infections okay now skin infections may
be of various type like you can say
rashes are observed you can say there's
a total dryness in your skin so there
are various types of skin infections
which are caused due to fungi not
different species of microbes you know
target your different parts of the body
like you can say they have different
point of entry if they enter your nose
they're likely to go to your lungs and
they can cause different
types of breathing problems like when
viruses they target the your lungs they
are commonly facing common cold and all
again when the bacteria enter your mouth
they go to the gut or you can say to
stomach and they call and they can cause
various types of food poisoning okay
again when the different bacterias are
you can say they enter your bloodstream
they can cause malaria non so these type
of microorganisms you know depend upon
different types of portal of entry
okay now infectious disease spread from
infected person to healthy person we
know and there are different types of
medias you can say modes of transmission
like it can transmit through air it can
transmit through water food vectors
physical contact social contact as we
have now we will see in detail about how
the bacterias are transmitted through a
now when a infected person is Karen is a
if a person is infected from common cold
what happens that that person during
coughing or sneezing any exhales
different different you can say
different types of bacteria so you can
say that particular bacteria which is
causing common code so healthy person
when inhales that air is likely to cause
common cold or you can say tuberculosis
or pneumonia again now through water if
the person is likely to drink unsafe
drinking water he is good I mean the
chances are increased of getting him to
get cholera or amoebic dysentery so
drinking unsafe water also causes the
person to get the disease so water
should be and so what is in also we can
say the most important mode of
transmission which transfers the
microorganisms again comes the vectors
vectors means then with organism or
in sedan which carries infectious agents
from sick person to potential host
example the best example we have seen of
mosquitoes that causes malaria that
means the plan mosquito is not causing
malaria Plasmodium vivax the protozoa
now Plasmodium vivax that is a protozoa
that is present in mosquito and that
enters into the body of a person and
he's likely to get the disease that is
malaria or dengue
okay again flies well now flies sit on
various if you say if you can say
example like if the fly sitting on a
dirty place and again that same fly
flies and comes and sits on your food
and if that food is consumed by you you
are likely to suffer from dysentery
typhoid or tuberculosis or diarrhea ok
so this was all about vectors next
through social contact means if you are
having unprotected sex or if the person
is suffering from HIV virus through
sexual contact this edge AIDS virus are
likely to get transmitted into a healthy
person okay so AIDS is caused due to HIV
virus again syphilis is caused due to
Treponema pallidum
this is also an microorganism which when
enters from healthy person to and from
infected person to a healthy person
caused due to chip anima pallidum this
organism now AIDS virus is also
transmitted through blood transmission
means if the same syringe is used from
the infected person to a healthy person
if the same syringe is used he is likely
to get acquainted with AIDS virus again
if a mother is infected by HIV virus
then during pregnancy or through
breastfeeding the baby is also
have the chances of getting HIV virus
now what happens in HIV infection is
that our immune system fails to destroy
this bacteria and this bacteria survives
in her body for long period of time
ultimately leading to all you can say
ultimately leading to death so this is
the most dangerous virus we can say so
this was all about modes of transmission
how disease are transmitted the next
session will cover about how these
diseases can be prevented or what all
treatment should be taken