Importance of Aero-Microbiology in Understanding Airborne Diseases
Microbiology
of
Air
Dr. H. VAJIHA BANU
Assistant Professor
Department of Microbiology
Jamal Mohamed College (Autonomous)
Tiruchirappalli-620 020
Class: II M.Sc MICROBIOLOGY
CONTENTS:
•
Aero-microbiology
•
Airborne
diseases.
•
Sources
of
microorganisms
in
Air
•
Microbes
in
atmosphere
•
Bioaerosol
Aero-microbiology:
Definition:
“Study
of
living
microbes
suspended
in
air”
•
Various
layers
present
in the
atmosphere
at
height
of 1000km
•
Nearest
to
earth
is
troposphere
•
troposphere
contains heavy
load
of
microorganisms
Sources
of
microorganisms
in
air:
•
Number
of
microorganisms
in
atmosphere
but
air is
not
a
natural
environment
for
microorganisms
because
it
does
not
contain
enough
moisture
and
nutrient
•
Soil
sources
of
microorganisms:
•
Digging
and
ploughing
the
soil
•
Wind
blow
•
Water
sources
of
microorganisms:
•
Splashing
of
water
by wind
action
Microorganisms
are
discharged
out
in
three
different
forms
Basis
on
their
relative
size
Moisture
content
Air
born
transmission:
Droplet:
•
Droplets
formed
by
sneezing,
coughing
and
talking
•
It
consists
of
saliva
and
mucous
•
It
contains
hundred
of
micro
organisms
which
may
be
pathogenic
mostly
respiratory
track
origins
•
Size
depend
of
duration
of
time
•
Pathogenic
microorganisms
may
be
a
source of
infectious
disease
Droplet
of
nuclei:
•
small
droplets
in
warm
and
dry
atmosphere
evaporate
rapidly
and
become
droplet
nuclei
•
Size
1-4μm
•
Factors
atmospheric
conditions
like
humidity,
sunlight
and
temperature
•
No
of
bacteria
in
a
single
sneeze
between
10000-100000
Air
born
transmission:
Infectious
dust:
•
Large aerosol droplets
settle
out
rapidly
from
air
•
Nasal
and
throat
discharge
from
a
patient
•
Air
born
diseases
transmitted
by
two
droplets,
depending
upon
their
size
•
Droplets
larger
than
100um
in
diameter
•
Dried
residues of
droplets
Air
borne
microbial
diseases:
Bacterial
diseases
:
•
Brucellosis:
occupational
disease
among
slaughter
house
workers
•
Pulmonary
Anthrax:
transmission
by
contaminated
animal
products
•
Streptococcus
pyogenes:
throat
and
skin
disease
•
Rheumatic
fever:
inflammation
and
degeneration
of
heart
valves
•
Streptococcal
pneumonia:
•
Meningitis:
common
in
children
•
Diphtheria:
infection
of
tonsils,
throat
and
nose
•
Tuberculosis:
respiratory
disease
•
Legionellosis:
cause
by
natural
water
contamination
Air
borne
microbial
diseases:
Fungal
diseases:
•
Cryptococcosis
:
caused
by
inhalation
of soil particles
•
Blastomycosis
:
lesion
formation
•
Coccidioidomycosis
:
influenza
fever
•
Aspergillosis
:
disease
of
human
Viral
diseases:
•
Common
cold
:
droplets
from
nose
•
Influenza
:
nasal
discharge,
headache,
muscle
pains,
sore
throat
•
Measles
:
red
blotchy
skin
rash
•
Mumps
:
swelling of
parotid
gland
and
salivary
glands
•
Adeno
viral
diseases
:
acute
respiratory
disease
and
eye infection
Microbes
in
atmosphere:
•
The
atmospheric
layer
are
important
forces
in
determining
viable
particles
in air
•
Aero
microbiological
pathways
AMP
•
The
layer
of
most
interest
and
significance
is the
boundary
layer
that
is
0.1km
from
earth
surface
•
Boundary
layer
responsible
for
transport
of
particles
both
short
and
long
distances
•
Boundary
layer
consist
of
three
parts
•
First
layer:
laminar
boundary
layer
•
Second
layer:
turbulent
boundary
layer
•
Third
layer:
local
eddy
layer
Dispersal
of
microbes
in
atmosphere:
•
Dispersal
begins
with
discharge
of
microbial
cell,
spores
to
the
atmosphere
•
Particles
transport
via
diffusion,
dispersion
and
deposition
•
Example:
liquid
aerosol
containing
influenza
virus
•
Deposition
of
microorganisms
occurs
through three
processes
•
launching
•
transport
•
and
deposition
Bioaerosol:
Definition:
“particles release
from
terrestrial
and marine
ecosystem
into
the
atmosphere
they
consist
of both living
and
non
living
components
including
organisms, dispersal
method
of
organisms
and
excretion”
•
Mist
of
dust
micrometer
in
range
•
General
range
from
0.02-100 um
in
diameter
•
Classification
on
basis
of
size:
•
Smaller
particle
<0.1um
in
diameter
are
in
nuclei
mode
•
Particle
0.1-2um
are
in
accumulation
mode
•
Larger
particles
are
coarse
mode
Launc
h
in
g
:
Definition:
“The
process whereby microbes
loaded
particles
become
suspended
within
the
earth’s
atmosphere
is
termed
launching”
factors:
•
Air
turbulence
•
Waste
materials
•
Natural
mechanical
process
•
Release
of
fungal
spores
Sources:
terrestrial
and
aquatic
•
Instantaneous
point sources
•
Continuous
point
sources
Bioaerosol
transport:
•
Transport
is
the
process
by
which
a
viable
particles
move
from
one
point
to
another
•
Sub
microscale
transport
involves
short
period
of
time
10mints
under
100m
•
Micro
transport
ranges
10mints
to
1
hour
and 100m
to
1km
•
Estimation
by
using Osbert
Reynolds
method
•
Re
=
velocity
x
dimension
viscosity
Bioaerosol
deposition:
•
Regarded
as the
Last
step
in AMB
pathway
•
Rate
of
deposition
of
a
particle
is
directly
proportional
to
its
mass,
volume
and
mass/volume
ratio
1
Gravitational
sittings:
•
Microbial
particles
that
are
exposed
to
wind
above
8
x
103
m/hrs
then
gravitational
deposition
may
be
negligible
2
Downward
molecular
diffusion:
•
Natural
air
currents
•
Force
of
winds
•
Deposition
rate
3
Surface
impaction:
•
Particles
make
contact
with
surfaces
such
as
leaves,
tree,
wall
and
furniture
•
Causes:
•
Allow
downward
molecular
diffusion
and
gravitational
setting
•
Allow
particles
to
escape
the
surface
Bioaerosol
deposition:
4.
Rain
and
electrostatic
deposition:
•
Rainfall occurs
as a
condensation reaction
b/w
two
particles which
combine
and
create
bioaerosol
with
a
greater
mass
making
it
to
settle
faster
•
Microorganism
have
negative
charge
due
to
which
they
associates
with
positive
charged
air
borne
particles
resulting
in
electrostatic
condensation
THANK YOU
THANK YOU
Aero-microbiology focuses on studying living microbes suspended in the air, with a particular emphasis on sources of microorganisms in the atmosphere. Airborne transmission of diseases through droplets and infectious dust is explored, highlighting the risks and factors affecting pathogenic microorganisms present in the air. The field of aero-microbiology plays a crucial role in understanding and preventing the spread of airborne diseases.
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Presentation Transcript
Microbiology of Air Class: II M.Sc MICROBIOLOGY Dr. H. VAJIHA BANU Assistant Professor Department of Microbiology Jamal Mohamed College (Autonomous) Tiruchirappalli-620 020
CONTENTS: Aero-microbiology Airborne diseases. Sources of microorganisms in Air Microbes in atmosphere Bioaerosol
Aero-microbiology: Definition: Studyof living microbes suspended in air Various layers present in the atmosphere at height of 1000km Nearest to earth is troposphere troposphere contains heavy load of microorganisms
Sources of microorganisms in air: Number of microorganisms in atmosphere but air is not a natural environment for microorganisms becauseit does not contain enoughmoisture and nutrient Soil sources of microorganisms: Diggingand ploughingthe soil Windblow Water sources of microorganisms: Splashing of water by wind action Microorganismsare discharged out in three different forms Basis on their relative size Moisturecontent
Air born transmission: Droplet: Droplets formed by sneezing, coughingand talking It consists of saliva and mucous It contains hundredof micro organisms which may be pathogenic mostly respiratory track origins Size depend of duration of time Pathogenic microorganisms may be a source of infectious disease Droplet of nuclei: small droplets in warm and dry atmosphere evaporate rapidlyand becomedroplet nuclei Size 1-4 m Factors atmospheric conditions like humidity, sunlight and temperature No of bacteria in a single sneeze between 10000-100000
Air born transmission: Infectious dust: Large aerosol droplets settle out rapidly from air Nasal and throat discharge from a patient Air born diseases transmitted by two droplets, dependingupontheir size Droplets larger than 100umin diameter Dried residues of droplets
Air borne microbial diseases: Bacterial diseases: Brucellosis: occupationaldisease amongslaughter house workers Pulmonary Anthrax: transmission by contaminated animal products Streptococcus pyogenes: throat and skin disease Rheumatic fever: inflammation and degeneration of heart valves Streptococcal pneumonia: Meningitis: commonin children Diphtheria: infection of tonsils, throat and nose Tuberculosis: respiratory disease Legionellosis: cause by natural water contamination
Air borne microbial diseases: Fungaldiseases: Cryptococcosis:caused by inhalationof soil particles Blastomycosis: lesion formation Coccidioidomycosis:influenza fever Aspergillosis:disease of human Viraldiseases: Commoncold:droplets from nose Influenza: nasal discharge, headache, muscle pains, sore throat Measles: red blotchyskin rash Mumps: swelling of parotid gland and salivary glands Adeno viral diseases: acute respiratory disease and eye infection
Microbes in atmosphere: The atmosphericlayer are importantforces in determining viable particles in air Aero microbiological pathways AMP The layer of most interest and significance is the boundary layer that is 0.1km from earth surface Boundary layer responsible for transport of particles both short and long distances Boundary layerconsist of three parts First layer:laminar boundary layer Secondlayer: turbulentboundary layer Third layer: local eddy layer
Dispersal of microbes in atmosphere: Dispersal begins with discharge of microbial cell, spores to the atmosphere Particles transport via diffusion, dispersion and deposition Example: liquid aerosol containing influenza virus Deposition of microorganisms occurs through three processes launching transport and deposition
Bioaerosol: Definition: particles release from terrestrial and marine ecosystem into the atmosphere they consist of both living and non living components including organisms, dispersal methodof organisms and excretion Mist of dust micrometerin range General range from 0.02-100 um in diameter Classification on basis of size: Smaller particle <0.1um in diameterare in nuclei mode Particle 0.1-2um are in accumulationmode Larger particlesare coarse mode
Launching: Definition: The process whereby microbes loaded particles become suspended within the earth s atmosphere is termed launching factors: Air turbulence Waste materials Natural mechanicalprocess Releaseof fungal spores Sources: terrestrial and aquatic Instantaneous point sources Continuous point sources
Bioaerosol transport: Transport is the process by which a viable particles move from one point to another Sub microscale transport involves short period of time 10mints under 100m Micro transportranges10mints to 1 hour and 100m to 1km Estimation by using Osbert Reynolds method Re = velocity x dimension viscosity
Bioaerosol deposition: 1 Gravitationalsittings: Microbial particles that are exposed to wind above 8 x 103m/hrs then gravitational deposition may be negligible 2 Downward moleculardiffusion: Natural air currents Force of winds Depositionrate 3 Surface impaction: Particles make contact with surfaces such as leaves, tree, wall and furniture Causes: Allow downward molecular diffusion and gravitational setting Allow particles to escape the surface Regardedas the Last step in AMB pathway Rate of deposition of a particle is directly proportional to its mass, volume and mass/volume ratio
Bioaerosol deposition: 4.Rain and electrostatic deposition: Rainfall occurs as a condensation reaction b/w two particles which combine and create bioaerosol with a greater mass making it to settle faster Microorganism have negative chargedue to which they associates with positive chargedair borne particles resulting in electrostatic condensation
THANK YOU THANK YOU
