C arrie rs :-
A p ath ogen in fe cte d p ers o n p osse ssin g s p eci? c in fe ctio us a gent
s h ow in g n o o r m ild s ym pto m s o f c lin ic a l d is e ase .
P ossib le s o urc e o f in fe ctio n t o o th ers .
T yp es o f c a rrie rs :-
a)A ctiv e c arrie r:-
In fe cte d in div id ual c a n t ra nsm it
d is e ase t o o th ers w it h out e xh ib it in g s ig ns a nd s ym pto m s .
In fe ctio n is
o bse rv e d t h ro ughout h is /h er c o urs e . e g:- p olio v ir u s, h epatit is A v ir u s
b)P assiv e c arrie r:-
In div id ual c o nta m in ate d w it h
p ath ogen c a n m ech anic a lly t ra nsm it it t o o th ers .T his c a rrie r s ta te m ay
o ccu r d urin g in cu batio n p erio d, c o nva le sce nt o f in div id ual w it h c lin ic a lly
r e co gniz a ble d is e ase .
– e xa m ple s o f in cu bato ry c a rrie rs :- M easle s ,C hic ke n p ox.
– e xa m ple s o f c o nva le sce nt c a rrie rs :-
Salm onella t y p hello, D ip hth eria .
c )H ealt h y ( c h ro nic ) c arrie rs :-
th ey c o ntin ue t o
h arb our a n in fe ctio us a gent f o r e xte nded t im e p erio d ( m onth o r y e ar)
b ut is n ot in poor health.
e xa m ple s:- H epatit is B v ir u s.
C arrie rs a re d an gero us b ecau se:-
T hey g enera lly d ont s h ould c lin ic a l s ym pto m s.
D i? cu lt t o d ia gnose t h em in c a se o f h ealt h y c a rrie r.
C arrie rs a re le ss in fe ctio us t h an t h e c a se s b ut
e pid id em io lo gic a klly m ore d angero us .
e xa m ple :- T yp hoid M ary
D is ea se t ra nsm is sio n:-
T ra nsfe r o f p ath ogen f ro m a n in fe cte d h ost t o h ealt h y in div id ual b y
d ir e ct o r in dir e ct c o nta ct.
M odes o f t ra n sm is sio n o f d is ease:-
D ir e ct
t ra nsm is sio n
I n dir e ct
t ra nsm is sio n
D ir e ct c o nta ct
D ro ple t in fe ctio ns
C onta ct w it h s o il
I n ocu la tio n in to s kin o r
m uco sa .
V ehic le -b orn e
V ecto r born e
a )M ech anic a l
b )B io lo gic a l
A ir -b orn e
F om it e -b orn e
1 ) D ir e ct t ra nsm is sio n
H ere t h ere is in sta nt t ra nsfe r o f
p ath ogen f ro m r e se rv o ir t o s u sce ptib le
h ost b y
d ir e ct c o nta ct o r d ro ple t s p re advert.
I t o ccu rs t h ro ugh S kin -t o -s kin c o nta ct,
s e xu al in te rc o urs e .
It a ls o r e fe rs t o c o nta ct w it h s o il o r
v e geta tio n h arb ourin g in fe ctio us
o rg anis m s.
E xa m ple s:- A ID s ,L epro sy, S TD s ,
S kin a nd E ye in fe ctio ns.
/
-B Y D R. P . V EN KATA Ok RIS H NAN ,
P ara s H osp it a l
2 )D ro ple t in fe ctio n:-
D ir e ct p ro je ctio n o f s p ra y o f d ro ple ts
o f s a liv a a nd n aso -p hary n geal
s e cre tio n.
C ause d b y s n eezin g, c o ughin g o r
e ve n t a lk in g. It s a f o rm o f d ir e ct a ir –
b orn e t ra nsm is sio n.
P artic le s le ss t h an 5 m m c a n
p enetra te d eeply a nd r e ach a lv e oli
c a usin g in fe ctio n.
E xa m ple s:- C om mon c o ld , T B ,
W ho opin g c o ugh.
/
h ttp s:/ / h em antm ore .o rg .in /s cie n ce/b io lo gy/
d is ea ses/1 1238/
three )C onta ct w it h s o il:-
D ir e ct e xp osu re o f s u sce ptib le t is su e t o d is e ase a gent in s o il.
E xa m ple :- H ookw orm
h ttp s:/ / e n .w ik ip ed ia .o rg /w ik i/ F eca l% E2% 80% 93ora l_ ro ute # /m ed ia /F ile :F -d ia gra m -Zero 1.jp g
four )In o cu la tio n in to s kin o r M uco sa :
–
P ath ogen is d ir e ctly in ocu la te d in to s kin o r m uco sa .
E xa m ple s:- R abie s, H epatit is B
h ttp s:/ / w ww.m 3in dia .in /c o nte n ts /n ew s/eight 0757/w hy-d elh i-
n eed s-t o -f o llo w -a ndhra -p olic y-o n-a uto
h ttp s:/ / w ww.m ed ic a ln ew sto day.c o m /a rtic le s/three 21806.p hp
