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ebiasis
Amoebiasis
A m o eb ia s is is a pa ra s itic in fectio n d ue to the in tes tin a l pro to zo a Entamoeba
histolytica.
T ra n s m is s io n is fa eca l- o ra l, b y in ges t io n o f a m o eb ic cys t s fro m fo o d o r
w a t er
co n ta m in a ted w ith fa eces . U s ua lly, in ges ted cys ts relea s e n o n -pa tho gen ic
a m o eb a e a n d
9 0 % o f ca rriers a re a s ym pto m a tic.
In 1 0 % o f in fected pa tien ts , pa tho gen ic a m o eb a e pen etra te the m uco us o f the
co lo n : this
is the in tes tin a l a m o eb ia s is (a m o eb ic d ys en tery). T he clin ica l picture is s im ila r to
tha t o f
s h igello s is , w hich is the prin cipa l ca us e o f d ys en tery.
O cca s io n a lly, t h e pa t h o gen ic a m o eb a e m igra t e via t h e b lo o d s t rea m a n d fo rm
periphera l a b s ces s es . A m o eb ic liver a b s ces s is the m o s t co m m o n fo rm o f extra -
in tes tin a l
a m o eb ia s is .
Clinical features
– Amoebic dysentery
• d ia rrho ea co n ta in in g red b lo o d a n d m ucus
• a b d o m in a l pa in , ten es m us
• n o fever o r m o d era te fever
• po s s ib ly s ign s o f d ehyd ra tio n
– Amoebic liver abscess
• pa in ful hepa to m ega ly; m ild ja un d ice m a y b e pres en t
• a n o rexia , w eight lo s s , n a us ea , vo m itin g
• in term itten t fever, s w ea tin g, chills ; cha n ge in o vera ll co n d itio n
Laboratory
– A m o eb ic d ys en tery: id en tifica tio n o f m o b ile tro pho zo ites (E. histolytica histolytica) in
fres h s to o l s a m ples
– A m o eb ic liver a b s ces s : in d irect ha em o a gglutin a tio n a n d E L IS A
tinidazole PO
Treatment
– Amoebic dysentery
• T he pres en ce o f cys ts a lo n e s ho uld n o t lea d to the trea tm en t o f a m o eb ia s is .
• A m o eb ia s is co n firm ed w ith a pa ra s ito lo gica l s to o l exa m in a tio n :
C hild ren : 5 0 m g/ kg o n ce d a ily fo r 3 d a ys (w itho ut exceed in g 2 g/ d a y)
A d ults : 2 g o n ce d a ily fo r 3 d a ys
o r metronidazole PO
C hild ren : 4 5 m g/ kg/ d a y in 3 d ivid ed d o s es fo r 5 d a ys
A d ults : 1 .5 g/ d a y in 3 d ivid ed d o s es fo r 5 d a ys
t•inI pifdatahzgeoerlee8Pis6On) .:oTs alraemab toefortraertaoatmmry,oefinresbttailainssefiostrreifaacmtomroreenecbtt tifcoredraydtsmyesneenntertteyfrofyorisrs5fhodigraeslylohsisgeisllohsaiss
(s ee
b een
in effective.
• O ra l rehyd ra tio n s a lts ( ORS) if there is ris k o f, o r if there a re s ign s o f d ehyd ra tio n
(fo llo w the W H O pro to co ls , pa ges 3 1 6 to 3 2 1 ).
– Amoebic liver abscess
Amoebiasis
A m o eb ia s is is a pa ra s itic in fectio n d ue to the in tes tin a l pro to zo a Entamoeba
histolytica.
T ra n s m is s io n is fa eca l- o ra l, b y in ges t io n o f a m o eb ic cys t s fro m fo o d o r
w a t er
co n ta m in a ted w ith fa eces . U s ua lly, in ges ted cys ts relea s e n o n -pa tho gen ic
a m o eb a e a n d
9 0 % o f ca rriers a re a s ym pto m a tic.
In 1 0 % o f in fected pa tien ts , pa tho gen ic a m o eb a e pen etra te the m uco us o f the
co lo n : this
is the in tes tin a l a m o eb ia s is (a m o eb ic d ys en tery). T he clin ica l picture is s im ila r to
tha t o f
s h igello s is , w hich is the prin cipa l ca us e o f d ys en tery.
O cca s io n a lly, t h e pa t h o gen ic a m o eb a e m igra t e via t h e b lo o d s t rea m a n d fo rm
periphera l a b s ces s es . A m o eb ic liver a b s ces s is the m o s t co m m o n fo rm o f extra -
in tes tin a l
a m o eb ia s is .
Clinical features
– Amoebic dysentery
• d ia rrho ea co n ta in in g red b lo o d a n d m ucus
• a b d o m in a l pa in , ten es m us
• n o fever o r m o d era te fever
• po s s ib ly s ign s o f d ehyd ra tio n
– Amoebic liver abscess
• pa in ful hepa to m ega ly; m ild ja un d ice m a y b e pres en t
• a n o rexia , w eight lo s s , n a us ea , vo m itin g
• in term itten t fever, s w ea tin g, chills ; cha n ge in o vera ll co n d itio n
Laboratory
– A m o eb ic d ys en tery: id en tifica tio n o f m o b ile tro pho zo ites (E. histolytica histolytica) in
fres h s to o l s a m ples
– A m o eb ic liver a b s ces s : in d irect ha em o a gglutin a tio n a n d E L IS A
tinidazole PO
Treatment
– Amoebic dysentery
• T he pres en ce o f cys ts a lo n e s ho uld n o t lea d to the trea tm en t o f a m o eb ia s is .
• A m o eb ia s is co n firm ed w ith a pa ra s ito lo gica l s to o l exa m in a tio n :
C hild ren : 5 0 m g/ kg o n ce d a ily fo r 3 d a ys (w itho ut exceed in g 2 g/ d a y)
A d ults : 2 g o n ce d a ily fo r 3 d a ys
o r metronidazole PO
C hild ren : 4 5 m g/ kg/ d a y in 3 d ivid ed d o s es fo r 5 d a ys
A d ults : 1 .5 g/ d a y in 3 d ivid ed d o s es fo r 5 d a ys
t•inI pifdatahzgeoerlee8Pis6On) .:oTs alraemab toefortraertaoatmmry,oefinresbttailainssefiostrreifaacmtomroreenecbtt tifcoredraydtsmyesneenntertteyfrofyorisrs5fhodigraeslylohsisgeisllohsaiss
(s ee
b een
in effective.
• O ra l rehyd ra tio n s a lts ( ORS) if there is ris k o f, o r if there a re s ign s o f d ehyd ra tio n
(fo llo w the W H O pro to co ls , pa ges 3 1 6 to 3 2 1 ).
– Amoebic liver abscess
