RT Book, Section
A1 Murray, Dennis L.
A2 Rudolph, Colin D.
A2 Rudolph, Abraham M.
A2 Lister, George E.
A2 First, Lewis R.
A2 Gershon, Anne A.
SR Print(0)
ID 7031685
T1 Chapter 347. Dientamoebiasis
T2 Rudolph's Pediatrics, 22e
YR 2011
FD 2011
PB The McGraw-Hill Companies
PP New York, NY
SN 978-0-07-149723-7
LK accesspediatrics.mhmedical.com/content.aspx?aid=7031685
RD 2024/04/18
AB Dientamoeba  fragilis  is  a  nonflagellate  trichomonad  parasite  that  inhabits  the  human  colon  and  has  been  associated  with  acute  and  chronic  gastrointestinal  symptoms.  Humans  are  likely  the  natural  host  for  D  fragilis.  Unlike  most  other  intestinal  protozoa,  D  fragilis  has  no  known  cyst  form  and  has  not  been  found  to  invade  tissues.1  The  organism  is  usually  7  to  12  μm  in  diameter  and  demonstrates  pointed  or  leaf-shaped  pseudopodia  (see  Fig.  347-1).  While  moving  actively  in  fresh  fecal  specimens,  the  organism  quickly  becomes  rounded  and  granular  and  is  therefore  less  identifiable  in  stored  specimens.  When  suitably  stained,  most  D  fragilis  reveal  two  characteristic  nuclei  that  each  contains  a  large  karysome  with  granules.  Some  large  uninucleate  forms  may  also  be  found.  The  organism  feeds  on  bacteria  and  will  ingest  human  red  blood  cells.1  Advances  in  culturing  techniques  have  improved  the  ability  to  detect  the  organism2-4  but  are  limited,  since  cultures  cannot  be  done  on  fixed  fecal  samples.  Because  of  its  small  size,  this  organism  may  be  overlooked  by  inexperienced  laboratory  personnel  or  can  be  lost  if  not  preserved  properly.