RT Book, Section
A1 Doherty, Gerard M.
SR Print(0)
ID 58109528
T1 Echinococcosis
T2 Quick Answers Surgery
YR 2010
FD 2010
PB The McGraw-Hill Companies
PP New York, NY
SN 
LK accesssurgery.mhmedical.com/content.aspx?aid=58109528
RD 2024/04/18
AB •  Hydatid  disease  caused  by  the  microscopic  cestode  parasites  Echinococcus  granulosus  and  Echinococcus  multilocularis•  Form  larval  cysts  in  mammalian  tissue•  Foxes,  coyotes,  dogs,  and  cats  are  the  definitive  hosts  that  harbor  the  adult  tapeworms  in  their  intestines•  Host  animals  are  not  harmed  by  the  worms  and  are  asymptomatic•  Ova  are  passed  in  the  feces  and  are  ingested  by  intermediate  hosts  such  as  cattle,  humans,  rodents,  and  particularly  sheep•  Ova  penetrate  the  intestine  and  pass  via  the  portal  vein  to  the  liver  (75%)  and  then  to  the  lung  (15%)  or  other  tissues•  Ovum  typically  develops  into  a  cyst  filled  with  clear  fluid•  Scoleces  bud  into  the  cyst  lumen•  Cysts  grow  slowly;  patients  may  be  asymptomatic  for  several  years•  Endocysts  may  cause  secondary  intraperitoneal  cyst  formation  if  spilled  into  the  peritoneal  cavity•  80%  of  hydatid  cysts  are  single  and  in  the  right  lobe