Jessica,
 
It might and might not be ECE.  The introduction of a new guy to an
established group will sometimes lead to diarrhea, some of it green tinged.
From what I've heard about ECE (fortunately haven't seen it) is that ECE is
a definite "antifreeze green" and will last for weeks or months.
 
Regardless, the treatment is the same.  Aggressive treatment with Kaopectate
(from 1/3 cc all the way up to 1 cc if necessary) every 3-4 hours if
necessary to control the diarrhea.  Carafate to heal/head-off ulcers.  Amoxi
to prevent secondary infections.  (Don't give the Carafate with the
Kaopectate.  Wait at least 45 minutes between them.) Lots and lots of water.
Duck Soup or similar.  Force feed and force water if necessary every 3-4
hours.  (Dribble the Duck Soup, water, medications in the corner of the
mouth between the lips and teeth - slowly so as to let them lap it.  You
don't want them to inhale it.) Call your vet.
 
Dick B.
[Posted in FML issue 1671]