I had 2 male barn cats die last winter.  One just dropped dead.  The
other was acting sick, I brought him indoors and gave antibiotics.  He
mostly had the "runs".  He recovered, but in early spring I noticed he
was weak, and had lost much weight.  Since it was warmer outdoors, I
put him in a shed and gave more antibiotics.  He was not getting
better so I was going to take him to the vet.  When I went to the shed
he was dead.

Well, I just loat another male cat Saturday.  A week ago he was fine.
About Wed. he was dragging around and had lost some weight.  On Thurs.
I placed him in a shed so he could eat alone because I have about a
dozen barn cats.  He ate well, and I let him back outside.  Friday he
looked worse, extremely skinny, sunken in eyes, and lethargic.  I
called the vet and they told me to get him on antibiotics over the
weekend, and if he is not better on Monday, bring him in.  I went to
give him the antibiotics, but could not find him.  Saturday morning I
found him laying on the lawn and having muscle spasms, twitching all
over.  I offerred food, he ate about 2 pieces of dry food and stopped.
I took a syringe and offerred some water, then gator aid.  It just ran
out of his mouth, and by this time he seemed to now have any idea what
was going on around him.  I placed him in a cage with some canned cat
food.  He was laid on his side and I could see he had no idea
whatsoever what was going on around him.  He took no interest to the
food at all.  Yet, his legs kept moving like he was walking.  I tried
to call the vet, but around here, there are no vets available, except
for livestock. (very rural area).  I decided to take him to the
nearest big city to find a vet (nearly 2 hours away).  I got ready to
leave, when I noticed he was getting stiff in the cage.  Just barely
breathing, and no response in his eyes when I waved my hand near his
face.  

This is when I knew there was no hope for him.  To avoid any further
pain, I euthanized him myself with my rifle.  (One of the hardest
things I have ever had to do).  

I hate posting all these horrible details, but I am trying to find out
what happened to him.  I originally suspected a disease, even though
the other cats are all fine.  I now wonder if he may have gotten
poisoned.  I have no poisons around here, except mouse poison in the
garage which is well hidden where no cat can get to it, and the garage
is kept closed too.  I have no stored or leaking antifreeze.
Hopwever, being a tom, I did see him up the driveway a few times, but
have never noticed him actually leave the farm.  Of course, one never
knows exactly where these cats wander off to.  

One thing I did notice is that there was a swarm of flies in one of my
sheds, and I sprayed fly spray, leaving thousands of dead flies on the
floor.  I did find a few cats in there eating those dead flies, but
those cats are still OK.  That shed door was left open, so the one
that died could have eaten some too.

One last think I want to mention is that ALL three of these cats were
toms, but one of the cats that died during the winter was kept inside
a shed, (with other cats), and not allowed to go outdoors.  I always
keep a few cats indoors that are not careful around moving vehicles,
and he was one of them.  THAT cat never left that shed.

Anyone have any idea what may have caused this?

Thanks

G.A