Ping Phil All the cats in the house are sick

They have been to a vet and he's running blood and stool tests.
The vet doesn't have a clue yet. I get the blood results today and the
stool tests in 5 days. I'm posting here to discover if anyone else has
had the problem. I am syringing chicken broth down their thoats all
the time as well as antibiotics and a high calorie vitamin mix

Here is the problem in detail.

Five healthy cats ranging in age from 10 months to 11 years
simultaneously stopped eating and drinking. They are indoor cats up to
date with their shots. They were not poisoned, did not ingest a toxin
of any kind. This has to be a bacteria, protazoa or virus.

Anyone have an idea?