What agent causes flu-like symptoms?

Answer 1

if non-lethal: Riot control agent

if with choking, vomiting, convulsions or seizures, pinpoint pupils: chemical

if burned or reddened skin, vomiting, hair loss: radiological/nuclear

to avoid any of these things, distance yourself to lessen you exposure and have a Disaster Response process to have some sort of preparedness.

Answer 2

Many things. "Flu-like symptoms" are the generic immune system response at the beginning of most infections, Allergies, and some toxic exposures before the immune system can produce a specific response to the actual threat itself.

Various viruses can cause flu-like symptoms. The "flu" causes a severe upper respiratory infection, not stomach problems.

Answer 3

all