Katie Pruszynski revealed being threatened is considered to be a regular part of being an MP or working in their team.
Mrs Cox was the first MP to be killed in office since Ian Gow more than a quarter of a century ago but others have been seriously injured.
Then Cheltenham MP Nigel Jones was severely injured by a Samurai-sword wielding attacker, who also killed a Liberal Democrat councillor, at his constituency office in 2000.
East Ham MP Stephen Timms was stabbed twice in the stomach in 2010 by a student angry at his support for the Iraq War.
Ms Pruszynski, a former assistant to Norwich North MP Chloe Smith who now lives and works in Sheffield, said: “If you speak to MPs’ offices there would always be someone who had experiences of being threatened by the public. People do get angry.
“MPs are lightening rods for people who are angry and frustrated.
“MPs are so public faicng and not infrequently you would get someone desperately upset and and emotional and that can extend into being threatening and abusive and sometimes there are people who are quite disturbed.
“I remember being screamed at by someone clearly quite disturbed that they would find me and eat me like a wolf.”
The threats faced by MPs and there offices go beyond individuals who are abusive or violent.
Mrs Pruszynski, who now runs her own business, Speakeasy Communications, said: “We had one incident in our constituency office where someone had posted some white powder and we had no idea what it was. We had to wait for the police to come and deal with it.”
Hull East MP Karl Turner was among those who decided to cancel planned advice surgeries in the wake of Mrs Cox’s death.
He said: “My caseworker was threatened with violence yesterday, by coincidence.
“People are suffering and that suffering sometimes comes out as frustration and is often taken out against MPs.
“It is something we put up With all parts of the public sector. Nurses, doctors, people shouldn’t have to put up with it.”
Mr Turner said MPs may review their security.
“I think it’s important members of the public can speak face to face regularly with elected representatives, that’s what democracy should look like but people’s lives shouldn’t be threatened.”