The daily Het Belang van Limburg reports that the suspect wild boar served in at least two Limburg restaurants hailed from Spain.
Of the nine Limburgers in hospital, one is in a very bad way, though is not in a life-threatening condition.
Dr Annemie Forier specialised in infectious diseases: "It's been ages since anybody became infected with the trichinella parasite in Belgium."
More people could be affected because symptoms are so similar to those of 'flu.
Dr Annemie Forier: "The incubation period is extensive and most people will not link their illness to that night out in a restaurant weeks ago."
If you suspect you have been infected you should alert your GP: "The disease hasn't occurred in Belgium for years and the symptoms don't immediately raise the alarm."
Belgium's Food Safety Agency is investigating where exactly the suspect meat was sourced from.
Symptoms include headache, muscle pains, fever and swellings to the face. People who suspect they have been infected should contact the Food Safety Agency or their GP.