An Epidemic of Trichinosis in France

Source: Thierry Ancelle, Hôpital Cochin, Paris, France
Date published
Oct, 2004
Last updated
23 Jan 2020


Learning Objectives:

At the end of this exercise, the participants should be able to:

  1. Describe the steps in an epidemic investigation
  2. Develop a case definition in the context of an outbreak investigation
  3. Construct and interpret an epidemic curve
  4. Choose an appropriate control group for case control study
  5. Calculate and interpret an odds ratio

On Friday, August 16, 1985 at 5 p.m., the chief of the internal medicine service at a suburban Paris hospital telephoned the Chief of Parasitology of a Paris teaching hospital. Four patients had just been admitted to the suburban hospital with fever >39°C, severe muscle pain (myalgias), and diarrhoea. All had eosinophil counts in excess of 1000 per mm3. Three of the cases were members of the same family. None had travelled outside France. The parasitologist suggested that serology be performed on the four patients to look for toxocariasis, trichinosis, and fascioliasis (liver fluke). The following week, two patients living in central Paris (14ème arrondissement) were hospitalised at the teaching hospital. Both presented with the same symptoms seen in the patients from suburban Paris. The serologies for the two teaching hospital patients and the four suburban patients were completed on 22 August. All serologic tests were negative except a single specimen from a suburban patient who was strongly positive for trichinosis.