A retrospective study of autochthonous strongyloõÈdiasis in ReÂgion Midi-PyreÂneÂes (Southwestern France) Jean-FrancËois Magnaval, Jean-Michel Mansuy, Laurent Villeneuve & Sophie Cassaing Service de Parasitologie, CHU Rangueil, Toulouse, France Accepted in revised form 11 October 1999 Abstract. In order to assess the existence of autoch- thonous strongyloõÈdiasis, a retrospective study was carried out in ReÂgion Midi-PyreÂneÂes (Southwestern France). Among 63 strongyloõÈdiasis cases diagnosed at the Consultation of the Department of Parasitol- ogy, CHU Purpan in Toulouse, 17 patients (27%) were identi®ed as likely harboring an autochthonous infection. The diagnosis was based upon the results of either Baermann's method for stool examination, or indirect ¯uoroimmunoassay using StrongyloõÈdiasis ratti L 3 larvae as antigen. Repeated contact with soil or mud, due to occupation or gardening, was found in 13 patients. Twelve cases lived in the upper basin of the Garonne River. The clinical and laboratory ®ndings were similar to those reported by the litera- ture. No case of larva currens was observed. These results suggest that a permanent transmission of strongyloõÈdiasis possibly exists in Re gion Midi- PyreÂneÂes, requiring further prospective studies. Key words: Autochthonous transmission, France, StrongyloõÈdiasis Abbreviations: CHU = University Hospital; IFA = indirect ¯uoroimmunoassay; SEM = standard error of the mean Introduction Whereas strongyloõÈdiasis has been intensively studied in tropical countries, few surveys have been carried out in Western Europe, where endemic pockets have only been reported in Northern Italy [1] and Southern Catalunya (Spain) [2]. The present retrospective work, conducted among French patients with no history of travel out of France, was designated to identify an area of possible autochthonous trans- mission in Re gion Midi-Pyre ne es (Southwestern France), and to study the features of the disease. Patients and methods Subjects Among 63 strongyloõÈdiasis cases diagnosed at the Consultation of the Department of Parasitology, CHU Purpan in Toulouse (France), 17 subjects were included in the study on the basis of an absence of any history of travel out of France. Patients from the French overseas territories were excluded. Albeit French citizens, 5 patients were former immigrants from Northern Italy. However, circumstantial evi- dence suggesting recent contamination might be recorded, namely the onset of a blood eosinophilia among these patients who periodically underwent total and dierential blood count due to various medical problems. Blood eosinophilia occurred be- tween 1 and 3 years before these 5 subjects attended our Consultation, whereas they had arrived in France between 45 and 66 years before this. After the diagnosis was done, patients were treated with albendazole (8 cases) or ivermectin (9 cases). Both treatments achieved in all patients a full re- covery of clinical symptoms, a regression of blood eosinophilia and a negative result from stool exami- nation. Laboratory methods Diagnosis of strongyloõÈdiasis was based upon the results of a single stool examination by Baermann's method or, for 4 patients, IFA using StrongyloõÈdes ratti L 3 larvae as antigen [3]. Serial dilutions of sera, beginning at 1:20, were incubated each with about 10 larvae, onto 12-circle slides. With the 1:40 dilution as cut-o value, the sensitivity of IFA had been previ- ously established at 51%, and the speci®city at 95.8% (J-F. Magnaval and J-M. Mansuy, unpublished data). Moreover, to avoid any problem of cross-reaction, the results of the immunodiagnostic tests for other European helminthiases, namely fascioliasis, cystic echinococcosis, toxocariasis and trichinellosis, had to be non signi®cant in all patients. Total and dierential blood count was done in the Laboratory of Haematology, CHU Purpan. Assay European Journal of Epidemiology 16: 179±182, 2000. Ó 2000 Kluwer Academic Publishers. Printed in the Netherlands.