Trichostrongylus colubriformis Nematode Infections in Humans, France

To the Editor: In April 2009, a 47-year-old woman in Saint-Jeannet in southern France reported stomach aches, abdominal bloating, and occasional diarrhea.Blood analyses found an increased eosinophil level (8,800 cells/mm 3 ), which represented 52% of 16,900 leukocytes/mm 3 .Parasitologic examinations for helminths were conducted with 6 fecal specimens obtained during June 9-July 2, 2009.Analyses included direct wet mount microscopic examination, Merthiolate-iodine-formaldehyde concentration, formalin-ethyl acetate concentration, and Baermann larval extraction.Results of direct examination and the Baermann technique were negative for all samples.The formalin-ethyl acetate concentration technique detected a parasite egg (Figure , panel A) and fi rst-stage larvae.Fecal cultures grew mature third-stage larvae (length 700-800 μm, 16 intestinal cells, length of the sheath <40 μm), belonging to the genus Trichostrongylus (Figure, panel B).Because of the ambiguous morphologic features of this genus, a molecular approach was necessary for specifi c identifi cation (1,2).Identical symptoms developed in 2 children of the patient and in 2 friends.The mother of the patient had additional symptoms (weight loss 5 kg in 1 month and 35,000 eosinophils/ mm 3 , which represented 85% of 43,200 leukocytes/mm 3 ).However, results of fecal examinations were negative for these 5 persons.DNA was extracted separately from 2 third-stage larvae (Figure, panel B) by using the DNA Tissue Mini Kit (QIAGEN, Hilden, Germany).