Molecular diagnosis of Pseudoterranova decipiens s.s in human, France

Abstract

Background: Anisakis and Pseudoterranova are the main genera involved in human infections caused by nematodes of the Anisakidae family. Species identification is complicated due to the lack of differential morphological characteristics at the larval stage, thus requiring molecular differentiation. Pseudoterranova larvae ingested through raw fish are spontaneously eliminated in most cases, but mechanical removal by means of endoscopy might be required. To date, only very few cases of Pseudoterranova infection have been reported in France.

Case presentation: A 19-year-old woman from Northeastern France detected, while brushing her teeth, a larva exiting through her mouth. The patient who presented with headache, diarrhea, and abdominal cramps reported having eaten baked cod. The worm was a fourth-stage larva with a size of 22 × 0.9 mm, and molecular biology identified it as Pseudoterranova decipiens sensu stricto (s. s.). In a second P. decipiens infection case, occurring a few months later, a worm exited through the patient's nose after she had eaten raw sea bream.

Conclusion: These two cases demonstrate that Pseudoterranova infection is not uncommon among French patients. Therefore, molecular techniques should be more widely applied for a better characterization of anisakidosis epidemiology in France.

Keywords: Anisakidae; France; Human infection; Molecular identification; Nematode; Pseudoterranova decipiens.

Fig. 1

P. decipiens sensu stricto anterior region with three anterior lips without any boring tooth

Fig. 2

P. decipiens sensu stricto tail with mucron

Fig. 3

Sequence alignment detailed of P. decipiens sensu stricto of this case