Usefulness of PCR analysis for diagnosis of alveolar echinococcosis with unusual localizations: two case studies

Abstract

The report presents two cases where diagnosis of alveolar echinococcosis was confirmed by Echinococcus multilocularis and Echinococcus granulosus PCR. The extrahepatic osseous involvement and the absence of initial hepatic involvement are unusual in both cases. Due to limitations of serological interpretation, PCR was useful to diagnose atypical echinococcosis.

FIG. 1.

Echinococcus Western blot IgG assays for patients 1 and 2. Most of the significant bands are indicated by arrows. Molecular sizes (in kilodaltons) are indicated. Lane N, negative-control serum; lane P, positive control (bands at 7, 16, 18, and 26 to 28 kDa); lane 1, case 1 (E. multilocularis pattern with bands at 7, 12, and 26 to 28 kDa and a narrow band at 18 kDa); lane 2, case 2 (E. granulosus pattern with bands at 7 and 26 to 28 kDa and a diffuse band between 16 and 18 kDa). Echinococcosis serum IgG specifically recognizes antigens with molecular sizes below 30 kDa. The presence of one band at 7 kDa and/or one band at 26 to 28 kDa is indicative of the presence of Echinococcus-specific IgG in serum. E. granulosus serum IgG specifically binds to a component of 16 to 18 kDa as a diffuse band. By contrast, E. multilocularis serum IgG specifically binds to antigens of 16, 17, 18, and 20 kDa as sharp bands.

FIG. 2.

E. multilocularis PCR on biological samples: material from the fistula of patient 1 (lanes 2 and 6), and biopsy samples of vertebrae from patient 2 (lanes 3 and 7). Lanes 1 and 9, molecular size marker; lane 4, negative control; lanes 5 and 8, positive control. Lanes 2, 3, and 5, E. multilocularis PCR positive (200 bp); lanes 6 to 8, internal control for inhibitor detection (371 bp).