Lethal infection by a previously unrecognised metazoan parasite

Lancet. 1996 Jun 29;347(9018):1797-801. doi: 10.1016/s0140-6736(96)91618-9.


Background: New microbial pathogens or variant clinical manifestations of known organisms may be first found in immunodeficient patients. An HIV-infected man developed a rapidly-enlarging abdominal mass, suggestive of a neoplasm, that subsequently invaded his liver and caused death. Initial studies showed unusual tissue morphology that could not be matched with any known disease process.

Methods: Tissues obtained from biopsy at laparotomy and necropsy were studied by light microscopy, immunohistochemistry, electron microscopy, and broad-range ribosomal DNA-amplification and sequence analysis.

Findings: Tissue lesions were characterised by peculiar cytoplasmic sacs containing minute cells with very prominent nucleoli. The pathological process was recognised as a parasitic infection, although its features were different from those of any known eukaryotic pathogen. Phylogenetic analysis of a 357 bp 18S rDNA sequence amplified directly from the involved tissue indicated that the causative agent was a previously-uncharacterised cestode.

Interpretation: Fatal disease produced by this newly recognised cestode may not be limited to immunodeficient hosts. Awareness of this metazoan infection may allow early diagnosis-by morphology and DNA sequence analysis--and perhaps successful treatment of subsequent cases.

Publication types

  • Case Reports
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • AIDS-Related Opportunistic Infections / parasitology*
  • AIDS-Related Opportunistic Infections / pathology
  • Adult
  • Animals
  • Base Sequence
  • Cestoda / classification
  • Cestoda / genetics*
  • Cestoda / isolation & purification
  • Cestode Infections / parasitology
  • Cestode Infections / pathology*
  • Fatal Outcome
  • Humans
  • Male
  • Mesentery / parasitology
  • Mesentery / pathology
  • Molecular Sequence Data