Diagnosis of Taenia solium infections based on "mail order" RNA-sequencing of single tapeworm egg isolates from stool samples

PLoS Negl Trop Dis. 2021 Dec 10;15(12):e0009787. doi: 10.1371/journal.pntd.0009787. eCollection 2021 Dec.

Abstract

Combined community health programs aiming at health education, preventive anti-parasitic chemotherapy, and vaccination of pigs have proven their potential to regionally reduce and even eliminate Taenia solium infections that are associated with a high risk of neurological disease through ingestion of T. solium eggs. Yet it remains challenging to target T. solium endemic regions precisely or to make exact diagnoses in individual patients. One major reason is that the widely available stool microscopy may identify Taenia ssp. eggs in stool samples as such, but fails to distinguish between invasive (T. solium) and less invasive Taenia (T. saginata, T. asiatica, and T. hydatigena) species. The identification of Taenia ssp. eggs in routine stool samples often prompts a time-consuming and frequently unsuccessful epidemiologic workup in remote villages far away from a diagnostic laboratory. Here we present "mail order" single egg RNA-sequencing, a new method allowing the identification of the exact Taenia ssp. based on a few eggs found in routine diagnostic stool samples. We provide first T. solium transcriptome data, which show extremely high mitochondrial DNA (mtDNA) transcript counts that can be used for subspecies classification. "Mail order" RNA-sequencing can be administered by health personnel equipped with basic laboratory tools such as a microscope, a Bunsen burner, and access to an international post office for shipment of samples to a next generation sequencing facility. Our suggested workflow combines traditional stool microscopy, RNA-extraction from single Taenia eggs with mitochondrial RNA-sequencing, followed by bioinformatic processing with a basic laptop computer. The workflow could help to better target preventive healthcare measures and improve diagnostic specificity in individual patients based on incidental findings of Taenia ssp. eggs in diagnostic laboratories with limited resources.

Publication types

  • Evaluation Study

MeSH terms

  • Animals
  • DNA, Mitochondrial / genetics
  • Feces / parasitology*
  • High-Throughput Nucleotide Sequencing
  • Humans
  • Ovum / chemistry
  • Postal Service
  • RNA, Helminth / genetics
  • Sequence Analysis, RNA / methods*
  • Species Specificity
  • Taenia solium / classification
  • Taenia solium / genetics*
  • Taenia solium / isolation & purification
  • Taeniasis / diagnosis*
  • Taeniasis / parasitology*

Substances

  • DNA, Mitochondrial
  • RNA, Helminth

Grants and funding

This study has been funded by the Validation fund of the Berlin Institute of Health to HS and MS, the Deutsche Forschungsgemeinschaft (DFG; German Research Foundation, https://www.dfg.de/) under Germany’s Excellence Strategy – EXC-2049-390688087 to MS, and the German Federal Ministry of Education and Research (BMBF, https://www.bmbf.de/) under Research Networks for Health Innovation in Sub-Saharan Africa – CYSTINET-Africa 01KA1618 to ASW. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.