A case of asymptomatic infection of Ascaris suum identified by PCR-restriction fragment length polymorphism and DNA sequence analysis

Diagn Microbiol Infect Dis. 2024 Sep;110(1):116444. doi: 10.1016/j.diagmicrobio.2024.116444. Epub 2024 Jul 14.

Abstract

Human ascariasis is a soil-transmitted helminthiasis and remains a neglected tropical disease. Ascaris suum has the potential to cause cross-infections between humans and pigs. In this study, we present a rare case of a patient with asymptomatic infection by Ascaris suum. A 66-year-old male underwent colonoscopy, and a white linear worm body was found in the hepatic curvature. The worm was collected by aspiration and submitted to the laboratory for parasite identification. The patient had no symptoms related to parasitic infection. The worm was highly suspected to be of the genus Ascaris. Because of the difficulty of morphological classification, genetic analysis was performed. From PCR-restriction fragment length polymorphism results and sequence analysis of the internal transcribed spacer-1 region, it was determined to be A. suum. The experience with rapid differentiation of A. suum by performing genetic analysis will be useful for future examinations of parasitic infections.

Keywords: Ascariasis; Ascaris suum; Genetic analysis; Zoonosis.

Publication types

  • Case Reports

MeSH terms

  • Aged
  • Animals
  • Ascariasis* / diagnosis
  • Ascariasis* / parasitology
  • Ascaris suum* / genetics
  • Ascaris suum* / isolation & purification
  • Asymptomatic Infections
  • DNA, Helminth* / genetics
  • DNA, Ribosomal Spacer / genetics
  • Humans
  • Male
  • Polymerase Chain Reaction* / methods
  • Polymorphism, Restriction Fragment Length*
  • Sequence Analysis, DNA*

Substances

  • DNA, Helminth
  • DNA, Ribosomal Spacer