P. cantonensis

• Parastrongylus cantonensis was previously classified under the genus Angiostrongylus
• Parastrongylus cantonensis is Also known as "Rat lungworm"
• First described by Chen in 1935 from domestic rats in Canton, China
• Known to cause eosinophilic meningoencephalitis in humans
• Human infection was first reported in Taiwan in 1945
• Adult worm:

  • Pale and filiform
  • Length of 17 to 25mm
• Adult male:

  • Length of 16 to 22 mm and diameter of 0.25 to 0.35 mm
  • Well-developed caudal bursa, kidney-shaped and single-lobed
• Adult female:

  • Length of 19 to 33 mm and diameter of 0.28 to 0.50 mm
  • Uterine tubules wound spirally around the intestine in a "barber's pole" pattern
  • Posterior end is blunt shaped
  • Can lay up to 15,000 eggs daily
• Eggs:

  • Elongated and ovoid in shape
  • Measures 46 to 48 um by 68 to 74 um and are unembryonated when oviposited
• 1st stage larva:

  • Found in the lungs of the rodent host
  • Has a distinct small knob near the tip of the tail
  • Infective stage for the molluscan intermediate host
• 3rd stage larva:

  • Have two well-developed chitinous rods below its buccal cavity
  • Have expanded knob-like tips
• Parastrongylus cantonensis Known intermediate hosts in the Philippines:

  • Achatina fulica
  • Hemiplecta sagittifera
  • Helicostyla macrostoma
  • Vaginilus plebeius
  • Veronicella altae
• Diagnosis of Parastrongylus cantonensis:

  • Primary site of infection is the brain
  • Examination of blood may reveal a high proportion of eosinophils
  • Examination of CSF
  • Meningeal lesions may be appreciated with CT scans
  • MRI may show lesions with hyperintense T2 signal
  • ELISA
  • PCR