Onchocerciasis

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2021年5月27日 (木) 22:59時点におけるVaccipedia.admin (トーク | 投稿記録)による版 (→‎Onchocerca volvulus)
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Onchocerca volvulus

Intermediate host
Category blackfly ブヨ, female
Latin genus Simulium
Inward infection blood-feeding of human
Organ midgut
Reproduction asexual
Course microfilariae has no sheath
  1. migrate to thoracic muscle
  2. metamorphoses L1→L2→L3 in thoracic muscle
  3. L3 migrate to proboscis
Detection
Outward transmission blood-feeding of human
Definitive host
Category HUMAN
Latin
Inward infection blood-feeding by female blackfly
Organ skin, lymphatics, blood, urine
Reproduction sexual
Course
  1. L3 into adult in subcutaneous
  2. subcutaneous nodule
    • female 33-50 cm (not mm), male 2-5 cm
    • live 15 years
  3. female produce microfilariae 9 years
    • 220-360 µm
    • 2 years
    • mainly skin, connective tissue, sometimes lymphatics, blood, urine, sputum
    • allergy and inflammation resulting in serious skin pruritis (leopard skin, anterior tibia) and keratitis (river blindeness)
Detection
    • skin snipping
      • no nocturnality, every time in a day available
    • microfilariae has no sheath
Outward transmission blood-feeding by female blackfly

Hall LR, Pearlman E. Pathogenesis of onchocercal keratitis (river blindness). Clin Microbiol Rev. 1999;12(3):445-453. doi:10.1128/cmr.12.3.445

診断

  • Skin snipping による皮膚断片の培養と顕微鏡下観察
    • 高浸淫地では有用だが,低感度なので有病割合が低下すると有用性が劣る
  • RDT
    • Onchocerca vulvolsのIgG4抗体および抗原をimmunochromatographで検出

治療