Filarial Worms

• FILARIAL WORMS Two known morphological forms:

  Microfilaria

  Adult worms
• retains embyronic sheath (present at the tail)

  Sheathed Microfilaria
• does not retain embryonic sheath

  Unsheathed Microfilaria
• Sheathed Microfilaria 3 examples

  Wuchereria bancrofti

  Brugia malayi

  Loa loa
• Unsheathed Microfilaria 3 examples

  Onchocerca volvulus

  Mansonella perstans

  Mansonella ozzardi
• LYMPHATIC FILARIAL PARASITES: One of the “most debilitating diseases” in tropical countries (Southeast Asia)
• Filariasis - parasitic infection caused by microscopic threadlike worms acquired through a mosquito bite (vector-borne)
• LYMPHATIC FILARIAL PARASITES: 

  Wuchereria bancrofti & Brugia malayi MOT


  Skin penetration through a vector
• LYMPHATIC FILARIAL PARASITES: 

  Wuchereria bancrofti & Brugia malayi habitat


  Lymphatic vessels (lymph nodes)
• Vector of W. bancrofti

  Aedes, Culex, Anopheles
• Vector of B. malayi


  Mansonia, Aedes, Anopheles
• Mansonia spp for B. malayi (2)

  M. bonnae

  M. uniformis
• Infective stages of lymphatic filarial parasites for man

  L3 larva or filariform larva
• Infective stages of lymphatic filarial parasites for microfilaria

  mosquito
• definite host of lymphatic filarial parasites


  human
• common name of W. bancrofti

  Bancroft's filarial worm
• B. malayi common name


  Malayan filarial worm
• vector of W. bancrofti

  Anopheles, Aedes, Culex
• Brugia malayi vector (1)

  mansonia
• area affected for W. bancrofti

  lower lymphatics
• area affected for B. malayi


  upper lymphatics
• periodicity of W. bancrofti

  nocturnal (8 or 9 PM to 4AM)
• periodicity of B. malayi

  subperiodic - 12 NN to 8:00 PM

  nocturnal - 10 PM and 2 AM or 4 AM
• length of microfilaria of Bancroftian Filariasis

  240-300 um length
• Microfilariae of Bancroftian Filariasis - sheath & nuclei?

  sheathed with no nuclei at the tip
• Adult worm of Bancroftian Filariasis are tightly coiled in nodular dilated nests
• female adult worm size in Bancroftian Filariasis

  40-100 mm
• male adult worm size of Bancroftian Filariasis

  20-40 mm
• Vector Biology of Bancroftian Filariasis

  Anopheles flavirostris and Aedes poecilus
• aquatic habitat Bancroftian Filariasis 


  axils of abaca and banana plant
• adult biting Bancroftian Filariasis

  day and night biting

  indoor and outdoor
• adult resting Bancroftian Filariasis

  base of abaca plants

  cool shady areas
• Malayan Filariasis microfilariae sheath and nuclei?

  sheathed with 2 nuclei at tip
• size of microfilaria Malayan Filariasis

  200 - 280 um length
• adult worm of Malayan Filariasis is tightly coiled in nodular dilated nests
• female adult worm size of Malayan Filariasis

  53 mm
• male adult worm size of Malayan Filariasis

  24 mm
• Vector Biology Malayan Filariasis

  Aedes, anopheles, mansonia spp
• adult biting Malayan Filariasis

  day and night biting

  indoor and outdoor
• aquatic habitat of Malayan Filariasis

  axils of abaca and banana plant, swamps