L3: Blood and Tissue Nematodes

• Filarial Nematodes - small and thread-like parasites
• Filarial Nematodes - much smaller than intestinal nematodes, found through microscopic analysis, they inhabit only in the blood and tissue
• Filarial Nematodes are subdivided to their anatomical location which they cause or infects - Blood Nematodes, Tissue Nematodes
• Blood nematodes : Lymphatic

  • Wuchereria bancrofti
  • Brugia malayi
• Tissue Nematodes

  SUBCUTANEOUS

  • Loa Loa
  • Onchocerca volvulus

  SEROUS CAVITY AND SUBCUTANEOUS

  • Mansonella Spp
• Adult filariae produce larvae called microfilariae that are usually detected in the blood
• Filarial Nematodes - may exhbit periodicity, a time where adult filaria are best recovered in samples
• Filarial Nematodes - usually found in vectors. distribution: usually found in asia, south, and central american, the carribean
• Filariasis - common in the Philippines
• Life cycle of Filarial Worms - all of the parasites under this have the same life cycle. the only difference is their intermediate host (blood sucking insects)

  
• L1 and L2, Intermediate host - blood sucking nematodes
• L3 - larval stage that is the time where they can infect. development occurs in this stage.
• Once human is infected and the microfilaria is transferred in the human system, this is the time they will go to the anatomic locations - lymphatic, subcutaneous tissues and serous cavities
• Filarial worms definitive host - human
• Filarial worms diagnostic stage - microfilariae in blood or skin of humans
• Blood nematodes

  1. Wuchereria bancrofti
  2. Brugia malayi
• need to consider in microfilaria :

  1. Sheats (anterior, posterior parts)
  2. Nuclei
  3. Periodicity
• Blood nematodes - usually contains sheaths (sock-like)
• Wuchereria bancrofti common name - Bancrofti’s filaria
• Wuchereria bancrofti causative agent of bancrofti’s filariasis or elephentiasis
• Wuchereria bancrofti size - 240 to 300 um
• Wuchereria bancrofti sheath is present
• Wuchereria bancrofti nuclei in the tail is not present on the tip of the tail. Usually blood nematodes contain nuclei except this. This is the dotted portion inside the parasite. In this parasite, the nuclei don’t go to the tip of the tail.
• Wuchereria bancrofti laboratory diagnosis - giemsa stain, knott technique, they can be seen through the blood that is why this stain is commonly used for this.
• Wuchereria bancrofti peak hours of blood collection : between 9pm to 4am; sometimes can be detected throughout the day and more prevalent in the late afternoon.
• Wuchereria bancrofti have a nocturnal periodicity
• Intermediate hosts of Wuchereria bancrofti - culex, aedes, anopheles spp
• Wuchereria bancrofti clinical symptoms: asymptomatic -

  • Eosinophilia
  • Enlarged lymph nodes, particularly in the inquinal area - this is because it inhabits the lymph nodes.
  • Self-limiting
• Wuchereria bancrofti clinical symptoms : symptomatic

  • fever and chills
  • eosinophilia
  • granulomatous lesions, lymphangitis, and lymphadenopathy (swelling of lymph nodes)
  • lower elephantiasis
  • calcification or formation of abscess
• Wuchereria bancrofti treatment

  1. Diethylcarbamazine
  2. For heavy infection : Ivermectin (Stromectol) + albendazole
  3. Surgical removal of the microfilariae (rare cases)
  4. Unna’s phase boots - use to reduce the enlargment of libs to drain down the fluid in the parts of lower limbs
  5. Elevation of infected area with bandages or simple elevation
• Wuchereria bancrofti : Adult female and male

  
• Wuchereria bancrofti sheat in the posterior and anteriror part is present, nuclei in the tail is not present
• Wuchereria Bancrofti Disease : Lower limb Elephantiasis

  
• Lower limb Elephantiasis - happens when the parasites infect the inguinal area. once they infect the area, the lymph will go through the infected area and will cause an enlargement of the limbs. caused by parasitic infection
• Heavy cases of Lower limb Elephantiasis - Lymphadenopathy
• Wuchereria bancrofti calcification or formation of abscess :

  • happens once parasites dies and leaves a remnant
  • not edema since edema is cause by water
  • calcification is caused by lymph nodes
• Brugia malayi common name - malayan filaria
• Brugia malayi causative agent of malayan filariasis or elephentiasis
• Brugia malayi size - 200 to 280 um
• Brugia malayi sheath is present with rounded anterior end