Filarial Worms and Microfilaria Quiz

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@EnviableMookaite4139

Study Notes

Adult worms live in lymphatic, subcutaneous tissue, connective tissue, muscle, or body cavities.
Filarial worms are viviparous.
Transmission requires an intermediate host (vector).
The first stage larva of the filarial worm is called microfilaria.

Microfilaria of pathogenic filarial worms exhibit periodicity, an adaptation related to mosquito bites.
Nocturnal periodicity: Microfilaria are found in greater numbers in peripheral blood during the night.
Diurnal periodicity: Microfilaria are found in greater numbers in peripheral blood during the day.
Non-periodicity: Microfilaria circulate at a constant level throughout the day and night.

Causes lymphatic filariasis.
Other names for the disease are Wechereiasis, Buncroften filariasis, or Elephantiasis.
Widely distributed in Asia, America, and Africa.
Habitat: Lymphatics
Intermediate host: Culex, Ades, and Anopheles mosquitos
Commonly affects lower extremities, and may involve genitals and breasts.
Adult worms are thread-like; males have a curved tail (40 mm), females (80-100 mm).
Adults typically remain coiled together in lymph vessels and nodes.

Blood examination:
- Nocturnal blood collection (22:00–04:00) or use diethylcarbamazine to stimulate circulation
- Wet preparation (motile microfilaria)
- Thick and thin blood films (Giemsa stain and hematoxylin)
Knott's centrifugation technique: Mix blood with a lysing agent, centrifuge to concentrate microfilaria, facilitating detection.

Chyluria: Lymphatic fluid (chyle) leakage into the urine, associated with W. bancrofti infection.
Urine Examination
- Milky appearance: Cloudy urine due to chyle presence
- Urine Sediment Test: Microscopic examination of urine sediment identifies fat droplets or lymphocytes.

Inflammatory reaction: Sensitivity to living and dead adult worm products leads to fever, chills, headache, acute lymphangitis in the spermatic cord, and orchitis (inflammation of testes).
Obstructive filariasis: Acute inflammation at the end converting to granuloma, damages lymphatic tissue, causing fibrosis, edema, and enlargement (elephantiasis).