Wuchereria bancrofti is a parasitic roundworm that causes lymphatic filariasis. It lives in the lymphatic system of humans and is transmitted by mosquitoes. The adult female worms release microfilariae that circulate in the bloodstream and can be detected via blood smears between 8 PM and 4 AM. Infection leads to swelling of the limbs and genitals known as elephantiasis. Diagnosis involves blood smears to detect microfilariae while treatment consists of medications like diethylcarbamazine, ivermectin, and albendazole. Prevention focuses on mosquito control and public education.
6. Morphology
Microfilariae:
244- 296 um by 7.5- 10 um
Nuclei not reaching tail end
No terminal nuclei
Nuclei regularly spaced, dispersed
Bigger, wider than B. Malayi
Graceful sweeping curves
Short head space (as long as
broad)
Sheath unstained with Giemsa
Bluntly rounded anteriorly and
pointed caudally
7. Microfilaria - is a miniature adult that retains the egg
membrane as a sheath.
8. Characteristics
Habitat of Adult worm : Lymphatic system
Habitat of Microfilaria: Blood
Intermediate Host : Anopheles minimus
var. Flavirostris
- principal vector for malaria in
Philippines
- bite indoors, night- biters
Others: Aedes poecilus ( in axils of plants)
Definitive Host : Man
9. Characteristics
Periodicity: Nocturnal periodicity, EXCEPT
South Pacific microfilariae
Nocturnal periodicity:
8 PM- 4 AM = best time to collect
Microfilariae may not be demonstrable in peripheral blood
if:
- low intensity of infection
- dead worms
- obstructed lymphatics
16. Diagnosis
Direct methods (visualization of larval stage or
microfilaria and adult worm)
Microfilaria can be seen on peripheral blood or other body fluids (eg.
urine, ascitic, hydrocoele, or lymph fluid).
Wet smear examination under the microscope where motility
can also be seen
Examination of stained peripheral blood smear which is also
useful in species identification based on morphologic features
of organism, especially the tail end
Thick or concentrated blood smears
concentration smears are useful in patients with low parasetimia
blood sample is taken during the period in the day when the
juveniles are in the peripheral circulation.
17. Diagnosis
Direct Methods
X- ray
adult worms can be demonstrated in lymph node biopsy
calcified adult worms are visualized
Doppler Ultrasonography
detect presence of motile adult worms in dilated lymphatics