The clinical manifestations of filariasis depend upon the stage
in the course of infection in the human host and the worm load
(adult). The stages in the course of infection may be described
as follows:
A. Stage of Invasion: The infective larva gains its entry into
the human host and starts undergoing further development. Diagnosis
at this stage rests on the triad of: Eosinophilia, lymphadenopathy
and a positive intradermal test with the supporting evidence of
history of residence in an endemic area.
B. Asymptomatic or Carrier Stage: This stage is usually with no
clinical manifestation. The microfilaria (mf) carriers are usually
detected by night blood examination.
C. Stage of Acute Manifestations: These comprise filarial fever,
lymphangitis, lymphadenitis and lymphoedema of the various parts
of the body and epididymo- orchitis in the male. It is mainly because
of the infection of the lymphatic vessels (channels) by the adult
worm.
D. Stage of Chronic Manifestations: The clinical manifestations
comprise of elephantiasis of genitals, legs or arms, hydrocele,
chyluria, etc.
Microfilaria of Wuchereria bancrofti seen under Compound Microscope
