General Parasitology and Protozoa
In trypanosomal infections all are true except:
|A||Trypomastigote form is seen in vertebrate host|
|B||T brucei has posterior station development|
|C||Intermediate host of African trypanoso-masis is Tse Tse fly|
|D||Tse tse fly bite during day|
a. T.brucei causes sleeping sickness/ African trypanosomasis.
b. T.brucei subsp.gambiense causes West African sleeping sickness.
c. T.brucei subsp.rhodesiense causes East African sleeping sickness.
d. The vector is tse-tse fly which bit during the day.
e. There are no extra human reservoir for T.brucei subsp.gambiense but several small mammals act as reservoirs for T.brucei subsp.rhodesiense.
Infective form for man is the metacyclic trypomastigote.
In African trypanosomiasis, there is anterior station development in tse tse fly. Procyclic, epimastigote and metacyclic trypomastigote stages are seen in the gut of the tse-tse fly.
The trypomastigote forms are seen in vertebrate hosts are of two types-short stumpy and long thin.
Clinical features: trypanosomal chancre→ febrile attacks, lymphadenopathy (Winterbottom’s sign: enlargement of posterior cervical lymph nodes)→ CNS involvement (Kerandel’s sign: pressure on palms of the hand or over ulnar nerve is followed by severe pain after pressure is removed)
Drug of choice for sleeping sickness is suramine in early stages and Melarsoprol in later stages.