African sleeping sickness Flashcards
how is African sleeping sickness transmitted
tsetse flies
what is the parasite called in African sleeping sickness
trapanosomes
how is African sleeping sickness spread
agriculture, fishing, hunting
what is African sleeping sickness called in animals
Nagana
what symptoms do animals have with nagana
extreme weight loss and lethargy
what is an important reservoir in African sleeping sickness
cattle
how can we control African sleeping sickness
- target parasite reservoir in the host
- target the vector
what are the 3 pathological stages of African sleeping sickness
- inflammation of tsetse bite
- early stage - haemolymphatic: parasites enter the blood & lymph
- late stage: encephalitic: trypanosomes cross ‘blood-brain’ barrier and enter the CNS
what are the symptoms of African sleeping sickness
coma, loss of consciousness, abnormal behaviour, swollen lymph nodes
what is a major reservoir in the trypanosome lifecycle
the skin
what are the two distinct trypanosome lifecycle stage in the host
slender and stumpy
what are the characteristics of slender
- long and slender
- proliferative
- specialised for glucose metabolism
- non-transmissible
what are the characteristics of stumpy
- short and stumpy
- cell cycle arrest
- adapted to survive inside the gut, resistant to proteases
how are stumpy forms predated for transmission
- slender forms proliferate
- at high levels of parasitaemia they differentiate into stumpy forms
- this is quorum sensing
- limits parasitaemia and
preserves life of the host - stumpy forms are transmitted via the tsetse bite
tsetse anatomy: what is the crop?
where the blood meal is taken during feeding
tsetse anatomy: what is the midgut
where the blood meal is digested
tsetse anatomy: what is the proventriculus:
acts a 3-way “valve” between crop, midgut and probotics
what do trypanosomes differentiate into when reaching the salivary glands?
metacylic cells
what are the steps of trypanosome invasion
- antibodies
- compliment (puncture pathogens)
- immune cells (macrophages)
what protects the trypanosome from being recognised
variant surface glycoprotein VSG
what are the functions VSG
- protects the cell from the host immune system
- protects underlying antibodies form antibody recognition
- protects the membrane from compliment
what is quorum sensing
caused by parasite factors, the differentiation of slender to stumpy forms
