Leishmania Flashcards
what is symbiosis
close biological interaction between two different species
what mutualism
is where a symbiotic relationship benefits both species
what is commensalism
one species benefits but the other is not harmed
what is a parisitism relationship
one species benefits whilst the other is harmed
what is visceral leishmaniasis
affects the organs
which type of leishmania is the most fatal
visceral
what does cutaneous leishmania affect
affects the skin
what type of leishmania is the most common
cutaneous leishmania
what is the mucotaneous leishmania
affects the skin and mucous membranes
why is leishmania more likely to increase
- associated with migration
- more likely to increase
- draught and family can cause people to migrate
- changes in urbanisation
what are the two types leishmania cells that invade immune cells
promastigote and amastigote.
what are the characteristics of the promastigote form
inoculated by the sandfly, powerful swimmer invades phagocytic immune cells
what are the characteristics of the amastigote
formed from the promastigote after first invasion invades phagocytic immune cells. infects the sand flies
which leishmania form is mobile
promastigote
what is the axonemal paraflagella rod PFR
essential for the beating of the flagellum
which leishmania form has the PFR on?
promastigote
what are leishmania
single-celled eukaryotes
what is the vector of leishmania
sand flies
what is the host of leishmania
mammal
how is leishmania transmitted
female sandfly
how have leishmania survived
subvert normal phagocytosis pathway and evolved to survive in macrophages and neutrophils
how does leishmania enter the macrophages
- parasite bind to phagocytic receptors on macrophage cell surface
- binding stimulates phagocytosis and leishmania becomes internalised in a parasitophorous vacuole PV
what happens after the lesihmanian parasite becomes internalised in the PV
the parasites subvert phagocytosis
what are leishmania parasites Called in the midgut of the sandlfly
amastigotes
promastigotes transform to amastigotes in response to…
drop in pH and temperature
what five stages do promastigotes go through
- Procyllc
- Nectomonad
- Leptomonad
f. Hapto monad - metacyclic
what is procylic
colonisation of the gut
what is metacylic
ready to infect mammalian host upon biting
how can parasites overcome insect defences (sandfly)
sandflys digest blood with proteases:
proteases secrete inhibitors
how can parasites overcome insect defences (sandfly)
sandfly produce AMPs that form lytic pores
parasites down regulate the pathway that makes AMPs
how can parasites overcome insect defences (sandfly)
blood meal and pathogens are expelled after digestion
parasites insert their flagellum onto the gut microvilli and bind to receptors prevents them from being expelled.
how does leishmania travel from sand-fly to human/mammal
- stomedal valve: allows blood to enter the sandfly during feeding
- parasites move to this stomedeal valve
- leishmania produces promastigate secretory gel PSG
- PSG forms a plug at the stomodel valve containing infectious parasites
- causes a blockage and forces the valve to remain open
- promotes delivery of parasite into the host by regurgitation
what does the sandfly saliva do?
promotes and exacerbates leishmania’s disease
