Leishmaniasis Biology + diagnosis Flashcards
what kind of parasite is leishmania?
kinetoplastid parasite - obligate intracellular protozoal parasite of the genus leishmania.
how is leishmaniasis transmitted?
by the sandfly vector (leishmania is the parasite)
what does the digenetic form of the parasite for leishmaniasis mean?
asmastigote form in vertebrates (loses its flagellum) and promastigotes in sandflies (with the flagellum)
what part of the sandfly transforms from amastigotes into promastigotes
in the midgut of the leishmania subgenus or the hindgut/midgut in the Vianna subgenus.
what are the arrows above and below pointing to and what kind of sample is this and what stain?
splenic aspirate, giemsa stain.
arrow above is leishmania nucleus and arrow below is is the KINETOPLAST which is the diagnostic feature for leishmaniasis.
what is the gold standard test for leishmaniasis ( VL)?
parasitological - tissue aspirate preferably a splenic ( then bone marrow then lymph node in that order) and microscopy to identify amastigotes.
what is the best mode of diagnosis of VL in someone that is HIV +ve?
rk39 RDT plus DAT plus biopsy
What is the best mode of diagnosis in an East African setting of VL?
rk39 + biopsy
what are the risk factors for developing mucocutaneous leishmaniasis?
being male, age, nutritional status, number of LCL lesions ABOVE waist, inadequate treatment and immune status.
what are the common presentations of PKDL in South Asia and E Africa?
macular in South Asia and papular in E.africa - also in S asia occurs usually 0-3yrs after initial VL and 0-13months in E Africa after initial VL.
what is the name given to relapsing LCL infection after being resolved months to years later?
Leishmaniasis Recidivans.
how would you describe this insect?
sandfly -
how would you describe this insect?
phlebotomus papatasi male sandfly - see the claspers at tip of abdomen.
how would you describe this insect?
Lutzomyia longipalpis female sandfly - no claspers like the male. abdomen is blunt ended or rounded in outline. unlike mosquitoes cannot tell the difference between the sexes by examination of the palps or antennae.
what is this?
phlebotomine sandfly larva - note the dark encapsulated head and tip of abdomen with 2 pairs of caudal setae. larval development takes 20-30days.
what is this? and what is circled?
phlebotomine sandfly pupae - retained larval skin from the last moult. adults emerge after 6-13days
