malaria

cause ..

protozoan parasite, genus plasmodium

how is malaria transmitted

by mosquito bite - from a female anopheles mosquito - blood meal is needed for egg development

5 methods of further malaria transmission

introduced malaria (mosquitoes bite people in endemic areas), airport malaria, transfusion malaria, mainline (via shared needles), congenital (infected mother to child)

3 stages of malaria

sporogonic - in mosquito. exo-erythrocytic - in human liver. erythrocytic - in human blood

stages in exo-erythrocytic cycle

sporozoites injected by bite, infects liver cell, forms a schizont. schizont ruptures and releases merozoites

erythrocytic cycle stages

merozoites invade RBCs and asexually reproduce, forms trophozoite which ingest haemoglobin, schizony occurs in RBC, releases merozoites when it ruptures

merozoite features

contain proteins needed for parasitic invasion, must invade RBCs to continue infection, disease causing stage

sporozoite features

enters blood vessel and circulates in bloodstream, must penetrate hepatocytes to initiate an infection, within liver cells plasmodium undergoes schizony

sporozoite to merozoite - features

once nucleus has divided many times, structure is named a schizont - ruptured schizont releases merozoites - infects RBCs

trophozoite features

single-celled nucleated mass of protoplasm, growing parasite, needs to acquire nutrients from the host, trophozoites ingest haemoglobin, plasmodium modifies RBC to allow it to take up nutrients

schizont features

schizony occurs within the RBC after several hours of growth, trophozoite divides to give 8-16 merozoites, released when RBC ruptures

stages of life cycle in mosquitoes

gametocyte, zygote, ookinete, oocyst, sporozoite

gametocyte features

some trophozoites develop into gametocytes, take around 4 days to mature, nothing happens to them unless they are taken up by a mosquito in a blood meal

zygote features

formed when male and female gametes fuse, male gametocyte produces 8 microgametes which fuses with female gametocyte

ookinete features

zygote differentiates into an invasive ookinete, which is motile and penetrates intestinal wall of mosquito, differentiates into an oocyst

oocyst features

grow rapidly and divide internally into sporozoites, produce sporozoites which are released when oocyst bursts, migrate to salivary glands

what happens when toxins are released from schizonts

mediates fever, bone marrow depression and erythrophagocytosis

clinical complications

fever, anemia, respiratory distress syndrome, hypoglycaemia, hepatomegaly, haemoglobin in blood plasma/urine, anoxia

methods of diagnosis

blood smears, stained with giemsa, rapid diagnostic tests, nucleic acid amplification-based diagnostics

treatment

chemotherapy, quinine/chloroquine