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Malaria

Cause :

Plasmodium vivax and Plasmodium falciparum are more common causes of malaria than others Plasmodium.

– Vector and definitive host for plasmodium is the female Anopheles mosquito.

Most of pathological finding of malaria results from destruction of RBCs due to release of merozoites and the action of spleen against the infected cells.

Falciparum malaria is more severe than caused by others (leads to hemorrhage & destruction of capillaries).

Extensive hemolysis & kidney damage occur result in hemoglobinurea (black color of pts urine is termed blackwater fever).

Fever cycle for P. malariae is 72 hours while 48 hours in others.

-falciparum causes a high level of parasitemia ( infects red cells of all ages), while p.vivax infects only reticulocytes & P.malaria infects only mature RBCs.

Sickle cell trait individuals (heterozygous) are protected against malaria (too little ATPase), also people with G6PD are protected.

Transmission :

Mosquito bites ,but transmission across placenta , in blood transfusion & I.V. drug abuse.

Diagnosis :

-Rests on microscopic examination of blood using both Thick and Thin Giemsa-stained smears.

-Thick smear used to screen presence of organism while thin smear used for species identification (treatment differ for each species).

-Ring –shaped trophozoites can be seen within infected RBCs.

-Gametocytes of p.falciparum crescent shaped (banana shaped) while others are spherical.

-If blood smears don’t reveal the diagnosis , PCR based for nucleic acid or ELISA for protein specific for falciparum.