Haemozoin is a disposal product formed from the digestion of blood by some blood-feeding parasites. These hematophagous organisms such as malaria parasites, Rhodnius and Schistosoma digest haemoglobin and release high quantities of free heme, which is the non-protein component of haemoglobin. Heme is a prosthetic group consisting of an iron atom contained in the center of a heterocyclic porphyrin ring. Free heme is toxic to cells, so the parasites convert it into an insoluble crystalline form called hemozoin. In malaria parasites, hemozoin is often called malaria pigment.
Plasmodium falciparum hemozoin crystals under polarised light.
Human red blood cell infected by the malaria parasite Plasmodium falciparum, showing a residual body with brown hemozoin.
Transport vesicle delivering a heme detoxification protein (hdp) to a malaria food vacuole (fv) containing crystals of hemozoin (hz). Scale bar is 0.5 μm.
Isolated P. falciparum hemozoin
Plasmodium falciparum is a unicellular protozoan parasite of humans, and the deadliest species of Plasmodium that causes malaria in humans. The parasite is transmitted through the bite of a female Anopheles mosquito and causes the disease's most dangerous form, falciparum malaria. It is responsible for around 50% of all malaria cases. P. falciparum is therefore regarded as the deadliest parasite in humans. It is also associated with the development of blood cancer and is classified as a Group 2A (probable) carcinogen.
Blood smear from a P. falciparum culture (K1 strain - asexual forms) - several red blood cells have ring stages inside them. Close to the center is a schizont and on the left a trophozoite.
Ring forms in red blood cells (Giemsa stain)
Anopheles mosquito, the carrier of Plasmodium falciparum