Malaria-infected red blood cell. The cell at upper right is misshapen due to infection with Plasmodium falciparum. This is the merozoite stage of the protozoan parasite. It invades red blood cells after the sporozoite stage is injected into the blood by an Anopheles mosquito. The merozoites replicate and destroy the red blood cell, causing hemolytic anemia.
✯ Cell infected with HIV. Coloured scanning electron micrograph (SEM) of HIV particles (red) budding from the membrane of a host cell. HIV (human immunodeficiency virus) attacks CD4+ T-lymphocytes (specialised white blood cells), which are crucial in the body's immune system. It enters the cell and makes many copies of itself, which then destroy the cell as they emerge through its membrane. This severely weakens the immune system, causing AIDS (acquired immunodeficiency syndrome).✯
Migrating cancer cell. Coloured scanning electron micrograph (SEM) of a cultured cancer cell moving (metastasising) through a hole in a support film. Numerous pseudopodia (arm-like), fillipodia (thread-like) and surface blebs (lumps) can be seen. These features are characteristic of highly mobile cells, and enable cancerous cells to spread rapidly around the body, and invade other organs and tissues (metastasis).