Safe drinking water is a privilege in North America. Though essential to good health, it is often taken for granted. It is delivered to our homes or offices for our enjoyment with little thought given to where it originated or how it got there. We expect water to come forth as required. We expect water to both look and taste good. And we
An electron microscope catches the immune system blooming into action. A white blood cell (red) wraps itself around a mycobacterium tuberculosis, the causative agent of most cases of tuberculosis. Phagocyte, as a white blood cell is known as, comes from the Greek word phagein (to eat), and that's what the cell does, rendering the infectious cell benign.
Malaria infected red blood cell. The cell at upper right is misshapen due to infection with a Plasmodium falciparum protozoan. 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 haemolytic anaemia.
E. coli bacteria, SEM Caption: E. coli bacteria. Coloured scanning electron micrograph (SEM) of Entero Pathogenic Escherichia Coli (EPEC) bacteria (red) attached to the surface of a human epithelial cell (green). The bacteria have induced the cytoskeleton of the host cell to form 'pedestals' on which the bacteria are sitting. EPEC is a pathogenic variety of a common gut bacteria.
Being tiny doesn't stop viruses, bacteria, certain insects and other microscopic critters from causing all sorts of misery. But under the microscope, we can see them for what they truly are. This image, made using a scanning electron microscope, shows the free-swimming protozoan Giardia, which causes diarrhea and other symptoms when it infects the small intestine, often as a result of contaminated drinking water.