False-color scanning electron micrograph of the protozoan Giardia lamblia. This parasitic single-celled organism with flagellae, causes the disease giardiasis (known also as lambliasis). It is an infection of the small intestine most common in tropical areas, and in people who have visited the tropics. Giardia lamblia attaches by means of sucking discs to microvilli in the human intestine reducing liquid absorption which may lead to diarrhoea. Abdominal discomfort, cramps, swelling, loss of appetite and nausea may also occur. Giardiasis is spread by direct contact with the sufferer or through contaminated food and water. Magnification: unknown.