SARS lung damage. Light micrograph of a section through tissue from the lung of a patient with SARS (severe acute respiratory syndrome), a fatal pneumonia-like disease. A giant cell is seen at center, which has numerous nuclei (dark). The white spaces are alveoli, tiny sacs in the lungs through whose walls gaseous exchange takes place. Several red blood cells (red) are seen in the tissue. Alveolar damage causes a cough and breathing difficulties. Other symptoms include fever, fatigue and joint pain. It is thought to be fatal in 6-20% of cases, with the elderly more at risk. It was first seen in China in 2002. Magnification unknown.