Plague bacteria. Light micrograph of Gram- stained Yersinia pestis bacteria. This bacterium is the cause of bubonic plague (generally agreed to have been the Black Death of the Middle Ages). The bacteria are rod-shaped,Gram-negative,non- motile bacilli. Y. pestis is primarily carried by fleas on rats. Transfer to humans occurs when the fleas feed on human blood. Infection is rapid,causing swollen lymph nodes,and leading to septicaemia and pulmonary infection. Extensive control measures against rats and their fleas have eliminated plague from Europe,but it still occurs in other regions of the world. Magnification: x1450 when printed 10cm wide | |
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Crédit: | Science Photo Library / CNRI |
Taille de l’image : | 5113 px × 3482 px |
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