False colour transmission electron micrography of a thin section of the whooping cough bacteria, Bordetella pertussis. The micrograph shows the genetic material (DNA) of the bacteria as white regions within the cell. The surrounding cytoplasm shows numerous small black dots called ribosomes, which are the sites of protein synthesis. The whooping cough bacteria parasitise only humans. They cause a respiratory tract infection characterised by fits of coughing that end in loud inspiratory whoops. The infection is usually contracted in childhood and is potentially fatal in infancy. Adults are sometimes affected. Magnification: X 8,570 at 35mm size. Original is bw print b220/205