False-colour scanning electron micrograph (SEM) of the whooping cough bacteria, Bordetella pertussis. This is a Gram-negative bacillus bacteria of which two specimens are seen here. Whooping cough, known also as pertussis, is strictly a human infectious disease, occurring mainly in infants. The bacteria cause a respiratory tract infection characterised by fits of coughing that end in loud inspiratory whoops. Potentially fatal in newborn and premature babies, these bacteria are spread in coughed drop- lets. Antibiotic drugs have limited effect and the disease must run its course; pertussis vaccination is effective. Magnification: x4,285 at 6x7cm size.