Scurvy, a disease historically associated with old-world sailors on long voyages, is making a surprise comeback in Australia with health officials Tuesday revealing a spate of cases. Caused by vitamin C deficiency, it used to be a common, and often fatal, curse among seafarers who went months without fresh fruit and vegetables. Now considered rare, it is reappearing due to poor dietary habits, said Jenny Gunton, who heads the Centre for Diabetes, Obesity and Endocrinology research at the Westmead Institute in Sydney.