Aust, optimism on TB, leprosy vaccine

Press, 8 June 1989, Page 26

Aust, optimism on TB, leprosy vaccine

NZPA-AAP Sydney Sydney researchers believe they may be only two years away from developing a dual vaccine against tuberculosis and leprosy, the second of which is increasing in incidence in Australia. Scientists from the Centenary Institute of Cancer Medicine and Cell Biology are about to test the genetically engineered substance on mice and cattle, after developing it over the last five years. The institute director, Professor Tony Basten, said New Zealand researchers, working in collaboration with his team, are producing a substance they hope will enable more accurate diagnostic tests to be developed. This was important as the 25 per cent of leprosy sufferers who were highly infectious were difficult to diagnose as their symptoms were generalised and not spectacular.

Professor Basten also said the number of leprosy cases in Australia had increased markedly, to the extent where a new case was diagnosed every six weeks among non-Abo-

rigines. This was a radical change from a decade ago when leprosy, usually regarded as a Third World disease, was rarely seen except in Aborigines. It was now more of a problem in the nonAboriginal population, largely because of the influx of refugees from South-East Asia. Professor Basten recently resigned his position as a senior Federal Government A.I.D.S. adviser to devote his energies to the institute, based at the Royal Prince Alfred Hospital, Sydney. Its research into leprosy, the only such research being undertaken in Australia, is likely to have many spinoffs for tuberculosis because the two diseases have many common features. Professor Basten’s team has identified a common component from the cells of the bacterium which produces the two diseases, and reproduced it through genetic engineering. A year ago, they cloned the gene responsible for producing the component,

and a month ago produced it for the first time in sufficient quantities to indicate it could be an economically viable vaccine. Professor Basten said they now needed to test the substance in animals to see if it produced immunity when manufactured. He expected to have the results within two years and was confident that if the vaccine worked in animals, it would also work in humans. Professor Basten said a vaccine was urgently needed to control leprosy, which affects about 15 million people worldwide. Antibiotic treatment was often not effective. Treatment alone did not prevent infectious carriers, who were often asymptomatic, from spreading the disease. “Not many people die of leprosy or if they do it takes 20 or 30 years,” Professor Basten said. “But the deformities • and the disfigurements can really be very, very nasty.” Professor Basten said about half a dozen other

research teams throughout the world were also researching a dual vaccine, but he believed the substance they were investigating was more likely to cause complications. “I would say we are two-thirds of the way down the track. I am very pleased with how the work is going.” Leprosy mainly spreads through skin contact, but develops in only 10 per cent of people exposed to the responsible bacterium. They could take up to 15 years to develop clinical symptoms, he said.