Culture-positive Tuberculosis in Western Australia

Notifications of 485 patients with culture-positive tuberculosis (TB) in Western Australia from 1980 to 1989 inclusive have been analysed. In 478 (98.6%) the disease was caused by Mycobacterium tuberculosis hominis and in seven (1.4%) M. bovis. Most (78.5%) of the disease was pulmonary with 4.3% pleural and 17.2% extrapulmonary. The annual incidence decreased from 4.6 per 100,000 in 1980 to 2.5 in 1985 steadying thereafter around 3.3. The Aborigines had over four times the average incidence of the non-Aboriginal Australians but less than a quarter that of the Asians. In a total 297 migrants, 51% of 253 with data available had been in Australia for over five years. Initial drug resistance was found in 48 patients giving an overall rate of 9.9%. In 32 (66.7%), resistance was against a single drug, mainly isoniazid and in 11 (22.9%) against two drugs, predominantly isoniazid and streptomycin. The most disturbing finding was the occurrence of multiple-drug resistance including both isoniazid and rifampicin in five immigrants (10.4%). This study has provided useful baseline TB data, raised important issues such as chemoprophylaxis and drug resistance, and clearly indicates that the campaign against TB is far from over. Continual surveillance, monitoring and regular evaluation of existing policies should be maintained.