Changing patterns of tuberculosis in Far North Queensland

To the Editor: Australia has a low incidence of tuberculosis (TB), which has remained constant for over a decade.1 However, the incidence is not uniform across the population; immigrants and Indigenous Australians have higher rates.

An audit of all cases of TB in Far North Queensland over 5 years showed an incidence of 35.9/100 000 per annum in Indigenous Australians, and poor outcomes in this group.2 This finding led to a number of policy changes, including an increase in directly observed therapy (DOT), made possible by increased use of Aboriginal health care workers in remote communities, and more aggressive and prolonged treatment of relapses.

A follow-up audit was undertaken to assess the effect of these changes. The results are shown in the Box for both time periods. New cases of TB in Indigenous Australians were significantly reduced (P < 0.0001 by Fisher’s exact test), and DOT had increased significantly (P < 0.0001). The number of deaths from TB had declined, as had relapses, but these falls were not statistically significant. There were no deaths among Indigenous Australians during the second 5-year period. Of the people who died in this period, three were elderly men suspected of having cancer, and one was a patient from Papua New Guinea (PNG) who had HIV co-infection with TB.

The most striking finding was the dramatic increase in cases in people from PNG (P < 0.0001). The outer Australian islands in the Torres Strait are only 3 kilometres from the PNG coast, and there is free movement of people across the border under a treaty arrangement.

Although there are no precise figures,3 it is clear that there are epidemics of both TB and HIV in PNG, and that these have extended to rural areas. Specialist outreach clinics with x-ray facilities have been established on the outer islands, but numbers have continued to rise. In 2005, of 38 cases of TB in Far North Queensland, 26 were from the Torres Strait including seven cases of multidrug resistant TB. This represents a significant public health threat and highlights the importance of local audits of TB control, as state and national data may not be adequate to identify emerging local problems.