Tuberculosis rates in Australia are increasing. While most notifications are from overseas born individuals there is transmission occurring in the community. Nonetheless the rates in Australia are still among the lowest in the world.
In 2011 there were 1385 active tuberculosis notifications in Australia representing a rate of 6.2 cases per 100,000. There has been a steady increase in cases in the past decade but the reates are still small considered with most of Africa where TB prevalence is >50/100,000 in most countries. Australia’s overseas-born population represent the majority (88%) of cases notified. Non-indigenous Australians have the lowest rate 0.9/100,000 compared with 4.9/100,000 among indigenous Australians. Western Australia in the same year had 119 notifications with almost all cases among overseas-born individuals1. Pulmonary tuberculosis accounts for 2/3 of cases and the second most common site are the lymph nodes.
Diagnosis of pulmonary tuberculosis can be made by obtaining early morning sputum samples with 70% sensitivity after two specimens. Sensitivity is around 90% with an induced sputum2. Plain chest x-rays often show abnormalities and CT chest does not increase sensitivity for the diagnosis of pulmonary TB. Classical upper zone cavitation as in figure 1. often occurs in advanced disease with surprisingly mild symptoms3. Tests such as TST (Mantoux) or QuantiFERON demonstrate TB infection not its activity.
Treatment is curative with six months of standard quadruple therapy (Isoniazid, Rifampicin, Pyrazinamide and Ethambutol) for susceptible cases, which comprise the large majority of clinical cases.
For more information go to the WA TB Control Program website http://www.health.wa.gov.au/acc/tb/.
References:
1. Tuberculosis Notifications in Australia, 2011 http://www.health.gov.au/internet/main/publishing.nsf/Content/cda-cdi3804m.htm 2. Testing for Tuberculosis. Konstantinos. Australian Prescriber 2010 http://www.australianprescriber.com/magazine/33/1/12/18/
3. Tuberculosis Testing, AFP July 2012 http://www.racgp.org.au/afp/2012/july/tuberculosis-testing/