Disease of the month: tuberculosis
With a history as long as mankind’s, TB lies dormant in one third of our global population.
The grim reaper among 19th and 20th century writers – think George Orwell, Keats and the Bronte sisters – tuberculosis (TB) is one of the world’s leading infectious causes of death, second only to HIV.
“The reason TB is fascinating and captures people’s imagination is that it’s been infecting humans since even before we were Homo sapiens,” says Dr Anna Ralph, Clinical Research Fellow and Infectious Diseases Physician at the Menzies School of Health Research. “Fossil records show that TB’s been around as long as humans have.”
Owing to first-class lab facilities and contact tracing systems (more on that later), TB is largely unheard of among Western countries.
“While TB rates are higher among our Indigenous population, if you’re Australian-born and non-Indigenous, your chances of getting TB are almost zero,” says Ralph.
Yet the picture in the developing and third worlds is far different.
Ninety-five per cent of TB sufferers live in low or middle-income countries such as China, India, Brazil or Indonesia. In 2009, TB deaths among parents orphaned 10 million children worldwide.
The disease is even more lethal among HIV sufferers, many of whom reside in Africa. Estimates are that among all those living with HIV, 25 per cent eventually die from TB infections.
A Highly infectious disease
TB bacteria are spread through air-borne routes, propelled into the atmosphere via coughing.
Infected patients typically have a persistent cough with traces of blood in their phlegm. They’re tired, have lost weight and are troubled by night sweats.
The World Health Organisation (WHO) believes that one third of the world’s population has latent TB – the type that sits dormant, spreading only if and when the disease morphs into the more active form of TB.
“Normally an incident will happen that compromises your immune system, and that’s when TB can become active in your system,” says Dr Ralph.
In the course of a year, someone with active TB can spread the disease to up to 15 people, and without proper treatment, around 10 of that group may die.
How to stem TB
The key to controlling it, Ralph says, is identifying TB early, treating it with antibiotics and performing ‘contact tracing’ of household members and other people who’ve had close contact with the TB patient.
In Australia, around 1,200 cases are reported each year, 85 per cent of which reside in our country’s migrant population. Cure rates are high due to good access to medical care.
Our near neighbours, however, suffer much higher TB rates: Indonesia, for instance, chalks up around 26,000 cases annually.
The deathly touch of TB may linger in the myth surrounding famed writers studied in high school English classes, but the reality of TB remains stark and current.
“There is already good knowledge about how to detect and cure TB, yet this scourge continues to plague lower-resource settings,” says Dr Ralph.
The most vital requirements in TB control are better diagnostics, which will allow more cases of TB to be picked up; as well as more more effective treatments. The current antibiotic course, for example, needs to be taken for six months straight.
“The future dream is for an effective vaccine which could prevent TB altogether,” Dr Ralph says.
What Menzies is doing about TB in our region
To gain more insight into the TB picture in Indonesia’s Papua Province and Malaysia, Menzies researchers first began studies in Papua in 2003, and this year, commenced work in Malaysia, led by Ralph.
This data – mostly collected on the incidence of drug-resistant TB and the occurrence of TB-triggered disabilities – was later channelled to the WHO and included in the organisation’s global statistics on TB.
To improve treatments and ultimately save lives, Menzies also tested nutritional interventions, such the impact that immune system boosters Vitamin D and the amino acid arginine have on the body’s ability to fight TB.
The results are due out later this year.“Our studies have added important information to the medical literature that details whether it’s important or not to use these specific treatments,” Dr Ralph says, ahead of the data’s publication.
Smaller scale breakthroughs have taken place at the Papua clinic itself, too.
As Dr Ralph says: “We’ve been able to make sure that all TB patients get an HIV test; we’ve developed a method for reading x-rays which has been adopted for use in Africa and elsewhere; and. just by being there, we’ve been able to update local doctors’ knowledge and support them to improve the care afforded to patients afflicted with TB.”
Small gains in TB can translate to big public health successes. The gains being made by Menzies researchers towards improved TB treatment and understanding immune responses to TB add vital pieces to the jigsaw puzzle.
“Each step brings us closer to the goals of better diagnostics and treatments for this age-old disease,” Dr Ralph says.