By Samuel Ognenis – Crossing Borders For Health Coordinator
As a Western medical student, it can sometimes be easy to forget the suffering inflicted upon millions of people each year by treatable and preventable infectious diseases.
After the 1980’s HIV epidemic, the disease lost vogue within mainstream Western culture, as numbers affected in nations such as our own fell. But the disease continues to kill around 1.8 million people each year. In fact, around 15 million people die from infectious diseases per annum, out of a total of 55 million deaths from all causes.
The second biggest ID killer? TB. It kills around 1.4 million people, every single year. TB is estimated to have killed one billion humans in the past 200 years alone, and it was the leading cause of death in much of the Europe, the US and Australia right up into the early 1900s. The World Health Organisation estimates around one-third of the world’s population has latent TB i.e. they are infected but are not yet ill or able to transmit the disease.
TB, or tuberculosis, caused by the bacterium Mycobacterium tuberculosis. Given the long course of illness many patients experience, it is very good at infecting large numbers of people. However, we possess a vaccine which provides a fair amount of immunity, and it is curable, often by an antibiotic cocktail of isoniazid, rifampicin, pyrazinamide and ethambutol.
That is, until the past few years, when antibiotic resistance hit these drugs. Multi-drug-resistance tuberculosis (MDR-TB) is our new opponent; TB resistant to both isoniazid and rifampicin.
According to the WHO, MDR-TB exists in around 3% of new TB cases. A further 9% of these cases also resistant to other drug classes, including one fluoroquinolone and one injectable drug (e.g. Capreomycin, amikacin), and are thus classed as extensively drug-resistant TB (XDR-TB). Overall, 5% of cases of TB are multi-drug resistant.
Drug resistant tuberculosis occurs when medications are not adequately administered, or administration is interrupted. Drug treatment for tuberculosis is long, and most often extends beyond the point when the patient feels better. As such, many patients may cease taking their medications before the course is finished. This is particularly an issue amongst poor patients in difficult social circumstances, where follow-up can be very difficult over a long time period. This is a perfect environment for drug resistance, which occurs when medications are not adequately administered, or administration is interrupted/stopped.
MDR-TB and XDR-TB are far, far more difficult and expensive to treat, and are growing in prevalence. One PNG national was diagnosed with XDR-TB, and was treated in Cairns, for a sum of $500,000, before she died after a year in isolation. If she had lived to complete treatment, it would have cost $1 million.
It is as though we have gone back to a pre-antibiotic era, where in many cases we are helpless to treat an infection that has the potential to do such damage.
Once a patient has developed a drug-resistant strain of TB, this can be transmitted to others in his or her community. The spread of drug-resistant TB can be attributed to a range of factors: the lack of rapid, cheap and accessible diagnostic methods, insufficient second line drugs, poor patient adherence to long treatment regimens, social stigma, poverty, and insufficient political will all play a part in this story. With fewer than one in five patients with MDR-TB being treated with second-line drugs, and only around half achieving treatment success, the need for new approaches has never been greater.
TB is of particular importance in Australia’s region, with more than half of the global burden affecting the Asia/Pacific region. Health systems across the region have been overwhelmed. Cambodia, Bangladesh, East Timor, Papua New Guinea, Pakistan and Vietnam each have a prevalence greater than 300 per 100,000 population.
Since TB was declared a global emergency by the WHO in 1993, there has been much progress in reducing death and prevalence of TB. However, billions of people are infected with M.tuberculosis, millions continue to suffer from active disease, and more than a million die from TB each year. With the rise of MDR-TB and XDR-TB, health systems and society-at-large are presented with new challenges.
To commemorate World TB Day 2013, The Lancet Infectious Diseases dedicated a special issue to a series of papers on Tuberculosis. The feature article of this series looked at what needs to be done to address this growing problem, and called “for visionary political leadership”.
Without concerted action and interest from political leaders, health policy makers, funding bodies, and the general public, health systems worldwide are at risk of being overwhelmed by increasing numbers of patients with treatment-resistant tuberculosis, due to the ease of international travel and thus transmission of drug-resistant TB.
So what needs to be done?
Most national programmes fail to diagnose and treat MDR-TB and XDR-TB. Therefore we need to:
- Scale up availability of drug-sensitivity testing.
- Improve access to quality treatment programmes – in particular second-line drugs. To contain spread, we need a consistent supply of 2nd line drugs supported by adequate resources.
Both of these require serious political commitment from national and international leaders, continued innovation and implementation of bold and pragmatic approaches. Coherent national programmes need to be underpinned by political will. We also need to:
- Improve access to treatment to young children; many of whom have severely restricted options at present.
- Control other infections (e.g. HIV).
- Target interventions in susceptible groups (e.g. alcoholics, drug users).
And we need collaboration between government and non-government groups:
- Fix funding shortfall for the Global Fund, and utilise the cooperation of pharmaceutical companies and public/private partnerships (PPP).
- Develop new drugs, new regimens and shorter treatment times to help compliance and improve outcomes.
We need a radical change in political and scientific thinking. We need to acknowledge that this is a serious threat before it overwhelms health systems, and that the problem will not subside until we address it as a global phenomenon.
We need you, in whatever field you are in. We need your interest, your enthusiasm and your expertise to win the war against TB.
References:
http://www.who.int/mediacentre/factsheets/fs104/en/index.html
http://www.theglobalmail.org/feature/plagued-tb-and-me/639/
https://extranet.who.int/sree/Reports?op=vs&path=/WHO_HQ_Reports/G2/PROD/EXT/MDRTB_Indicators_map
http://www.who.int/tb/challenges/mdr/MDR_TB_FactSheet.pdf
http://report.nih.gov/nihfactsheets/ViewFactSheet.aspx?csid=31
http://www.thelancet.com/journals/laninf/article/PIIS1473-3099%2813%2970030-6/abstract
Image: ‘Miliary Tuberculosis’ by Teseum available at http://www.flickr.com/photos/teseum/4457244023/ under a Creative Commons Attribution 2.0. Full terms at http://creativecommons.org/licenses/by-nc-sa/2.0/