Thursday 11 April 2013

TUBERCULOSIS: Latent TBc



Ray Chambers

Posted: 04/02/2013 4:47 pm

A few months ago, I was visiting Dr Lucica Ditiu, the Romanian doctor who runs the Stop TB (Tuberculosis) Partnership, at her office located at the Headquarters of the World Health Organization in Geneva, Switzerland. I learned something that shocked me. If everyone in the world were tested for latent infection with tuberculosis (a status that predisposes people to develop active disease) today, at least 1 billion people would be positive. While this was surely "old news" to the many hardworking people leading the world's efforts against TB, it was news to me. Next time you are in a train, a plane or in a crowded room look around. If averaged out, in a space of 20 people, more than three people around you could have "latent" TB; "latent," because it is a dormant infection and there is no obvious symptom that they have it. Nor are they infectious to others yet.
From the World Health Organization's 2012 Global Tuberculosis Report I learned more: Of those with latent TB, 100 million or 10 percent are likely to get full blown or active TB during a lifetime, with the majority getting it in the first year after having been exposed. Every year, approximately 6 million of the active TB cases are properly diagnosed and treated, but at least one-third of the people with active TB don't know they have it and are not detected, thus innocently infecting, on average, 15 to 20 more people themselves. You can picture the exponential spread of the disease and recognize how frighteningly quickly those numbers add up: 1.4 million people will die from the disease this year--two to three people every second, nearly 4000 every day.
Those particularly vulnerable are patients with compromised immune systems, with over 430,000 HIV patients dying in 2011 from TB. Additionally, up to 500,000 of those with active TB will develop a form of TB that doesn't respond to standard medications (an exceptionally dangerous threat known as multi-drug resistant TB, or MDR TB). Treating these cases can take 2 years or more and can cost about 100 times as much in drugs only. Even more worrisome is the emergence of "Totally Drug Resistant TB", spawning fears of a superbug that cannot be treated with any of the current medications. And for those of you in the US or Western Europe reading this column with compassion, but also with the detached stance of one who doesn't have to worry, think again: 100,000 Americans have latent TB, of whom 10,000 are likely to get complete and active TB, and recent outbreaks in London and Los Angeles demonstrate that as our world becomes more interconnected, so do our contagions. Many of you might remember the scare in March 2007, when airline passengers and crewmembers were exposed to a traveler from the USA with a drug-resistant TB (http://www.nytimes.com/2007/05/30/us/30tb.html).
A little over a week ago, March 24th, was World TB Day. While many more efforts were made this year than ever before to put TB on the map, it went unnoticed by much of the world. That is a pity. More people might be aware thanks to Anne Hathaway's Oscar winning performance in Les Miserables, where the character Fantine dies tragically of TB. The good news is much has changed with TB since the French Revolution.
There were huge reductions in Europe, the United States, and Japan during the last century, and globally the death rate has dropped by over 40 per cent since 1990. Advancements in TB research also give us hope -- a new rapid diagnostic test and new treatments are being developed, which is key as the current treatments take at least 6 months to complete and are difficult to comply with; and while it won't be ready before 2020, there is promising work being done to develop a vaccine.
My meeting with Dr. Ditiu and subsequent conversation with Dr. Raviglione, director of WHO's TB programme, gave me reason to believe this progress will continue, but ultimate success will take two major efforts: one from individuals -- people must get promptly tested, get treated, and, when necessary, get prophylaxis, so that we can prevent others from getting the disease. Significant progress can be achieved with the current tools if used optimally. At the same time, we must increase support for research so we can develop more effective ways of testing, treating, and preventing the disease. A crucial partner in all of this is the Global Fund, which currently channels 80 percent of the international financing for TB. A strong fight against TB requires a strong Global Fund, another reason we all need to call on government leaders to increase contributions to the Fund.
As I mentioned in last week's post, we have just over 1,000 days to the December 2015 deadline for achieving the Millennium Development Goals. By then, we must ensure that the 6 million patients currently treated for TB each year increases to the 9 million who actually need it - achieving what is known as "universal coverage". While the 3 million yet to be detected each year are also the hardest to find, relatively new initiatives, such as one called "TB REACH" are proving that with modest investments but focused attention and efforts, many of these patients can be found. If we bridged this gap and we tested all for drug susceptibility, we would also treat 500,000 TB cases that are multi-drug resistant - a clear threat to our collective security.
Just $25 will cover the cost of the medicine, stop transmission, and ensure that the creation of drug resistant TB is stopped.
The choice is ours. I ask the question again, how will you spend your next 1000 days? If you have a cough or fever, get tested. Get diagnosed. And let's meet the goal of treating all 9 million people who need it, through support of entities like the Global Fund. Only then do we have a fighting chance of getting TB under control by 2015.
Hear inspiring stories of those living with TB, and the efforts to halt the airborne disease:
 

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