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Totally Drug-Resistant TB Emerges In India 346

Posted by Soulskill
from the it's-all-darwin's-fault dept.
ananyo writes "Physicians in India have identified a form of incurable tuberculosis there, raising further concerns over increasing drug resistance to the disease (abstract). Although reports call this latest form a 'new entity,' researchers suggest that it is instead another development in a long-standing problem. The discovery makes India the third country in which a completely drug-resistant form of the disease has emerged, following cases documented in Italy in 2007 and Iran in 2009."
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Totally Drug-Resistant TB Emerges In India

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  • by Samantha Wright (1324923) on Friday January 13, 2012 @03:01PM (#38689758) Homepage Journal
    Nah, it happens all over the place, including in countries that start with "Russia". The antibiotic-resistant TB there is just not quite as bad. Unfortunately, it lives in the prison system.
  • by Samantha Wright (1324923) on Friday January 13, 2012 @03:07PM (#38689862) Homepage Journal
    For those interested in exactly how prevalent this sort of thing is, be aware that drug resistant TB is in almost every country in the world; it's just really bad in those particular three countries. This journal article from 2006 [oxfordjournals.org] has maps showing the incidence rates per country.
  • by dooode (1134443) on Friday January 13, 2012 @03:11PM (#38689912)

    I am not surprised that they found a drug resistant TB strain in India. The only thing that surprises me is why not every disease is drug resistant in India.

    Many poor Indians would pop anti-biotic tablets like candies after buying them for few cents from an over the counter store (its in direct contrast to the US system where even after paying a fortune you don't get antibiotics). They are often cheap, more or less affective and gets them rid of the problems...but not always.

    Antibiotics would require you to finish an entire course, else they become ineffective for ever. There are uneducated idiots in India who would pop one or two tablets and never heed to advice by the pharmacist (and at times they would not have enough money to buy the complete course too).

    So why are we surprised that there is an emergence of a strain that no antibiotics can cure? Most likely the previous commenter is right - they haven't found an alternative antibiotic yet. I am sure some random Indian lab would develop it in a few months, but it won't work for long - its more of a systemic problem than a medical issue.

  • by s_p_oneil (795792) on Friday January 13, 2012 @03:13PM (#38689938) Homepage

    It might be popular if it stood a chance of working...

    Wikipedia quote:
    One third of the world's population is thought to be infected with M. tuberculosis,[3][4] and new infections occur at a rate of about one per second.[3] In 2007 there were an estimated 13.7 million chronic active cases,[5] and in 2010 8.8 million new cases, and 1.45 million deaths, mostly in developing countries.[6] The absolute number of tuberculosis cases has been decreasing since 2006 and new cases since 2002.[6] In addition, more people in the developing world contract tuberculosis because their immune systems are more likely to be compromised due to higher rates of AIDS.[7] The distribution of tuberculosis is not uniform across the globe; about 80% of the population in many Asian and African countries test positive in tuberculin tests, while only 5–10% of the U.S. population test positive.[1]

    It sounds like many Asian and African countries need the opposite (a place for all the healthy people to go).

  • by ATestR (1060586) on Friday January 13, 2012 @03:14PM (#38689956) Homepage

    STANDARD != FREE. Where I live, TB vaccinations are required for kids entering school. This is STANDARD. FREE is when you get somebody else to pay for it. Admittedly most of us have insurance to pay for it. Those without generally get the vaccinations for free anyway.

  • by ColdWetDog (752185) on Friday January 13, 2012 @03:18PM (#38690020) Homepage

    It is becoming common problem in EU too. Maybe not totally resistant TB, but very hard to cure. What amazes me, is that in North America the TB vaccine is not standard (read my leaps: FREE), and the result is that when (not if) some american catches TB, he will be helpless.

    There is no good tuberculosis vaccine. There is the BCG vaccine which confers some measure of immunity, but it's not very impressive. The problem with BCG is that is screws up SCREENING for TB via the PPD (skin prick test). Once you've had a BCG vaccination, you are going to test positive for TB in that screen, so you have to go to expensive and slightly dangerous X rays to determine active disease and you're pretty much hosed at determining 'latent' disease (where someone has been exposed, has the bug stuck deep inside their lungs but the critter hasn't multiplied - yet - in a couple of percentage points of people with latent TB it will go active at some point in their life so they often get treated before it progresses).

    In countries where TB is epidemic, it often makes sense to use BCG. In the US and Western Europe, probably not but it's a complicated argument.

    We really need 1) better vaccines and 2) better ways of detecting early infections. It's not for want of trying, it's just a nasty little bug.

  • by tgibbs (83782) on Friday January 13, 2012 @03:55PM (#38690578)

    Antibiotic rotation is an idea that sounds good but that doesn't seem to work well in practice. What seems to happen is that microorganisms evolve in such a way as to neutralize the cost of being resistant. Usually, the initial mutation reduces fitness in the absence of the antibiotic, but then there is selective pressure to accumulate compensatory mutations that eliminate that cost. Once that happens, there is no longer selective pressure to revert to sensitivity even if the use of that antibiotic is discontinued. Moreover, with the compensatory mutations in place, it is possible that reversion of the original resistance mutation may reduce fitness. In this case, resistance becomes "locked in," and reversion is unlikely to happen even over an extended period of non-use of the antibiotic.

  • by ChumpusRex2003 (726306) on Friday January 13, 2012 @05:40PM (#38691764)

    Some of it is. TB requires prolonged treatment. 3 months is regarded as the absolute minimum treatment duration. 6 months is suitable for most cases. 12-24 months is needed for severe cases, or for cases affecting certain organs (brain or spine). Anti-TB antibiotics also have severe side effects - liver damage, nerve damage, permanent eye damage, they severely disrupt the biochemistry of other drugs (potentially causing them to become ineffective, or overactive), etc.

    In poorer countries, patients/doctors may not be able to afford a full course of drugs, and may therefore cut it short. Uneducated patients may also stop the treatment when they start to feel better, and not carry the course through to the end (and in poorer countries, there may not be a system for doctors/law enformcenet to trace them and bring them back for treatment).

    Additionally, tests for TB have are very time-consuming and expensive. It can take 8 weeks to get a drug-sensitivity test, and that's if the test comes back positive anyway (one of the problems with TB, is that it is very good at hiding, and the bugs are very difficult to grow). Where funding is constrained, diagnosis is simply by looking for the bugs in a sputum specimen with a microscope - which tells you nothing about the sensitivities. There is a signficant cost of incubating the specimens on special growth media for 8 weeks, and a low success rate. Because of this, doctors in these countries may not be able to diagnose drug resistance, except when drugs fail to halt the disease after 6 months.

    The avoidance of resistance in anti-biotic treatment is best achieved by mixing multiple drugs of different types. Conventionally TB is treated with a cocktail of 3 or 4 drugs. If, however, you use those 3 drugs, ih a population that is infected with a bug that is resistant to 2 of them, then resistance to the single functioning agent, can develop very rapidly.

    Things are changing with advanced test kits and DNA amplification technology, which are able to detect the genes that confer resistance, and give a result, with high accuracy and high reliability within 24 hours. The problem is the significant cost of this testing technique.

     

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