Drug-resistant TB

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WHO report on MDR-TB is out...

The global war on TB
Friday, February 29, 2008 - How to beat the raging TB contagion

Call It the cough heard round the world. The World Health Organization's Feb. 26 report on how super strains of tuberculosis are on the loose has shaken physicians and policy makers everywhere to the marrow. And rightly so. The study, based on a massive survey of 90,000 patients worldwide, is eloquent testimony to the ravages of a modern killer: multi drug resistant tuberculosis, known as MDR TB in the chilly shorthand of public health, and its even deadlier next of kin, extensively drug resistant tuberculosis, or XTR-TB, which is practically untreatable.

It's no surprise that poor countries rife with malnutrition, claustrophobic slums, and especially AIDS are super TB's closest ally. Precisely because HIV strafes the human immune system, patients are sitting ducks for infection by TB. Worst hit are the fragments of the old Soviet Union (led by Baku, the capital of Azerbiajan, where one in four new tb patients have the super variety) and Africa, with the highest rate of TB in the world and the worst public health statistics (only six nations on the continent managed to report to Geneva). At this rate the Economic Forum at Davos might have to be scrapped in favor of the sanatorium that once crowned that Magic Mountain.

There is one bright spot in the developing world's deathlock with super TB: Brazil. That may sound odd. Nearly a quarter of the 185 million Brazilians live below the poverty line, where contagions rage, and some 620,000 have AIDS (a third of all cases in Latin America). But unlike almost every other developing nation, Brazil has managed to keep drug-resistant TB at bay. The reason is as simple as it is controversial: free meds for HIV and AIDS patients. In 1996, the Brazilian congress passed a law requiring the government to hand out antiretrovirals to anyone with HIV free of charge. Drug companies were disgruntled, not least because Brazil browbeat them into slashing prices for the three-way cocktail of antiretrovirals, the state of the art medicine used to combat the virus. The same policy encouraged nearly two dozen other developing countries to take on the biggest pharmaceutical corporations as well.

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DR-TB spreading...

U.N. Chief Urges Action On Tuberculosis
March 24, 2008 : Secretary-General Says Epidemic That Kills 4,000 A Day Is Spreading

Secretary-General Ban Ki-moon urged stepped-up international action on World TB Day to stop the global tuberculosis epidemic that is killing 4,000 people every day. In a message on Monday to mark the day, Ban said "the man-made multi-drug resistant strain and its even more lethal form, extensively drug-resistant TB, are both spreading."

"That is why the theme of this year's day is `I Am Stopping TB'," he said. "This is a fight that can be won only with the collective commitment of millions of individuals — donors and researchers, doctors and health care workers, patients and family members." In a report last week, the World Health Organization said the fight to control TB has slowed to a crawl, threatening efforts to control the disease.

The worldwide rate of TB infection has been declining since it peaked several years ago, but the rate of new cases fell by less than 1 percent between 2005 and 2006, which WHO called "very modest." Ideally, health officials want to see yearly decreases of 5-7 percent. Compounding the problem is that drug-resistant TB is growing faster than ever, according to last month's WHO report.

"Thanks to a broad coalition of partners working to stop TB, the proportion of people who become ill with the disease is slowly falling," Ban said. "But this progress is not keeping pace with population growth, so more and more people are becoming infected with tuberculosis." "World TB Day is an occasion to urge action to stop tuberculosis, a disease which still kills an appalling 4,000 people every day," he said.

More U.N. Chief Urges Action On Tuberculosis, Secretary-General Says Epidemic That Kills 4,000 A Day Is Spreading - CBS News

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Genetic link to TB...

Gene mutation linked to most severe TB
Fri., March. 28, 2008 - Finding shows need for targeted treatments for potentially fatal disease

People who carry a mutant gene can develop potentially fatal meningitis if they get infected with the drug resistant Beijing strain of tuberculosis, a study in Vietnam has found. Tuberculous meningitis is the most severe form of the disease in which the infection spreads to membranes enveloping the brain and the spinal cord. One in three people who develop TB meningitis dies, even if he or she gets hospital treatment.

The study published in the open-access journal PLoS Pathogens, found people most likely to develop TB meningitis were those who carried a variant of the TLR2 gene and who get infected with the Beijing TB strain, prevalent in Asia and the former Soviet states. Previous studies have linked TLR2 to the immune system and it seems to be important for recognizing and initiating a defensive response to the TB bacteria.

The researchers took bacteria samples from 187 patients who suffered tuberculous meningitis and 236 other patients dwho suffered the more common pulmonary tuberculosis. Most of the patients then had their genes analyzed to see if they carried the TLR2 variant. “Together, these results suggest that the association of the (variant gene) with tuberculous meningitis is strongest among those infected with the Beijing lineage,” the scientists wrote.

More Gene mutation linked to most severe TB - Infectious diseases - MSNBC.com

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Now the flu is becoming drug-resistant...

Flu bugs developing ability to dodge drugs
Mon., May. 19, 2008 WASHINGTON - Findings suggest flu viruses more unpredictable than ever thought

Seasonal flu viruses are developing the ability to evade influenza drugs globally, but how and why this is happening is not clear, experts told a conference on Monday. Europe is the worst-affected by strains of influenza that resist the effects of antiviral drugs, but the resistance is growing globally, they told a meeting of the Infectious Diseases Society of America. "A significant proportion of resistant viruses were observed in Europe this winter," Dr. Bruno Lina of Claude Bernard University in Lyons, France, told the meeting.

The resistance also varies by strain, with a quarter of H1N1 flu viruses resistant in Europe and about 11 percent of H1N1 in the United States, but far fewer cases of H3N2 and influenza B viruses. Their findings show that flu viruses — already known to mutate speedily — may be even more unpredictable than anyone thought. Experts fear drugs may become quickly useless to fight an unusually severe flu season or the emergence of a new strain of flu that may cause a pandemic. They have been stressing the need to develop new flu drugs and also quicker and better ways to make vaccines.

The World Health Organization and the U.S. Centers for Disease Control and Prevention have been collecting samples of the annual flu viruses to check them against the four available flu drugs: amantadine and rimantadine, and the newer drugs Tamiflu and Relenza. The viruses changed rapidly over the past 2007-2008 flu season, Lina said. "We started with something like 10 percent in Europe," Lina said. By April of this year, 25 percent of the viruses tested were resistant to Tamiflu.

Dodging drugs

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TB behavior modification technique...

Potential new weapon against TB: free cell minutes
13 June `08 — Researchers at MIT believe they've discovered a new weapon in the battle against tuberculosis: Free cellphone minutes.

For years, doctors have struggled to get some TB patients to take all their medication, which generally involves a six-month regimen of multiple drugs. Now a student-led group at the Massachusetts Institute of Technology has developed a way to use cellphones to let patients test themselves. And if the tests show patients are following doctor's orders, they get rewarded with free minutes.

"We're piggybacking on one of the bigger rollouts of infrastucture out there, which is wireless technology and telecom technology," said Jose Gomez-Marquez, one of the project's leaders. The system works like this: Patients test their urine using a strip that reveals a numeric code if it detects TB medicine. They then text message the code to their health care provider and get credit toward incentives such as free minutes.

The in-home tests also eliminate the need for health care workers to make several patient-monitoring visits a week, a routine that is often impractical in remote places, Gomez-Marquez said. Mobile phones are good tools for the project because they are common in the developing world, where it's often cheaper to erect cell towers than miles of poles and wires, Gomez-Marquez said.

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New TB test looks promising...

Officials Praise New Test for Drug-Resistant TB
July 1, 2008 - A new test that can detect multiple-drug-resistant tuberculosis in two days instead of the standard two to three months promises to help significantly improve treatment and prevent the spread of the airborne infection, the World Health Organization said on Monday.

Multiple-drug-resistant TB, or MDR-TB, is a growing public health problem in the world. Five percent of new TB cases are resistant to first-line drugs. That is 450,000 of the nine million new TB cases that are detected each year, the W.H.O. says. In the United States, the prevalence of drug-resistant tuberculosis among foreign-born TB patients has been about 1.5 percent, roughly three times the percentage among American-born patients with TB.

“The new test is revolutionary,” said Dr. Mario C. Raviglione, W.H.O.’s director of tuberculosis control, because “it changes completely the way we will be dealing with MDR-TB.” The difficulty in detecting cases rapidly and accurately is a major obstacle in tuberculosis control. In most developing countries, cases cannot be detected easily or at all, leading to lags in starting proper treatment that can lead to a patient’s death and the further spread of resistant strains.

The new test was described for reporters by telephone on Monday by officials from the W.H.O. and three other international health groups, the Stop TB Partnership, Unitaid and the Foundation for Innovative New Diagnostics, or FIND. The TB test, called a line probe assay, costs less than $8 and detects mutations in bacterial DNA linked to drug resistance. It is based on the same laboratory methods that scientists have used to determine parentage and detect certain genetic diseases, said Dr. Richard O’Brien, an official of FIND.

More http://www.nytimes.com/2008/07/01/health/01tb.html?hp

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Asia needs to work on their TB problem better...

WHO: Asia Should Act Against TB
Monday, Jul. 21, 2008 — The World Health Organization urged Asian countries on Monday to take action against the growing threat of drug-resistant tuberculosis, warning that even more virulent forms of the disease could spread if they fail to do so.

WHO said many Asian countries lack adequate laboratory facilities to detect multidrug-resistant TB, and only 1 percent of the estimated 150,000 people infected with the disease in East Asia and the Pacific are receiving appropriate treatment. "No country in the region is rushing to fight multidrug-resistant TB," Dr. Pieter Van Maaren, WHO's Western Pacific regional adviser for tuberculosis, said in a statement. He said Asian leaders "need to wake up and realize what is at risk. This is a disease that you can transmit in a cough to your children."

WHO said multidrug-resistant TB is caused by mismanagement of standard tuberculosis treatment, and that mobility, migration and urban housing are also fueling the highly contagious disease. Multidrug-resistant TB — which resists treatment by at least two of the best anti-TB drugs — accounts for 5 percent of 9 million new tuberculosis cases worldwide, WHO said. In China, one out of every 10 new tuberculosis cases is multidrug-resistant, it said. WHO said drug-resistant TB is also a serious problem in the Philippines.

"We are more vulnerable than ever to the multidrug-resistant TB threat," Dr. Shigeru Omi, WHO's regional director for the Western Pacific, said in the statement. WHO warned that inadequate action against multidrug-resistant TB could result in the spread of "extensively drug-resistant TB," a form of tuberculosis resistant to all of the most effective drugs. A 2005 outbreak of extensively drug-resistant TB, which is virtually impossible to treat, killed 52 people in South Africa, WHO said.

Source

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Immigrants bringin' TB here...

Foreign-born TB cases need better control, US says
Jul 22, `08 - Tuberculosis cases continue to fall in the United States, but some immigrants have disturbingly high rates of the disease, according to a study released Tuesday that called for more aggressive action.

TB rates were highest among residents from lower Africa and parts of Southeast Asia. Most drug-resistant TB cases also were from foreign-born residents, the study noted. The researchers called for wider testing, including efforts to seek out latent cases of TB from long-term immigrant residents in certain populations. Rates of at least 250 TB cases per 100,000 were found among people from African countries such as Ethiopia, Kenya and Somalia and from Southeast Asian nations including Vietnam, Cambodia and the Philippines.

By comparison, the overall rate of TB in the U.S. is fewer than 5 per 100,000, according to researchers at the Centers of Disease Control and Prevention, whose study is based on data from 2001-06. Their findings are being published in Wednesday's Journal of the American Medical Association. Dr. Henry Blumberg of Emory University's medical school, said the research shows "that it's in the interest of the United States to try to enhance global TB efforts." Of those infected, drug-resistant TB was found in 20 percent of recent immigrants from Vietnam and 10 percent of foreign-born residents overall, compared with a little more than 4 percent of U.S.-born residents. Public health officials worry that drug-resistant TB could become a worldwide scourge because of global travel and immigration. The issue made headlines last year when an Atlanta attorney with drug-resistant TB flew to several countries. Tests later showed he did not infect anyone on those flights.

U.S. law requires TB screening for people who want to immigrate to the United States, said the CDC's Dr. Kevin Cain, the study's lead author. Another step that would help curb the rise of tuberculosis, he said, would be to find and treat latent TB infections. He said the study helps identify which foreign-born groups would be most appropriate for such an effort. While most TB cases come from recent arrivals, a significant number involve people who have lived in the United States for at least 20 years, the study authors said. Most of these likely resulted from latent infections acquired years earlier abroad, they wrote.

Latent, non-contagious infections mean germs are present but the body is able to fight off symptoms. Latent infections can morph into active disease, causing contagious illness, at any time, particularly as people age and their immune systems weaken. Latent infections are detected with skin tests and treated with nine months of antibiotics. Foreign-born U.S. residents aren't routinely tested for latent TB. And with more than 37 million foreign-born people living in the United States, giving all of them skin tests "would be daunting to say the least," Cain said.

My Way News - Foreign-born TB cases need better control, US says

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Immigrants bringin' TB here...

Foreign-born TB cases need better control, US says
Jul 22, `08 - Tuberculosis cases continue to fall in the United States, but some immigrants have disturbingly high rates of the disease, according to a study released Tuesday that called for more aggressive action.

TB rates were highest among residents from lower Africa and parts of Southeast Asia. Most drug-resistant TB cases also were from foreign-born residents, the study noted. The researchers called for wider testing, including efforts to seek out latent cases of TB from long-term immigrant residents in certain populations. Rates of at least 250 TB cases per 100,000 were found among people from African countries such as Ethiopia, Kenya and Somalia and from Southeast Asian nations including Vietnam, Cambodia and the Philippines.

By comparison, the overall rate of TB in the U.S. is fewer than 5 per 100,000, according to researchers at the Centers of Disease Control and Prevention, whose study is based on data from 2001-06. Their findings are being published in Wednesday's Journal of the American Medical Association. Dr. Henry Blumberg of Emory University's medical school, said the research shows "that it's in the interest of the United States to try to enhance global TB efforts." Of those infected, drug-resistant TB was found in 20 percent of recent immigrants from Vietnam and 10 percent of foreign-born residents overall, compared with a little more than 4 percent of U.S.-born residents. Public health officials worry that drug-resistant TB could become a worldwide scourge because of global travel and immigration. The issue made headlines last year when an Atlanta attorney with drug-resistant TB flew to several countries. Tests later showed he did not infect anyone on those flights.

U.S. law requires TB screening for people who want to immigrate to the United States, said the CDC's Dr. Kevin Cain, the study's lead author. Another step that would help curb the rise of tuberculosis, he said, would be to find and treat latent TB infections. He said the study helps identify which foreign-born groups would be most appropriate for such an effort. While most TB cases come from recent arrivals, a significant number involve people who have lived in the United States for at least 20 years, the study authors said. Most of these likely resulted from latent infections acquired years earlier abroad, they wrote.

Latent, non-contagious infections mean germs are present but the body is able to fight off symptoms. Latent infections can morph into active disease, causing contagious illness, at any time, particularly as people age and their immune systems weaken. Latent infections are detected with skin tests and treated with nine months of antibiotics. Foreign-born U.S. residents aren't routinely tested for latent TB. And with more than 37 million foreign-born people living in the United States, giving all of them skin tests "would be daunting to say the least," Cain said.

My Way News - Foreign-born TB cases need better control, US says

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The end for TB?...

Scientists identify potential therapeutic target for tuberculosis
July 31,`08 : Researchers from Weill Cornell Medical College claim to have identified a potential therapeutic target for tuberculosis.

The study led by Omar H. Vandal, a postdoctoral fellow in the lab of study co-senior author Dr. Sabine Ehrt, associate professor of microbiology and immunology at Weill Cornell Medical College, has found a membrane protein called Rv3671c, which is critical to bacteria's defence against immune cell acidification during Mycobacterium tuberculosis infection. "Using novel techniques, we have identified a key membrane protein that's essential to the defense that M. tuberculosis mounts against the acidic environment of immune cells called macrophages," Nature quoted the researchers as saying.

"Without this protein, called Rv3671c, the bacterium becomes vulnerable to acidification and is killed," they added. Dr. Carl F. Nathan, also a senior author of the study, R.A. Pritchett Professor of Microbiology and chairman of the Department of Microbiology and Immunology at Weill Cornell said, " M. tuberculosis does not depend on Rv3671c under standard growth conditions in the test tube, so it has been overlooked as a candidate drug target.

"However, when M. tuberculosis infects the host, then the Rv3671c protein becomes essential," added Dr. Ehrt. "This is an example of a new class of potential targets for anti-infective agents," said Dr. Nathan, "those that the pathogen only needs in order to survive in the host environment."

More Scientists identify potential therapeutic target for tuberculosis