Mutant gene linked to most severe type of TB

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 (plospathogens.org), 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 recognising 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 who suffered the more common pulmonary tuberculosis.

Most of the patients then had their genes analysed 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.

The "Beijing" family of TB strains is prevalent in Asia and former Soviet states. It has become more drug resistant in recent years and has been responsible for outbreaks of multi-drug resistant tuberculosis in the United States.

More than one-third of the world's population is infected with TB and the infection rate is one every second. However, only one in 10 infected persons will develop symptoms and that usually happens when their immune systems are weak.

Left untreated, TB kills half its victims. The disease kills over 2 million people each year.

One of the researchers, Maxine Caws at the Hospital for Tropical Diseases in Vietnam, said the latest finding was a reason to develop more sophisticated and targeted treatments and vaccines.

"This is particularly important in this era of emerging 'untreatable' bacteria infections due to antibiotic resistance," Caws wrote.

Under-the-tongue vaccine may be best to lick flu

Administering flu vaccines under the tongue may be more effective and offer more protection than injecting or inhaling the drug, a study with mice in South Korea has found.

"It (the base of the mouth) is a very good absorbent and competent tissue ... in taking vaccine and presenting it to the immune system ... to initiate an immune response," Cecil Czerkinsky, biological sciences professor at the Seoul National University, said in a telephone interview.

There is currently no vaccine that is administered under the tongue, or what is known as the sublingual area.

But there have been recent studies testing its effectiveness in inducing immune responses in mucosal tissues in the respiratory system, gut and inside of the cheek, and blood.

In an article published in the Proceedings of the National Academy of Sciences, the researchers described how they administered both live and killed flu vaccines under the tongues of mice and then exposed the rodents a few weeks later to lethal doses of influenza viruses.

"All the mice were protected ... they (vaccines) also gave cross-protection to other flu viruses," Czerkinsky said.

Unlike injected vaccines, which induce antibody production mainly in the blood, the sublingual method "induced antibodies in both lungs (mucosal lining) and the blood," he said.

"Influenza is a mucosal disease. That (sublingual method) is better because then you tackle the infection at the very early stage before the infection (goes to the blood)."

Such a method is different from the oral route, often seen as subjecting drugs to the erosive effects of digestive fluids.

The correct way to do it would be for the person to hold the vaccine in the base of the mouth for about 30 seconds.

"In 30 seconds, the sublingual area absorbs the vaccine and immediately the vaccine is taken up and processed by the immune system and it initiates very rapid stimulation of antibodies, within days," Czerkinsky said.

The study also suggested that this method may be safer than administering vaccines intranasally, or through inhaling.

There are nerve fibres in the nose, which opens up the possibility, however rare, that viruses in vaccines could enter the central nervous system, the researchers said.

Control groups of mice were given vaccines intranasally. The scientists later detected virus in the olfactory nerves of mice that were given vaccines containing killed viruses, which raised safety questions.

Mice that were given vaccines containing live, attenuated virus intranasally all died very quickly.

The scientists plan to conduct a clinical study later this year.

Black Death did not kill indiscriminately

The Black Death that decimated populations in Europe and elsewhere during the middle of the 14th century may not have been a blindly indiscriminate killer, as some experts have believed.

An analysis of 490 skeletons from a London for Black Death victims demonstrated that the infection did not affect everyone equally, two U.S. scientists said on Monday.

While many perfectly healthy people certainly were cut down, those already in poor health prior to the arrival of the plague were more likely to have perished, they found.

"A lot of people have assumed that the Black Death killed indiscriminately, just because it had such massive mortality," anthropologist Sharon DeWitte of the University at Albany in New York, said in a telephone interview.

People already in poor health often are more vulnerable in epidemics. "But there's been a tradition of thinking that the Black Death was this unique case where no one was safe and if you were exposed to the disease that was it. You had three to five days, and then you were dead," DeWitte said.

The plague epidemic of 1347 to 1351 was one of the deadliest recorded in human history, killing about 75 million people, according to some estimates, including more than a third of Europe's population.

DeWitte analyzed skeletons unearthed from the East Smithfield cemetery in London, dug especially for plague victims and excavated in the 1980s, for bone and teeth abnormalities that would show that people had health problems before they died of plague.

She found such abnormalities in many skeletons, suggesting these people had experienced malnutrition, iron deficiencies and infections well before succumbing to the Black Death.

The proportion of people with such signs of frailty in the cemetery, compared to those who appeared to have been of robust health before the epidemic, indicated that the infection was somewhat selective in who it killed, DeWitte and Pennsylvania State University anthropologist James Wood reported in the Proceedings of the National Academy of Sciences.

Some experts have thought the Black Death -- named after the black spots the bubonic form of the plague caused on the skin -- killed indiscriminately regardless of age, sex or level of health because it was so virulent and the European population so immunologically unprepared, DeWitte and Wood wrote.

"The Black Death was highly virulent and undoubtedly killed many otherwise healthy people who would have been unlikely to die under normal-mortality conditions," they wrote. But people already in poor health were more likely to die, they wrote.

Many scientists think the plague was caused by Yersinia pestis, a bacterial disease spread by fleas from rats. It still kills between 100 and 200 people a year.

The Black Death pandemic thought to have begun in Asia, then spread into the Middle East, Africa and Europe.

"On average, it killed between 30 to 50 percent of affected populations. But we know that there were some areas where mortality was even higher. So there would have been villages that were completely wiped out," DeWitte said.

Other experts now think the Black Death may have been caused not by bubonic plague but by a viral hemorrhagic fever, similar to the disease caused by the Ebola or dengue viruses.

Black Death did not kill indiscriminately

The Black Death that decimated populations in Europe and elsewhere during the middle of the 14th century may not have been a blindly indiscriminate killer, as some experts have believed.

An analysis of 490 skeletons from a London for Black Death victims demonstrated that the infection did not affect everyone equally, two U.S. scientists said on Monday.

While many perfectly healthy people certainly were cut down, those already in poor health prior to the arrival of the plague were more likely to have perished, they found.

"A lot of people have assumed that the Black Death killed indiscriminately, just because it had such massive mortality," anthropologist Sharon DeWitte of the University at Albany in New York, said in a telephone interview.

People already in poor health often are more vulnerable in epidemics. "But there's been a tradition of thinking that the Black Death was this unique case where no one was safe and if you were exposed to the disease that was it. You had three to five days, and then you were dead," DeWitte said.

The plague epidemic of 1347 to 1351 was one of the deadliest recorded in human history, killing about 75 million people, according to some estimates, including more than a third of Europe's population.

DeWitte analyzed skeletons unearthed from the East Smithfield cemetery in London, dug especially for plague victims and excavated in the 1980s, for bone and teeth abnormalities that would show that people had health problems before they died of plague.

She found such abnormalities in many skeletons, suggesting these people had experienced malnutrition, iron deficiencies and infections well before succumbing to the Black Death.

The proportion of people with such signs of frailty in the cemetery, compared to those who appeared to have been of robust health before the epidemic, indicated that the infection was somewhat selective in who it killed, DeWitte and Pennsylvania State University anthropologist James Wood reported in the Proceedings of the National Academy of Sciences.

Some experts have thought the Black Death -- named after the black spots the bubonic form of the plague caused on the skin -- killed indiscriminately regardless of age, sex or level of health because it was so virulent and the European population so immunologically unprepared, DeWitte and Wood wrote.

"The Black Death was highly virulent and undoubtedly killed many otherwise healthy people who would have been unlikely to die under normal-mortality conditions," they wrote. But people already in poor health were more likely to die, they wrote.

Many scientists think the plague was caused by Yersinia pestis, a bacterial disease spread by fleas from rats. It still kills between 100 and 200 people a year.

The Black Death pandemic thought to have begun in Asia, then spread into the Middle East, Africa and Europe.

"On average, it killed between 30 to 50 percent of affected populations. But we know that there were some areas where mortality was even higher. So there would have been villages that were completely wiped out," DeWitte said.

Other experts now think the Black Death may have been caused not by bubonic plague but by a viral hemorrhagic fever, similar to the disease caused by the Ebola or dengue viruses.

Snoring can lead to bronchitis

People who snore are more likely to develop chronic bronchitis, the hacking cough most often associated with cigarette smoking or breathing polluted air, Korean researchers reported on Monday.

Why snoring might lead to bronchitis is not clear, said a team led by Inkyung Baik of Korea University Ansan Hospital in South Korea.

The report, published in the Archives of Internal Medicine, covered 4,270 men and women between 2001 and 2006. Of the group, 314 came down with chronic bronchitis.

"We collected information on snoring at baseline and identified incident cases of chronic bronchitis during a four-year follow-up period," Baik's team wrote.

After taking into account whether those in the study smoked or were otherwise at risk for bronchitis, the investigators concluded that people who snored five nights a week or less were 25 percent more likely to develop bronchitis than those who never snored.

The risk was 68 percent higher for those who snored six to seven times a week.

"Our findings provide support for the hypothesis that snoring is associated with chronic bronchitis," the researchers wrote.

It could be that snoring vibrates the upper airways, stressing them and leading to inflammation, the researchers said.

Rates of diabetes among U.S. elderly rose

More elderly Americans are contracting diabetes and the majority develop complications such as heart disease that might be prevented if they properly monitored their health, a researcher said on Monday.

The study of Medicare beneficiaries found 2.7 percent of a group of 1.5 million enrollees in the government-funded insurance program for the elderly were diagnosed with diabetes in 2003, compared to 2.2 percent diagnosed in 1994.

Overall, one-quarter of those 65 or older had type-2 diabetes in 2003, up from 15 percent in 1994, the report said. The 1.5 million people studied represented a group of 5 percent of Medicare enrollees whose health is being tracked by the program.

"The prevalence of diabetes mellitus is increasing, in part because of population aging, but also in younger persons," Frank Sloan of Duke University Medical Center in Durham, North Carolina, and colleagues wrote in the Archives of Internal Medicine.

Making matters worse, nine out of 10 of those diagnosed with diabetes in 1994 and 1999 developed some other ailment within six years of diagnosis, against seven out of 10 of elderly without diabetes who were studied for comparison purposes.

Diabetes damages blood circulation and is known to increase the risks of heart disease, blindness and skin ulcers, among other ailments.

"What we're concerned about is the rate of complications," Sloan said in a telephone interview.

"Our overall conclusion is they're not getting any better" over time, he said, citing increasing cases of kidney function deterioration and lower extremity problems, which can result in foot amputations.

"It shouldn't be happening if you're monitoring your blood pressure, your cholesterol, keeping your blood glucose in line, getting your eyes checked, getting your feet checked, so the complications can be caught and monitored," he said.

Rates of congestive heart failure, heart attack and stroke remained fairly stable at about three out of 10 people diagnosed with diabetes in 1994, 1999, and 2003.

Roughly one-third of diabetics diagnosed in 1994 and 1999 died within six years, compared to one-fourth of non-diabetics. For those surviving with the disease, the accumulation of other ailments places heavy burdens on the health care system, the report said.

"The message is how can we encourage people to adhere to recommended care and reduce these complications," Sloan said. "It's not an issue of uninsured people. (The elderly) frequently go to the doctor but we're not making inroads in terms of postponing these complications the way we should be."