For the better part of a century, antibiotics have given doctors great powers to cure all sorts of bacterial infections. But due to bacteria’s nasty habit of evolving, along with widespread overuse of these drugs, disease-causing bacteria are evolving antibiotic resistance at an alarming rate, making it much harder, and at times impossible, to wipe them out. DARPA, the military’s research agency, is eyeing an innovative solution to the problem: Rather than struggling to make better antibiotics, ditch them altogether. It may be time to start killing bacteria a whole new way.
What’s the News: Researchers found that squalamine, a steroid present in the bodies of the dogfish shark, has a protective effect against several human viruses, all of which are difficult or impossible to cure with existing drugs. The chemical has so far been shown to be relatively safe in humans and can be synthesized, suggesting it could have promise as an antiviral drug in humans.
The European Food Safety Authority has released a scientific report on the deadly E. coli outbreak that has sickened more than 3,500 people and killed at least 44 in the last seven weeks, and the news is grim: the apparent source of the contamination, a shipment of fenugreek seeds from Egypt, has been scattered all across the continent, making recall tricky and new outbreaks likely until the seed packets reach their expiration date in three years. Maryn McKenna of Superbug expertly breaks down the report in all its chilling detail:
Could Neanderthal DNA have protected our ancestors from diseases?
What’s the News: While we humans have certainly outlasted our hominin cousins, new research shows that Neanderthal and Denisovan genes may have helped us spread far and wide. By mating with the two species, our ancestors acquired genes that allowed them to adapt to diseases outside of Africa far quicker than would have been otherwise possible, according to Peter Parham, a professor of microbiology and immunology at Stanford University.
What’s the News: A massive outbreak of E. coli is spreading through Europe, with 17 people dead in the last two weeks and 1,500 people sickened in Germany alone, where the outbreak began. Authorities are still trying to figure out where the outbreak originated and how it can be treated.
Virions from a smallpox vaccine
What’s the News: Global health officials are expected to decide whether to destroy the world’s last caches of smallpox at the 64th World Health Assembly this week. The disease was declared eradicated by the World Health Organization in 1979, but two small stores of the virus remain: one at the Centers for Disease Control and Prevention in Atlanta and one in a Russian government lab.
Now, public health officials are divided on how to ensure that the disease stays eradicated. Some say our best bet is to keep the remaining samples of the virus safe and continue to study them, then destroy them at a later date; others say the safest course is to destroy them now, once and for all.
The bacterium called Neisseria gonorrhoeae is what gives humans the sexually transmitted infection gonorrhea. And it also takes something: human DNA. Northwestern University researchers report in the journal mBio that they’ve found pieces of human DNA in samples of the bacteria.
Gonorrhea is one of very few diseases exclusive to our species, and is one of the oldest recorded diseases in human history. An ancient disease that resembles gonorrhea’s symptoms is even described in the Bible, according to Hank Seifert, senior author of a paper on the gene transfer. [Popular Science]
Seifert and colleague Mark Anderson looked at 14 different samples of N. gonorrhoeae. Three of them possessed the chunk of human DNA. And they only saw it in the gonorrhea bacteria:
The pair looked for the same human DNA fragment in the genetically related bacterium Neisseria menigitidis, known to cause meningitis. “We screened many isolates and it wasn’t present,” says Seifert. That means the transfer to N. gonorrhoeae must have occurred since the two bacterial species diverged around 200,000 years ago. [New Scientist]
Swarms of genetically modified mosquitoes? This isn’t science fiction: The Malaysian government announced earlier this week that it unleashed 6,000 genetically modified (GM) skeeters into a forest as part of a plan to fight dengue fever, a potentially fatal affliction that can affect up to 100 million people each year.
The news appears to have caught the Malaysian media and public by surprise; many recent news stories reported that the study had been postponed after intense protests. As recently as 17 January, the Consumers’ Association of Penang and Sahabat Alam Malaysia, two groups opposing the use of GM insects, called on the National Biosafety Board to revoke its approval for the study. Scientists, too, were under the impression that the work had yet to begin, says medical entomologist Bart Knols of the University of Amsterdam. A 24 January blog post by Mark Benedict, a consultant at the Centers for Disease Control and Prevention in Atlanta who monitors the field closely, mentioned that the Malaysian study was “planned.” [ScienceNOW]
The study itself included the release of 12,000 male mosquitoes in total: 6,000 unaltered and 6,000 GM Aedes aegypti mosquitoes. The goal was to track how well the two types survived and how far they spread. U.K. biotech firm Oxitec created the modified mosquitoes, which don’t produce viable offspring. Researchers hope that if these altered males mate with wild females, it will bring the overall mosquito population down. The strategy has been tried once before in the Grand Cayman Islands, and results from that experiment are due to be published soon.
Around two million people die each year from TB, and the bacterial infection is startlingly widespread—the World Health Organization says about one in three people around the world carry Mycobacterium tuberculosis (and humans may have been carrying it around for at least 9,000 years). Thankfully, TB is latent in the vast majority of these cases. But tuberculosis’ pervasiveness presents the question of just how the bacteria evades our immune system to set up shop on a long-term basis.
According to a study led by Gobardhan Das in the Proceedings of the National Academy of Sciences, stem cells might be the answer. Particularly, mesenchymal stem cells (MSC).
TB recruits mesenchymal stem cells to the lungs, where they help suppress the immune system that fights disease… The stem cells produce nitric oxide, a chemical that reduces the type of white blood cells called T-cells, the researchers wrote. [Bloomberg]
A new study is providing insights into the 2009 swine flu epidemic, and why more serious complications arose in healthy middle-aged people than expected. The researchers say the culprit may be antibodies to seasonal flu found in the seriously ill patients, which might have caused an immune system overreaction in the lungs.
“Nobody really had a good explanation for why middle-aged people seemed to have more severe disease than would have been expected,” says Richard Scheuermann, an immunologist at the University of Texas Southwestern Medical Center in Dallas. “This explanation is the first one that I’ve seen that actually makes sense.” [Nature News]
Normally, severe flu illness happens in the very young (who haven’t been previously exposed to the flu and don’t have protective immunity) and the elderly (who have weakened immune systems). Instead of affecting these groups, the 2009 pandemic H1N1 “swine flu” primarily caused severe reactions in middle-aged adults.