Rich countries have gotten very good at keeping people alive in earthquakes. But that doesn’t mean poor countries should try to emulate them.
BY CHARLES KENNY | MARCH 14, 2011
The death and destruction in Japan may be horrifying, but the record earthquake that struck March 11 off the east coast of Honshu island still suggests one important lesson: Building codes and land use regulations can save lives. Japan’s strict guidelines have been widely credited for keeping the death toll down to a fraction of the casualties in Haiti’s quake last year. But that doesn’t mean we should import them lock, stock, and barrel to the developing world, where the great majority of earthquake-related mortality occurs. The regulations are also complex and expensive. And there are much cheaper and more straightforward ways to save lives.
It is too early to know the full extent of the tragedy still unfolding in Japan. But one thing we do know is that the great majority of deaths — and most of the problems at the nuclear plants — are the result not of the quake itself, but of the resulting tsunami. Things could have been much worse. Although the YouTube images of shaken workers and crashing shelves in Tokyo were frightening, there were very few injuries or deaths reported in the capital city — or anywhere else where flood waters didn’t come rushing ashore. This despite the earthquake being the largest recorded in Japan’s history — and orders of magnitude larger than the devastating Haiti quake.
That means the usual pattern has been repeated: Earthquakes don’t kill people in rich countries; they kill people in poor countries. The 1988 earthquake in Armenia was half as strong as the 1989 quake in Loma Prieta near San Francisco, and yet caused 25,000 deaths compared with 100 in San Francisco. The 2003 Paso Robles quake in California had the same power as the Bam quake in Iran in 2003; the death toll was two in California and 41,000 in Iran. Again, Chile’s recent earthquake was more powerful than Haiti’s, but the death toll was considerably lower. Chile is a member of the OECD club of rich countries; Haiti is the poorest country in the Western Hemisphere.
Regulation keeps people safe in rich countries. Japan is a perfect case study. The last major earthquake that country experienced hit Kobe in 1995, resulting in 6,000 deaths. But buildings constructed after a 1981 revision of Japan’s building codes were far less likely to collapse than older buildings. As the regulation gets better, the death tolls get smaller.
The story is very different in poor countries. The 2010 Haiti quake was closer than the Japan quake to a large population center (Port-au-Prince) but, perhaps more crucially, the Haitians in that population center were mostly living in shoddily constructed buildings. Building regulations and land use codes were mostly disregarded, and rarely enforced. The result was 230,000 people dead. Similarly, many of the 17,000 deaths from the 1999 Marmara earthquake in Turkey were blamed on collapse due to poorly constructed reinforced concrete frames, construction using concrete diluted with too much sand, or construction near fault lines.
Why don’t we learn our lesson? Why can’t we at least earthquake-proof the most vulnerable major cities of the world? Simply put, it costs too much. Earthquake-resistant engineering solutions are expensive and technically demanding. In Istanbul, the cost of reinforcing 3,600 public structures to make them better able to withstand earthquakes, or retrofitting, was estimated at $1 billion — approximately $280,000 per structure and a full third of the cost of rebuilding them from scratch. And that’s just public buildings — retrofitting all the private dwellings in the city would undoubtedly have cost far more.
Moreover, it’s probably not money well spent — at least in the developing world. The cost-effectiveness of these solutions is often unfavorable compared with other interventions designed to save lives in risk-prone countries. In part, that’s because a lot of people live in areas at risk of an earthquake, but only a few actually witness large earthquakes in any particular year and deaths are concentrated in only a very few locations. It is impossible to predict where serious quakes are going to happen with any accuracy — seismic risk maps had only put Haiti at moderate risk of a large quake before last January, for example. So earthquake preparedness necessarily involves spending a lot of money on strengthening buildings that may never be put to the test.
By contrast, countries like Haiti witnesses many thousands of deaths from very easily — and cheaply — prevented diseases in every month of every year. Choosing one over the other may be unfortunate, but it’s hardly irrational. In Istanbul, the cost efficiency of retrofitting public buildings has been estimated at about $2,600 per healthy year of life saved. But in developing countries, millions of people die each year from diseases that can be cured using a simple regime of oral antibiotics, which costs as little as $0.25. More broadly, there are a range of interventions that cost less than $2 per healthy year of life saved in the developing world.
It is particularly tragic when children die when their schools collapse during earthquakes, as was the case in Sichuan, China, in 2008 when some 7,000 students died. In an average year, as many as 2,500 kids worldwide die each year in school collapses. And schools and hospitals should be first in line both for inspection to make sure they meet standard building codes and for resources to strengthen them against earthquakes.
But consider this tragedy: 10 million children under age 5 die each year from other causes before they can even make it to school — the majority of which can be easily and cheaply prevented. And getting girls into school in the first place is one of the best ways to reduce future child mortality, as well as infant and maternal mortality. If there’s $10 million for school construction and the choice is between building more schools (thus admitting more students) that may collapse in a large enough earthquake or building fewer schools that are completely earthquake-proof, you may actually save more lives by making the first choice than the second.
Even if the money is available, it takes more than cash to ensure safe construction. The regulations regarding reinforcement and design have to be enforced. Turkey’s Marmara quake was of a magnitude and type accounted for by existing design specifications in the Turkish seismic code — but it was lack of enforcement that led to deaths. Turkey, in short, wasn’t Japan: Municipalities had weak and underfunded engineering and planning departments staffed with unaccredited engineers prone to corruption. In 2006, 40 municipal officials in three towns in Turkey were arrested for taking bribes in return for allowing unlicensed construction. Across a range of countries, construction permitting appears to be a regulatory area particularly prone to corruption.
That means that strict codes that are unenforced not only fail to save lives, but can also carry significant costs on the poor. Because non-code construction is illegal, it provides ongoing opportunities for officials to demand bribes while denying many owners legal title. At the turn of the millennium, as much as half of Turkey’s urban population lived in illegal settlements with no rights to sale or transfer. That’s a major factor in keeping them poor.
Earthquake deaths aren’t “acts of God” — they are the result of poverty and weak governance. And in poor, weakly governed countries, there are a lot of deaths cheaper and more straightforward to prevent — from malaria, diarrhea, or measles, for example. In rich countries with well-functioning regulatory systems, building regulations and land use codes specifically responding to earthquake threats have a place. In poor countries where regulation is capriciously enforced, they may even be harmful. If we want to change that grim calculus, we have to learn to treat earthquake deaths as a symptom of misery — not the cause.
- Human activities emit roughly 135 times as much climate-warming carbon dioxide as volcanoes each year.
- Volcanoes emit less than cars and trucks, and less, even, than cement production.
- Climate change skeptics have claimed the opposite.
NordicPhotos /Getty Images
Colossal, mind-bogglingly hot and capable of spewing billowing clouds of flight-grounding smoke and searing, molten lava, volcanoes are spectacular displays of the massive forces at work inside our planet. Yet they are dwarfed by humans in at least one respect: their carbon dioxide emissions.
Despite statements made by climate change deniers, volcanoes release a tiny fraction of the amount of carbon dioxide emitted by human activities every year.
In fact, humans release roughly 135 times more carbon dioxide annually than volcanoes do, on average, according a new analysis. Put another way, humans emit in under three days the amount that volcanoes typically release in a year, according to the best estimates of volcanic emissions.
“The question of whether or not volcanoes emit more CO2 than human activity is one I get more than any question in my email from the general public.’ said Terrence Gerlach, a retired volcanologist, formerly with the Cascades Volcano Observatory, part of the US Geological Survey in Vancouver, Wash. Even earth scientists who work in other areas often pose him the question, he said.
To lay out a clear answer, Gerlach compiled the available estimates of CO2 emissions from all global volcanic activity on land and undersea and compared them with estimates for human emissions. He published the compilation in Eos, a publication of the American Geophysical Union.
Researchers estimate the amounts of carbon dioxide released by terrestrial volcanic eruptions by methods including remote sensing or flying through clouds of erupting volcanic gas, and by measuring certain isotope concentrations near undersea volcanoes. Carbon dioxide is dissolved in magma at great depths and is released as the magma rises to the surface.
“A lot of climate skeptics claim that volcanoes emit more CO2 than humans do,” Gerlach said. “They never give any numbers, but the fact is you will never be able to find the volcanic gas scientist that will agree to that,” he said.
One example of these skeptic’s claims is the 2009 book, “Heaven and Earth: Global Warming, the Missing Science” by Ian Plimer of the University of Adelaide, who did not respond to Discovery News’ requests for comment.
“The main reason, I think, that this myth persists,” Gerlach said: “First of all, the emissions are extremely spectacular. When people see volcanic eruptions on television and it’s awesome, and it’s very easy for people to imagine that huge amounts of CO2 are being emitted to the atmosphere.”
“However, these spectacular volcanic explosions that are so stunning on TV last only a few hours,” he added. “They are ephemeral. In contrast, the sources of anthropogenic CO2 (smokestacks, exhaust pipes, etc) are comparatively unspectacular, commonplace, and familiar, and in addition they are ubiquitous, ceaseless, and relentless. They emit CO2 24/7.”
While there is uncertainty in the measurements–researchers estimate between 0.13 and 0.44 billion metric tons per year, with their best estimates between 0.15 and 0.26 billion tons–even the highest end of the range is dwarfed by anthropogenic emissions of 35 billion metric tons in 2010.
Gerlach noted that human land-use changes alone, which include deforestation, release 3.5 billion metric tons per year. Cars and light-duty trucks produce 2 billion metric tons; even cement production produces 1.5 billion tons. Any of these by itself is still several times higher than the annual emissions of all of the world’s volcanoes .
Pakistan or Kazakhstan each produce about the amount of CO2 as volcanoes do each year, Gerlach noted in the article.
In yet another comparison, Gerlach reported that in order for volcanic emissions to match those made by humans, the May 18, 1980, Mount St. Helens eruption would need to happen every 2.5 hours. The June 15, 1991, Mount Pinatubo eruption would need to occur every 12.5 hours.
“There is no way you can escape the fact that volcanoes are releasing a tiny amount of emissions right now,” said Bernard Marty of the Centre de Recherches Petrographiques et Geochimiques in Nancy, France. “There is no doubt about this.”
“Even if you do the reverse and you compute how much volcanism should happen to match atmospheric levels, you end up with completely unrealistic eruption rates,” he said.
Marie Edmonds, a volcanologist at Cambridge University agreed. While volcanoes are the most important natural source of atmospheric CO2, she noted, “The results show clearly that the amount is 100-150 times less than anthropogenic amounts.”
Virtually every forbidden topic imaginable has been covered on television, except for one. The last taboo on television is television itself — and how it is profoundly biased toward high consumption lifestyles that the earth cannot sustain. In the U.S. the average person sees more than 25,000 commercials a year on TV. Commercials represent far more than a pitch for a particular product; they are also advertisements for the attitudes, values and lifestyles that surround the consumption of that product. Mass entertainment is being used to capture a mass audience that is then appealed to by mass advertising to promote mass consumption that, in turn, is devastating the Earth’s biosphere. By programming television for commercial success, the television industry is also programming the mindset of civilizations for ecological failure.
Nearly all of the world’s problems are, at their core, communication problems. Therefore, the future of the world will depend largely on the quality and depth of human communication. I agree with Lester Brown, author of the respected State of the World book series, who said that to respond to the global ecological crisis, “The communications industry is the only instrument that has the capacity to educate on a scale that is needed and in the time available.” At the heart of the communications industry is television. In the U.S. 98% of all homes have a TV set and the average person watches approximately four hours per day. Television has become our primary window onto the world: most of the people get most of their news about the world from television. Like it or not, television has become the central nervous system of modern society. The question then becomes, how well is our “social brain” responding to the immense challenge of sustainability?
The unrelenting consumerist bias of television distorts our view of reality and social priorities, leaving us entertainment rich and knowledge poor. Television may be our window onto the world, but the view it provides is cramped and narrow. Television may be the mirror in which we see ourselves as a society, but the reflection it gives is often distorted and unbalanced. Our evolutionary intelligence is being tested by how well we use this powerful vehicle to communicate collectively about our future.
Just how urgent our situation has become was made clear nearly two decades ago by a 1992 Warning to Humanity that was signed by over 1600 scientists, including a majority of the living Nobel laureates in the sciences. They said that “human beings and the natural world are on a collision course” and that, “A great change in our stewardship of the earth and the life on it, is required, if vast human misery is to be avoided and our global home on this planet is not to be irretrievably mutilated.” If the future of human civilization is now at stake, then what is the mass media doing? Currently, the communications industry is actively participating in the “irretrievable mutilation” of the planet by aggressively promoting a lethal addiction — obsessive consumerism.
World leaders are wrestling with how to stabilize the planet’s population and achieve sustainable development. In an historic bargain, poor countries are being urged to curb their birth rates and rich countries are being urged to curb the rate at which they use up the world’s resources and pollute the planet’s environment. Yet, how can we in the wealthy nations be expected to consume less when the media that dominates our consciousness continuously tells us to buy ever more?
This linkage is one of the paramount political and social issue of our time, and yet it is rarely mentioned. Television almost never turns its cameras around to look at itself and its unrelenting consumerist bias. Building a sustainable future requires at least two major changes:
- Viewer Feedback Forums — We need to create publicly sponsored, televised forums that hold the mass media accountable in the court of public opinion. Using live polling and citizen feedback in both local and national “feedback forums,” citizens can use the power of moral persuasion and public opinion to promote a more mature and balanced diet of programming.
- Earth Commercials — To balance the onslaught of aggressively pro-consumerist commercials, we need “Earth commercials.” These could be ads for other species of animals, the rain forests, appeals from our great-great grandchildren, and so on. They could be done with humor, creativity, playfulness and intelligence to awaken our awareness of the web of life and the needs of future generations.
Most people understand that our planet is in trouble and that we will soon have to make dramatic changes in our manner of living, working and consuming if we are to live in harmony with the Earth. Never before in human history have so many people been called upon to make such sweeping changes in so little time. If a problem recognized is a problem half-solved, then we can make an enormous leap forward by breaking the last taboo on television and taking back a portion of the public’s airwaves for purposes of mature conversation about our common future.
By Gayathri Vaidyanathan of Nature magazine
Germany is still recovering from one of the world’s worst outbreaks of enterohaemorrhagic Escherichia coli, which as of 18 June had sickened more than 3,200 people and caused 39 deaths. The unusually deadly bacteria moved undetected through the food supply from livestock to agriculture to the dinner table, and the response to the outbreak was branded slow and inefficient by physicians and scientists (see ‘Microbe outbreak panics Europe‘).
Now a group of health professionals assembled by the US Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, has called for biosurveillance efforts in the United States and worldwide to be streamlined to help recognize and respond to threats quickly.
“We are trying to create an international immune system, a system that has the capacity to recognize abnormalities,” says Ian Lipkin, co-chair of the National Biosurveillance Advisory Subcommittee (NBAS) and director of the Center for Infection and Immunity at the Mailman School of Public Health at Columbia University, New York.
The NBAS report, Improving the Nation’s Ability to Detect and Respond to 21st Century Urgent Health Threats, is the second by the group originally assembled by former President George W. Bush over fears about bioterrorism. The report is now under consideration by the White House and the US Department of Health and Human Services.
The report recommends that the various US federal agencies that monitor infectious disease combine their operations. Currently, disease outbreaks are monitored by the CDC, the US Department of Agriculture, the Food and Drug Administration, the defense department, the Department of Homeland Security and state-level health agencies. The NBAS report calls for more common language and more ‘data liquidity’ between the agencies to promote the sharing of information. This would also allow better analyses to help detect relevant patterns in health complaints.
The NBAS wants the hub of biosurveillance to move from the CDC to the White House. This would free up agency budgets to invest in a program currently lacking in the United States and globally: surveillance of domestic animal, wildlife, plant, food, vector, disease and environmental sources, integrated with monitoring of human health.
“It is clear given the events of the recent past, like the E. coli outbreak, that we weren’t prepared to deal with it,” says Lipkin. “We don’t have common terminology, we don’t have boots on the ground, we don’t have people who have the capacity to recognize these risks, analyze them and present them in a way policy-makers can appreciate.”
It took weeks before bean sprouts were finally identified as the source of the German E. coli outbreak, and a second, isolated outbreak in France has shifted suspicion to sprouted seeds. Yet the German outbreak is instructive, according to David Fisman, an epidemiologist at the Dalla Lana School of Public Health at the University of Toronto, Canada. If there had been a centralized database tracking pathogen profiles in animals, food and the environment–information that already exists at some level within disparate agricultural, food and drug, and human health agencies–it wouldn’t have taken so long to isolate the cause of the outbreak, says Fisman.
A good tracking system would include pathogen profiles in a global database, according to Jorgen Schlundt, director of food safety, zoonoses and foodborne diseases at the World Health Organization headquartered in Geneva, Switzerland. In the event of disease, physicians would do a database search to discover where else the pathogen is found in the environment to try to stop infections at the source.
“The way we’ve done it in the past, you wait until you find them [the pathogens] in the humans and then you go back and say ‘okay, where did that come from?’,” he says. “But if everything was working in a good way, you would find them in the animal production units and then you’d prevent them getting to humans.”
Funding for the proposals in the NBAS report would have to be figured out in this era of budget cuts and austerity, but Lipkin is optimistic. “There’s going to be concern about investing here, but we think that if you take a look at the investments being made by all these agencies and you consider what would happen if we had an organized approach to this, I’m not even certain it would cost more money.”
This article is reproduced with permission from the magazine Nature. The article was first published on June 28, 2011.
Contaminated water can be cleaned much more effectively using a novel, cheap material, say researchers.
Dubbed “super sand”, it could become a low-cost way to purify water in the developing world.
The technology involves coating grains of sand in an oxide of a widely available material called graphite – commonly used as lead in pencils.
The team describes the work in the American Chemical Society journal Applied Materials and Interfaces.
In many countries around the world, access to clean drinking water and sanitation facilities is still limited.
The World Health Organization states that “just 60% of the population in Sub-Saharan African and 50% of the population in Oceania [islands in the tropical Pacific Ocean] use improved sources of drinking-water.”
The graphite-coated sand grains might be a solution – especially as people have already used sand to purify water since ancient times.
Coating the sand
But with ordinary sand, filtering techniques can be tricky.
Given that this can be synthesized using room temperature processes and also from cheap graphite sources, it is likely to be cost-efficient”
Mainak Majumder Monash University, Australia
Wei Gao from Rice university in Texas, US, told BBC News that regular coarse sand was a lot less effective than fine sand when water was contaminated with pathogens, organic contaminants and heavy metal ions.
While fine sand is slightly better, water drains through it very slowly.
“Our product combines coarse sand with functional carbon material that could offer higher retention for those pollutants, and at the same time gives good throughput,” explained the researcher.
She said that the technique the team has developed to make the sand involves dispersing graphite oxide into water and mixing it with regular sand.
“We then heat the whole mixture up to 105C for a couple of hours to evaporate the water, and use the final product – ‘coated sand’ – to purify polluted water.”
The lead scientist of the study, Professor Pulickel Ajayan, said it was possible to modify the graphite oxide in order to make it more selective and sensitive to certain pollutants – such as organic contaminants or specific metals in dirty water.
Another team member, Dr Mainak Majumder from Monash University in Melbourne, Australia, said it had another advantage – it was cheap.
“This material demonstrates comparable performance to some commercially available activated carbon materials,” he said.
“But given that this can be synthesized using room temperature processes and also from cheap graphite sources, it is likely to be cost-efficient.”
He pointed out that in Australia many mining companies extract graphite and they produce a lot of graphite-rich waste.
“This waste can be harnessed for water purification,” he said.
By IBTimes Staff Reporter | Jun 21, 2011 04:17 AM EDT
The swollen Missouri River had posed a serious threat to a riverside nuclear power plant in the state of Nebraska in the United States after levees built to hold back the rising floodwaters failed.
The Fort Calhoun nuclear power plant was reportedly very close to getting engulfed by the floodwaters, raising fears of a crisis similar to Japan’s Fukushima disaster.
Though the nuclear plant declared the event as “unusual,” the Nuclear Regulatory Commission (NRC) maintained that there was no risk of disaster.
Tokyo Electric Power Company (TEPCO)’s Fukushima Dai-ichi nuclear power plant in Fukushima prefecture, Japan, was devastated by Tsunami waves in March 2011, leading to leakage of radioactive water into the ocean.
As a massive earthquake and tsunami killed thousands of people in Japan, radiation woes and a much more severe nuclear crisis took the country’s economy into recession affecting businesses, consumer spending and tearing apart supply chains.
Federal officials widened flood gates last week to allow record, or near-record water releases to ease pressure on six major reservoirs swollen by heavy rains and melting snow, Reuters reported.
But later in the week, Missouri River floodwaters reached a levee built up to protect Hamburg, Iowa, after the main protection along the river failed, a county emergency official said.
Check out some of the latest pictures of Missouri river flooding below:
By IBTimes Staff Reporter | Jun 27, 2011 02:43 AM EDT
Thousands of houses got swallowed up by the flooding of Souris River, while the rapidly rising waters forced emergency evacuation of residents of Minot, North Dakota, on Sunday.
The flooding Souris River poured over flood defenses in North Dakota, overwhelming efforts to delay the deluge, Reuters reported.
The Souris River spilled over levees and dikes over the weekend, submerging about 4,000 houses and letting about 10,000 to 12,000 residents flee, officials estimate.
Flood projections have forecast about 18 more inches of water before levels begin dropping.
Check out some of the latest aerial view of submerged houses in Minot city:
More on disasters in US:
Houses are submerged in flood waters in Minot, North Dakota, as the Souris River spills over levees and dikes June 25, 2011.
Source: REUTERS/Allen Fredrickson
Houses in Minot, North Dakota are lost to floods as the Souris River spills over levees and dikes June 25, 2011.
Source: REUTERS/Allen Fredrickson
Houses in Minot, North Dakota are lost to floods, as the Souris River spills over levees and dikes June 25, 201
Source: REUTERS/Allen Fredrickson
A train crossing and train tracks are covered with flood water near Minot, North Dakota, as water from the Souris River spills over levees and dikes June 25, 2011.
Source: REUTERS/Allen Fredrickson
Floodwater from the Souris River submerges property in Sawyer, North Dakota June 25, 2011.
Source: REUTERS/Allen Fredrickson
A section of a trailer park is seen submerged in flood waters in Minot, North Dakota June 25, 2011.
Source: REUTERS/Allen Fredrickson
|This false-color image take by NASA’s EO-1 satellite shows the eruption of Nabro volcano on June 24.
Eritrea’s Nabro volcano has been erupting for a week, but few details of the event are known because of the volcano’s remoteness. But a pair of new satellite photos have revealed the first detailed look at the volcano’s erupting vent and lava flows.
Nabro began erupting on June 12, and has sent ash drifting over much of East Africa and the Middle East. It is located in an isolated region along the border between Eritrea and Ethiopia.
Because of the volcano’s remoteness, satellite remote sensing is currently the only reliable way to monitor the ongoing eruption. These images of the eruption were taken by the Advanced Land Imager (ALI) aboard the Earth Observing-1 (EO-1) satellite on June 24. [See the Nabro volcano from space ]
The bright red portions of the false-color image above indicate hot surfaces. Hot volcanic ash glows above the vent, located in the center of Nabro’s caldera.
To the west of the vent, portions of an active lava flow (particularly the front of the flow) are also hot. The speckled pattern on upstream portions of the flow are likely due to the cool, hardened crust splitting and exposing fluid lava as the flow advances.
The bulbous blue-white cloud near the vent is likely composed largely of escaping water vapor that condensed as the plume rose and cooled. The whispy, cyan clouds above the lava flow are evidence of degassing from the lava.
The natural-color image below shows a close-up view of the volcanic plume and eruption site. A dark ash plume rises directly above the vent, and a short, inactive (cool) lava flow partially fills the crater to the north.
A gas plume, rich in water and sulfur dioxide (which contributes a blue tint to the edges of the plume) obscures the upper reaches of the active lava flow. Black ash covers the landscape south and west of Nabro.
There’s a new paper out in the CDC’s journal Emerging Infectious Diseases that makes a provocative claim: There is enough similarity between drug-resistance genes in E. coli carried by chickens and E. coli infecting humans that the chickens may be the source of it.
If it is correct — and it seems plausible and is backed by past research — the claim provides another piece of evidence that antibiotic use in agriculture has a direct effect on human health.
Here are the details:
The paper is a collaboration by researchers from several hospitals in the Netherlands, plus the Netherlands’ National Institute of Public Health and Environmental Protection, the University of Birmingham and a section of the UK’s National Health Service. They isolated E. coli from patients in four Dutch hospitals over 2.5 months in 2009, and compared those with E. coli strains isolated from randomly chosen supermarket meat that was bought in the hospitals’ local areas during the same time period. They compared both those sets of isolates against a third set, of E. coli from blood cultures taken from patients in the hospitals during the same months.
In each set of samples, they were looking at the E. coli to see whether they harbored genes for the type of resistance known as ESBL, for “extended-spectrum beta-lactamase,” an enzyme that denatures a category of drugs used for serious infections that occur mostly in hospitals. When the extended-spectrum beta-lactams no longer work, only a few last-resort drugs are left. (Back in the 1980s, the most common genes for ESBL were blaTEM or blaSHV, but in the past 10 or so years there has been a rapid global increase in the occurrence of a different ESBL gene, blaCTX-M.)
Here’s what they found:
- Out of 876 patients tested by rectal swab — because E. coli is a gut bacterium, carried in and spread by feces — 45 (5 percent) harbored ESBL genes.
- Out of 31 blood cultures in the hospitals’ labs, 23 (74 percent) contained ESBL genes.
- Out of 262 meat samples, 79 (30 percent) harbored an ESBL gene. Broken down by type of meat, there was ESBL in 80 percent of the chicken samples, 5 percent of the beef, 2 percent of the pork, and 9 percent of ground or otherwise mixed meat.
When they broke down the organisms by type, they looked like this. Note the amount in each pie chart that is given over to the ESBL genes blaCTX-M, and the significant correspondence of blaCTX-M-1 in red.
When they put the genes through a second level of genetic analysis, multi-locus sequence typing, 57 percent of the rectal specimens and 57 percent of the blood cultures were closely related to the strains in the chicken meat.
There’s an important backdrop to this research. The Netherlands has one of the lowest rates of human antibiotic resistance in the world, thanks to especially stringent infection control and drug-conservation policies. Paradoxically, it has the highest rate of antibiotic use in agriculture in Europe. As a result, when something starts to move into humans, it is easier to distinguish, because there is no “background noise” of high rates of hospital and community drug resistance such as there are in the US. And because there are no competing resistance factors from other sources, it is easier to identify and explain.
Thus, the researchers can comfortably say:
We conclude that the high rate of ESBL contamination of retail chicken meat in the Netherlands, which involves many of the same ESBL genes present in colonized and infected humans, is a plausible source of the recent increase of ESBL genes in the Netherlands. The similarity of E. coli strains and predominant drug resistance genes in meat and humans provides circumstantial evidence for an animal reservoir for a substantial part of ESBL genes found in humans.
If something about this research sounds familiar, it’s because a similar study was published a few months ago, also from the Netherlands, with a partially overlapping analysis: chicken meat and blood-culture records, but no swabs from simultaneous patients. That study too found a high degree of correlation between ESBL-containing organisms in humans and in chickens.
These findings won’t come as a surprise to anyone who accepts — as most good science and a number of public health authorities do — that antibiotic overuse in large-scale farming creates drug-resistant organisms that affect human health. The question, for those who don’t accept such a link, is: How much evidence is enough?
(Footnote: In addition to being published in EID, this study was also presented by Dr. Jan Kluytmans, the senior author, during the World HAI Forum taking place this week in France. I’ll have more on the HAI Forum in a future post.)
Cite: Overdevest I et al. Extended-spectrum ?-lactamase genes of Escherichia coli in chicken meat and humans, the Netherlands. Emerg Infect Dis. 2011 Jul. http://www.cdc.gov/EID/content/17/7/1216.htm