The Ebola virus that killed more than 11,000 people in four African countries in 2014-2015 has broken out again - this time in a remote village in the Democratic Republic of Congo. So far, 17 people have died from the newest outbreak, including one nurse who was caring for victims.
The 2014-2015 outbreak was so deadly because the countries involved and various medical aid agencies were slow to respond. This time around, health officials are taking no chances. The World Health Organization is mobilizing a rapid response force that includes medical experts, equipment, and medical supplies, including a new Ebola vaccine. The affected area is just three hours away by road from a city of over a million people. If the virus reaches the city, containment of the outbreak could become much more difficult.
From past experience, health officials believe that by attacking viral disease outbreaks early and hitting them hard, outbreaks can be stopped in their tracks before they can spread very far. It worked (minus the new vaccine) in stopping a previous Ebola outbreak in the Democratic Republic of Congo in 2017. Let's hope it works again.
Showing posts with label ecosystems and populations. Show all posts
Showing posts with label ecosystems and populations. Show all posts
Saturday, May 12, 2018
Monday, September 11, 2017
H7N9 Bird Flu is Still Around
Have you forgotten about bird flu? Well, don't, because it's still around. In fact the 2017 flu season was the worst ever, according to the CDC. From Oct. 2016 to the summer of 2017, the H7N9 strain of bird flu infected 759 people. About a third of them - 281 people - died. That's nearly as many as the total number of deaths in the four previous years combined.
CDC officials consider H7N9 to "the influenza virus with the highest potential pandemic risk", according to a weekly report from the agency. Fortunately, the virus has not yet evolved to be easily transmitted between humans; nearly all cases to date have been the result of contact with infected birds. But if the virus ever does mutate to become more easily transmissible between humans, watch out!
Health officials continue to monitor the virus closely for any signs that it is changing in ways that would make it a worldwide threat. But so far, all cases have been in China, Hong Kong, and Macao.
CDC officials consider H7N9 to "the influenza virus with the highest potential pandemic risk", according to a weekly report from the agency. Fortunately, the virus has not yet evolved to be easily transmitted between humans; nearly all cases to date have been the result of contact with infected birds. But if the virus ever does mutate to become more easily transmissible between humans, watch out!
Health officials continue to monitor the virus closely for any signs that it is changing in ways that would make it a worldwide threat. But so far, all cases have been in China, Hong Kong, and Macao.
Wednesday, August 3, 2016
Hybrids and the Environmental Protection Act
In the 43 years since it was written, the Endangered Species Act (ESA) has played a key role in the recoveries from near-extinction of several species, including the bald eagle, the humpback whale, and the gray wolf. However, the ESA doesn't address hybrids - organisms produced when individuals of two different species mate and produce viable offspring. The problem of what to do about endangered hybrids has now come to the forefront, thanks (or no thanks) to a powerful new tool in biology, DNA sequencing.
The classic definition of a species is "a group of organisms that under natural conditions tend to breed within that group." Most species can't breed with other species and produce viable offspring. But there are exceptions; wolves, for example, can (and occasionally do) interbreed with dogs or coyotes. And that brings us to the problem of which wolves, if any, should be protected by the ESA.
The ESA currently recognizes (and protects) two species of wolves. Gray wolves are found primarily in the western U.S.; their population is recovering, thanks to protection under the ESA. Red wolves were once found in the southeast U.S. but now exist only in captivity; they, too, are protected. In addition, scientists have recently suggested that wolves in the eastern U.S. should also be listed as a separate protected species, to be called the Eastern wolf.
But now new research, using DNA sequencing, has revealed that the Eastern wolf and the red wolf are actually hybrids, produced by interspecies mating between gray wolves and coyotes. That creates a problem for the ESA. If Eastern and red wolves are just hybrids of two true species, should we attempt to save them? And if there is just one species of wolf, does its total population still warrant protection under the ESA?
The Environmental Protection Act is showing its age. It needs to be able to take into account new findings derived from DNA sequencing. And it needs to address what to do (if anything) about hybrids.
The classic definition of a species is "a group of organisms that under natural conditions tend to breed within that group." Most species can't breed with other species and produce viable offspring. But there are exceptions; wolves, for example, can (and occasionally do) interbreed with dogs or coyotes. And that brings us to the problem of which wolves, if any, should be protected by the ESA.
The ESA currently recognizes (and protects) two species of wolves. Gray wolves are found primarily in the western U.S.; their population is recovering, thanks to protection under the ESA. Red wolves were once found in the southeast U.S. but now exist only in captivity; they, too, are protected. In addition, scientists have recently suggested that wolves in the eastern U.S. should also be listed as a separate protected species, to be called the Eastern wolf.
But now new research, using DNA sequencing, has revealed that the Eastern wolf and the red wolf are actually hybrids, produced by interspecies mating between gray wolves and coyotes. That creates a problem for the ESA. If Eastern and red wolves are just hybrids of two true species, should we attempt to save them? And if there is just one species of wolf, does its total population still warrant protection under the ESA?
The Environmental Protection Act is showing its age. It needs to be able to take into account new findings derived from DNA sequencing. And it needs to address what to do (if anything) about hybrids.
Sunday, December 13, 2015
Increased Mortality Among Middle-Aged Whites
Mortality rates for most age- and racial-groups have declined over the past several decades. But among middle-aged whites, the mortality rate has actually increased. No other rich country has shown such a trend. Among poorly-educated white non-Hispanic Americans between the ages of 45 and 54, for example, mortality rate increased more than 10% between 1999 and 2013.
The culprit, it appears, is not one or more of the chronic diseases usually associated with more developed countries, such as obesity, diabetes, heart disease, stroke, and cancer. The main causes are suicides, and deaths due to drugs and alcohol, according to research published in the Proceedings of the National Academy of Sciences. These are generally signs of stress in a population, not consequences of affluence.
Although the mortality rate for middle-aged whites is the only mortality rate that is rising at the moment, it's still 40% lower than that for blacks. So perhaps we shouldn't make too much of this recent finding, except that it may tell us that in the future we'll have to focus on mental health and the sense of well-being for all racial groups, if we are to make any additional progress on mortality rates.
The culprit, it appears, is not one or more of the chronic diseases usually associated with more developed countries, such as obesity, diabetes, heart disease, stroke, and cancer. The main causes are suicides, and deaths due to drugs and alcohol, according to research published in the Proceedings of the National Academy of Sciences. These are generally signs of stress in a population, not consequences of affluence.
Although the mortality rate for middle-aged whites is the only mortality rate that is rising at the moment, it's still 40% lower than that for blacks. So perhaps we shouldn't make too much of this recent finding, except that it may tell us that in the future we'll have to focus on mental health and the sense of well-being for all racial groups, if we are to make any additional progress on mortality rates.
Thursday, November 19, 2015
China To Allow Two Children Per Couple
Back in 1979, China introduced a one-child-per-couple policy in order to curb what it saw as too high a rate of population growth. The country offered government subsidies for only the first child; levied fines for having more than one child; in some cases even resorted to sterilizations and forced abortions in an effort to enforce the rule. The policy was so effective that by 2000 the national fertility rate was only 1.5, well below the fertility rate of 2.1 at which a population stabilizes. Even worse, the policy has led to a newborn sex ratio of 116 boys to 100 girls; if they are only allowed to have one child, most Chinese couples would prefer that it be a boy.
In recent years China has begun to realize that the country will face a shortage of workers to support an aging population if current trends continued. In 2013 China relaxed the one-child policy somewhat by allowing people who were an only child to have a second child. And last month, China revised its policy to allow all couples to have two children, according to a CNN news article. However, it may be a case of too little, too late; even if the fertility rate does rise to 2.0 by 2050, the overall population will rise increase only 2% - hardly enough to take care of all those over-65 retired people.
One thing the new policy may do, however, is reverse the trend toward an over-abundance of male children. And that may ultimately improve marriage prospects for young Chinese males, who currently find it hard to find a suitable mate.
In recent years China has begun to realize that the country will face a shortage of workers to support an aging population if current trends continued. In 2013 China relaxed the one-child policy somewhat by allowing people who were an only child to have a second child. And last month, China revised its policy to allow all couples to have two children, according to a CNN news article. However, it may be a case of too little, too late; even if the fertility rate does rise to 2.0 by 2050, the overall population will rise increase only 2% - hardly enough to take care of all those over-65 retired people.
One thing the new policy may do, however, is reverse the trend toward an over-abundance of male children. And that may ultimately improve marriage prospects for young Chinese males, who currently find it hard to find a suitable mate.
Saturday, July 18, 2015
Producing Omega-3 Oils in GM Plants
Aside from tasting good, oily fish such as salmon are good for you because they contain special types of fish oils - called omega-3 oils - that are known to reduce the risk of heart disease by reducing the risk of atherosclerosis. However, salmon do not actually make the oils. Omega-3 oils are made by single-celled algae, which are eaten by small herbivorous fish, which are in turn eaten by small carnivorous fish and so on up the food chain. Eventually the omega-3 oils end up in the salmon.
The demand for wild-caught salmon is leading to a depletion of salmon stocks worldwide. An alternative choice food choice would be farmed salmon, raised in enclosed bays or in pens in the oceans. Increased consumption of farmed salmon could reduce the demand for wild-caught salmon and thus prevent wild salmon from being overfished. Unfortunately, farmed salmon contain lesser quantities of omega-3 oils unless they are fed a steady diet of small fish such as wild-caught anchovies. That leads to a problem; feeding farmed fish wild-caught fish to boost their omega-3 content may just lead to overfishing of those other smaller species. And from the fish farmer's point of view, feeding farmed salmon a diet of wild-caught fish is expensive.
A solution may be on the horizon, but not everyone is going to like it because it involves genetic engineering and the creation of genetically modified organisms (GMOs). A team of scientists in England has managed to genetically modify an oil-producing plant related to rape (the plant that produces canola oil) so that it produces high yields of omega-3 oils. The new GM plant contains genes from several other plant species, including a moss and an alga. It produces enough omega-3 oils that farmed salmon could be raised on a diet of GM fish chow.
So here's the dilemma; do we want to raise farmed salmon on GM chow, producing a healthy food alternative to wild salmon and reducing the fishing pressure on wild salmon populations? Or do we want to continue to shun GMOs and deplete the world's oceans of fish?
Sometimes our choices are not all that easy.
The demand for wild-caught salmon is leading to a depletion of salmon stocks worldwide. An alternative choice food choice would be farmed salmon, raised in enclosed bays or in pens in the oceans. Increased consumption of farmed salmon could reduce the demand for wild-caught salmon and thus prevent wild salmon from being overfished. Unfortunately, farmed salmon contain lesser quantities of omega-3 oils unless they are fed a steady diet of small fish such as wild-caught anchovies. That leads to a problem; feeding farmed fish wild-caught fish to boost their omega-3 content may just lead to overfishing of those other smaller species. And from the fish farmer's point of view, feeding farmed salmon a diet of wild-caught fish is expensive.
A solution may be on the horizon, but not everyone is going to like it because it involves genetic engineering and the creation of genetically modified organisms (GMOs). A team of scientists in England has managed to genetically modify an oil-producing plant related to rape (the plant that produces canola oil) so that it produces high yields of omega-3 oils. The new GM plant contains genes from several other plant species, including a moss and an alga. It produces enough omega-3 oils that farmed salmon could be raised on a diet of GM fish chow.
So here's the dilemma; do we want to raise farmed salmon on GM chow, producing a healthy food alternative to wild salmon and reducing the fishing pressure on wild salmon populations? Or do we want to continue to shun GMOs and deplete the world's oceans of fish?
Sometimes our choices are not all that easy.
Saturday, March 28, 2015
The Ebola Outbreak is Subsiding
The Ebola outbreak in Guinea, Liberia, and Sierra Leone seems to be subsiding somewhat. The number of new cases is currently running at about 100-150 per week, down sharply from the 800-1,000 cases per week in October-November of 2014. The overall death toll now stands at 10,326 out of 24,907 confirmed cases for a death rate of just over 40%, according to the World Health Organization. There have been only four cases (and one death) in the United States.
Several factors are contributing to the slowing of the outbreak. The virus never went airborne, to the huge relief of health officials. And it turns out that patients are most likely to infect others late in their infection, rather than early. As a result, identifying and isolating infected persons quickly and then tracking down and testing persons with whom they have been in contact has been the key to containment. Getting people to change cultural practices, such as kissing and shaking hands as greetings and washing the dead prior to burial, has slowed the spread of the disease as well.
Nevertheless, it's still too soon to declare the outbreak over. It takes a lot of manpower to find and test all the persons who may have been exposed to someone with the disease, and the three countries with the most cases lack those kinds of resources. Nearly half of all new cases are identified only post-mortem (after death), which makes containment and tracking of exposed persons more difficult.
There are still no cures or effective preventative vaccines for Ebola. Let's hope we can continue to keep this outbreak contained until cures are available.
Several factors are contributing to the slowing of the outbreak. The virus never went airborne, to the huge relief of health officials. And it turns out that patients are most likely to infect others late in their infection, rather than early. As a result, identifying and isolating infected persons quickly and then tracking down and testing persons with whom they have been in contact has been the key to containment. Getting people to change cultural practices, such as kissing and shaking hands as greetings and washing the dead prior to burial, has slowed the spread of the disease as well.
Nevertheless, it's still too soon to declare the outbreak over. It takes a lot of manpower to find and test all the persons who may have been exposed to someone with the disease, and the three countries with the most cases lack those kinds of resources. Nearly half of all new cases are identified only post-mortem (after death), which makes containment and tracking of exposed persons more difficult.
There are still no cures or effective preventative vaccines for Ebola. Let's hope we can continue to keep this outbreak contained until cures are available.
Monday, January 26, 2015
Preventing the Spread of Bioengineered Bacteria
Bacteria have been bioengineered (genetically modified) for all sorts of reasons. Some are used to make pharmaceuticals or chemicals; others can degrade specific toxic substances. And although it hasn't happened yet, scientists are concerned that sooner or later, one of these bacteria will get out of the laboratory or industrial plant and cause disease or damage the environment. Could such an accident be prevented?
Scientists at Yale University think they have found a way. They insert a genetic code into bacteria that encodes for a synthetic amino acid that is not present in the environment naturally. That way, the bacteria are totally dependent on that particular amino acid for growth and reproduction. Any bacteria that escape into the environment simply wouldn't survive or reproduce.
Most bioengineered bacteria are used within enclosed environments, such as a research laboratory or an industrial production facility. But one could envision how making a bioengineered bacteria totally dependent on a synthetic amino acid might allow the bacteria to be used effective outside the laboratory as well, without fear of the bacteria getting out of control. For example, bacteria that had been modified to degrade oil at an oil spill site could be restricted to that site by spraying the synthetic amino acid only on the location of the spill.
It's an interesting idea.
Scientists at Yale University think they have found a way. They insert a genetic code into bacteria that encodes for a synthetic amino acid that is not present in the environment naturally. That way, the bacteria are totally dependent on that particular amino acid for growth and reproduction. Any bacteria that escape into the environment simply wouldn't survive or reproduce.
Most bioengineered bacteria are used within enclosed environments, such as a research laboratory or an industrial production facility. But one could envision how making a bioengineered bacteria totally dependent on a synthetic amino acid might allow the bacteria to be used effective outside the laboratory as well, without fear of the bacteria getting out of control. For example, bacteria that had been modified to degrade oil at an oil spill site could be restricted to that site by spraying the synthetic amino acid only on the location of the spill.
It's an interesting idea.
Sunday, November 30, 2014
The Declining Availability of Fresh Water
The natural fresh water cycle (the cycling of water from oceans to the atmosphere, becoming precipitation in the form of rain and snow) is the source of the fresh water in the Earth's lakes, streams, and underground aquifers. The water cycle is timeless and largely unaffected by man, except for the probable influence of global warming. But the supply of clean fresh water available to humans (where humans choose to locate) is slowly but surely declining.
Many western U.S. cities rely primarily on water derived from the winter snowpack in nearby mountain ranges. The cities are growing and demand for water is up. To make matters worse, the winter snowpack has been declining in recent years. Some of the snowpack's decline may be due to global warming, but it may also be partly due to normal decades-long cyclic fluctuations in the water cycle. Centuries-old glaciers have been receding; some have disappeared entirely. If the current 30-year trend continues, Montana's Glacier National Park in may not have a single glacier by 2030. This does not bode well for Western lakes and streams.
Some human populations rely heavily on ancient underground aquifers for water to irrigate thirsty crops. China, India, and the U.S. plains States all rely heavily on aquifers that are not being replenished at the rates at which they are being used. Wells in some areas are going dry, leading to a loss of agricultural productivity.
Pollution of freshwater is a constant concern. Industries that use a lot of water or that run the risk of polluting rivers and streams, such as mining for coal, copper, and gold, face increasing government regulation or outright opposition from environmental groups. The world's largest gold mining company, Barrick Gold, shut down a major investment in a massive mine in Chile due in part to costs related to the risk of polluting nearby rivers and streams.
These are not problems that are going to go away quickly. Humans will have to adapt. We'll need to reduce water use in our homes, recycle water wherever possible, locate our human populations nearer to abundant supplies of fresh water, develop agricultural crops that require less water, irrigate crops more efficiently, and improve industrial techniques that require water. Some of these actions are already being taken. As they must, if we are to prosper in the long run.
Many western U.S. cities rely primarily on water derived from the winter snowpack in nearby mountain ranges. The cities are growing and demand for water is up. To make matters worse, the winter snowpack has been declining in recent years. Some of the snowpack's decline may be due to global warming, but it may also be partly due to normal decades-long cyclic fluctuations in the water cycle. Centuries-old glaciers have been receding; some have disappeared entirely. If the current 30-year trend continues, Montana's Glacier National Park in may not have a single glacier by 2030. This does not bode well for Western lakes and streams.
Some human populations rely heavily on ancient underground aquifers for water to irrigate thirsty crops. China, India, and the U.S. plains States all rely heavily on aquifers that are not being replenished at the rates at which they are being used. Wells in some areas are going dry, leading to a loss of agricultural productivity.
Pollution of freshwater is a constant concern. Industries that use a lot of water or that run the risk of polluting rivers and streams, such as mining for coal, copper, and gold, face increasing government regulation or outright opposition from environmental groups. The world's largest gold mining company, Barrick Gold, shut down a major investment in a massive mine in Chile due in part to costs related to the risk of polluting nearby rivers and streams.
These are not problems that are going to go away quickly. Humans will have to adapt. We'll need to reduce water use in our homes, recycle water wherever possible, locate our human populations nearer to abundant supplies of fresh water, develop agricultural crops that require less water, irrigate crops more efficiently, and improve industrial techniques that require water. Some of these actions are already being taken. As they must, if we are to prosper in the long run.
Wednesday, October 1, 2014
First U.S. Ebola Case
A man who traveled to the U.S. from Liberia via Europe is now the first person to be diagnosed with Ebola while within the U.S. At least one of the major news services is giving this one "event" continuous coverage all day, which of course raises our fear level; it makes it sound like this one case of Ebola could lead to an epidemic in this country.
Nothing could be further from the truth. According to the CDC, Ebola is transmitted primarily in bodily fluids such as urine, saliva, or blood. In addition, Ebola patients can only infect others when they are actually sick - not before and not after. The patient in question didn't feel sick until several days after he arrived in the U.S. And four days after he began to feel sick, he was isolated in a hospital prepared to deal with diseases such as this. That means, for example, that he did not infect anyone on his incoming transatlantic flight, and he's probably not going to infect anyone else after the time he was hospitalized. At most, he could have infected some of the people with whom he had close contact in the four days during which he felt sick before he was hospitalized.
Public health officials certainly have their hands full finding all the people with whom the Ebola patient had direct contact, and monitoring them for 21 days. Surveillance is tedious, but it works. So relax; at least one expert doesn't think an Ebola epidemic is likely in this country. Ebola is just not transmitted easily enough.
Sensationalism sells. But the news services should dial back their continuous coverage of what is probably a non-event.
Nothing could be further from the truth. According to the CDC, Ebola is transmitted primarily in bodily fluids such as urine, saliva, or blood. In addition, Ebola patients can only infect others when they are actually sick - not before and not after. The patient in question didn't feel sick until several days after he arrived in the U.S. And four days after he began to feel sick, he was isolated in a hospital prepared to deal with diseases such as this. That means, for example, that he did not infect anyone on his incoming transatlantic flight, and he's probably not going to infect anyone else after the time he was hospitalized. At most, he could have infected some of the people with whom he had close contact in the four days during which he felt sick before he was hospitalized.
Public health officials certainly have their hands full finding all the people with whom the Ebola patient had direct contact, and monitoring them for 21 days. Surveillance is tedious, but it works. So relax; at least one expert doesn't think an Ebola epidemic is likely in this country. Ebola is just not transmitted easily enough.
Sensationalism sells. But the news services should dial back their continuous coverage of what is probably a non-event.
Monday, September 29, 2014
Ebola Update
The U.S. Centers for Disease Control and Prevention (CDC) reports that as of last week, over 6,000 people have been infected with the Ebola virus and more than 2,900 have died. Although Ebola infections have been identified in five countries, to date the epidemic is confined primarily to just three; Guinea, Sierra Leone, and Liberia. Senegal has had just one case (a man who traveled from Guinea) and Nigeria, with 8 deaths, hasn't had a new case in almost three weeks.
The death rate among infected persons remains close to 50%. This is a virus that kills its victims rather quickly and is difficult to treat. Fortunately, person-to-person transmission requires close contact in the form of exchange of fluids. But that means that the people at highest risk of becoming infected are health care workers. The World Health Organization reports that more than 120 health care workers have died since the outbreak began. The lack of proper facilities and equipment to effectively isolate patients and protect health care workers is a factor.
Most airlines have cancelled commercial flights to the three countries at the center of the outbreak. Travel between and within the three countries has been restricted as well. A side effect of travel bans is that the flow of health care workers and medical equipment/supplies to affected areas is made more difficult.
This epidemic is not over yet. It may not even have peaked.
The death rate among infected persons remains close to 50%. This is a virus that kills its victims rather quickly and is difficult to treat. Fortunately, person-to-person transmission requires close contact in the form of exchange of fluids. But that means that the people at highest risk of becoming infected are health care workers. The World Health Organization reports that more than 120 health care workers have died since the outbreak began. The lack of proper facilities and equipment to effectively isolate patients and protect health care workers is a factor.
Most airlines have cancelled commercial flights to the three countries at the center of the outbreak. Travel between and within the three countries has been restricted as well. A side effect of travel bans is that the flow of health care workers and medical equipment/supplies to affected areas is made more difficult.
This epidemic is not over yet. It may not even have peaked.
Wednesday, August 20, 2014
Why Societies Collapse
Why have some of the greatest human societies of all time essentially collapsed to insignificance, or at least undergone steep declines? What fate awaits today’s most important societies, or even the human race as a whole? Is collapse inevitable?
A study to be published in Ecological Economics offers some interesting observations on these questions, based on a mathematical modeling analysis of past societies. According to the authors of the paper, two commonly-observed events associated with societal collapse or steep decline are; 1) resource over-use beyond carrying capacity, and 2) social stratification (increased separation into rich versus poor). The first factor should be obvious to any student of biology: Any population, whether it be bacteria or humans, must ultimately undergo a decline in population or at least a decline in living standards if it depletes the resources available to it. That concept is at the heart of the philosophy that ultimately humans must learn to live within a “sustainable world” if we are to stay healthy, happy, and successful.
The second factor, social stratification, is not so obvious. The authors propose several ways that increased separation between rich and poor could affect a society. One might be that the rich over-utilize resources, leaving too few resources for the poor. Another could be that as the poor make it into the rich category, there are too few workers left to do a society’s work.
Press reports of the study have made it sound as if we’re doomed. But nothing about the study implies that at all. There’s no reason why an enlightened society couldn’t make an effort to minimize social stratification and learn to use its resources wisely. Forewarned is forearmed.
A study to be published in Ecological Economics offers some interesting observations on these questions, based on a mathematical modeling analysis of past societies. According to the authors of the paper, two commonly-observed events associated with societal collapse or steep decline are; 1) resource over-use beyond carrying capacity, and 2) social stratification (increased separation into rich versus poor). The first factor should be obvious to any student of biology: Any population, whether it be bacteria or humans, must ultimately undergo a decline in population or at least a decline in living standards if it depletes the resources available to it. That concept is at the heart of the philosophy that ultimately humans must learn to live within a “sustainable world” if we are to stay healthy, happy, and successful.
The second factor, social stratification, is not so obvious. The authors propose several ways that increased separation between rich and poor could affect a society. One might be that the rich over-utilize resources, leaving too few resources for the poor. Another could be that as the poor make it into the rich category, there are too few workers left to do a society’s work.
Press reports of the study have made it sound as if we’re doomed. But nothing about the study implies that at all. There’s no reason why an enlightened society couldn’t make an effort to minimize social stratification and learn to use its resources wisely. Forewarned is forearmed.
Friday, August 15, 2014
First Antibiotic-Resistant Bacteria; Now Herbicide-Resistant Weeds
Nearly all of the corn and soybeans planted in this country have been genetically modified to make them resistant to a common herbicide called Roundup (glyphosate). Such genetically modified organisms (GMOs) can be sprayed with Roundup during the growing season to kill weeds without harming the crop.
Given what we know about how the over-use of antibiotics has led to the appearance of antibiotic-resistant strains of bacteria, what did we think would happen when we began spraying GMO crops heavily with a single herbicide? Why, of course - Roundup-resistant weeds! According to a recent New York Times article, an invasive Roundup-resistant weed called palmer amaranth (carelessweed) is already sweeping northward from the south, wreaking havoc on farmers’ fields.
Monsanto, the manufacturer of Roundup and the developer of the GMO seeds most farmers now plant, is planning even more genetic modification of corn and soybeans to make them resistant to other herbicides as well, allowing farmers to spray more than one herbicide on their crops. Each new modification will buy farmers some time in the perpetual battle against weeds (and also enrich Monsanto). But it’s not hard to see that in the long run this is a losing game; the over-use of any herbicide will ultimately lead to the emergence of herbicide-resistant weeds. Adaptation and evolution are hallmarks of the natural world. Farmers will have to develop other approaches (in addition to just spraying herbicides) to combat weeds effectively.
Given what we know about how the over-use of antibiotics has led to the appearance of antibiotic-resistant strains of bacteria, what did we think would happen when we began spraying GMO crops heavily with a single herbicide? Why, of course - Roundup-resistant weeds! According to a recent New York Times article, an invasive Roundup-resistant weed called palmer amaranth (carelessweed) is already sweeping northward from the south, wreaking havoc on farmers’ fields.
Monsanto, the manufacturer of Roundup and the developer of the GMO seeds most farmers now plant, is planning even more genetic modification of corn and soybeans to make them resistant to other herbicides as well, allowing farmers to spray more than one herbicide on their crops. Each new modification will buy farmers some time in the perpetual battle against weeds (and also enrich Monsanto). But it’s not hard to see that in the long run this is a losing game; the over-use of any herbicide will ultimately lead to the emergence of herbicide-resistant weeds. Adaptation and evolution are hallmarks of the natural world. Farmers will have to develop other approaches (in addition to just spraying herbicides) to combat weeds effectively.
Saturday, August 9, 2014
Two Experimental Drugs Used to Treat Ebola
Desperate times call for desperate measures.
Two drugs are currently being used to treat patients with Ebola hemorrhagic fever (Ebola). Both are relatively untested, meaning they are a long way from being formally approved by the FDA. But when the choice is between watching patients die or trying something, it seems that trying something wins out.
The use of untested drugs and/or drugs in very short supply raises all kinds of ethical issues, of course. The first drug, called ZMapp, had never been tried on humans before now. It was first used on the two Americans who contracted the disease in Liberia and who have since been flown to Atlanta. Aside from the issue of risk to the two patients, there’s the troubling ethical question of favoritism; why was it given to the two Americans first, and not to any of the many African patients? (On the other hand, had it been given first to Africans, there would be complaints that Africans were being used as guinea pigs. You can’t win this one!).
The second drug, called TKM-Ebola, was already in the human testing phase when the Ebola epidemic began. But the tests, which were being conducted on normal human volunteers, had been halted temporarily because of side effects in one volunteer. Given the current situation, though, the FDA took the unprecedented step of approving TKM-Ebola for Ebola patients anyway. Apparently the FDA felt that the potential benefits to patients who actually had Ebola far outweighed the risks.
It takes time to ramp up the production of any drug. Both drugs will be in short supply in the near future, which means that choosing which patients will get them will remain an issue for a while. From a medical point of view, it’ll be interesting to see how effective they actually are.
Two drugs are currently being used to treat patients with Ebola hemorrhagic fever (Ebola). Both are relatively untested, meaning they are a long way from being formally approved by the FDA. But when the choice is between watching patients die or trying something, it seems that trying something wins out.
The use of untested drugs and/or drugs in very short supply raises all kinds of ethical issues, of course. The first drug, called ZMapp, had never been tried on humans before now. It was first used on the two Americans who contracted the disease in Liberia and who have since been flown to Atlanta. Aside from the issue of risk to the two patients, there’s the troubling ethical question of favoritism; why was it given to the two Americans first, and not to any of the many African patients? (On the other hand, had it been given first to Africans, there would be complaints that Africans were being used as guinea pigs. You can’t win this one!).
The second drug, called TKM-Ebola, was already in the human testing phase when the Ebola epidemic began. But the tests, which were being conducted on normal human volunteers, had been halted temporarily because of side effects in one volunteer. Given the current situation, though, the FDA took the unprecedented step of approving TKM-Ebola for Ebola patients anyway. Apparently the FDA felt that the potential benefits to patients who actually had Ebola far outweighed the risks.
It takes time to ramp up the production of any drug. Both drugs will be in short supply in the near future, which means that choosing which patients will get them will remain an issue for a while. From a medical point of view, it’ll be interesting to see how effective they actually are.
Tuesday, August 5, 2014
An Ebola Outbreak in West Africa
A recent outbreak of a viral disease called Ebola hemorrhagic fever (Ebola HF) has killed over 700 people in the West African nations of Guinea, Liberia, and Sierra Leone. Infected persons initially exhibit symptoms including a fever, fatigue, and joint, muscle and abdominal pain, similar to the flu. But unlike the flu, Ebola HF interferes with mechanisms involved in blood clotting, ultimately leading to hemorrhage in multiple organs. Over 55% of all persons infected with Ebola HF have died, making Ebola HF one of the most deadly viral diseases currently infecting humans.
Before you get too worried, you should know that the virus that causes Ebola HF is NOT transmitted through the air (like the common cold) or even by casual physical contact (e.g. a handshake). It is transmitted primarily through direct contact with bodily fluids. Persons most at risk are people who live with an infected person, health care workers, and persons who work with infected cadavers, such as funeral workers. The availability of good medical care (not always available in West Africa) reduces the death rate significantly. So far, two Americans have contracted the disease while working in Liberia; both have been transported to the U.S. and are being treated in a special medical unit at Emory University in Atlanta. Both are expected to recover.
The CDC will be sending 50 additional disease experts to the region within the next month in an effort to contain the outbreak. For updates and more information about Ebola HF, see the CDC’s website page on the topic.
Is there anything you should be doing right now to protect yourself? Well, yes… according to the CDC you should “avoid nonessential travel to the west African nations of Guinea, Liberia, and Sierra Leone”. Shouldn’t be too hard for most of us.
Before you get too worried, you should know that the virus that causes Ebola HF is NOT transmitted through the air (like the common cold) or even by casual physical contact (e.g. a handshake). It is transmitted primarily through direct contact with bodily fluids. Persons most at risk are people who live with an infected person, health care workers, and persons who work with infected cadavers, such as funeral workers. The availability of good medical care (not always available in West Africa) reduces the death rate significantly. So far, two Americans have contracted the disease while working in Liberia; both have been transported to the U.S. and are being treated in a special medical unit at Emory University in Atlanta. Both are expected to recover.
The CDC will be sending 50 additional disease experts to the region within the next month in an effort to contain the outbreak. For updates and more information about Ebola HF, see the CDC’s website page on the topic.
Is there anything you should be doing right now to protect yourself? Well, yes… according to the CDC you should “avoid nonessential travel to the west African nations of Guinea, Liberia, and Sierra Leone”. Shouldn’t be too hard for most of us.
Monday, May 19, 2014
First Case of MERS Transmission Within the U.S.
According to the Centers for Disease Control and Prevention (CDC), an Illinois man has contracted the Middle East respiratory syndrome (MERS) virus in this country. There are now three confirmed cases of MERS virus in the U.S. The other two patients had traveled to or lived in Saudi Arabia. It is presumed that they picked up the virus there. The Illinois man met with the first MERS patient several times in the U.S. before the patient knew he was carrying the virus, and shook hands with him. He did not become particularly ill and did not require medical treatment.
MERS first appeared in humans in Saudi Arabia about two years ago. Scientists believe that it may have made the jump to humans from camels. It is a virus in the coronavirus family, making it a close relative of the common cold and of the SARS (sudden acute respiratory syndrome) virus that caused nearly 800 deaths a decade ago. Symptoms of MERS are similar to those of the common cold or flu, except that it can lead to pneumonia, kidney failure, and even death. Nearly 30% of the approximately 700 confirmed cases of MERS infection (most of them in the Middle East) have died. Transmission between humans seems to require close contact; most of the cases involve health care workers or relatives of infected patients.
A virus found in only three people in the U.S. hardly seems worth mentioning. Nevertheless, MERS is being watched closely because it is fairly deadly and because if it ever mutates to become easily transmissible (by casual contact, such as riding in the same bus), a major pandemic could ensue. For now, though, officials stress that the public is not at risk.
MERS first appeared in humans in Saudi Arabia about two years ago. Scientists believe that it may have made the jump to humans from camels. It is a virus in the coronavirus family, making it a close relative of the common cold and of the SARS (sudden acute respiratory syndrome) virus that caused nearly 800 deaths a decade ago. Symptoms of MERS are similar to those of the common cold or flu, except that it can lead to pneumonia, kidney failure, and even death. Nearly 30% of the approximately 700 confirmed cases of MERS infection (most of them in the Middle East) have died. Transmission between humans seems to require close contact; most of the cases involve health care workers or relatives of infected patients.
A virus found in only three people in the U.S. hardly seems worth mentioning. Nevertheless, MERS is being watched closely because it is fairly deadly and because if it ever mutates to become easily transmissible (by casual contact, such as riding in the same bus), a major pandemic could ensue. For now, though, officials stress that the public is not at risk.
Tuesday, January 21, 2014
A New Subtype of Bird Flu in China
A new subtype of bird flu known as H7N9 has emerged recently in China, according to the CDC. The first infections of humans by H7N9 occurred in March of 2013 in Shanghai province. Within two months, 132 people had been infected and 44 had died. The outbreak died down over the summer months, only to emerge again in October. Just last week there were 14 new cases of H7N9 bird flu in humans.
This latest bird flu virus is genetically slightly different but overall functionally similar to the H5N1 virus that has killed over 300 people since it first appeared in 2003. Like the H5N1 virus, the newer H7N9 virus is highly virulent, killing 33% of all the persons it infects. And also like the H5N1 virus, the new H7N9 appears to be transmitted to humans only from birds. There have been no documented cases of sustained human-to-human transmission of either of these viruses, at least not yet. The big worry, of course, is that a genetic shift in one of these viruses will make it highly transmissible between humans, much like the common cold. If that happens, the combination of high virulence and rapid human-to-human transmission could lead to a pandemic, meaning that millions of humans might die.
We need to keep an eye on this one.
This latest bird flu virus is genetically slightly different but overall functionally similar to the H5N1 virus that has killed over 300 people since it first appeared in 2003. Like the H5N1 virus, the newer H7N9 virus is highly virulent, killing 33% of all the persons it infects. And also like the H5N1 virus, the new H7N9 appears to be transmitted to humans only from birds. There have been no documented cases of sustained human-to-human transmission of either of these viruses, at least not yet. The big worry, of course, is that a genetic shift in one of these viruses will make it highly transmissible between humans, much like the common cold. If that happens, the combination of high virulence and rapid human-to-human transmission could lead to a pandemic, meaning that millions of humans might die.
We need to keep an eye on this one.
Sunday, April 7, 2013
New Bird Flu Virus, H7N9
A second strain of bird flu virus, called H7N9, has now made the jump from birds to humans. According to the World Health Organization (WHO), there have been 18 reported cases of human infection so far, all in China. Six people have died.
Like the other bird flu virus (H5N1), the H7N9 virus is not capable of being transmitted from human to humans. But unlike H5N1, the new H7N9 virus is not very virulent in birds. That makes it more difficult to detect than H5N1 (which kills most infected birds), because birds infected with H7N9 may not even appear to be sick. In humans, however, six deaths out of 18 infections is pretty virulent!
Authorities in China are handling this new outbreak better than they did the original outbreak of H5N1. The Chinese authorities are informing Chinese citizens, working with health officials around the world, closing bird markets in infected areas and slaughtering birds when it is deemed advisable.
The U.S. is monitoring the situation and is working on a vaccine. In the meantime, the virus seems to be treatable with Tamiflu.
By the way, have you ever wondered how flu viruses get their unique names of letters and numbers? All Type A influenza viruses have two types of proteins on their surface, called hemagglutinin (H) and neuraminidase (N). Each of these proteins comes in multiple forms (16 different forms of H and 9 different forms of N are known in birds). So every flu virus's name reflects its unique combination of H and N protein forms. That’s probably more than you wanted to know, but at least it will make their names less mystifying to you.
Like the other bird flu virus (H5N1), the H7N9 virus is not capable of being transmitted from human to humans. But unlike H5N1, the new H7N9 virus is not very virulent in birds. That makes it more difficult to detect than H5N1 (which kills most infected birds), because birds infected with H7N9 may not even appear to be sick. In humans, however, six deaths out of 18 infections is pretty virulent!
Authorities in China are handling this new outbreak better than they did the original outbreak of H5N1. The Chinese authorities are informing Chinese citizens, working with health officials around the world, closing bird markets in infected areas and slaughtering birds when it is deemed advisable.
The U.S. is monitoring the situation and is working on a vaccine. In the meantime, the virus seems to be treatable with Tamiflu.
By the way, have you ever wondered how flu viruses get their unique names of letters and numbers? All Type A influenza viruses have two types of proteins on their surface, called hemagglutinin (H) and neuraminidase (N). Each of these proteins comes in multiple forms (16 different forms of H and 9 different forms of N are known in birds). So every flu virus's name reflects its unique combination of H and N protein forms. That’s probably more than you wanted to know, but at least it will make their names less mystifying to you.
Friday, September 28, 2012
A Water Desalination Plant for San Diego
Only 1% of Earth’s water is fresh water; 97% is saltwater and the remaining 2% is frozen in glaciers. Worse yet, water is not evenly distributed around the world. Growing cities frequently have problems getting enough fresh water to supply their needs.
The city of San Diego, after years of dealing with water shortages and expensive water sources, has decided to take matters into its own hands. The city signed a deal this week to purchase all of the output of what will be the largest desalination plant in the Western hemisphere, if/when it is completed in 2016. The new plant, to be located in Carlsbad, California, is expected to produce 50 million gallons of freshwater a day
Desalination of seawater may seem like a good idea, but it has yet to catch on in a big way. For one, desalination uses a lot of electricity, and thus is still fairly expensive compared to most natural sources of water. In addition, by removing the salt from seawater and returning it to the sea, desalination plants can raise the local seawater salinity, affecting sea life if the salt is not sufficiently disbursed.
The Carlsbad desalination plant is likely to be watched with interest by officials from other coastal cities with water shortages. Either it will prove to be a one-of-a-kind project that didn’t go quite as well as planned, or it will lead the way to the development of other desalination plants for supplying water to other thirsty coastal cities.
The city of San Diego, after years of dealing with water shortages and expensive water sources, has decided to take matters into its own hands. The city signed a deal this week to purchase all of the output of what will be the largest desalination plant in the Western hemisphere, if/when it is completed in 2016. The new plant, to be located in Carlsbad, California, is expected to produce 50 million gallons of freshwater a day
Desalination of seawater may seem like a good idea, but it has yet to catch on in a big way. For one, desalination uses a lot of electricity, and thus is still fairly expensive compared to most natural sources of water. In addition, by removing the salt from seawater and returning it to the sea, desalination plants can raise the local seawater salinity, affecting sea life if the salt is not sufficiently disbursed.
The Carlsbad desalination plant is likely to be watched with interest by officials from other coastal cities with water shortages. Either it will prove to be a one-of-a-kind project that didn’t go quite as well as planned, or it will lead the way to the development of other desalination plants for supplying water to other thirsty coastal cities.
Friday, June 22, 2012
Bird Flu Papers Finally Published
After months of delay, two controversial papers about the bird flu virus have finally been published. The papers appear in May 2 issue of Nature and in the June 22 issue of Science.
Publication of both papers was held up because of the potentially dangerous nature of the information they contained; both papers documented methods that increased the airborne transmissibility of the bird flu virus in species other than birds. Although the current virus is highly contagious and deadly in birds and deadly to humans in the rare cases when humans have become infected, so far the virus has not shown the ability to be transmitted easily from birds to humans. And there is no documented case (yet) of transmission between humans; all infected humans have gotten the virus from birds.
Both papers contain basic information about genetic modifications of the virus that lead to increased transmissibility of the virus between mammals (ferrets). Government officials were worried that the information might be used by bioterrorists to create a strain of the virus that would be highly contagious between humans. When news of the papers’ potential publication first appeared back in December, the National Science Advisory Board for Biosecurity asked that publication be delayed so that the issue could be studied. However, after much discussion it has been decided that publication should be allowed after all.
Interestingly, both papers reported that modification of the virus to make it more transmissible also reduced its virulence. In fact, none of the ferrets infected with the modified viruses died. Whether the modified virus would also be less virulent in humans isn’t known. But if so, that would certainly reduce the value of the current papers to potential terrorists.
Publication of both papers was held up because of the potentially dangerous nature of the information they contained; both papers documented methods that increased the airborne transmissibility of the bird flu virus in species other than birds. Although the current virus is highly contagious and deadly in birds and deadly to humans in the rare cases when humans have become infected, so far the virus has not shown the ability to be transmitted easily from birds to humans. And there is no documented case (yet) of transmission between humans; all infected humans have gotten the virus from birds.
Both papers contain basic information about genetic modifications of the virus that lead to increased transmissibility of the virus between mammals (ferrets). Government officials were worried that the information might be used by bioterrorists to create a strain of the virus that would be highly contagious between humans. When news of the papers’ potential publication first appeared back in December, the National Science Advisory Board for Biosecurity asked that publication be delayed so that the issue could be studied. However, after much discussion it has been decided that publication should be allowed after all.
Interestingly, both papers reported that modification of the virus to make it more transmissible also reduced its virulence. In fact, none of the ferrets infected with the modified viruses died. Whether the modified virus would also be less virulent in humans isn’t known. But if so, that would certainly reduce the value of the current papers to potential terrorists.
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