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Swine flu, not vaccine, may trigger narcolepsy
THIS WEEK
Michael Le Page
IN HIS Gaia hypothesis, James Lovelock famously suggested that living organisms could affect clouds – and he was eventually proved right. Now it seems the effect may be even stronger than we thought. Organic vapours released by organisms such as trees, marine bacteria and livestock appear to play a far more important role in cloud formation than suspected. “This was a big surprise,” says Jasper Kirkby at CERN near Geneva, Switzerland, whose team made the finding. Since our activities have such a huge impact on the biosphere, this hints at a previously unknown way in which humans can affect the climate, he says. Anything that affects cloud formation can in theory affect climate, because clouds can either reflect or trap the sun’s heat depending on conditions. Cloud droplets can form only on particles above 50 nanometres. In much of the atmosphere, dust, smoke and sea-spray provide more than enough of these cloud condensation nuclei, or CCNs. High in the atmosphere, however, such particles are scarce. Here, cloud formation depends partly on trace gases condensing to form particles just 1 nanometre across, which can then grow large enough to act as CCNs. Kirkby is part of the CLOUD experiment at CERN to investigate whether cosmic rays influence cloud formation. The team started by looking at the formation of the very small particles – a process called aerosol nucleation – by mimicking atmospheric conditions inside an ultraclean steel “cloud chamber”, which Kirkby says is the cleanest ever 12 | NewScientist | 27 August 2011
created. Cleanliness is vital since contaminants can themselves become sites of aerosol nucleation. Aerosol nucleation is known to require sulphuric acid, but Kirkby’s team found that it is not enough by itself at low altitudes – the presence of an additional organic trace vapour is needed (Nature, DOI: 10.1038/ nature10343). “If there is too little of either component then nucleation will not occur at an
“Living organisms are more important to cloud formation than even James Lovelock thought” appreciable rate in the low atmosphere,” says Kirkby. That means the organic component – and thus the role of living organisms – is more important than had been thought, although the full implications are not yet understood.
China’s swine flu linked to narcolepsy
IN SPRING last year, the number of narcolepsy cases in Beijing, China, multiplied threefold. Now, it looks like the swine flu pandemic of the previous winter was to blame. Previously, similar rises in cases of narcolepsy – a disorder that causes sleepiness at inappropriate times – have been linked to use of a swine flu vaccine. The cause was presumed to lie in the vaccine’s adjuvants, additives that boost a person’s immune response to the shot. The claim puzzled researchers who saw a rise in narcolepsy cases in China, where few people had opted to get vaccinated and those who did received a vaccine without adjuvants. Some began to suspect that the flu itself was to blame. To find out, Fang Han and his colleagues at Beijing University People’s Hospital looked at the medical profiles of 906 people who had come to the hospital with narcolepsy since 1998. The team found that, even before the vaccine was introduced in October 2009, the number of narcolepsy cases followed a seasonal pattern, dropping significantly around November and spiking in April. The peak was higher than normal in the spring after the swine flu pandemic (Annals of Neurology, DOI: 10.1002/ ana.22587). The idea that flu causes narcolepsy fits in with the theory that the sleep disorder is triggered by the immune system’s response to airway infections, says Masashi Yanagisawa at the University of Texas Southwestern Medical Center in Dallas, who was not part of the study. However, he adds that there is “no direct cellular evidence” to support the idea yet. Study co-author Juliette Faraco at Stanford University’s Center for Narcolepsy in California agrees that a direct link between swine flu virus and narcolepsy has yet to be established, ”but we think this [study] –Cloud formers?– raises a big red flag”. Sujata Gupta n Frans Lemmens/getty
No clouds without vapours of life
“If it is significant on a global scale, it might mean that the natural emissions of organics is also important in cloud formation,” says Bart Verheggen of the Energy Research Centre of the Netherlands in Petten. Some physicists think galactic cosmic rays – high-energy particles originating from faraway stars – might affect cloud formation. To test their effect on aerosol nucleation, Kirkby’s team fired beams similar to cosmic rays through the chamber and found it increased nucleation between 2 and 10 times . But he points out that an increase in 1 nanometre particles does not necessarily translate into the 50 nanometre CCNs needed for cloud formation. Other evidence shows that even if cosmic rays do affect the climate, the effect must be small. Changes in the number of cosmic rays hitting the atmosphere due to changes in solar activity cannot explain global warming, as average cosmic ray intensities have been increasing since 1985 even as the world has warmed – the opposite of what should happen if cosmic rays produce climate-cooling clouds. n
Michael Le Page
IN HIS Gaia hypothesis, James Lovelock famously suggested that living organisms could affect clouds – and he was eventually proved right. Now it seems the effect may be even stronger than we thought. Organic vapours released by organisms such as trees, marine bacteria and livestock appear to play a far more important role in cloud formation than suspected. “This was a big surprise,” says Jasper Kirkby at CERN near Geneva, Switzerland, whose team made the finding. Since our activities have such a huge impact on the biosphere, this hints at a previously unknown way in which humans can affect the climate, he says. Anything that affects cloud formation can in theory affect climate, because clouds can either reflect or trap the sun’s heat depending on conditions. Cloud droplets can form only on particles above 50 nanometres. In much of the atmosphere, dust, smoke and sea-spray provide more than enough of these cloud condensation nuclei, or CCNs. High in the atmosphere, however, such particles are scarce. Here, cloud formation depends partly on trace gases condensing to form particles just 1 nanometre across, which can then grow large enough to act as CCNs. Kirkby is part of the CLOUD experiment at CERN to investigate whether cosmic rays influence cloud formation. The team started by looking at the formation of the very small particles – a process called aerosol nucleation – by mimicking atmospheric conditions inside an ultraclean steel “cloud chamber”, which Kirkby says is the cleanest ever 12 | NewScientist | 27 August 2011
created. Cleanliness is vital since contaminants can themselves become sites of aerosol nucleation. Aerosol nucleation is known to require sulphuric acid, but Kirkby’s team found that it is not enough by itself at low altitudes – the presence of an additional organic trace vapour is needed (Nature, DOI: 10.1038/ nature10343). “If there is too little of either component then nucleation will not occur at an
“Living organisms are more important to cloud formation than even James Lovelock thought” appreciable rate in the low atmosphere,” says Kirkby. That means the organic component – and thus the role of living organisms – is more important than had been thought, although the full implications are not yet understood.
China’s swine flu linked to narcolepsy
IN SPRING last year, the number of narcolepsy cases in Beijing, China, multiplied threefold. Now, it looks like the swine flu pandemic of the previous winter was to blame. Previously, similar rises in cases of narcolepsy – a disorder that causes sleepiness at inappropriate times – have been linked to use of a swine flu vaccine. The cause was presumed to lie in the vaccine’s adjuvants, additives that boost a person’s immune response to the shot. The claim puzzled researchers who saw a rise in narcolepsy cases in China, where few people had opted to get vaccinated and those who did received a vaccine without adjuvants. Some began to suspect that the flu itself was to blame. To find out, Fang Han and his colleagues at Beijing University People’s Hospital looked at the medical profiles of 906 people who had come to the hospital with narcolepsy since 1998. The team found that, even before the vaccine was introduced in October 2009, the number of narcolepsy cases followed a seasonal pattern, dropping significantly around November and spiking in April. The peak was higher than normal in the spring after the swine flu pandemic (Annals of Neurology, DOI: 10.1002/ ana.22587). The idea that flu causes narcolepsy fits in with the theory that the sleep disorder is triggered by the immune system’s response to airway infections, says Masashi Yanagisawa at the University of Texas Southwestern Medical Center in Dallas, who was not part of the study. However, he adds that there is “no direct cellular evidence” to support the idea yet. Study co-author Juliette Faraco at Stanford University’s Center for Narcolepsy in California agrees that a direct link between swine flu virus and narcolepsy has yet to be established, ”but we think this [study] –Cloud formers?– raises a big red flag”. Sujata Gupta n Frans Lemmens/getty
No clouds without vapours of life
“If it is significant on a global scale, it might mean that the natural emissions of organics is also important in cloud formation,” says Bart Verheggen of the Energy Research Centre of the Netherlands in Petten. Some physicists think galactic cosmic rays – high-energy particles originating from faraway stars – might affect cloud formation. To test their effect on aerosol nucleation, Kirkby’s team fired beams similar to cosmic rays through the chamber and found it increased nucleation between 2 and 10 times . But he points out that an increase in 1 nanometre particles does not necessarily translate into the 50 nanometre CCNs needed for cloud formation. Other evidence shows that even if cosmic rays do affect the climate, the effect must be small. Changes in the number of cosmic rays hitting the atmosphere due to changes in solar activity cannot explain global warming, as average cosmic ray intensities have been increasing since 1985 even as the world has warmed – the opposite of what should happen if cosmic rays produce climate-cooling clouds. n