bird flu
revere | December 12, 2006Many readers of this site come here because they are interested in or worried about bird flu. Bird flu isn't the only thing people are worried about and no doubt there are sites that talk about each of them --asbestos or nanotechnology or genetically modified foods, for example. Most of us are glad we only have room for a few of these worries. But some people worry about all of them as part of their jobs. Actuaries -- the professionals who help insurance companies estimate their risks and what to charge for premiums -- do this for a living.
While nanotechnology and bird flu are as different…
revere | December 11, 2006A serviceable and knowledgeable article by AP's Maria Cheng, lately of the WHO public information office, has just appeared on the wires. Readers of this site won't find much new, but what is interesting are the headlines. Yes, headlines, in the plural. Here are ten different headlines to the same article:
What Ever Happened To Bird Flu? (Forbes)
After pandemic fear, experts wonder: What happened to bird flu? (Houston Chronicle)
After pandemic panic, experts wonder: What happened to bird flu?(Santa Barbara News-Press)
Despite panic, bird flu pandemic hasn't appeared (Minneapolis Star-Tribune…
revere | December 11, 2006Compared to other viruses, the influenza virus is relatively simple, although its biology is not. To date, the eight genetic segments in the viral genome (the totality of its genetic information) has been shown to code for only eleven proteins. A virus can get away with this because it hijacks the host cell's extensive protein making machinery and doesn't use its own. But we are still learning about those eleven proteins, what their role is, how they work and even what they look like. A paper that just appeared in Nature (.pdf, subscription only) is the first to reveal what one of these…
revere | December 10, 2006Rodney King was the African American made famous when his violent arrest by the Los Angeles Police Department was videotaped by a bystander. The acquittal of the arresting officers in 1991 set off three days of civil disorder. In a bid to stop the rioting, King appeared in front of television cameras and asked, "People, I just want to say, you know, can we all get along?" Maybe we should send Mr. King to China to ask the same question of scientists squabbling about whether there was an unreported new strain of bird flu (H5N1) widely circulating there:
"Instead of having a battle in the media…
revere | December 9, 2006You may think bird flu is a disaster still waiting to happen, but in one way it is a disaster that already happened. One of the shoes dropped between October 2005 and May 2006 when the H5N1 subtyupe of highly pathogenic avian influnza spread to the poultry flocks of 50 countries. Since 2003 the outbreak has resulted in the slaughter of some 240 million birds. In 2005 it burst out of Asia and spread into Europe, the Middle East and Africa. So even without the "other shoe" dropping -- a change in the virus to allow easy transmissibility from human to human -- the damage already done is immense…
revere | December 8, 2006Part of raising awareness about the potential problems we would have in an influenza pandemic is saying the same thing over and over again, sometimes in different ways and sometimes just repeating it. So we're going to do it again. From the Globe and Mail (Toronto):
Severe restrictions that allowed only emergency patients to be admitted to hospitals during the 2003 SARS outbreak in Toronto would not be enough to handle the flood of patients expected during even a mild flu pandemic, a new study has found.
[snip]
"The [various governments' pandemic flu] plans are quite comprehensive, but the…
revere | December 7, 2006There is a new paper in the Journal of Immunology I found more than a little disconcerting. University of Rochester scientists have found that the cells in the immune system responsible for antibody production, the B-cells, also express high levels of the enzyme cyclooxygenase-2 (Cox-2). Overproduction of Cox-2 can cause pain and fever, which frequently accompany reaction to infection. The problem is that treatment of B-cells with inhibitors of the enzyme (Cox-2 inhibitors) also markedly affected the ability of the B-cell to produce antibody. What are some Cox-2 inhibitors? Aspirin, Ibuprofen…
revere | December 6, 2006Four months ago Nigeria had its first cases of avian flu in poultry. None since. We think. Or maybe we should say, we hope. Because as experts gather this week in Mali, no one seems to be that confident there's nothing there, or anywhere else in Africa:
Health experts say insufficient surveillance means they don't really know the true level of bird flu. The two-day conference that opens Wednesday in Mali, and follows similar international meetings in China and Austria, will focus on preparedness as the next bird flu season approaches, including marshaling financial and other resources to…
revere | December 5, 2006After all this time and no small amount of heated argument, we are still unsure how H5N1 is making its way around the world in birds. The commercial movements the poultry trade, smuggling of exotic birds or poultry by-products and the migrations of wild birds over long distances have all been blamed. Bird conservationists are fearful that pinning the virus's travel on migrating wild birds will result in destruction of their habitats and crucial stops on their flyways, while the public health community has tended to be more concerned, as has the commercial poultry industry.
The bird folks have…
revere | December 4, 2006It is quite evident from the reports we see but sometimes we fail to recognize it, that the confirmed victims of bird flu to date have been overwhelmingly young compared to what we see in seasonal flu. Here is the age distribution in the latest WHO tally, as graphed for us by WHO's Pacific Regional Office:
Source: WHO Western Office for the Regional Pacific
There are two principal reasons I can think of for this difference in pattern, and my guess is both are operating simultaneously. The first has to do with what epidemiologists call observation bias. Death from acute respiratory failure in…
revere | December 3, 2006One frequent refrain about why we don't have to worry about a bird flu pandemic is the astounding progress we've made in medical science in the 88 years since 1918. It's a good point. In 1918 we didn't even know the causative agent.
In this spirit I offer you an excerpt from a December 1918 report of the American Public Health Association's committee on influenza, sent to me by a loyal reader:
It is the opinion of this committee that epidemic influenza is spread solely through the discharges from the nose and throat of infected persons finding their way into the nose and throat of susceptible…
revere | December 1, 2006Health Canada is following the US FDA in warning of adverse neurobehavioral effects of the influenza antiviral, Tamiflu. The drug is prescribed much more often in Japan, where it is used in seasonal flu, than in the US. The effects have been reported mainly in children and have included some suicides. It isn't known whether the drug was responsible for these deaths and if so, how. The US FDA has not made any determinations but issued the warning as a precautionary measure.
The Vancouver Sun ran the story under the headline, "Bird flu vaccine leaves 10 Canadians dead." (hat tip,…
revere | November 30, 2006Helen Branswell had an interesting piece about a rumor there was a human case of H5N1 in Canada, in a child. Branswell's pieces are the occasion for frequent posts here, although this is a bit awkward as it turns out she quotes us. Accurately. Which is characteristic of all her reporting and also why she has the best contacts and gets more information out of them then any other flu reporter. Everyone trusts her to report reliably.
Anyway, here's the story:
The power of the Internet rumour mill slammed up against a hospital in Rimouski, Que., on Wednesday, leaving doctors and administrators…
revere | November 29, 2006There's been a lot of notice that the South Koreans are responding to two outbreaks of bird flu (H5N1) not only with the culling of poultry by the hundreds of thousands, something that has become quite routine, now, but also the slaughter of neighboring dogs and pigs. Pigs are a well known host for influenza and dogs are susceptible to several subtypes, although there have been only a few reports of infection with H5N1. The South Koreans insist that dogs have also been killed elsewhere but the fact not publicized. I don't know if it is true or not. The big news in the West is killing the dogs…
revere | November 29, 2006The "father" of epidemiology is a nineteenth century doctor, John Snow. He had more than one disciplinary child, since he is also considered the "father" of anesthesiology, having popularized the use of chloroform in obstetrics by using it on Queen Victoria in the 1850s. That distinction aside, Snow is famous for his pioneering studies showing cholera was a waterborne disease. I've been thinking about this in relation to bird flu. Here's the connection.
In Snow's Victorian London, the predominant scientific theory on cholera's etiology was from miasmas, a general term for noxious elements in…
revere | November 24, 2006This week The New England Journal of Medicine (NEJM) published three articles on the evolving story of the influenza A/H5N1 panzootic that has the potential to become a human pandemic. Two are rather meager case series, one from Turkey and one from Indonesia. It is an extraordinary indication of the paucity of information that these papers could get published in one of the world's premier medical journals, a fact duly noted by Canadian Press's Helen Branswell. The two papers have some moderately interesting information, none of it startling for those who follow this issue. But the Commentary…
revere | November 17, 2006Another "big" science story on the mutations in H5N1 that will a make it a pandemic strain. Same ending as the other stories. Not exactly.
Some of the blame for this rests with the scientists who can't resist going beyond what's in the paper when talking to reporters. I understand. I've done it myself, probably, although I try not to. On the one hand there are scientific conventions that suppress over interpretation in the published report, even when there are plausible speculations about larger meanings. On the other hand, there is the natural tendency to please the reporter, who is not…
revere | November 13, 2006In this week's Science magazine Stephen Morse calls attention to what we have been saying here for a long time. We don't really know how influenza spreds from person to person. A recent review of the aerosol transmission route by Tellier in Emerging Infectious Diseases provides some additional information of interest.
There are four possible modes of transmission: aerosol, large droplet, direct contact via inanimate objects (called fomites in epidemiological jargon) and the gastrointestinal route. At this point we know very little about the gastrointestinal route, although some H5N1 cases…
revere | November 12, 2006As a sometime modeler myself it now makes my heart sink when I read about a "new" model that tells us that such and such is going to happen with avian influenza. Box's adage that all models are wrong but some models are useful is apt, but telling which ones are useful is becoming so difficult we'll need a model to help us do it. Two cases in point: a new economic model from Australia telling us not worry, the economic effects won't be that bad; and another airline model, this one that says if we shut down international air travel we'll gain time in the US -- enough time, according to the…
revere | November 10, 2006In an example of the adage, "Be careful what you wish for," China's choice for WHO Director General, Dr. Margaret Chan, is already finding her reputation will be held hostage to the behavior of China itself, not an enviable position.
The new chief of the World Health Organisation, Margaret Chan of China, pledged to put her nationality aside and to use her leverage on Beijing to combat major threats such as bird flu.
"Now I'm elected as the WHO's Director General I no longer carry my nationality on my sleeve. I leave it behind," she told reporters after her nomination was endorsed by more than…