General Epidemiology
tsmith | May 17, 2006When I was in school, I was taught about the 5 kingdoms of life: Monera (all bacteria), and the eukaryotes: Protista, Fungi, Plantae, and Animalia. Since that time, there's been a bit of a change in the organization. This is largely due to investigation of the Archaea (sometimes still referred to as "archaebacteria"). It was recognized that these organisms were so unlike bacteria (and of course, unlike the eukaryotes) that they deserved their own grouping. Therefore, the most common strategy currently employs 3 domains of cellular life at a level above the kingdom: Bacteria,…
tsmith | May 13, 2006More topics I'd have liked to discuss, given the time...
The Vigil after Dover. A free public forum, May 17, 2006 8 PM EST at The Florida State University College of Medicine Auditorium. Featuring Eugenie Scott, Michael Ruse, John Haught, Robert Pennock, and others, it will apparently be broadcast live as well.
An article on "Europe's unknown viral nasties", discussing the importance of surveillance (especially at the animal-human interface) to help detect emerging infectious agents.
Discussion of a new study that chipmunks and acorns hold the key to forecasting Lyme disease:
The…
tsmith | May 11, 2006I very briefly mentioned new research suggesting mercury fillings aren't harmful back here last month. In Saturday's Guardian, Ben Goldacre (who runs the Bad Science blog) had a short article on the topic. In it, he addresses the lack of coverage of the research in the UK media, despite stories in the last decade suggesting how dangerous mercury was. He notes:
Panorama did an excellently chilling documentary in 1994 called The Poison in Your Mouth. As far as I am aware there is no Panorama documentary in the pipeline covering the startling new research data suggesting that mercury fillings…
tsmith | May 9, 2006 Grand Rounds has eaten up most of my blog time for today, but I do want to direct you to this article on neonatal mortality in the United States and globally. Not good news for the U.S. and the UK--we're tied for the bottom of industrialized countries. The numbers, overally, are terrible:
Each year, according to the report, more than a half-million women die as a result of pregnancy and childbirth difficulties, 2 million babies die within their first 24 hours -- more than 5,000 deaths a day -- 2 million more die within their first month and 3 million are stillborn.
It's a brief article,…
tsmith | May 4, 2006Cheyenne shelter dogs to be euthanized
All 70 to 80 dogs at the Cheyenne Animal Shelter will be euthanized because of an outbreak of canine influenza that has closed the shelter for more than two weeks, shelter officials announced.
Shelter officials said there was no way to test for the virus quickly and thus no way to tell which dogs were infected. Shelter director Alan Cohen said that unless all the dogs were killed, he couldn't guarantee that they wouldn't re-infect themselves and other animals.
"If I do not euthanize these animals, how can I let them loose knowing they might spread it to…
tsmith | May 2, 2006I see that Hank's still touting his "Padian found ZERO seroconversions among 176 discordant heterosexual couples over 6 years" line, even after that study was extensively analyzed here (and his ideas about it were shown to be mistaken). At least he's dropped it from 10 years down to 6 years--progress, I suppose. He's now discussing a new MMR report that documents 88 HIV transmission events over a 17-year period in Georgia prisions. Despite the fact that Hank doesn't dispute that these sexual transmission events occurred (noting that the "infectivity is low, low, low"), Hank still ends his…
tsmith | May 1, 2006[From the archives; originally published Nov. 3, 2005]
Ebola is one of my favorite pathogens. With the reputation it has, many people assume it's killed many more worldwide than it actually has. People hear of Ebola and all kinds of grotesque images come to mind: organs "liquefying" (doesn't really happen quite like that); bleeding from every orifice (okay, that one can be on-target); the victims dying a horrible death from a virus with an incredibly high mortality rate. There are four known subtypes of Ebola, named for their place of isolation: Ebola Reston, Ivory Coast, Sudan, and Zaire.…
tsmith | April 29, 2006More topics I'd have covered this week, given endless time and energy:
An update on the Chikungunya outbreak I discussed here (and see this comment on the outbreak from a medical entomologist in the region dealing with it first-hand).
Orac on viruses as cancer treatment, inspired by a recent episode of House (more episode reviews by Scott at Polite Dissent can be found here).
An update on mumps activity from the Iowa Department of Health. I haven't written about this in a few days because there's not much more to tell. Cases are still increasing, and they're recommended that students…
tsmith | April 26, 2006Novel Swine Influenza Virus Subtype H3N1, United States
In several of my influenza posts, I've discussed ways that the viruses can evolve. These are termed "antigenic drift," where the virus accumulates small mutations in the RNA genome; and antigenic shift, where large sections of the genome are swapped, generally in their entirety. While it was long thought that the latter was the most likely type of mutation to cause a pandemic, we now know that even the right kind of antigenic drift may be enough to allow a novel influenza virus to enter the human population, which seems to have…
tsmith | April 24, 2006So, I've had this research article on multiple drug-resistant Salmonella in the drafts section for about a week now, waiting for me to do a bit of background research before commenting on it. (Anything involving Salmonella always makes me a bit hesitant--one almost needs a PhD on the bacterium just to keep up with the nomenclature). This morning I'm doing my quick glance-through of my blogroll, and lo and behold, what do I find but these posts by Mike the Mad Biologist, who just happens to have been quoted in the New York Times write-up of the research.
Michael Feldgarden, who helps…
tsmith | April 22, 2006Again, I never get to discuss all the topics I find interesting. So to keep you busy over the weekend, check out a few that I didn't have time to emphasize this week:
Neurotopia on the zombies among us.
Orac's series on medicine and evolution:
Part 1Part 2Part 3Part 4Part 4a
New studies suggesting that mercury fillings aren't harmful.
Can you name that virus over at Buridan's ass?
Professional societies spurning women editors? (More here from Evolgen).
Ewen on the science behind the recent monoclonal antibody drug trial gone bad.
The National Science Foundation website is up for a…
tsmith | April 21, 2006Skeptics warn bird flu fears are overblown
Doomsday predictions about bird flu seem to be spreading faster than the virus itself. But a small group of skeptics say the bird flu hype is overblown and ultimately harmful to the public's health.
There's no guarantee bird flu will become a pandemic, and if it does there's no guarantee it will kill millions of people. The real trouble, these skeptics say, is that bird flu hysteria is sapping money and attention away from more important health threats.
While I agree with some points the so-called "skeptics" make (we don't know if H5N1 will become…
tsmith | April 20, 2006I've discussed preparedness issues previously (like here, here, here, here, and here, for instance), and noted that we're still sorely unprepared for an outbreak of pandemic influenza. It's also been a frequent topic at Effect Measure, and of course at the flu wiki. What's largely been discussed, however, is preparedness at the personal level, and at the federal level. Discussed less frequently has been preparedness at the local/community level (though again, I should note this definitely has been a concern and emphasis of the flu wiki folks, and is specifically included on this page of…
tsmith | April 19, 2006According to msnbc:
Normally adventurous Chinese diners are eating fewer owls, civets and other wildlife due to fears of SARS and bird flu, according to a survey released Tuesday by U.S. and Chinese conservation groups.
The survey of 24,000 people in 16 cities found that nearly 72 percent had not eaten wild animals in the past year, up from 51 percent in a similar 1999 survey, said San Francisco-based WildAid and the official China Wildlife Conservation Association.
For those who may be unfamiliar with civets, they're almost like a cross between a cat and a weasel, and have been linked to…
tsmith | April 18, 2006I started this as a comment to this thread, but perhaps this is enough for its own spin-off discussion. IndianCowboy said:
I'm not denying the influence of these genes on one's ability to maintain a certain weight. I'm not even denying the size of their influence, but one thing that bothers me is that many researchers, bloggers, reporters, whatever impute more into the findings than they should.
And I agree with that. Clearly it's not all genetic, and diet + exercise play a large role. Additionally, any one genetic locus (which is what's usually found in a study) alone is unlikely to be…
tsmith | April 15, 2006I don't know how other bloggers decide what to post. For me, everytime I run across a "oh, that would be so cool to discuss" topic/link/story etc., I copy the topic/link/story etc. into a new entry here, hoping to have time to elaborate on it at a later date. Some of them I get to--some of them just drift slowly to the bottom of the pile, untouched. But they're still interesting topics, so here are a few more that I didn't have time to write about, and as new topics come up, probably won't be able to get to in the immediate future:
A recent CNN story referring to the hygiene hypothesis.…
tsmith | April 13, 2006Orac highlighted here a post over at Vox Populi which doubted the effectiveness of the mumps vaccine, in light of the recent epidemic in Iowa. I was prepared to write a whole post on the math of it, but Mark at Good Math, Bad Math saved me some work. Nevertheless, I have a few things to add after the jump.
As has been mentioned, the given efficacy rate for the mumps vaccine is 95%. This is actually likely a bit high; previous outbreaks have suggested it's more like 85-90% effective, so that as many as 15% of the vaccinated population won't actually be immune. The key to telling whether…
tsmith | April 13, 2006 Okay, so I lied. I was planning to wrap up the emerging diseases and zoonoses series with the post on monkeypox, but I think I'll just continue it as a sporadic event, since a new paper fits into the series perfectly.
I talk a lot here about streptococcus. As regular readers know, there's a good reason for that. Though my main research right now is on Streptococcus agalactiae (group B streptococcus, GBS), I also have a project working on a related organism, Streptococcus suis. As the "suis" name suggests, this is mainly a pathogen of swine. Indeed, it's kind of the pig equivalent of…
tsmith | April 7, 2006 For the final post of the series, I want to discuss yet another outbreak, this one a bit closer to home: that of monkeypox in the United States in 2003.
First, I should note that "monkeypox" is a bit of a misnomer. Though the virus--a relative of smallpox and cowpox--can infect monkeys (and humans), the reservoir host is likely a rodent. Previously, monkeypox had been found mainly in sub-Saharan Africa, in forested regions. 2 clades of the virus had been identified. One was common in West Africa, and generally didn't cause severe disease when humans became infected with it. The other…
tsmith | April 6, 2006 I've touched on the broad issue of "cultural practices" that can lead to emerging diseases in a few posts already (such as farming practices and cockfighting and avian influenza, or petting zoos and bacterial diseases), but today I'm going to go into a bit more detail with the specific example of the emergence of Nipah virus in Malaysia.
Nipah is a paramyxovirus, in the same family as measles and mumps. The virus was first recognized in 1999, during an encephalitis outbreak in Malaysia that had begun the previous September. The vast majority of the cases had occupational exposure to…