infectious disease
revere | June 20, 2006As you read this a meeting of more than three dozen avian flu experts should be convening in Jakarta to discuss the disastrous state of public health in that country. Many poor countries have disastrous public health systems, but Indonesia has something else: a huge population of people living in close contact with a huge population of poultry infected with an influenza A subtype (the H5N1 subtype) that has crossed the bird/human species line. Influenza A is a major killer of human beings worldwide, but the global population has substantial (at least partial) immunity to the circulating…
tsmith | June 19, 2006[From the archives; originally posted November 28, 2005]
Have you ever wondered how Kevin Bacon and the lights of fireflies related to malaria and power grids? I know it's something that's kept me up many a sleepless night. One word: interconnections.
Many of you have probably heard of the "Six degrees of Kevin Bacon"game. This is based on the work of Stanley Milgram beginning in the 1960s, and brought up again more recently in a 1998 Nature paper, "Collective Dynamics of 'Small-World' Networks," by mathematicians Watts and Strogatz. Milgram conducted a number of studies using his "lost…
revere | June 19, 2006One of the distinctive things about influenza outbreaks in humans is its seasonality. That's why we call "ordinary" influenza seasonal influenza. Interestingly, we don't know what controls that seasonality, nor do we know if it also is a factor in pandemic strains. Pandemic strains are different in many ways and perhaps seasonality will be one of them. The second wave of 1918 started in August.
The question is even muddier when it comes to avian influenza, as WHO is acknowledging.
"We do know that the bird flu virus can survive for a time in colder weather, but it's really not clear at this…
revere | June 17, 2006The 64 World Cup soccer (fotbol) matches started a week ago in 12 German cities and will continue until July 9. Three million soccer fans are expected from Europe and beyond. Three of the cities where matches will be played, Cologne, Dortmund and Gelsenkirchen, are in the German state of Nordrhein-Westfalen. So is a measles outbreak in children and young adults. The Ukraine is also experiencing a large measles outbreak, with case numbers exceeding 20,000 by the end of February. The Ukrainian National team qualified for the tournament and will undoubtedly have many fans there. Meanwhile…
tsmith | June 16, 2006[From the archives; originally posted October 20, 2005]
Measles is one of those diseases that we don't give much thought to in the United States anymore. Following an incubation period of about 10 days, flu-like symptoms appear: fever, malaise, cough, congestion, conjunctivitis. Soon, the rash appears, first near the ears, then the forehead, the face, and over the rest of the body. Complications were common. These could include a seconary bacterial pneumonia, encephalitis, myocarditis, miscarriage, and a condition called subacute sclerosing panencephalitis (SSPE).
(Continued below...)
SSPE…
tsmith | June 16, 2006Welcome to the June edition of Animalcules! Apologies for the lateness; I only had a few minutes to get online yesterday, and that was mainly devoted to checking email and making sure there were no crises that needed my attention. So, without further ado...
From the Scientific Creative Quarterly comes a humorous entry: Prokaryotes of America Unite. Almost makes me feel bad. (You also may want to check out Scientific Creative Quarterly editor David Ng's new blog here at Scienceblogs: The World's Fair.
Jennifer over at Science Matters has a nice post discussing background information on…
tsmith | June 15, 2006[From the archives; originally posted November 16, 2005]
I know, everyone's so sick of all the new "omics"es. But "metagenomics" is one that I don't see going away anytime soon. At its core, metagenomics is a way of looking at organisms in concert as a complex ecology, rather than as an individual, as genomic analysis has traditionally been done. Rather than isolating 10 different species of bacteria from, say, a gram of soil and analyzing them all separately, a metagenomics strategy would investigate all the organisms in the soil (or in sea water, dental plaque, or even human feces). A huge…
tsmith | June 14, 2006[From the archives; originally published November 18, 2005]
Malaria is one of the world's leading infectious killers. World-wide, almost 40% of the world's population is at risk of acquiring this disease--many of them in poor countries with limited resources to control the disease. Each year, malaria causes 300-500 million infections, and up to 3 million deaths--about 5000 Africans die of the disease every day; one child succumbs every 30 seconds. Mosquito-borne, simple devices (such as mosquito nets over beds) have been shown to drastically decrease the incidence of disease. Though these…
tsmith | June 14, 2006[From the archives; originally posted October 27, 2005]
Pili (singular: pilus) are bacterial organelles--thin tubes of protein that function in attachment and bacterial sex, as well as immune evasion. Traditionally, studies of pili have been carried out in gram-negative bacteria, such as E. coli and Neisseria species; very little was known about pili in gram-positives. A few recent high-profile papers have changed that.
Back in July, an Italian group analyzed the genomic sequences of 2 isolates of Streptococcus agalactiae, or group B streptococcus, in order to identify surface proteins…
tsmith | June 13, 2006 Sometimes it's amazing just how little we know about the microbes around us. For precious few microbes, we know a good deal about virulence factors--genes and proteins that, when present, increase the severity of disease either in animal models or in humans (or both). However, much of this research has been done investigating acute infectious diseases, where one is infected, becomes ill, and gets better in the course of a few weeks to a month. Much less is known about factors that affect long-term (or chronic) infection. A recent study addressed one gap in this research, examining what…
revere | June 12, 2006Computer programmers are associated with computer viruses, not human viruses. But at the end of April an Indian computer programmer landed in Boston incubating measles virus. He had been hired by a business investment firm whose offices were on the 18th floor of a Boston skyscraper, the John Hancock Tower. May 5 he developed fever, cough and then a rash and became the index case in what is so far an 11 person outbreak, the largest number of measles cases in the city since 1989. (Boston Globe) The outbreak is of special interest for what it says for the spread of infectious disease in the era…
tsmith | June 11, 2006Like a Saturday roundup, but a day delayed. Some other topics I found interesting this week, but didn't have a chance to elaborate on...
Afarensis mentions new research on the evolution of the Crenarchaeota, a group of archae.
Laura Bush speaks on the President's malaria initiative.
Both Ed and Janet muse on the FDA approval of the new HPV vaccine--and ramifications thereof.
Via Eastern blot, 2006's Art of Science winners.
Wanna work at Seed? They're looking for fall interns; deadline is July 6th.
And of course, don't forget to send in your submissions for this week's Animalcules…
tsmith | June 9, 2006I wrote recently how evolution and phylogenetic analysis of HIV isolates has provided evidence that the progenitor to HIV jumped into humans in Cameroon or a nearby area. Obviously it's a topic that's interesting to me, but may seem a bit esoteric to some. RPM over at Evolgen has a new post showing another application of phylogenetic analysis to HIV that may be of interest to readers here, where infectious disease epidemiology meets CSI.
tsmith | June 9, 2006The new issue of Nature Medicine has a number of excellent articles on topics in infectious disease. I'm going to discuss a few of them in more detail next week (or possibly the week after; next week will be a short one for me), but in the meantime, I'll highlight two articles in particular that may interest readers: Here on the midwest mumps outbreak, and this story on phage therapy to treat "superbug" infections. (It just happens to be written by Thomas Häusler, who is the author of the book I reviewed in this post.
tsmith | June 9, 2006Over at Doc Around the Clock, Dr. IBear has a nice post on Lyme disease: what it is, what it's not, and how to deal with ticks (appropriately, not as his mom removed them). He mentions this:
Most of the time people who get Lyme disease don't even know or remember being bitten by a tick. Thus, it stands to reason that if you do remember being bitten by a tick you probably don't have Lyme disease.
I want to elaborate on this just a bit, below.
A reason many people don't realize they've been bitten is because when the tick bites the human to transmit the Borrelia spirochete, it's not always a…
tsmith | June 7, 2006 A recent story detailing an outbreak of sexually-transmitted diseases has gotten a good deal of attention from news outlets and blogs. The reason it's newsworthy is because the individuals affected aren't teenagers or single twenty-somethings; they're senior citizens. So, let me point out the obvious: even "old people" have sex.
This sometimes uncomfortable fact of life was driven home to me when I was just a teenager myself, when my grandma was discussing the difficulty she had showering (she'd just had surgery). Someone had asked whether grandpa was much help, and she mentioned that…
tsmith | June 6, 2006If you ever have a few minutes to kill and need someplace interesting to go on the web, the NIH's National Library of Medicine has a ton of interesting stuff. That's where I found the this reference from the early 1900s on raising children. I ran across another gem--a manuscript from 1721 written by minister Benjamin Colman regarding "Some Observations on the New Method of Receiving the Smallpox by Ingrafting or Inoculating (containing also The Reasons which first induced him to, and have since confirmed him in, his favourable Opinion of it).
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What a different time…
tsmith | June 6, 2006Once again, I'm wrong. I said yesterday that HIV deniers accused scientists of thinking of Robert Gallo as a deity. Silly, silly me--my mistake. Turns out he's just a high preist:
We point to this phenomenon of how easily religious belief triumphs over the most irrefutable evidence to the contrary, in order to challenge all critics of HIV/AIDS to answer this question:
How does this kind of thought-resistant religiosity differ in the slightest from the twenty year adherence of believers in HIV to their favored dogma in the face of similar overwhelming evidence against the belief?
We suggest…
tsmith | June 5, 2006Yesterday, the New York Times op-ed by John Moore and Nicoli Nattrass discussing denial of HIV. They also featured an article suggesting that more human-to-human transmission of H5N1 has occurred than previously thought.
tsmith | June 5, 2006Liam Scheff has now turned his attention from HIV to avian influenza, with predictable results. Analysis below...
Scheff's self-stated goal is to "...review some of the bright and shiny inconsistencies that have come into view on the bird flu." However, he's not exactly consistent himself, ranging from minor errors to total contradictions of his own words. He starts off discussing "stray cats and Chinamen:"
In March, 2006, The Associated Press reported: "In Austria, state authorities said Monday that three cats have tested positive for the deadly strain of bird flu in the country's…