General biology
tsmith | April 3, 2008Early this week, grant application; yesterday and today, IRB and IACUC for another project. But once again, fellow Sbers are keeping me busy reading about stories I'd like to be writing on; see yet again Mike on E. coli O157:H7--everything old is new again; Ed on a new study showing yet again how amazing bacteria are; and DrugMonkey discussing heroin addiction as a family legacy, and notes that this sad story again shows that Narcan saves lives.
tsmith | March 25, 20081980 marked a milestone in infectious disease epidemiology: the World Health Organization declared the smallpox virus eradicated in the wild. However, while smallpox currently exists only in frozen stocks, poxviruses as a class certainly haven't disappeared. A related virus, monkeypox, regularly causes illness in Africa, and even spread half a world away in the American midwest.
Additionally, Africa isn't the only area with endemic poxvirus infections. Brazil has been dealing with their own poxvirus outbreak, and poxviruses have popped up in Europe as well. More on both of those after…
tsmith | March 24, 2008In this NY Times article on parents who are opting out of vaccinations, one mom notes her objections:
"I refuse to sacrifice my children for the greater good," said Sybil Carlson, whose 6-year-old son goes to school with several of the children hit by the measles outbreak [in San Diego]. The boy is immunized against some diseases but not measles, Ms. Carlson said, while his 3-year-old brother has had just one shot, protecting him against meningitis.
"When I began to read about vaccines and how they work," she said, "I saw medical studies, not given to use by the mainstream media, connecting…
tsmith | March 19, 2008
Did Yersinia pestis really cause Black Plague? Part 1: Objections to Y. pestis causation
Did Yersinia pestis really cause Black Plague? Part 2: Examination of the criticisms
Did Yersinia pestis really cause Black Plague? Part 3: Paleomicrobiology and the detection of Y. pestis in corpses
Did Yersinia pestis really cause Black Plague? Part 4: Plague in modern times
Did Yersinia pestis really cause Black Plague? Part 5: Nail in the coffin
tsmith | March 7, 2008It's just not been Vegas' week. First a ricin-laced hotel room, then a clinic-associated outbreak of hepatitis C virus (and potentially hepatitis B and HIV) that could become enormous. Meanwhile, an outbreak of hepatitis E is raging in Uganda. So what are these virues, and how in the world could a medical catastrophe of this magnitude happen in the U.S.? More after the jump...
The group of hepatitis viruses (A, B, C, D, E, and G) are related in name only. They've all been either associated with or found to cause hepatitis--inflammation of the liver. This can be acute inflammation (short…
tsmith | February 29, 2008
I really need more time to fill in a gap in my microbiology education: environmental microbiology. I run across papers all the time that are absolutely fascinating, and wish I had a free year to just take some additional coursework in this area. For instance, a paper in today's Science magazine discusses how atmospheric bacteria result in the formation of snow; more after the jump.
The authors here were looking at ice nucleators (IN) in snowfall. Think of this like crystal experiments you did as a kid--you had to stick something into the solution to serve as a seed for the crystal to…
tsmith | February 27, 2008This is the sixth of 6 guest posts on infectious causes of chronic disease.
By Ousmane Diallo
I was dumbfounded when I read this news article relating HPV to the increase of lip and oral cancers because of oral sex.
It reminded me my younger years, as a med student, debating with my professor of psychology the fundamentals of Freudian psychoanalysis, the Id, the Ego and the Super-ego. It was a rather philosophical debate more than anything else, a combination of religious and cultural reciprocal statements of beliefs. At that time, we were exposed to the new French "sexual education"…
tsmith | February 26, 2008This is the third of 6 guest posts on infectious causes of chronic disease.
By Whitney Baker
While working out at the gym last night, I was perusing the latest SHAPE magazine to help pass the time. In it, I read a small article about researchers finding an association between Adenovirus-36 and human obesity. Since I am in the infectious disease field, I was already aware of this proposed link- an infectious cause (or contributor) for obesity. But for the millions of health-conscious readers hearing of this for the first time, what would they make of it? Would they have visions of…
tsmith | February 25, 2008This is the second of 6 guest posts on infectious causes of chronic disease.
By Courtney Cook
Scientists have been aware of a relationship between infections and mental illnesses for quite some time. For example, during the 1918 influenza pandemic, some patients were seen to exhibit a delirium unlike that which had typically been associated with a viral infection. In a 1926 report, Karl Menninger called it a "schizophrenic syndrome" and further observed that two-thirds of those diagnosed with schizophrenia after having influenza fully recovered from the mental illness within five years.…
tsmith | February 25, 2008This is the first of 6 guest posts on infectious causes of chronic disease.
by Matthew Fitzgerald
Viruses cause cancer?
Cancer researchers have for decades known that viruses can cause cancer. It is now estimated that 15% of the world's cancers are caused by infectious diseases including viruses. Some of these include: Human Papilloma Virus (HPV) and cervical cancer; Epstein-Barr Virus (EBV) and nasopharyngeal cancer & lymphoma; Hepatitis B and liver cancer. In fact cancer researchers use this knowledge of viruses causing cancer by utilizing EBV and SV40 and other viruses to "…
tsmith | January 31, 2008You're probably familiar with the Seinfeld episode where George commits yet another social faux pas, getting caught "double-dipping" a tortilla chip. Just in time for your Superbowl festivities, turns out a soon-to-be-published manuscript (described in the New York Times) examined just how many bacteria are actually transferred by "double-dipping." I have more at Correlations, and the Seinfeld clip is after the jump.
[Edited to add: Steve uploaded the poster describing the research here.]
tsmith | January 23, 2008 Though there still may be some lingering doubt about the cause of the Black Death and subsequent outbreaks of plague, the pathogen behind the outbreaks that have taken place in the last 150 years or so is much less ambiguous.
While Koch and Pasteur ushered in the golden age of microbiology, an outbreak of plague began in China and spread from there. In 1894, while plague was raging in Hong Kong, the Pasteur Institute sent Alexandre Yersin, a physician who had trained with both Pasteur and Koch, to investigate. Yersin was able to access material from a corpse, and inoculated material he…
tsmith | January 17, 2008 Yesterday I introduced criticisms that have been raised against Y. pestis causation of the Black Death and subsequent plague outbreaks. Today I'll discuss what I see as weaknesses in these criticisms, after the jump.
Selective quoting and interpretation of evidence
First and foremost, a big issue I have with the claims by Duncan and Scott are that they are rather selective in what evidence they choose. For example, they selected several quotes from medieval manuscripts and diaries that suggest that people at the time "knew" it was directly contagious from person to person, and…
tsmith | January 16, 2008 As I noted last week, Shelley mentioned a topic that's been brought up here a few times in the comments section: alternative theories for causes of the Black Plague (the devastating plague that ravaged Europe beginning in ~1347 and eventually killed more than a third of the population). Though the bacterium Yersinia pestis is almost universally accepted as the causative organism, like many areas of science, there are a few individuals who disagree with the consensus. To this end, several alternative etiologies for Black Plague have been put forth, and shortcomings with the mainstream Y.…
tsmith | January 15, 2008Over at Evolgen, RPM notes an interesting study in PNAS, looking at antibiotic use and how it serves to drive the emergence and maintenance of antibiotic-resistant strains. The current paradigm for antibiotic use is to prescribe relatively high doses of drugs for a few days to a few weeks (or months, in the case of tuberculosis), and patients are cautioned to stay on them until all the doses are finished. However, the new study RPM describes suggests this may be doing more harm than good, looking at what happens with Plasmodium species treated with antimalarials in a mouse model.
Do…
tsmith | January 14, 2008
Darwin Day is fast approaching, and we'll be celebrating with 2 and a half days' worth of festivities here in Iowa next month.
We'll kick off Thursday night, February 14th, with Dr. Massimo Pigliucci reading from his latest book at Live from Prairie Lights, with drinks and snacks following at a location TBA.
Friday February 15th will consist of academic talks by Dr. Pigliucci and Dr. Martha McClintock. Friday evening we're hosting a dinner for the speakers and the general public at the Linn Street Cafe. Tickets are limited in number, and $40 a person (which includes an appetizer, salad…
tsmith | November 19, 2007 It still amazes me sometimes what viruses are capable of doing. I've written a number of times about one virus in particular, the human papilloma virus (HPV). This is the virus implicated in cervical cancer, and it also plays a role in head and neck cancers. There are a number of different strains of HPV--some of them are oncogenic (cancer-causing), while others cause more benign infections, such as warts.
A related virus in rabbits also causes a type of warts, which can replicate out of control and form horny growths (indeed, this is the likely origin of the jackalope myth). Humans…
tsmith | November 13, 2007 Over the summer, I wrote about Vinay Chakravarthy, a doctor of South Asian descent who had been recently diagnosed (at the age of 28 and fresh out of medical school) with leukemia and was in need of a bone marrow transplant. However, as Razib and others noted, the odds of him finding a match were quite slim (~1 in 20,000), given the small donor pool that was most genetically similar. Vinay's friends and families took his misfortune and turned it into something positive, organizing bone marrow drives in several states, and concentrating on getting additional minority donors to join the…
tsmith | November 8, 2007 Both Mike and Revere have new posts up documenting swine as a new threat to human health (beyond the pork chops and bacon), via carriage of methicillin-resistant Staphylococcus aureus in these animals. Several papers have been published recently documenting high rates of MRSA carriage in swine in the Netherlands, and also have documented transmission of this bacterium from swine to humans. However, even more worrisome to me than the Dutch publications is a new one out in Veterinary Microbiology, showing high rates of MRSA in Canadian swine--and guess where we import about 9 million hogs…
tsmith | November 6, 2007 I've written a post or two (or a dozen) discussing science journalism--the good, the bad, and, mostly (because they're the most fun), the ugly. There was this story about how blondes "evolved to win cavemen's hearts." Or this one that completely omitted the name of the pathogen they were writing about. Or this one, where a missing "of" completely changed the results being discussed.
I ran across another glaring example yesterday, dealing interestingly enough with one of my favorite topics: chocolate, and bringing in an "omics" prospective to it.
The news story covered a recent…