Infectious causes of chronic disease
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 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 2, 2006John Hawks highlights a new article in today's Science, Metagenomic Analysis of the Human Distal Gut Microbiome. This goes nicely with the posts here recently on the topic of how our microbes affect our health and weight (part I; part II). A bit of discussion of the new article below...
First, I want to briefly mention what "metagenomics" means. There's a nice overview of it here on wikipedia. Basically, instead of sequencing and assembling a genome one at a time, you take a raw sample (such as dental plaque, sea water, soil, or fecal material, in this case), isolate the DNA, sequence it…
tsmith | May 30, 2006Busy today, so sequels are on tap. There's an interesting story from Nature news that's a nice follow-up to this recent post on how microbes can influence weight. More after the jump.
Scientists have identified a key microbe in our guts that helps us glean more calories from food. The discovery backs the idea that the type of microbes in our gut help to determine how much weight we gain, and that seeding the intestine with particular bugs could help fight obesity.
Samuel Buck of Washington University in St Louis, Missouri, and his colleagues focused on one microbe called…
tsmith | May 22, 2006 Razib mentioned here an article in the Boston Globe "which profiles researchers who suggest that variation in gut flora (the mix of bacteria) might be the cause of differences in body weight." The comments are somewhat skeptical, and I started to write a comment on the topic but it became a bit unweildly--so I've added it below instead.
As I've discussed previously, figuring out the relative contributions of environment versus genetics in obesity isn't an easy feat. As with so many human diseases/conditions, the "cause" is certainly multi-factorial. It's pretty clear that the genetics…
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 | April 12, 2006 A new study in the journal Pediatrics suggests this common procedure may improve the condition of kids diagnosed with attention defecit/hyperactivity disorder (ADHD). I think it's an excellent case of some true "alternative explanations" for the data.
Creationists often try to validate their position by saying that both they and mainstream scientists start from the same data, but that creationists use their "Bible glasses" to interpret it, while scientists view it through their "evolution glasses." In other words, they're not wrong--it's just a different interpretation of the same data,…
tsmith | April 1, 2006At the risk of starting an infectious cancer/HIV/AIDS fight over at The Loom, I'll point your attention to Carl's post discussing, well, those topics here. He elaborates on a study I mentioned here but didn't delve very much into the science. Zimmer does--check out the link to find out how he relates it to HIV.
tsmith | March 28, 2006I mentioned previously that a new virus had been found that's associated with prostate cancer. Several ongoing studies are finding tons of new species of microbes, and we're learning more about the diversity that is around us every day. And though most of these newly-discovered organisms won't harm us, some just might.
A new study (summarized here points to a calicivirus (genus Vesivirus, a relative of the Norovirus that has gotten much attention recently as the cause of gastroenteritis on cruise ships) as a potential cause of human illness. Vesivirus has an oceanic reservoir and has…
tsmith | March 27, 2006Part One: Introduction to Emerging Diseases and Zoonoses
Part Two: Introduction to Emerging Diseases and Zoonoses continued
Part Three: Bushmeat
Part Four: War and Disease
Part Five: Chikungunya
Part Six: Avian influenza
Part Seven: Reporting on emerging diseases
Part Eight: Disease and Domesticated Animals
Part Nine: The Emergence of Nipah Virus
Part Ten: Monkeypox
Part Eleven: Streptococcus suis
Part Twelve: Salmonella and fish
Part Thirteen: new swine influenza virus detected
Part Fourteen: dog flu strikes Wyoming.
Part Fifteen: Clostridium species.
Part Sixteen:…
tsmith | March 17, 2006 Is Crohn's disease caused by Mycobacterium avium pseudotuberculosis (MAP)?
In an article out yesterday, Australian Dr. Thomas Borody claims yes, and that the medical community is simply too "stuck in their ways" to admit it. I explain below why I think this is incorrect--or at least, premature.
I mentioned several times in the various AIDS threads and in the prostate cancer/virus thread that it's often difficult to determine an infectious cause of a so-called "chronic" disease. Not only is there generally a time lag between infection and disease development, but it may be that only…
tsmith | March 6, 2006Okay, my morning meeting went a bit faster than expected so I can sneak in a quick post before my first lecture. We were discussing infectious causes of cancer here. I received an email stating how "inconsistent" I was by asserting that a disease could be infectious but not contagious. So, rather than keep giving more examples of other chronic diseases that develop due to an infectious agent, I thought I'd take a different approach (after the jump...)
Y'see, as I've mentioned before, one of my interests is planning for any kind of major infectious disease outbreak--which includes…
tsmith | February 24, 2006This time for prostate cancer.
In a surprising discovery, researchers say they have found a virus in some prostate cancer patients, a finding that opens new research avenues in the most common major cancer among men in the United States.
The virus, closely related to one previously found only in mice, was found in cancerous prostates removed from men with a certain genetic defect. The researchers, with the University of California, San Francisco and the Cleveland Clinic, warn that they have not discovered any links between the virus and prostate cancer, but they were nonetheless excited about…
tsmith | February 3, 2006I've noted previously that infectious causes of so-called"chronic" diseases--illnesses such as cancer, heart disease, and autoimmune disease--are an interest of mine. The Guardian has a nice overview of infectious causes of cancer--and why one can't simply "catch" cancer as you catch a cold. It's a much better article (or at least headline) than this one, which discusses recent findings that a few types of adenovirus could play a role in the development of obesity. However, this does not mean--as the headline suggests--that "obesity is contagious." You're not going to "catch fat." Even…
tsmith | January 27, 2006 Speaking of chronic diseases caused by microbial agents, one of the earliest characterized of these is the group A streptococcus (Streptococcus pyogenes). In addition to causing acute diseases such as strep throat and scarlet fever, a wide range of post-infectious sequelae (complications that appear following resolution of infection) have been attributed to S. pyogenes. It can cause glomerulonephritis, a kidney disease. It's long been known infection with the organism can lead to a condition called Sydenham's chorea, a neurologic disease characterized by jerky movements. Infection with S…
tsmith | January 20, 2006Carl Zimmer over at The Loom has post discussing Toxoplasma, and how it can affect behavior--and may play a role in the development of schizophrenia. (Check out his post for the details).
As Zimmer mentions, this is a controversial hypothesis. Though support is growing for acceptance of the idea that infectious agents can cause all kinds of diseases that have traditionally been deemed "genetic" or "lifestyle" diseases, it is a slow and uphill battle. It also happens to be an interest of mine. I discussed another putative cause of schizophrenia, Chlamydia species, here. These type of…
tsmith | October 31, 2005 As mentioned in the comments to this post, there is a brewing controversy over upcoming guidelines outlining who should receive the "cervical cancer vaccine," a vaccine against the human papilloma virus (HPV). Briefly, the HPV vaccine is a highly effective (100% in a 2-year clinical trial) vaccine which is targeted against two specific serotypes of the human papilloma virus: HPV 16 and HPV 18. Together, these types cause about 70% of cervical cancers in the United States. Previously, Bridget Maher of the Family Research Council, a leading Christian lobby group, has said this about the HPV…
tsmith | October 3, 2005But I thought biologists were too "close-minded?"
Australians Barry J. Marshall and Robin Warren won the 2005 Nobel Prize in medicine Monday for showing that bacterial infection, not stress, was to blame for painful ulcers in the stomach and intestine.
The Australians' idea was "very much against prevailing knowledge and dogma because it was thought that peptic ulcer disease was the result of stress and lifestyle," Staffan Normark, a member of the Nobel Assembly at the Karolinska institute, said at a news conference.
This is a great example of how science works. These men proposed a…