General Epidemiology
tsmith | August 18, 2006I mentioned yesterday that one way to help prevent new HIV infections is to treat people who are infected with herpes, another sexually-transmittted virus that infects as much as 20% of the population in the United States. That may seem odd; how does treating one viral infection prevent infection with a second virus?
Studies have shown that, generally, HIV isn't one of the more highly infectious viruses out there. For example, the hepatitis B and C viruses are transmitted via many of the same routes as HIV (such as sexual activity shared needles), but vary in their infectivity. If, for…
tsmith | August 17, 2006 If one thing has been hammered home this week (and, indeed, over the past 25 years) regarding HIV/AIDS, it's that prevention is key. Treatments, while improving, are still a distant second place to preventing primary infection as far as the fight against AIDS goes, and a large portion of the world's HIV-infected population still has no access to these treatments. Prevention, therefore, is critical. And while the condom has become the symbol for HIV prevention, strategies go far beyond that tool.
Over at WebMD, they have a nice summary of many of the key points from this week's…
tsmith | August 17, 2006This week's issue of the New England Journal of Medicine contains two articles on AIDS that are available free of charge.
The first article, Changing the Paradigm for HIV Testing -- The End of Exceptionalism, goes over content I blogged about here, discussing moving toward a more universal testing paradigm. The article focuses on issues specifically in the United States, but certainly many of the points have broad applicability.
The second article, AIDS in 2006 -- Moving toward One World, One Hope? is a broad overview of the lessons learned and problems still faced regarding HIV therapy…
tsmith | August 16, 2006Ran across this interesting article in New Scientist on natural resistance to HIV.
Researchers are launching a project to discover how certain people, dubbed "elite controllers", are successfully able to fend off the HIV virus without using drugs.
More and more cases of such people - also known as "elite suppressors" - are coming to light. Unlike the sex workers in Kenya identified a decade ago as being HIV-negative despite their constant exposure to the virus, elite controllers are infected, and do develop antibodies to the virus, but at a very, very low level.
More over at AIDS at 25.
tsmith | August 16, 2006DarkSyde over at DailyKos has his own post up today on the anthrax letters. He asks for "Thoughts, plots, conspiracies?", and gets quite a few in the comments, so be sure to check those out as well.
tsmith | August 14, 2006 The control and eventual eradication of the smallpox virus from the wild is one of the most heralded success stories in all of public health. Indeed, smallpox has played a central role in the history of vaccination. Even prior to Edward Jenner's use of the related cowpox virus to protect against smallpox disease, it was known that inoculation with materials from an infectious smallpox pustule or scab (dubbed "variolation") could protect an individual from death due to smallpox, generally resulting instead in a mild form of the illness. Jenner's observation that milkmaids seemed to be…
tsmith | August 11, 2006 Missed this while I was out last weekend, but John Hawks has a link to a story noting that a new analysis shows that Holy Roman Emperor Charles V suffered from gout, thought to play a key role in his abdication of the throne.
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A 450-year-old piece of Charles V's pinkie lends support to the theory that it was gout that led one of the most powerful rulers of all time to abdicate, Spanish researchers report.
Holy Roman Emperor Charles V, whose empire stretched across Europe and included Spanish America, was diagnosed with gout by his doctors in early adulthood. By the end of…
tsmith | August 10, 2006So it would seem.
West Nile is spreading beyond birds, horses and humans. A squirrel has tested positive for the virus and hundreds more are showing the same symptoms
People are finding squirrels in their yards or parks that look like they've been injured because they aren't able to walk. In some cases they're disoriented, running around in circles or shaking. Now it's believed they're suffering from West Nile.
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West Nile virus (WNV) is another arbovirus; that is, a virus that's transmitted by an arthropod (in this case, the mosquito). Typically, the virus cycles between birds…
tsmith | August 10, 2006I wrote several posts on mumps outbreak here in Iowa this past spring. However, we aren't the only I-state to have dealt recently with an outbreak of vaccine-preventable disease. An editorial in yesterday's New York Times highlights the dangers of withholding vaccincations.
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In the spring of 2005, an outbreak of measles occurred in Indiana. The unvaccinated index case had been traveling in Romania on a missionary trip, where she picked up the virus. Measles is one of the most infectious viruses we know of, and when she returned home, she ended up spreading the virus…
tsmith | August 9, 2006And the winner of today's bad headline award goes to:
Sexual lyrics prompt teens to have sex
Teens whose iPods are full of music with raunchy, sexual lyrics start having sex sooner than those who prefer other songs, a study found.
Whether it's hip-hop, rap, pop or rock, much of popular music aimed at teens contains sexual overtones. Its influence on their behavior appears to depend on how the sex is portrayed, researchers found.
Songs depicting men as "sex-driven studs," women as sex objects and with explicit references to sex acts are more likely to trigger early sexual behavior than those…
tsmith | August 9, 2006The name "dengue" means "breakbone fever" due to the extreme bone pain it causes. The virus is a member of the flavivirus family, which includes the virus that causes yellow fever. Both viruses are arboviruses--viruses that are transmitted by arthropods. In the case of dengue and YF, the arthropod in question is the mosquito; specifically, the Aedes aegypti, an urban mosquito that lives in close contact with humans.
Dengue infections cause an enormous amount of morbidity and mortality in areas where the virus is endemic. It's estimated to infect 50-100 million people each year. Though…
tsmith | August 2, 2006 I mentioned just last month the dearth of research into what really makes an influenza virus easily transmissible from host to host, noting:
If we had a better handle on the factors that caused an avian strain of influenza virus to be more efficiently transmitted among humans, then we could better focus our resources and know when to really sound the alarm--unlike now, when we're flying blind in many ways.
A new paper in PNAS has started to do just that, and the research findings have prompted such headlines as Bird Flu Pandemic may not develop (via Effect Measure). Revere has already…
tsmith | July 31, 2006I was busy over the weekend (and disgusted by the hot, nasty weather that will not die), so I don't have a lot on tap for today. Luckily, though, there's some interesting stuff elsewhere that's already written up--thoughtfully saving me some of the trouble.
I discuss the link between infectious and "chronic" disease with some regularity on this site. I think it's a fascinating area; perhaps oversold by some, perhaps over-criticized by others, but certainly a hot topic and an interesting direction for research in microbiology. This weekend's New York Times had a new story that touched on…
tsmith | July 29, 2006More fascinating topics I didn't get around to:
Orac disses a report linking Ipods to autism. Really. He also has the low-down on snake oil salesman Kevin Trudeau's unbelievable new book. You think having a few people on a blog deny the germ theory is bad; it's even worse when an author who'll sell millions of books does so.
Carl Zimmer has an excellent post discussing circuits and evolution, and even touching on network theory.
Joseph wonders about the gender gap in academic medicine.
The Bad Astronomer asks, is the government trying to kill us?
Dr. Charles gives the details on a…
tsmith | July 28, 2006Chuck Darwin posed a very good question here that I'm spinning off into a new discussion.
The work Taubenberger and others are doing on the evolution of influenza a century ago is fascinating and could very well be pertinent to prediciting future influenza virus genetic drift/shift, host-virus interactions, etc. However, I ask myself if the benefits of this work for future public health, as well as for general scientific interest, is worth the risks when it comes to biosecurity. With reverse genetics methods introduced a few years ago, any influenza virus can be generated through relatively…
tsmith | July 28, 2006A reader sent me a link to this site, which contained a reprint of a story by CBS 47 in Jacksonville. Mostly, it was a repeat of the story I already discussed, but it added this tidbit of information:
The NPA teamed up with the Oklahoma State Department of Health to study the creepy crawlers.
They took skin samples from 20 patients who claim they have the bugs, but were diagnosed by their doctors as delusional.
Researchers found collembolan, a microscopic critter, in 18 of the 20 patients.
Collembola feed on algae, bacteria and decaying matter. They thrive in wet or damp surroundings, and…
tsmith | July 27, 2006Somehow I missed this story in the June issue of Science:
...Jeffery Taubenberger of the Armed Forces Institute of Pathology (AFIP) in Washington, D.C., said that RNA found in tissue samples from pneumonia patients who died in 1915 shows that the virus's hemagglutinin--an all-important coat protein--is a subtype called H3. If confirmed, "that's tremendously exciting," says molecular biologist Ian Wilson of the Scripps Research Institute in San Diego, California. Knowing the virus's entire genetic makeup--which Taubenberger believes is possible--would shed fresh light on where the 1918 killer…
tsmith | July 26, 2006Every couple of months, it seems, comes a new media story on Morgellons disease, a "mysterious ailment" in which
Most individuals with this disease report disturbing crawling, stinging, and biting sensations, as well as non-healing skin lesions, which are associated with highly unusual structures. These structures can be described as fiber-like or filamentous, and are the most striking feature of this disease. In addition, patients report the presence of seed-like granules and black speck-like material associated with their skin.
Sounds like something that's right up my alley of interest, but…
tsmith | July 25, 2006 I've mentioned previously the potential role that mild or asymptomatic infections with influenza may play in transmission and evolution of the virus. Right now, most of our reports of H5N1 have been due to serious infections that caused a patient to seek medical care. These cases are the tip of the iceberg in a normal influenza outbreak, when most of us don't have physician-diagnosed influenza. Instead, we recognize the signs and symptoms, and stay at home to ride it out. Is this happening in Indonesia, Thailand, and elsewhere? For every person who shows symptoms of H5N1 infection, are…
tsmith | July 18, 2006 I've mentioned previously the role, or potential role, that bats play in disease transmission. They have long been suspected, and recently identified, as hosts for the Ebola virus. (Whether they're the main reservoir species and what--if any--role they play in transmission of the virus to humans remains to be determined). They've also been implicated in the emergence of SARS and Nipah virus, and of course, have long been associated with the maintenance of rabies virus. A new paper reviews the role of bats in the maintenance and emergence of novel viruses.
Bats represent a huge portion…