General Epidemiology
tsmith | May 30, 2007 I blogged back in March about World TB day, the theme of which was "TB anywhere is TB everywhere." We know that someone can simply hop on a plane halfway across the world, and be practically anywhere else on the globe in the span of about a day--and their bacteria and viruses are just along for the ride. This is particularly disconcerting when it comes to respiratory diseases, where fellow airline passengers may be coughing and sneezing all over you, or touching shared objects without washing their hands. This is also a scenario that's known to have spread SARS, and may spread a future…
tsmith | May 23, 2007 Everyone knows about the "butterfly effect": the idea that a butterfly flapping its wings in Brazil could eventually result in the formation of a tornado in Texas by virtue of very small alterations in the initial conditions of a system. Though this description of it is often decried by people who study chaos theory as an inaccurate oversimplification, it's a useful illustration of the tiny perturbations that can have vast effects on a downstream chain of reactions.
When it comes to infectious diseases, climate change may be the beginning, but environmental effects extend much farther…
tsmith | May 22, 2007I haven't had a chance yet to mention Seed's promotion of the Intel Science and Engineering Fair, the cream of the science fair crop. It's so prestigious, in fact, that it attracts young adults from all over the world to share their research. However, one brought more than the judges bargained for, as she also happened to be in the early stages of measles:
A 15-year-old girl from India who was visiting for the Intel International Science and Engineering Fair has been hospitalized with measles, and New Mexico health officials say she was likely infectious when she was traveling and while at…
tsmith | May 21, 2007 I had a strange worry as a kid. I was very scared of getting bit by a tick and developing Rocky Mountain Spotted Fever (RMSF). I know, weird--even for nerdy kids like me, who knows about Rocky Mountain Spotted Fever? How many readers are even familiar with it?
For those who aren't, RMSF is a zoonotic rickettsial disease transmitted by several species of ticks. Though the disease is named after the geographical region where it was first described back in the late 1800s, the bacterium that causes it, Rickettsia rickettsii (an obligate intracellular pathogen), has been found in almost all…
tsmith | May 18, 2007 I think it must be difficult to study infectious disease without having some kind of interest in history. The field is so rich in stories from decades and centuries past, and infectious disease has played an enormous role in shaping our societies today. As with many fields, I believe our understanding of the present can be improved if we view it through the lens of the past--realizing as much as we can the historical influences and legacies that have brought us to where we are today.
I mentioned a few weeks back that, despite its eradication in the natural world, the smallpox virus still…
tsmith | May 17, 2007I wrote several posts last year on the mumps outbreak here in Iowa. We didn't get hit with mumps this year, but there has been an ongoing outbreak in Canada, primarily in Nova Scotia. So how do I fit into this?
Most recently, mumps has been diagnosed in Toronto:
Canada's ongoing mumps outbreak has hit the country's biggest city. And Toronto's public health officials expect the current case count of three infections to climb before the outbreak subsides.
"I think we may see more cases," Dr. Barbara Yaffe, director of communicable disease control for Toronto Public Health, said in an…
tsmith | May 1, 2007 A few weeks back during the whole Egnor kerfuffle, I mentioned how important an understanding of evolutionary biology was to many areas of epidemiology, and specifically, for vaccine development and implementation. As one example, I brought up the phenomenon of serotype replacement, which can occur due to the use of what are called "multi-valent vaccines." Essentially, these vaccines include strains of pathogens which are either the most common, or the most likely to cause disease--thereby protecting individuals from infection with these specific serotypes, but not making the recipient…
tsmith | April 27, 2007I wrote a post back in February about HIV's "Kitzmiller vs. Dover" trial. The trial was appealing the sentence of one Andre Chad Parenzee, a native of South Africa who'd been convicted in Australia back in 2004 of infecting one woman with HIV (and exposing two others). Parenzee knew of his HIV+ status, telling the women he had cancer instead and not disclosing his infection nor using condoms. In the appeal, the HIV "dissidents" led the way, with Valendar Turner and Eleni Papadopulos-Eleopulos of the Perth group taking the stand and denying that HIV even existed. Papadopulos-Eleopulos…
tsmith | April 27, 2007Of all the vaccines in a child's repertoire, perhaps the most controversial is the vaccine against Hepatitis B virus. It's not because of concerns about the vaccine's safety necessarily; parents tend to be more worried about the MMR vaccine, since that has received so much press. But many parents feel that the HBV vaccine is unnecessary. HBV is transmitted primarily via exposure to blood or other body fluids, or by sexual transmission. Because they assume their kids will be smart, stay away from drugs, and not have sex with the "wrong" people, they assert that the vaccine is a waste and…
tsmith | March 30, 2007I don't know if you've seen any of the posts here at Scienceblogs or Panda's Thumb about the Discovery Institute's newest protégé, Dr. Michael Egnor. A professor of neurosurgery at SUNY-Stony Brook, Dr. Egnor has been pontificating on how "Darwinism" has nothing to offer to medicine; and indeed, that evolutionary biology has "hijacked" other fields of study. Mike has already aptly pointed out many of Egnor's strawmen and intellectual dishonesties, so I won't review them all. I've stayed out of the fray until now because I've had limited time and others have been handling it quite ably,…
tsmith | March 29, 2007Influenza season is wrapping up here in the United States, and it seems so far that the 2006-7 season was pretty typical. The first cases of the disease were reported in late October, and cases were sporadic throughout November and early December. After increasing a bit in mid-late December of 2006, outbreaks declined slightly in January, and then picked up again later that month, increasing again in February before falling again, and continuing to do so in March. Early reports suggest that the vaccine matched the circulating strains pretty well, and that most of the isolates which were…
tsmith | March 24, 2007Mycobacterium tuberculosis infection is as old as civilization. The bacterium infects approximately a third of the world's population--roughly 2 billion individuals. It's estimated that 8 million new cases are contracted each year--around a new infection every second. ~2 million individuals die as a result of TB every year. The bacterium also plays a prominent role in the history of microbiology: it was on March 24, 1882, that Robert Koch announced his discovery of the causative agent of the dread disease tuberculosis:
"If the importance of a disease for mankind is measured by the number…
tsmith | March 23, 2007I have a host of collected links and one-liner posts that I hoped I'd get to this week, but just didn't have the time for. So, rather than let them collect dust any longer, I'll put a number of "greatest hits" in microbiology and public health from the past week or so after the fold:
John McCain isn't sure if condoms help to prevent HIV transmission. Mike and Josh take him down.
The fight against guinea worm, an excruciatingly painful disease, is in the home stretch--but facing one of its toughest obstacles.
The proposed childrens' health study may receive funding after all.
A new…
tsmith | March 15, 2007 When we think of the spread of antibiotic resistance between animals and humans, we tend to think of it going from Them to Us. For example, much of the research over the past 20 years on the sub-clinical use of antibiotics in animal feed has looked how this use of antibiotics as a growth promotant breeds resistant organisms in animals, which can then enter the human population via the food we eat. Along a similar line, I just mentioned Burt's post post on cephalosporin use in cattle and the evolution of antibiotic resistance, where the worry is that use of these broad-spectrum antibiotics…
tsmith | March 13, 2007I was out yesterday, and as such missed Lynn Margulis' blog tour stop at Pharyngula. For those who may not be familiar with Margulis, she's a professor at the University of Massachusetts, Amherst, and was the one who pushed the (now accepted) idea that chloroplasts and mitochondria in cells came about due to symbiosis. In the post announcing her impending arrival, there were lots of questions about her stance on HIV/AIDS. This is mostly due to a review she co-authored on Amazon of Harvey Bialy's biography of HIV denier Peter Duesberg. The review ends: "As both Bialy and Duesberg…
tsmith | February 2, 2007Introduction to Microbiology and Infectious Disease
You and your normal flora, Part I
You and your normal flora, Part II
tsmith | February 2, 2007It's been awhile since I've written about HIV/AIDS denial on here. To be honest, the whole area has just burned me out a bit; it gets tiresome to even discuss issues with people who so fundamentally deny the basic tenets of microbiology and infectious disease epidemiology. But in my absence, there's been quite a bit going on, much of it collected here at the AIDStruth website. However, I have to draw your attention to a notable story today.
The first is like something out of "Law and Order." An HIV-positive man is appealing his conviction in Australia of endangering the lives of three…
tsmith | February 1, 2007 Heart disease is still often considered a disease of men. Ask the average joe on the street, and they'll probably tell you that men die of heart attacks, and women die of breast cancer. Of course, this is incorrect. In fact, heart disease is the leading killer of women in America: 1 in 3 women dies of heart disease. To make women more aware of the danger of heart disease, the National Heart, Lung, and Blood Institute (NHLBI) and partner organizations are sponsoring a national campaign called The Heart Truth. The campaign's goal is to give women a personal and urgent wakeup call about…
tsmith | January 30, 2007Readers who are regulars at Effect Measure or Deltoid will be familiar with the opinions of attorney and author Michael Fumento. Fumento considers himself an avian flu "skeptic," and recently issued a "challenge" (the title, "My avian flu challenge to the leftist bird-brained squawkers", might give you some clue as to its scientific value) to bloggers, in response to one blogger's comment that "... there was a "50%/50%" chance of [an influenza] pandemic in the next year":
I took advantage of Mr. Paramedic's oversight to bet him 10-1, with him picking the dollar amount, that there would be…
tsmith | January 25, 2007Measles deaths down 60 percent in six years
Though we tend to think of measles as a mere childhood disease here in the U.S.--a nuisance more than anything--this is a reminder that worldwide, it's still a significant cause of morbidity and mortality. To counter this, a mass vaccine campaign was begun in 2001, and has served to drastically reduce the burden due to the disease:
Deaths from measles have fallen by 60 percent worldwide since 1999 in what experts described on Friday as an historic victory for global health.
Accelerated control measures including an increase in routine measles…