Did Yersinia pestis really cause Black Plague? Part 1: Objections to Y. pestis causation

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. pestis causation assumption have been suggested. More on that after the jump…
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Less is more when it comes to antibiotic use?

Over 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 their results overturn the paradigm? I’m not convinced. First, RPM states that antibiotic resistance is a dichotomy: either sensitive, or resistant strains. But that’s not the case–those are simply the extremes of the spectrum, with many organisms that are some shade of partially resistant to various antibiotics. (For example, while penicillin resistance is rare in Streptococcus pyogenes, it takes much higher doses of the drug to kill them today than it did, say, 40 years ago; they have “intermediate” resistance or susceptibility). As noted in the comments, it’s not only the fully resistant organisms we’re worried about when it comes to antibiotic resistance: it’s also those for which it takes a lot of the drugs to kill, but they’ll die eventually (or at least, the drugs will inhibit their growth). This study doesn’t take those into account, which is a limitation–but then again, it seems designed to be more of a paper to get fellow scientists thinking about these ideas in general, rather than an exhaustive test of every potential hypothesis stemming from them.

Either way, antibiotic resistance is certainly a huge problem, and we need to find better ways to preserve the drugs we do have. Reducing their use in this manner (lower and shorter doses) is certainly worth a second look.

Where did syphilis come from?

Some infectious agents, it seems, have been with us since the rise of humanity. Bacteria like E. coli or salmonella don’t appear to have one moment enshrined in history where they first appeared on the scene. They’ve probably long been with us, causing disease sporadically but not spectacularly.

Other agents, however, seem to make their presence known. Syphilis is one of these. The first recorded outbreaks of syphilis (caused by the bacterium Treponema pallidum subspecies pallidum) were documented in Europe in 1495. These weren’t syphilis as we know it today. Currently, syphilis is a sexually-transmitted infection that typically has 3 phases of disease. Primary syphilis is the initial phase, characterized by perhaps a lesion on the genitalia. This typically resolves on its own, and the patient may either get better or progress to secondary syphilis. Secondary syphilis is characterized by a distinctive rash, which is fairly unique in that it is present not only on the usual areas of the body (typically the extremities for this rash), but also presents on the palms of the hands and soles of the feet. This feature could be diagnostic, but it’s not always present. Infection progresses to the secondary phase generally weeks to months after the primary symptoms.

Tertiary syphilis is the final phase of the disease, and the most difficult to diagnose on symptoms alone. There can be neurological involvement, leading to the “madness” of syphilis; or it can attack the cardiovascular system or the digestive system, leading to heart failure or painful bowel problems that can last for years. Tertiary syphilis is not only insidious in its diverse array of symptoms, but also in its lag time from initial infection: as little as one year, or as many as 50. The disease is a complex and often mysterious one.

However, just as mysterious has been the origin of T. pallidum. As I mentioned, the disease we see today bears little resemblance to syphilis when it was first recognized in Europe during the late 15th century. At this point, syphilis wasn’t a hidden venereal disease: it was a highly virulent infection that could run its course in a matter of weeks to months, covering the victim in sores from head to toe until they died an excruciating death. However, this highly pathogenic form was soon replaced with a milder version of the disease, more similar to what we see today.

But a larger question looms: where did syphilis come from? It’s widely agreed upon by scholars that syphilis appears to be a “new” disease to Europeans at this point in history–so had it been hiding in another reservoir prior to this time? Did a new subspecies emerge from older, related infections? Or did the voyages of Columbus bring this microbe back to the Old World from the New? There have been a number of conflicting publications on this over the past several years (and indeed, the debate is as old as Columbus’ voyages themselves), with archaeological evidence and that from microbiology sometimes coming into conflict regarding the origin and evolution of subspecies of Treponema pallidum. A new study swings it back to Columbus, suggesting that Treponema pallidum likely has its origin in the New World. More after the jump…
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Medblog awards open for voting

Every year, the folks over at Medgadget.com host the Medical Weblog Awards. I’ve been nominated a few times, and even did OK in the best new blog category a few years back. This year, I’m apparently nominated in the Best Clinical Weblog category–which, honestly, I don’t think I fit into. So I won’t ask for your votes here, but I’ll suggest you check out some of the other fine blogs that are nominated, and the others that are nominated for all the other awards (including fellow Scienceblogger Orac). If you see something you like, pass along a vote or two.

Darwin Day 2008 in Iowa City

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, main course, dessert and soda or coffee, plus tax and tip–a bargain for those of you who are familiar with the Linn Street Cafe). Drop me an email if you’re interested in attending–this is the only part of the weekend that will need to be reserved in advance (and we expect tickets to go quickly!).

Saturday then will be a series of talks followed by an informal reception. University of Iowa paleontologist Dr. Christopher Brochu will kick off the afternoon, whose topic will be “The Dead Speak: What we learned from the Tyrannosaurus.” Dr. Brochu was the lead researcher on the analysis of “Sue” the tyrannosaurus at Chicago’s Field Museum.

Dr. McClintock will follow, discussing “Social Isolation and Breast Cancer: Psychosocial Regulation of Gene Expression”.

Dr. Pigliucci will be the last of the afternoon’s talks, speaking on “What’s science got to do with it? When scientists misspeak about religion”–a topic sure to bring about some interesting discussion. A panel discussion and Q&A session with all of the speakers will wrap up the afternoon, and a reception will follow.

Hope some of you can join us! It promises to be an exciting and stimulating few days–and we’re also looking for ideas (and manpower!) for Darwin Day 2009.

Retrospectacle does plague

I’ll have new posts up here next week, but meanwhile, over at Retrospectacle, Shelley’s made this week plague week. She introduces the topic here, and next dishes about plague fashion. Also in the comments, it’s asked:

I recently heard that there is some doubt now that the Black Death may not have been bubonic plague. The doubt based on the speed of transmission, but no alternate disease was mentioned. Is there any other disease that matches the symptoms that could be a likely alternative?

Long time readers know that I’ve referred to this previously and promised to post on it, so if even Shelley’s jumping into this game, I should probably get off my rear and get that post written. I’ll have that up, and some additional posts on plague, syphilis, and more next week.

Aetiology–live from LA

No, I’ve not dropped off the face of the earth. I’m currently here in rainy Los Angeles for a meeting with the WIRED SCIENCE/Correlations people, where I met up with fellow Correlations bloggers Clifford Johnson, Michael Tobis, and Sheril Kirshenbaum, as well as WIRED SCIENCE producer Damon Gambuto and a number of other folks who work behind the scenes there. I arrived here on Thursday (thus missing all the caucus hoopla back home), but unfortunately I spent all day sick as a dog in my hotel room, finally hit by the norovirus that swept through my family earlier in the week (and that I’d thought had spared me; at least symptoms didn’t hit until after I was off the plane).

The past week and a half has also been crazy work-wise: I took a few days off for the holidays, then got back to work submitting yet another grant proposal, and have been working overtime in the lab on a brand-spankin’-new project since the first of the year, hoping to have enough data for an abstract deadline on Monday.

On top of all this, I’ll be facilitating discussion in two weeks at the 2008 Science blogging conference in North Carolina, on the topic of blogging public health and medicine. Becky has added some topics to the list already, but I’m interested in reader input as well; anything we should discuss that’s not on there?

I hope everyone’s holiday season went well; back with more regular blogging soon…