infectious disease
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 15, 2008 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…
tsmith | January 11, 2008I'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…
revere | January 10, 2008Whenever confirmed human cases of bird flu appear in an area there usually follows heightened sensitivity to new cases of severe pneumonia. Are they bird flu too? Severe pneumonia is pretty common, so you can't automatically assume that "if it quacks like a duck and walks like a duck it must be a duck." It turns out there are a lot of birds that look like ducks that aren't ducks, at least when it comes to influenza-like illnesses. On the other hand, "testing negative" with PCR, which on its own is a pretty sensitive and specific test is also not foolproof. "On its own" means under the best…
revere | January 9, 2008Every year "flu season" comes during which there is a marked uptick in influenza-like illnesses (ILIs) in the community. An ILI is defined to be cough or sore throat together with a fever of over 100 degrees F. (37.8 degrees C.) or self-reported fever and chills as well as no other obvious cause (e.g., strep throat). But are all ILIs influenza? No. They are ILIs. In the absence of lab work (and since most are thought to be of viral origin, only non-specific symptomatic and supportive therapy is recommended and no diagnostic lab work is usually done), an ILI could be from influenza virus or…
revere | December 31, 2007Everyone seems to have an opinion about whether bird flu will be the next terrible global pandemic. In current parlance "bird flu" means human infection with the highly pathogenic avian influenza/A subtype H5N1. There is no doubt that this is the 800 pound gorilla in the global health room at the moment, but not because it is more likely to become a pandemic (NB: pandemic by definition is a globally dispersed sudden increase in infection among humans; the same situation for animals is called a panzootic, and it is plausible to say we have an H5N1 panzootic for birds now). On the basis of…
tsmith | December 30, 2007 As another Ebola outbreak simmers in Uganda (and appears to be increasing), I recently was in touch with Zoe Young, a water and sanitation expert with Médecins Sans Frontières (MSF*, known in the US as Doctors without Borders), who was working in the Democratic Republic of Congo during the DRC Ebola outbreak earlier this fall (and blogging it!)
Regular readers know of my interest in this virus, but I'm obviously geographically removed from any of the outbreaks. As such, Zoe and her colleague, physician Armand Sprecher, were generous enough to answer my questions about their work with…
revere | December 22, 2007WHO [World Health Organization] is now saying that human to human (H2H) transmission has not been ruled out in China or Pakistan:
China:
The World Health Organization said Friday it was impossible to say whether a case of bird flu in China involving a 52- year-old man was due to human-to-human transmission - but, even if it was, it was down to very close contact between the victims.
The Assistant Director-General for Health Security at WHO, Dr David Heymann, said the only proven transmission of this nature so far, in Indonesia and Thailand, had been as a result of very 'close contact' in a '…
tsmith | December 21, 2007 It's been awhile since I wrote anything on influenza. It's certainly not that nothing interesting has happened recently--far from it, there are new stories on influenza out every day. Rather, there are just a lot of people out there covering it, and covering it well. However, it's been an unusually busy few days on the influenza front, so I thought I'd update after the jump.
First, though much of the mainstream media has lost interest in avian influenza, scientists are still busy keeping an eye on things--and H5N1 is still spreading. Human cases have now been reported in Pakistan,…
revere | December 21, 2007It's been less than a week since the first reports out of Pakistan that cases of bird flu were appearing there. At the time we warned that the coming of flu season meant these kinds of reports were to be expected, but by the weekend concern increased as a family cluster appeared. As common in the early days of an outbreak news reports were contradictory and confusing. We elected to wait. By Sunday, some excellent reporting by Helen Branswell and diligent combing of the news by flusites allowed us to make a preliminary summary. We fully expected more surprises.
The biggest surprise so far is…
revere | December 20, 2007Nature's senior correspondent, Declan Butler, was one of the first to raise the profile of a pandemic threat in the scientific community and has had done some superb reporting since, including several stories on sharing gene sequences. The problematic actors in his earlier stories were respected scientists and the business-as-usual way they were approaching release of genetic sequences even as the world worried that the virus they were studying, influenza A, was inexorably searching for the right recipe to enhance its own raison d'etre, to make still more copies of itself, potentially with…
tsmith | December 17, 2007 In my field, many things that cause the average man-on-the-street to get a bit squeamish or squicked are rather commonplace. My own studies include two types of bacteria that are carried rectally in humans (and other animals), so I spend an absurd amount of time thinking about, well, shit, and the lifeforms that inhabit it and collectively make up our normal gut flora. The vast majority of these species don't harm us at all, and many are even beneficial: priming our immune system; assisting in digestion; and filling niches that could be colonized by their nastier bacterial brethren.
It…
revere | December 16, 2007If I knew for sure what was going on with the reported human bird flu outbreak in Pakistan's northwest border region I'd tell you. At this point it appears no one knows for sure -- not WHO, not CDC, not even the Pakistani authorities. The region where the cases are reported is near the Afghan border and is not under firm government control. The unsettled political situation merely adds to the usual confusion inevitable in the early days of any outbreak. We are all looking for a pandemic signal embedded in a lot of noise, difficult enough, but we don't even know what the signal sounds or looks…
revere | December 15, 2007As noted yesterday, it's flu season. That includes bird flu. So we are seeing cases pop up. Yet another in Indonesia and the father-son cases in China. Then reports out of Pakistan of the first human cases on the Indian sub-continent. Those case are as yet unconfirmed. Now WHO is confirming cases in Burma (aka Myanmar), the first in that military dictatorship not known for being open about what goes on there:
The World Health Organisation (WHO) announced Myanmar's first human case of bird flu, the victim a seven-year-old girl who survived the disease.
The girl, from the northeastern Shan…
revere | December 12, 2007The dramatic infectious agents like MRSA, Ebola and bird flu get the headlines but there are a lot of others out there, some of them capable of being just as nasty. Consider the new variant of adenovirus serotype 14, for example:
Infectious-disease expert David N. Gilbert was making rounds at the Providence Portland Medical Center in Oregon in April when he realized that an unusual number of patients, including young, vigorous adults, were being hit by a frightening pneumonia.
"What was so striking was to see patients who were otherwise healthy be just devastated," Gilbert said. Within a day…
revere | December 11, 2007Concern about cutting down the rain forests is not just a conservationists hobby horse. As more and more trees are cut down for their wood and the land cleared for agricultural use the unplanned consequence is that more an more mobile and traveling humans come in contact with animals for the first time. These animal populations are reservoirs for many viruses, some, like Ebola and AIDS, make their way into new homes, human bodies. The rain forest is no more than an incubation period's travel from major cities.
But this isn't the only way animals and humans are thrown together in intimate and…
tsmith | December 10, 2007Still playing end-of-year catch-up with grants and manuscripts so posting will be sporadic, but I'd be remiss not to mention this story regarding presidential candidate Mike Huckabee's past views on HIV/AIDS:
In 1992, Huckabee wrote, "If the federal government is truly serious about doing something with the AIDS virus, we need to take steps that would isolate the carriers of this plague."
"It is difficult to understand the public policy towards AIDS. It is the first time in the history of civilization in which the carriers of a genuine plague have not been isolated from the general population…
revere | December 10, 2007The debate about how much wild migratory birds contribute to the spread of highly pathogenic influenza/A H5N1 goes on. According to a sensible Commentary in Nature (Dec. 6) it needn't. We should have taken steps some time ago to answer an answerable question. But we didn't and still haven't initiated those steps:
Two years ago, some believed that H5N1 viruses were poised to spread around the globe on the wings of migrating wild birds. A massive effort was mounted to track their movement but, as of September 2007, very few positive birds have been found in tests of over 300,000 healthy wild…
revere | December 9, 2007There's a growing Ebola outbreak in Uganda. We've been watching it and I've gotten an email or two wondering why we weren't posting on it. There are a lot of nasty disease outbreaks in the world and we don't cover most of them. Ebola gets news because it is a hideous disease with high fright value but it isn't alone in that department. Ebola also isn't very contagious and like SARS, is mainly so in the later stages of the disease so less likely to spread worldwide. We discuss bird flu here because it is a way for us to talk about public health more generally. But we do talk about other…
revere | December 5, 2007Most people in the developed world think of measles as a pesky but fairly benign childhood disease. For the current generation, who has had the benefit of immunization with measles vaccine, it is also a historical curiosity. Not so for the developing world, where measles has been a major killer of children and infants. Africa has become the poster child for failed public health programs so it is nice to be able to say that when it comes to measles prevention, Africa is a special success story:
Africa, which has long had the most measles deaths, has seen the biggest drop, 91 percent. In many…