infectious disease
tsmith | December 5, 2005Clostridium difficile has joined MRSA, SARS, avian influenza, and West Nile as a hot new emerging disease. This bacterium, a cousin to Clostridium tetani-the causative agent of tetanus--and Clostridium botulinum--the botulism bacterium--is a spore-forming anaerobe. Carried by about 3 percent of healthy adults, the bacterium is generally present as a metabolically inactive spore. The bacterium typically causes problems in the nosocomial (hospital) environment, where up to 40 percent of hospital patients may be colonized. Clinical disease generally presents as watery diarrhea and cramps, and…
tsmith | December 1, 2005As I've mentioned before, Ebola is a virus near and dear to my heart. (Figuratively, not literally. I'm not quite that enamored of it). In that previous post, I mentioned that we didn't know the reservoir of Ebola in nature. It certainly isn't for lack of trying that it wasn't determined previously. The first field studies took place shortly after the initial 1976 outbreaks in the Democratic Republic of Congo (DRC) and Sudan. In the former, 818 bedbugs, 1500 mosquitoes, 10 domestic pigs, one cow, seven bats, 123 rodents, eight squirrels, six Cercopithecus monkeys, and three small antelopes…
tsmith | November 22, 2005I've mentioned many times on here reservations I have over the current avian flu numbers--how many subclinical or mild infections are being missed? Are they indeed offset by the number of serious disease cases we're also missing? There's a reason for these questions, and it's now out in electronic form in Clinical Infectious Diseases.
A bit of background. I work in Iowa as part of the Center for Emerging Infectious Diseases. One of our pet pathogens happens to be influenza virus, and we have ongoing studies looking at serological evidence of prior infection with swine and avian viruses in…
tsmith | November 17, 2005 Just a few weeks back, I discussed new research showing that prions had been found in urine. Now, a new paper in Nature(Nature summary) shows that the prion protein has been found in the mammary glands of sheep affected with scrapie:
The inflamed mammary glands of sheep have been found to contain protein particles that cause scrapie, a sickness similar to mad cow disease. This suggests that the suspect proteins, called prions, may also be present in the milk of infected animals.
If prions exist in the milk of cows infected with both an inflammatory illness and mad cow disease, formally…
tsmith | November 9, 2005Wonder what the anti-vaccination crowd makes of this?
Measles cases and deaths fall by 60% in Africa since 1999
Largely due to the technical and financial support of the Measles Initiative and commitment from African governments, more than 200 million children in Africa have been vaccinated against measles and one million lives have been saved since 1999. Measles cases and deaths have dropped by 60%, thanks to improvements in routine and supplementary immunization activities in Africa.
This dramatic drop has occurred in only a few years, coinciding with a massive measles vaccination campaign…
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 24, 2005Doctors recommend hepatitis shot for kids
Hepatitis A is a virus that causes (obviously) hepatitis, as well as jaundice, fatigue, nausea, fever, loss of appetite, and diarrhea. It's often spread fecal-orally; that is, you put something in your mouth that has fecal contamination. (Just makes you want to run to the bathroom and brush your teeth, doesn't it?) It also can be spread via sexual contact and shared needles (or other contact with blood or body fluids). It's estimated that there are ~40,000 acute cases of Hep A per year, with many of them going undiagnosed. It's one of those diseases…
tsmith | October 19, 2005It's situations like this that really irk me.
I mentioned the tularemia detection in DC here almost 2 weeks ago, already annoyed that there hadn't been more information about it. There has been some discussion on the ProMed list, but it's hardly been a blip in the mainstream media. Yesterday, there was an article in Salon further discussing it.
The background:
On Sept. 24, 2005, tens of thousands of protesters marched past the White House and flooded the National Mall near 17th Street and Constitution Avenue. They had arrived from all over the country for a day of speeches and concerts to…
tsmith | October 18, 2005Ah, how rare is it that my interest in stomping creationists and my interest in infectious disease collide. But I guess that when there's a topic as hot as avian influenza, it's inevitable that even the folks at the DI will sit up and take notice, as Casey Luskin has in this post: Avian Flu: An Example of Evolution?
First, as Luskin admits in the article, the answer to his titular questions is, "well, duh; of course it is." And alas, it doesn't get any better from there.
Allow me a moment to rant a bit here. It's painful for any expert in a field to read articles authored by those who are…
tsmith | October 17, 2005We still don't know what's going on with Idaho, where there have been 9 suspected cases of Creutzfeldt-Jakob disease in 2005. More below the fold.
Let me back up a bit. CJD comes in several forms. It can be inheirited, it can appear spontaneously, or it can be acquired (so-called "variant" CJD). It's the latter form--"mad cow disease," or if you want to be technical, bovine spongiform encephalopathy, that has made most of the headlines, as an outbreak occurred in Britain due to contaminated beef (more on that here). Typically, the variant form has affected young people, while the…
tsmith | October 17, 2005Andrea Bottaro has an excellent review of prion genetics over at Panda's Thumb. Prions are, of course, the transmissible agents that cause diseases such as kuru and Creutzfeldt-Jakob in humans, and related disease such as "mad cow" disease, scrapie, and chronic wasting disease in animals. Though there was initially much controversy about these agents in the early years (most notably, because they did not contain any nucleic acids), Bottaro notes that this is a "heresy" that the science community has embraced (similar to the ulcer & Helicobacter connection I mentioned a couple weeks ago):…
tsmith | October 12, 2005On Monday, I mentioned a survey MSNBC and Zogby conducted regarding attitudes about sex and STDs. Today on MSNBC, they have another article on the rise of STDs in America, highlighting some depressing trends. Meanwhile, in what you'd think would be across-the-board good news, a vaccine has been tested against 2 types of human papilloma virus (HPV), an STD which is the most common cause of cervical cancer. Despite having a 100% effectiveness in preventing infection with these viruses (which together cause ~70% of all cervical cancers), there is organized resistance to the vaccine, on the…
tsmith | October 12, 2005In the October issue of Emerging Infectious Diseases, James Hughes and Jeffrey Koplan discuss the problem of safe water. Hazardous drinking water and poor sanitation is something that gets brought up when there's a disaster (like Katrina, or the tsunami earlier this year), but many people don't realize that a large portion of the earth's population has to deal with this situation everyday.
Unsafe water is a global public health threat, placing persons at risk for a host of diarrheal and other diseases as well as chemical intoxication. Unsanitary water has particularly devastating effects…
tsmith | October 10, 2005Okay, so it's just an MSNBC survey (aided by none other than Dr. Ruth), but geez, when will people ever wise up about sex?
MSNBC.com and Zogby International asked online readers to share some intimate details about their personal lives, and more than 56,000 adult men and women -- one of the largest responses ever to a sex survey in the United States -- revealed that many are playing a pretty risky game.
Just 39 percent of people who took the survey always ask whether a new partner is infected with HIV, the virus that causes AIDS, or other STDs. Nearly one-third said they never check on a…
tsmith | October 7, 2005Thus far this week, I've discussed the history of pandemic influenza in general, and avian flu in particular. I've discussed some issues that must be addressed to prepare us for a pandemic, and the groundbreaking resurrection of the Spanish influenza virus. Today I want to end the series with a look at how prepared we currently are as a nation, and highlight some personal preparedness steps you can take.
If you recall from Tuesday, the first outbreak of H5N1 was back in 1997. The anthrax attacks were in 2001. Surely by now we're prepared for some kind of serious, large-scale, biological…
tsmith | October 6, 2005I know I said I was going to discuss a bit more about pandemic preparedness today, but I think I'll hold off on that to discuss this story:
It sounds like a sci-fi thriller. For the first time, scientists have made from scratch the Spanish flu virus that killed millions of people in 1918.
Why? To help them understand how to better fend off a future global epidemic from the bird flu spreading in Southeast Asia.
Researchers believe their work offers proof the 1918 flu originated in birds, and provides insights into how it attacked and multiplied in humans. On top of that, this marks the first…
tsmith | October 5, 2005The scientific community is all too familiar with the dangers an influenza pandemic could bring. The politicians and general public are starting to become aware of the issue as well; indeed, one can hardly open a newspaper or turn on the television without hearing about "bird flu." So, what's actually being done to prevent an influenza catastrophe? What are the issues? What can be done?
These are the questions that keep public health officials awake at night, because the answer is always that we're not doing enough. While we may be resigned to the fact that a future pandemic can't be…
tsmith | October 4, 2005Anyone working in the area of influenza virus epidemiology is familiar with the name Robert Webster. A virologist at St. Jude's Children's Hospital in Memphis, the native New Zealander has been leading the charge against influenza for well over 40 years. Barely out of graduate school, Webster hypothesized that something like genetic reassortment (which had not yet been discovered) occurred to cause the big changes that appeared among human influenza viruses, driving pandemics. He performed a simple experiment that cemented the course of his career: he found that serum from patients who had…
tsmith | October 3, 2005It's hard to avoid hearing about influenza virus these days. In all the noise, it's tough to sort out the facts from the rumors and conspiracy theories. I've already discussed a bit about the basic biology of the virus in this post, so I'm not going to review that here (though a good overview can be found here for those of you who need to bone up on your influenza virus biology). So, this week, as a part of Pandemic influenza awareness week, I'll be writing a 5-part series about various issues regarding influenza. Today, I'll discuss the history of influenza, focusing on past pandemics. The…
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…