Friday, February 29, 2008

Largest Beef Recall in US History...too late?

The 143 million pounds of beef that were recalled this February have most likely already been consumed! The Westland Hallmark Meat Packing Plant was investigated after the Humane Society accused this plant of abusing cows that were unable to stand. Videos show workers dragging cattle with chains, jabbing them with fork-lifts, and using electric shock on the cows in order to move them to be slaughtered. Beyond the atrociousness of these inhumane acts, the fact that these "downed" cows were slaughtered and sold is a serious threat to the American meat eaters because as we know, difficulty with balance and eventually, the inability to stand are symptoms of mad cow disease. Since the release of the video, the plant has been shut down and the two workers on the video are now facing charges of animal cruelty (however, the plant as a whole has no such charges). So...maybe hold off on the burgers for a while? For more: Click Here

To watch the video: Click Here.

How to swab a frog for chytrid fungus

Mad Cow Disease in Canada

Canada confirmed a new case of mad cow disease on Tuesday, the 12th. The animal in question was a six-year-old dairy cow from Alberta that had most probably eaten infected feed. The Canadian Food Inspection Agency, which vows to eradicate bovine spongiform encephalopathy (BSE) within a decade, has consistently said it expects to find a few cases of the disease. The CFIA said no part of the animal had entered the human or animal food supply. The cow was born after Canada and the United States introduced a ban in 1997 on cattle feed that contained ingredients made from rendered cattle and other ruminants. At least four other cases have involved animals born after 1997. "Many trading partners in the past have shut their borders to Canadian cattle and beef products after the first home-grown case in 2003, dealing a massive blow to the industry, and Ottawa has fought hard to restore market confidence. Last May the World Organization for Animal Health relaxed its security rating on both the United States and Canada, classifying both nations as controlled risk in a sign it was happy with their efforts to combat BSE. "This case will not affect Canada's controlled risk country status," the CFIA said in a statement. "Based on science, it is not expected that this case should impact access to any of Canada's current international markets for cattle and beef." Mexico noted last Friday that it would soon lift a ban on Canadian cattle imports that dated back to 2003. Here's the link to the article.

Mad Cow USA

I think it is fair to say that the Organic Consumers Association is not exactly without an agenda, however since the Mad-Cow disease Homepage moved their daily news listing over there they have also become one of the best sources for information on BSE, CJD and all thing mad and bovine. If you think the story is over, well it might just be getting started. FYI, I'm not a vegetarian, but since doing some research about BSE a little over 10 years ago and finding out about how the whole industrial food process works I just haven't felt like eating beef.....

Zoonoses as Biological Weapons

While it is generally known that throughout the 19th century numerous countries have utilized various programs to develop biological agents as weapons for war, what is lesser known is that a majority of these agents are zoonoses. Anthrax, plague, tularemia, and rabies are just a few examples of the many zoonoses used in biological warfare. The fact that most zoonoses are not highly contagious and are relatively easy to control and deploy makes them a favorable choice for biological weapons. Furthermore, Dr. David R. Franz, the Vice President of the Chemical and Biological Defense Division Southern Research Institute claims that they are also appealing as bio weapons because their threat to public health may, "justify a state-sponsored research program, which may serve as a cover for a biological warfare program".

Terrorists have also utilized zoonotic agents as a means of weaponry. Although biological weapons are much more complicated and dangerous to deal with than typical terrorist bombs, the immense consequences that they are capable of producing make them appealing. Not until recently has the United States instituted programs to confront the growing threat of biological warfare. The response to such weapons includes advancements in the physical protection of soldiers against bio agents, monitoring research programs around the world, and participating in many large scale treaties. For more: Click Here

Thursday, February 28, 2008

Patients flee, drawing attention to quarantine dilemma

A report in Nature Medicine this week

This past December, not too long before the Christmas holiday, 49 people being held in a facility near Port Elizabeth, South Africa cut through a perimeter fence and escaped. These people weren't criminals locked away in a prison; they were patients at the Jose Pearson Hospital diagnosed with highly infectious, drug-resistant tuberculosis.
The use of mandatory isolation to keep disease such as tuberculosis in check is a centuries-old practice. Isolating people with confirmed or suspected infection has helped protect the public from diseases such as smallpox and, more recently, severe acute respiratory syndrome (SARS). A newly published review of 51 studies has found that physical barriers work better than drugs at preventing the spread of respiratory viruses

You will need to be on a campus computer or use the library proxy to access the Nature and British Medical Journal links directly.

Drug resistant TB

The World Health Organization published a report on drug resistant Tuberculosis this week. There's a report on it in the Journal Nature and lots of newspapers had articles.
I think this is one of those problems that we could fix with appropriate investment and effort. The problem is, as the report highlights, that we are not putting in the necessary investment:

WHO estimates that US$4.8 billion is needed for overall TB control in low- and middle-income countries in 2008, with US$1 billion for MDR-TB and XDR-TB. But there is a total financing gap of $2.5 billion, including a US$ 500 million gap for MDR-TB and XDR-TB.

Not investing the money to fix these problems now could get very expensive in the long run. Wired magazine asked WHO's 'Stop TB program' director Mario Raviglione why the US should be concerned about XDR-TB given that there4 have only been 49 cases here to date:

Even a couple cases a year costs the U.S. system tremendously. It costs several hundred thousand dollars to treat a case; they might need to have surgery, and the cost of drugs is tremendously high, as is the cost of following that person to make sure they're taking the drugs. Even a few casses a year is a very costly exercise. The best thing is to prevent MDR-TB and XDR-TB.

A billion dollars or two is a very small fraction of the federal budget - this is the sort of money politicians regularly lose down the back of the sofa. We should see spending on controlling drug resistant TB as an investment in the future.

Wednesday, February 27, 2008

Sea otters

The sea otter and toxoplasmosis research at UC Davis I mentioned is funded by NOAA (National Oceanic and Atmospheric Administration), part of the Department the Interior. They have a nice report on the work at the NOAA website here.

Stolen MRSA

A scientist stole MRSA and E coli in a suicide attempt. A little depressing but I found it interesting.

Tuesday, February 26, 2008

Amphibian decline

For more information on the worldwide Amphibian declines you can check out the articles on it at Amphibiaweb and Wikipedia. For the latest research news you can do a search on amphibian decline at Science Daily. There's a couple of interesting stories there:

Bacteria Show Promise In Fending Off Global Amphibian Killer - (May 25, 2007) — First in a petri dish and now on live salamanders, probiotic bacteria seem to repel a deadly fungus being blamed for worldwide amphibian deaths and even extinctions.

Parasites Might Spur Evolution Of Strange Amphibian Breeding Habits Parasites can decimate amphibian populations, but one researcher believes they might also play a role in spurring the evolution of new and sometimes bizarre breeding

Monday, February 25, 2008


One thing we desperately need is better communication of science research by journalists. You don't actually need to be a journalist to help with this, many newspapers and magazines will accept submissions from anyone. Universities are a great place to start because there are often some friendly places to start off - student newspapers, magazines and journals.

Andrea Swei, a grad student in my wife's lab who actually works on the Lyme disease project, wrote this summary of the chytridiomycosis project for the Berkeley Science Review. You heard much of this story today, how would you have summarized it - what would you have left in and taken out?

Sunday, February 24, 2008

It's not all bad.....

A new technique developed by a University of Central Florida chemist will help physicians more quickly identify the bacterial infections patients have so they can be treated in hours instead of days.

The technique uses gold nanoparticles coated with a sugar and a protein that binds to sugars. Meanwhile, a variety of antibiotics are placed in the same solution. A spectrophotometer reads optical variations in the gold nanoparticle solution as the sugar and protein shift , which in turn demonstrate which antibiotics effectively halt bacteria growth and which ones do not. Results can be obtained within a couple of hours, in contrast to the traditional methods, which can take days to complete. And hundreds of samples can be tested at once using this technique because the amount of bacteria and antibiotic needed is small.

The research paper is published in the journal 'Analytical Chemistry' but there is a summary here.

Saturday, February 23, 2008

Another toxoplasmosis post....

There was nice article by Carl Zimmer in the New York Times in 2006 describing some recent research that uncovered how Toxoplasmosis is able to move around inside the host body so quickly. Zimmer is the author of Parasite Rex, which is well worth a read if you'd like to know more about parasites and also has a blog called The Loom where he frequently posts about parasites and many other topics concerning biology and evolution.

Friday, February 22, 2008

Does Latent Toxoplasmosis really increase risk of traffic accidents? The BIG Picture.

Road Deaths:

Do you notice a difference between the maps? Probably not considering there hardly is any discrepancy between the two. In the upper map, found on , territory size shows the proportion of all road traffic accident deaths worldwide that occurred there. In the second lower map (which looks strikingly similar to the upper one to me), the territory size shows the proportion of the world population that lives there. If latent toxoplasmosis really increases the risk of traffic accidents, wouldn't we expect the countries with higher prevalence of this infection to have more road deaths? For example, rather than remaining relatively consistent with the proportion of the population that lives there, wouldn't we expect to see a higher amount of road deaths in France, Germany, the Netherlands, and Brazil where prevalence of toxoplasmosis infection exceeds 70 percent of the total population?

Another effect of Latent Toxoplasmosis? Having Boys?

Yet another study in the Czech Republic has come to some rather peculiar results concerning the effect of latent toxoplasmosis infection. After examining the clinical records of nearly 1800 newborn babies, they found that women infected with latent toxoplasmosis were more likely to give birth to baby boys. While the results of this study implied a higher likeliness of infected women to give birth to males, the researchers caution that it was simply an observational study and no conclusive cause and effect has been discovered. (For more on this study: Click Here)

While searching for some interesting articles about toxoplasmosis I was amazed by the range of effects of latent toxoplasmosis that various studies have claimed to find. Increased risk in traffic accidents, higher levels of intelligence, decreases in body weight, and lower guilt proneness are just a few of the many effects of dormant toxoplasmosis which I saw on just one google search! The subjective nature of some of these results, the lack of cause and effect evidence, and the fact that such a huge portion of the population is infected with latent forms of toxoplasmosis leads me to believe that some of these experiments may be trying to make something out of nothing...but that's just me.

Thursday, February 21, 2008

Toxoplasmosis Prevention

The CDC posted a new link last month on prevention and control for people who are healthy to follow the guidelines to reduce risk of toxoplasmosis.

To prevent risk of toxoplasmosis and other infections from food:

  • Cook food to safe temperatures. A food thermometer should be used to measure the internal temperature of cooked meat. Do not sample meat until it is cooked.
    1. Beef, lamb, and veal roasts and steaks should be cooked to at least 145°F throughout.
    2. Pork, ground meat, and wild game should be cooked to 160°F.
    3. Whole poultry should be cooked to 180°F in the thigh.
  • Peel or wash fruits and vegetables thoroughly before eating.
Washing kitchen counter

Photo courtesy of USDA.

  • Wash cutting boards, dishes, counters, utensils, and hands with hot soapy water after contact with raw meat, poultry, seafood, or unwashed fruits or vegetables.
  • Freeze meat for several days before cooking to greatly reduce chance of infection.

To prevent risk of toxoplasmosis from the environment:

  • Avoid drinking untreated drinking water, particularly when traveling in less developed countries.
  • Wear gloves when gardening and during any contact with soil or sand because it might be contaminated with cat feces that contain Toxoplasma. Wash hands thoroughly after gardening or contact with soil or sand.
  • Keep outdoor sandboxes covered.
  • Feed cats only canned or dried commercial food or well-cooked table food, not raw or undercooked meats.
  • Change the litter box daily If you own a cat. The Toxoplasma parasite does not become infectious until 1 to 5 days after it is shed in a cat's feces. If you are pregnant or immunocompromised:
Woman and man with cat

(CDC Photo)

  1. Avoid changing cat litter if possible. If no one else can perform the task, wear disposable gloves and wash your hands thoroughly with soap and water afterwards.
  2. Keep cats indoors.
  3. Do not adopt or handle stray cats, especially kittens. Do not get a new cat while you are pregnant.

Toxoplasmosis and Schizophrenia

It was found that people exposed to toxoplasma had a 24% higher risk of developing schizophrenia. Researchers did a study out of180 study individuals diagnosed with schizophrenia, 7 percent had been infected with toxoplasma prior to their diagnosis, compared to 5 percent among the 532 healthy recruits. The difference, while seemingly small, is important, researchers say, because the ability to explain even a small portion of the 2 million cases of schizophrenia in the United States may offer clues to the disease and some possible treatments. There have been previous studies reported on the link between schizophrenia and the presence of toxoplasma antibodies, which are evidence of past infection, but this is the first study to show that infection with the parasite can precede the initial onset of symptoms and subsequent diagnosis with schizophrenia. While most people infected with toxoplasma never develop schizophrenia, the parasite may be a trigger in those genetically predisposed to the disorder, a classic example of how genes and environment come together in the development of disease. Here's the link to the article.

Coping with antibitotic resistance

With the recent rise in both antibiotic resistance and concern about that antibiotic resistance we are now seeing more studies that look at the best way to deal with this problem. Here are two reports from the last couple of days as reported on by Science Daily.

MRSA: Mathematical Modeling Offers New Approaches To Fight Dual-resistant Hospital Infections
A mathematical model that looks at different strategies for curbing hospital-acquired infections suggests that antimicrobial cycling and patient isolation may be effective approaches when patients are harboring dual-resistant bacteria.

Changing The Way Antibiotics Are Prescribed May Be Key To Controlling Epidemics.
A sophisticated new mathematical model has identified what may be the key to getting this growing health problem under control: Changing the way that antibiotics are prescribed and administered.

Wednesday, February 20, 2008

Parasite makes men dumb, women sexy

I hope you find the Toxoplasmosis story as strangely fascinating as I do. Here are some links to other articles and news reports if you want to read a little further.

Toxoplasmosis changing human behavior was reported on by the Times (archived here) and, more sensationally, by the Australian Sydney Morning Herald with the great headline 'Parasite makes men dumb, women sexy'.

For such an amazing result the Toxoplasmosis/traffic accident story was largely ignored by the press although the BBC did do a news story. The Czech traffic accident survey has now been repeated in Turkey with essentially the same result.

I don't quite know what to make of this one. Apparently women affected with Toxoplasmosis are more likely to have sons than daughters.

Tuesday, February 19, 2008

All fun and games...

...until someone loses an eye.

From John's post about horrifying parasites, I found a link to a news video about a parasite which attacks unwitting contact-lens wearers. The name of the parasite sounded familiar, and being a contact wearer myself, I did some more research:

Acanthamoeba is a group of amoeba that are common in the environment, in soil and water. Some of them are pathogenic to humans, causing encephalitis when they enter wounds, or potential blindness when they enter the eyes. The video mentions that people have gotten such infections from contaminated water coming into contact with their contact lenses (such as musician Momus).

Many sources suggest that one could contract this parasite by wearing their contacts while swimming, surfing, etc. The risk in wearing contacts while swimming is that when the parasite gets between the lens and the eye, it is protected from removal by blinking action. The incidence is low (like 1.5 cases per million people per year in the U.S.), though contact-lens wearers are at higher risk. Thats a risk I'll have to take as I definitely need my contacts when surfing, but it is something to think about in relation to the public pool (and hot tubs). The literature suggests that cleaning lenses after swimming, throwing them out, or just not wearing them are the best prevention.

I also recalled some uproar about parasites in eyewash stations in science laboratories, so did a quick search and found a few articles mentioning that yes, acanthamoeba have been cultured from eye wash stations... (and this). A huge number of eye-wash stations seem to be sources of bacteria, amoeba, and fungi. But if they are cleaned/flushed regularly, this is much less of a problem. And again, preventive measures from getting nasty chemicals in one's eyes can reduce the risk of needing to use one in the first place.

Refer to wikipedia article for a teaser of how acanthamoeba might interact with MRSA.

Monday, February 18, 2008

Attack of the killer parasites

As a prelude to the upcoming week's lectures here is a video inspired by an article on horrifying parasites. I should note that the video is more for amusement than scientific accuracy but if you've already watched it hopefully you figured that out. The video was created entirely from public domain footage from old b-movies, forgotten creature features and cheesy instructional films with a couple of title cards and the voice over being the only additions.

Sunday, February 17, 2008

What has public health ever done for us?

I was watching an old episode of the Ben Stiller show on DVD the other night and there was an amusing sketch entitled 'B- time traveller'. Janeane Garofalo plays a character who travels to key moments in history but can never quite remember enough to be useful. She knows that Washington crosses the Delaware but doesn't know if he's attacking or retreating, she knows that Pearl Harbor is attacked but can't remember exactly which day will live in infamy. Anyway, this got me thinking about the old Mark Twain novel A Connecticut Yankee in King Arthur's Court. As you can probably guess from the title, even if you haven't read it, a 19th century American is transported back in time in the novel to medieval England. After the usual confusion he ends up applying his technological knowledge and ingenuity to modernize the society. He prints newspapers, starts industrialization and 'invents' electric fences and guns. Although the book is a satire, it is undoubtedly true that a 19th century American might have had a lot more practical technological knowledge than we do today. If you were transported back to 6th century England what technological expertise would you bring? Personally I thought I couldn't do much. I couldn't tell them how to make steel, I couldn't make an engine, or a printing press, or a weaving loom. I couldn't design or build an airplane or car and I couldn't even build a clock. In fact let's face it I probably couldn't even make fire or catch animals so I'd be at a disadvantage to the inhabitants of the 6th century. But then I realized the knowledge that I hope almost everyone has today that would be useful in the middle ages. Can you imagine what an impact you could have had on society if you just got people to wash their hands, cook their food properly, eliminate rodents and isolate their drinking water from sewage? I feel better already.

Saturday, February 16, 2008

This is a funny cartoon version of hand washing
4 basic principles of Hand Awareness. Here's the link if anyone is interested. Also, here's a cartoon version of how to wash your hands.

Hospital infection rates

State health regulators approved a sweeping crackdown designed to stem the spread of infections inside hospitals, a crisis blamed for thousands of patient deaths and millions of dollars in unnecessary medical expenses. The Public Health Council voted unanimously to dispatch state inspectors regularly to hospitals to make sure they are following rules on preventing infections and reporting them promptly when they happen. The panel also approved a plan to issue report cards on infection rates for each hospital and to post that information on a state government website. A hospital that failed to comply with the rules or continued to have an excessive number of infections could potentially forfeit its license.

A state report last summer found that potentially lethal infections contracted during hospital stays could be responsible for up to $473 million in medical costs annually in Massachusetts, a reflection of extended hospital stays and medication and surgical costs. National studies estimate that up to 90,000 patients a year die because of infections they catch while in medical facilities, with deadly germs gaining entry through surgical incisions and catheters and sometimes transmitted by doctors and nurses who fail to wash their hands. Here is the link to this article by the Boston globe.

MRSA infection

There are 2 main strains of MRSA: hospital-acquired and community-acquired. Hospital-acquired MRSA is when an individual would obtain MRSA from the hospital and community-acquired MRSA is where you get MRSA basically anywhere outside of the hospital. Because hospital and community strains of MRSA generally occur in different settings, the risk factors for the two strains differ. Here is a list of the different risk factors.

Risk factors for hospital-acquired (HA) MRSA include:

  • A current or recent hospitalization. MRSA remains a concern in hospitals, where it can attack those most vulnerable — older adults and people with weakened immune systems, burns, surgical wounds or serious underlying health problems. A 2007 report from the Association for Professionals in Infection Control and Epidemiology estimates that 1.2 million hospital patients are infected with MRSA each year in the United States. They also estimate another 423,000 are colonized with it.
  • Residing in a long-term care facility. MRSA is far more prevalent in these facilities than it is in hospitals. Carriers of MRSA have the ability to spread it, even if they're not sick themselves.
  • Invasive devices. People who are on dialysis, are catheterized, or have feeding tubes or other invasive devices are at higher risk.
  • Recent antibiotic use. Treatment with fluoroquinolones (ciprofloxacin, ofloxacin or levofloxacin) or cephalosporin antibiotics can increase the risk of HA-MRSA.

These are the main risk factors for community-acquired (CA) MRSA:

  • Young age. CA-MRSA can be particularly dangerous in children. Often entering the body through a cut or scrape, MRSA can quickly cause a wide spread infection. Children may be susceptible because their immune systems aren't fully developed or they don't yet have antibodies to common germs. Children and young adults are also much more likely to develop dangerous forms of pneumonia than older people are.
  • Participating in contact sports. CA-MRSA has crept into both amateur and professional sports teams. The bacteria spread easily through cuts and abrasions and skin-to-skin contact.
  • Sharing towels or athletic equipment. Although few outbreaks have been reported in public gyms, CA-MRSA has spread among athletes sharing razors, towels, uniforms or equipment.
  • Having a weakened immune system. People with weakened immune systems, including those living with HIV/AIDS, are more likely to have severe CA-MRSA infections.
  • Living in crowded or unsanitary conditions. Outbreaks of CA-MRSA have occurred in military training camps and in American and European prisons.
  • Association with health care workers. People who are in close contact with health care workers are at increased risk of serious staph infections.
To help reduce the threat of antibiotic resistance, doctors may drain an abscess caused by MRSA rather than treat the infection with drugs. Here's the link by cnn posted last july.

Friday, February 15, 2008

More Sources of HIV infection

A follow up to the post below since I'm not sure I can post links in comments to posts.

Great question. The answer to this question (what percentage of people acquire HIV from sexual intercourse, through the sharing of needles, and by other means) will vary a lot depending on the time period you are asking about and the country you are asking about.

Let's look at a few examples.

According to the CDC, in 2005 the cumulative figures for the AIDS epidemic in the US were:

Male to male sexual contact - 48%
Intravenous drug use - 26%
Both Intravenous drug use and male to male sexual contact - 7%
Heterosexual sex - 17%
Other - 2%

The sample size here is almost a million people.
BUT in the year 2005 alone, the figures were:

Male to male sexual contact - 43%
Intravenous drug use - 20%
Both Intravenous drug use and male to male sexual contact - 5%
Heterosexual sex - 30%
Other - 1%

Spot the difference? Heterosexual transmission has almost doubled and now accounts for 30% of cases. The other figures have gone down accordingly.

The final example is Africa, where data is harder to come by but numerous sources suggest 80% of the HIV infections in Africa are due to heterosexual sex with mother to child (vertical) transmission accounting for most of the rest. This paper has further data on African and some other areas plus a few useful references.

Sources of HIV Infection

In my section on Thursday there was a question about what percentage of people acquire HIV from sexual intercourse, through the sharing of needles, and by other means. I was unable to find any general statistics on the subject but I did find a study conducted in Norway which examines the number of people infected by different sources from 1984 to 2006. The results of this study show that nearly fifty percent of all new cases during these period were acquired by heterosexuals through sexual intercourse, 31 percent by homosexuals through sexual intercourse, 15 percent from the use of contaminated needles, and 1 percent from both blood transfusions and from mother to child. For more specifics on this: Click Here.

Thursday, February 14, 2008

Nasal carriers

There was a question in class about whether those individuals who carry Staphylococcus aureus are more likely to get nosocomial infections. Great question, and the answer is fascinating. Kindly provided by a study of:
Risk and outcome of nosocomial Staphylococcus aureus bacteraemia in nasal carriers versus non-carriers
Published in the Lancet journal in 2004. This is so relevant I think I'll actually mention this one in class. The answer is that as a carrier you are three times more likely to get an infection but much less likely to die of an infection if you get one. Non carriers are thus less likely to get infected but more likely to die if they do get infected!

Wednesday, February 13, 2008

Almost inevitable

Lest any of you thought I was exaggerating the dangers of MRSA here is a report from an Australian newspaper today. Australian doctors are not afraid to make some pretty blunt statements:

"If you go into an intensive care unit in a major Sydney hospital it is almost inevitable that you will get MRSA if you stay long enough."
Richard West, chair of the Royal Australasian College of Surgeons infection control advisory committee.

A google news search on MRSA will bring up several thousand articles.

It's painfully obvious that what we most need is a new acronym. Fortunately the CDC is available to bring us HA-MRSA: Healthcare-Associated Methicillin Resistant Staphylococcus aureus.

Tuesday, February 12, 2008


After hearing about the lack of research surronding the Ebola virus due to the fact that countries with a prevalence of Ebola do not usually have a market for purchasing vaccines and drugs, I was reminded of the hot topic of TRIPs. TRIPs (Trade Related Aspects of Intellectual Property) is an international agreement that was put forth by the World Trade Organization. This agreement sets up international standards of protection for intellectual property through copyrights and patents. While seemingly an effective plan at protecting the incentives and ideas of people worldwide, it has unfortunate effects on drug availability in developing countries. TRIPs enforces patents for 20 years on all fields of technology, preventing companies in developing countries from producing generic, more afforable, versions of new drugs. While adaptations have been made on this agreement, many argue that TRIPs continues to maintain higher drug costs across Africa (specifically creating consequences for AIDS).

For more about TRIPs: CLICK HERE

Sexually transmitted Lyme Disease ?

Yesterdays post reminded me of some articles I was reading a while back about the possibility that Lyme Disease could be spread sexually. A conference presentation from 2001 documents the recovery of Lyme spirochetes by PCR in semen samples of previously diagnosed Lyme disease patients. This, of course, does not necessarily mean active infection is transmitted this way. Some documents state that there are no documented cases of sexually transmitted Lyme disease (eg the CDC here and here) whilst others strike a more cautious note:

The CDC position on sexual intra-human Borrelia burgdorferi (Bb) transmission is that it does not occur. We find no study that addresses sexual transmission of Bb among humans; conversely, we find no study supporting that it does not occur. Inferential data, however, suggest the possibility of human sexual transfer. The data come from sound veterinary studies, the finding of Bb in human semen and breast milk, and by similarity to Treponema pallidum where sexual transfer is abundantly documented. Our clinical experience strongly suggests that predictable, possibly inevitable Bb transfer between sexually active couples occurs.

From: Lyme disease': ancient engine of an unrecognized borreliosis pandemic?
W. T. Harvey, P. Salvato

Monday, February 11, 2008

Sexually transmitted Ebola ?

Because Ebola is transmitted via infected bodily fluids someone asked whether it could be sexually transmitted. I suggested this was unlikely because individuals are not infectious until they are very sick. However I was forgetting about the 10-50% of people who do recover from Ebola. Apparently even though they have recovered from the disease they can still have virus in their semen up to seven weeks after they recovered. Recovered Ebola patients are advised to 'not have sex for 3 months or until tests show that semen is free of the virus.' Another possibility is that there may be some asymptomatic carriers of Ebola. These individuals may transmit the disease sexually. I hasten to add that transmission via this route is not thought to have contributed in a significant way to any of the known outbreaks. Interesting though.

Hot off the press is a news report that Ebola may not be so hard to work with in the future after all. By removing a single gene from the virus scientists were able to stop it replicating. That's one result they might want to double check......

Sunday, February 10, 2008

When monkeys attack

This article, on the 'Best, dangerous science jobs' from WIRED magazine last year isn't especially in depth or especially funny or interesting but I just love the graphics. I'll be using the monkey one in class a couple of times next week so I thought I'd pass on the credit here. Thomas Fuchs I salute you.

Popular Science magazine has an annual article on the worst jobs in science. Cherie mentioned that tick dragger made the list in their very first year. Their latest listing is here.

Discussion Reading Changes: Read Ch5 for 2/14 or 2/15

Given changes in the lecture schedule, we will also be changing the reading material for discussion this week. Previously, we were going to discuss a scientific paper on toxoplasmosis. Instead, please read Chapter 5 of The Coming Plague "Yambuku" which is about Ebola virus.

So, for Week 6, homework is to read Chapter 5.

For more 'background' on Ebola, check out the movie "Outbreak." It's fiction, and its not actually about Ebola (just an Ebola-like virus), but you are welcome to use this as an excuse to watch TV in the name of education. See if you recognize one of the characters from the sitcom "Friends."

I also highly recommend Richard Preston's non-fiction book "The Hot Zone," which is about Ebola and other hemorrhagic viruses. This book, and the aforementioned movie, were some of my favorites in high school.

Saturday, February 9, 2008

Super spreading double dipping

What is it with Seinfeld? I don't even particularly like the show but somehow I seem to have seen most of the episodes. It has replaced M.A.S.H. for the program that you are likely to watch when stranded in a motel or airport. The only reason I don't like it is that it is often too true to life, too painful to watch. I think the writing is wonderful and some of the best that has ever been on TV. The number of phrases that have made it into everyday language is amazing. Yadda yadda yadda... Anyway, this is all relevant to the class because of the classic 'double-dipping' episode. Science has now caught up with sit-com and the risks of double dipping have been quantified.

"I like to say it's like kissing everybody at the party — if you're double dipping, you're putting some of your bacteria in that dip."

Friday, February 8, 2008

Mid-course roundup

I updated the glossary and the weekly summary to include week 5. I waited until after the midterm to do this because I thought it would be useful for you to have these documents just with the material on the midterm. I'm that nice.

I think the midterm went well. Tom and I managed to grade most of it today and we'll be able to get it finished on Monday so you'll get it back in section next week. If you have feedback on the format of the midterm then I'd love to hear it, the final will roll around before we know it.

Plus, we are now halfway through the course so if you have comments on the course then now would be a great time to pass them on. I do welcome and read all the feedback I get on the end of course evaluations but if you give me feedback before the course is over I may be able to improve the course for you.

Thursday, February 7, 2008

Endogenous retroviruses

There's was great article in the New Yorker just a couple of month's ago on endogenous retroviruses. It describes their discovery and their potential influence on human evolution as well as links to AIDS and the recreation of the so called Phoenix virus in Thierry Heidmann's lab. I've been very impressed with science articles I have read in the New Yorker, I wonder if they could ever be persuaded to put out a Science textbook? The only thing remotely close to this I can think of is Bill Bryson's book, A Short History of Nearly Everything, which also conveys some of the sense of excitement of science with a genuine and infectious sense of wonder.

Wednesday, February 6, 2008

The Lost Children of Rockdale County

In the spring of 1996, as Atlanta prepared to host the summer Olympic Games, an outbreak of syphilis struck a group of teenagers in the prosperous bedroom community of Conyers, Georgia. When epidemiologists interviewed the victims, they were shocked by what they heard: children as young as fourteen named scores of sexual partners, others told of all-night orgies and sex parties.

I'm pretty unshockable but I found this PBS show on an outbreak of syphilis in Georgia pretty amazing. Although the show was aired in 1999, thanks to good old PBS you can access a lot of information about it at a website dedicated to the show and even read a complete transcript.

The website will also give you access to details about the actual investigation of the outbreak, the techniques used and the results. For example this paper shows the complete network visualization of the outbreak I presented in class.

STD versus STI

Somebody asked me about the replacement of the term STD (sexually transmitted disease) with the term STI (sexually transmitted infection). A little research suggests that this is becoming a widespread term for two reasons. First, it helps emphasize that many sexually transmitted diseases can be transmitted by those who are infected but do not show clinical signs of the disease. Secondly, the term "infection" carries less of a social stigma than the term "disease."

I'm not clear who initiated this trend but many organizations are now using both STD/STI (eg American Social Health Association) some are sticking with STD (eg the Center for disease Control and Prevention) and some are just using STI (eg the World Health Organization)!

The terms are not synonymous, as Wikipedia points out:
'The term STI — which refers to infection with any germ that can cause an STD, even if the infected person has no symptoms — is a much broader term than STD. The distinction being made, however, is closer to that between a colonization and an infection, rather than between an infection and a disease.'

Midterm info.

  • All the questions on the midterm can be answered using material from lecture.
  • Week 5 material is not included on the midterm - just the first 4 weeks.
  • You do not need to bring a blue book or scantron.
  • You do need to bring a pen and please, please write legibly.
  • Use the glossary and terminology summary as a guide to the terms you need to know but you will also need to know concepts from lecture.
  • The class grades may be curved - but only to your benefit. I'm quite happy for everyone to get an A grade and if that happens I will be delighted. On the other hand if everyone gets a C and, after consultation, it looks like this was my fault for being too tough I will set a curve.

Tuesday, February 5, 2008

Lyme Disease Poem

I thought I share this funny poem on Lyme Disease. If you like it, theres more on this link


My forgetters getting better
But my rememberer is broke.
To you that may seem funny,
but to me that is no joke.
For when I'm "here" I'm wondering
If I really should be "there"
And, when I try to think it through,
I haven't got a prayer!
Oft times I walk into a room,
Say "what am I here for?"
I wrack my brain, but all in vain
A zero, is my score.
At times I put something away
Where it is safe, but, Gee!
The person it is safest from
Is generally, me!
When shopping I may see someone,
Say "Hi" and have a chat,
Then, when the person walks away
I ask myself, "who's that?"
Yes, my forgetters getting better
While my rememberer is broke,
And it's driving me plumb crazy
And that isn't any joke.

Book recommendations

I hope some of you are enjoying reading the Coming Plague. I've mentioned a couple of books in class already but I thought I'd gather them all together here. Please add a comment if there are additional books you would recommend. I'm linking to Amazon not because I'm endorsing them or getting a kickback but because they host book reviews so you can read more about a particular book regardless of whether you buy it there or not. In no particular order:

The Mold in Dr. Florey's Coat by Eric Lax- an interesting account of the discovery and development of penicillin. It focuses on the people and gives you a good perspective on the difficulties they faced.

Disease in History by Frederick Cartwright - a little old now but really a classic text on the impact of disease on history.

The hot zone by Richard Preston. The dramatic and chilling story of an Ebola virus outbreak in a surburban Washington, D.C. laboratory. Richard Preston has also written a book about the potential use of smallpox as a biological weapon called The demon in the Freezer. I like the fact he got Stephen King to write a blurb for the back including this quote: 'One of the most horrifying things I've read in my whole life'.

The Ghost Map: The Story of London's Most Terrifying Epidemic--and How It Changed Science, Cities, and the Modern World by Steven Johnson. I think I already mentioned this one, a recent book discussing John Snow, Cholera and the origin of epidemiology.

Monday, February 4, 2008

The World as You've Never Seen It

This Worldmapper website re-sizes countries for each area of interest. In the picture above, the territory size represents the proportion of people infected with HIV living there. Use the worldmapper to check out everything from the amount of smoking men to the amount of Cholera cases to the amout of car accidents to the amount of hospital beds. It is a great site that is fun and interesting to fool around on so, go for it! Worldmapper Home


The 2007 UNAIDS epidemic update, published in November 2007, reports on the latest developments in the global AIDS epidemic. It provides the most recent estimates of the AIDS epidemic and explores new findings and trends in the epidemic’s evolution.

FYI the Isla Vista Medical Clinic at 970 Embarcadero Del Mar offers both Confidential and Anonymous HIV testing.

Sunday, February 3, 2008

2009 CDC Budget

As you may have seen details of President Bush's 2009 budget have been in the newspapers this weekend. He will submit it to congress on Monday. It projects a budget deficit around $400 billion in a $3 trillion dollar budget. Defense spending is projected to rise by about 7 percent to $515 billion and homeland security money by almost 11 percent. Most other programs see their budgets frozen or reduced.
The Centers for Disease Control and Prevention face a 7% cut of more than $430 million, including $27 million cut from its efforts to detect and control infectious diseases, and $28 million cut from chronic disease prevention and health promotion.

My math could be wrong here but it looks like the entire CDC budget (which must be around 6 billion if $430 million is 7% of it) is less than a fifth of the defense spending increase proposed for this year (the increase must be about $36 billion if it is 7% of $515 billion). It gets confusing when you have trillions, billions and millions in the same story....

WHO reports Tamiflu-resistant flu in U.S. and Europe

Influenza strains circulating in Europe have been found to have high levels of resistance to the antiviral drug Tamiflu. This is of concern because Tamiflu would be one of the main defenses against an Influenza pandemic.

The height of reckless irresponsibility

'The height of reckless irresponsibility on the part of ABC and its parent company The Walt DisneyCo.'
Renee Jenkins, president of the American Academy of Pediatrics.

I didn't see it but ABC started a new show last week in which the storyline involved the hypothesis that autism is caused by a mercury-based preservative formerly used in common childhood vaccines. Despite the fact there is virtually no scientific data linking vaccines and autism and numerous studies have failed to find a link, the show treats the hypothesis as being credible and only presented a notice at the end to say "The preceding story is fictional and does not portray any actual persons, companies, products or events". The New York Times has an article about it.

Interesting issues here, do TV companies have moral obligations or are they simply beholden to their owners and/or shareholders? We have seen the effect of declining vaccine uptakes in other countries sparked by rumors so it would be naive to suggest that a TV show couldn't have an effect.

Friday, February 1, 2008

The Lyme Disease Controversy

Given that Lyme disease is a relatively recently awknowledged illness, there is quite a bit of debate concerning its diagnosis and treatment. The Office of Professional Medical Conduct (OPMC) has argued that Lyme disease is easily diagnosed and properly treated by administering antibiotics for four or so weeks; however, many Chronic Lyme disease patients, as well as their doctors, feel differently. They believe that due to many of the long term symptoms, treatment for Chronic Lyme disease should extend well beyond the typical four week period and medicines in addition to antibiotics should be offered. This debate only made headlines however, when the OPMC began to persecute and actually revoke the licenses of doctors whom offered unconventional care to Lyme disease patients. These actions by the OPMC began an ongoing legislative fight by the Lyme disease community to protect physicians who administer innovative treatment to their patients.

For more information: Click Here or Here.