Vaccines and Autism

Autism has become more prevalent in the past 20 years, as have early childhood vaccinations. Seeking an answer for the increase in autistic children, many people have began to blame vaccinations as the primary cause. Is this justified? Well, thimerosal, which is a mercury-based preservative, was used in childhood vaccinations up until about a decade ago (however, it is still used in the Flu shot). And there have been associations of high mercury levels in autistic children, a possible link to the vaccination theory. However, as of yet, no research has proven vaccinations as a cause of Autism. The higher mercury levels may be due to the inability to process metal as efficiently as non-autistic children because of biochemical defects. Additionally, testosterone has been shown to affect mercury levels, and most autistic children are males. So why are people still so convinced that vaccinations cause Autism? Children get vaccinated around the same time that a child with Autism would begin to show symptoms. Parents need an explanation for what is happening to their children, yet there have been no definitive causes of Autism, so they just associate the onset of Autism with the most recent change in their child's life, vaccinations. Until further, definitive research is discovered, the debate about Autism and vaccines will continue.

For more information, check out this article in The New York Times.

Mortal Terror in a Partial Zombie Population

Okay, the graph is moderately amusing (and I am confident enough in my nerdiness that I can admit to finding most of the graphs on Graphjam moderately amusing) but the relevant point here is the discussion it sparked when posted on BoingBoing.

Yeah, this seems very inaccurate. If we're talking about "total amount of terror," it should go down the more people get zombified. If, as seems more likely, we're talking about the amount of terror in the average non-zombie, it still wouldn't be a smooth curve like that. It would plateau pretty damn early. The difference between 0% and 10% would be a lot bigger than the difference between 10% and 90%. And 100% wouldn't be zero terror, it would just be N/A: there is no more population.

This is directly relevant to SIR models because you can easily get confused if you fail to distinguish between individual and population level parameters. The confusion here is because 'terror' is not defined - is this your individual level of terror (a feature of the number of zombies and their fearsomeness), or the total amount of terror in the population (a feature of the number of zombies and their fearsomness AND the number of unzombified people around to be scared by those zombies).

Really cool SIR model demonstration

Some of you may be familiar with the programming software Mathematica, which has many tools for manipulating and visualizing mathematical models. Now before you zone out, take a look at this: an interactive visualization of the SIR epidemic disease model that allows you to see how changing parameters like number of contacts and fraction immune affects disease dynamics. You can play with the sliders to change parameter values, and the graph of the number of susceptibles and infecteds changes automatically. It is a very cool way to get an intuitive handle on how the SIR model works. Think about how the quantities you can manipulate in the Mathematica demonstration relate to the parameters we discussed in class: beta and gamma. Note that the model they use does not have a Recovered/Removed class--only susceptible and infected.

In order to play with the demonstration, you have to download a free copy of Mathematica Player 7 (the site will walk you through it when you click on the demonstration). It is totally worth it because I'm telling you, this demonstration is cool and it will really help you understand how the epidemic model works. If you get into it you can search Mathematica's demonstration website and find other cool ones. It's good geeky Friday fun.

IMPORTANT

Don't forget to print and read the Ewald paper on the evolution of virulence for section next week (even you Monday people, read it after you take the midterm if necessary). It wouldn't hurt to jot down a few questions or comments about it to prepare for discussion, since I will be grading you on participation. Besides, if you don't read then discussion will be lame and your TA will be :(

Syphilis, Yaws and Columbus

A network path for four informative substitutions shows that New World subsp. pertenue, or yaws-causing strains, are the closest relatives of modern subsp. pallidum strains.

Syphilis, caused by a spirochete bacteria, was first reported in Europe in 1495 and there have been a number of hypothese to explain its relatively recent appearance. I briefly mentioned the possibility that the Black Death may have played a role in its emergence.

For a long time the emergence of syphilis was associated with the discovery of the New World and is sometimes cited as being the only new disease to make the journey from New World to Old World (lots of diseases made the journey the other way, and diseases like smallpox and measles decimated the New World populations). But other diseases such as Yaws, caused by the same species of bacteria, have a widespread distribution in both the New and Old World.

A paper this week in PLoS Neglected Tropical Diseases provides evidence from a phylogenetic study that suggests that while other forms of the Treponema pallidum bacterium have plagued humans since early in our evolution, it emerged as venereal syphilis only when carried back to Europe by Columbus and his crew.

Pharaohs' Plague

The National Geographic magazine had this running article: Bubonic Plague Traced to Ancient Egypt

Panagiotakopulu came upon clues to the plague's presence in ancient Egypt by accident. She had been looking at fossil insect remains to learn about daily life more than 3,000 years ago.

"People lived close to their domestic animals and to the pests that infected their household," Panagiotakopulu said. "I just started looking at what diseases people might have, what diseases their pigs might have, and what diseases might have been passed from other animals to humans."

The researcher used a fine sieve to strain out remains of insects and small mammals from several sites. Panagiotakopulu, who is conducting similar work on Viking ruins in Greenland, said that looking at insects is a key way to reconstruct the past. "I can learn about how people lived by looking in their homes and at what was living with and on them," she said.

In Egypt Panagiotakopulu combed the workers'-village site in Amarna, where the builders of the tombs of Egyptian kings Tutankhamun and Akhenaton lived. There, the researcher unearthed cat and human fleas—known to be plague carriers in some cases—in and around the workers' homes. That find spurred Panagiotakopulu to believe that the bubonic plague's fleaborne bacteria could also have been lurking in the area, so she went in search of other clues.

Previous excavations along the Nile Delta had turned up Nile rats, an endemic species, dating to the 16th and 17th century B.C. The plague's main carrier flea is thought to be native to the Nile Valley and is known to be a Nile rat parasite.

According to Panagiotakopulu, the Nile provided an ideal spot for rats to carry the plague into urban communities. Around 3500 B.C., people began to build cities next to the Nile. During floods, the habitat of the Nile rat was disturbed, sending the rodent—and its flea and bacterial hitchhikers—into the human domain.

Egyptian writings from a similar time period point to an epidemic disease with symptoms similar to the plague. A 1500 B.C. medical text known as the Ebers Papyrus identifies a disease that "has produced a bubo, and the pus has petrified, the disease has hit."

It's possible that trade spread the disease to black rats, which then carried the bacteria to other sites of plague epidemics. Panagiotakopulu suspects that black rats, endemic to India, arrived in Egypt with sea trade. In Egypt the rats picked up plague-carrying fleas and were later born on ships that sailed across the Mediterranean to southern Europe.

Fortune cookie wisdom

I have added two items that may be useful to you in preparation for the forthcoming midterm. Both of these are available at the list of links on the right side of this page.

The first is a list of the glossary items we have covered to date and the second is a sample midterm. It doesn't have a full set of questions but it does have the same format and samples of each type of question.

I'd just got this stuff together and was putting together the midterm at the same time when I got hungry and went to the UCEN for lunch. I got the following fortune cookie:




Hmmm.....

Weaponized Pneumonic Plague

According to Colonel Bryon Weeks, M.D., the best weaponized form of pneumonic plague was developed in Russia. This system utilizes canisters that release the plague in powdered form from a cruise missile, which is difficult to detect. While the Japanese attempted to weaponize the plague via the use of infected fleas, the Soviets met more success with creating an aerosol form. This form can be quite dangerous, due to the contagiousness of the plague. This weaponized form is resistant to at least 16 different antibiotics, and a vaccine used against the bubonic plague up until 1998 was not effective against this form.

Details can be found here:
http://archive.newsmax.com/archives/articles/2001/10/16/134822.shtml

According to this CDC video, the plague has been used as a weapon as early as the Tartars, who catapulted infected corpses into the city of Kaffa in an attempt to spread the disease. However, scientists believe that the city got the disease through flea-ridden rats. The Japanese unit 731, under General Shiro Ishii, also used the plague by dropping infected flea-filled bombs in China. The United States researched an offensive use of the plague but had difficulties maintaining its virulence. The Soviets, however, overcame the problem and according to defector, Dr. Alibek, are said to have 1,500 metric tons of the plague.

Video can be found here:
http://www.bt.cdc.gov/training/historyofbt/03plague.asp

Pie Jesu domine, dona eis requiem

Is it possible to go to YouTube to find a specific clip and then leave without watching something else? I suspect not. Thinking of the Black Death and the Middle Ages always makes me think of this clip from Monty Python and the Holy Grail.



But I had totally forgotten the brief appearance of a group of 'flagellants' at the start of the witch scene. Classic.

More on Global Warming and Lyme Disease

So I know this is a little late for Lyme disease, but I found an article about it that draws and expands on Reikan Lin’s post from Sunday, “Global Warming as an Anthropogenic Factor.” Apparently, global warming is wreaking havoc in more ways than one. There is now a risk that global warming episodes may be associated with more epidemics of tick-borne diseases.

Dog ticks, mostly prevalent in spring, do not usually bite humans--the only cases have been in the summer because the ticks do not respond well to high temperatures. However, the current rising temperature of the earth is causing a problem, in that dog ticks now have an increasing affinity to bite humans. This is confirmed in both history and experimental models, where "under the effect of warmth, it was as if the ticks had gone mad and started to bite humans."

At least the Lyme GIANTmicrobe is cute!

Eyam

A few links to follow up on stories from today. More on the plague outbreak in the village of Eyam here and here.

The CCR5 story has attracted quite a lot of attention. Some argue that it was more likely to be smallpox than the black death that altered the gene frequency and others have shown that the mutant form of CCR5 does not appear to offer protection against the plague, in mice at least.

Previous posts of interest:

• The Plague as a Biological Weapon
• The Great Chinatown Fire
• Flagellation in German rock video

Thanks

I want to thank everyone who has been posting here. There have been some great posts and the blog has really taken off this year. I'd totally forgotten I had Google Analytics installed on the blog. Here are some statistics to let you know that your posts are not in vain. People do visit the site!

The blog gets between 30 and 60 unique visitors per day. It averages about 5 when the class isn't running so discounting this background rate and assuming a few people visit from more than 1 computer in a day then there's probably still between a quarter and a half the class visiting each day.

Most visitors come directly to the site but a few (probably mainly non-class visitors) find the blog via search engines. Given the eclectic nature of the blog people have found it using some very strange search terms. Here are a few of my favorites:

• cholera stuffed animal
• morticia addams nail varnish
• scrofula humor
• sports drinks
  

Saving ferrets from the plague?

From lecture, we learned that while rare, bubonic plague still exists in North America, carried by fleas and the rodents they feed on. What rodents are these? In the southern U.S., it’s usually prairie dogs.
While the likelihood of a human catching bubonic plague from a prairie dog is not high, other problems exist from the high prevalence of plague in the prairie dog population. The largest is the risk that the plague poses to the black-footed ferret, an animal indigenous to the American southwest.
Black-footed ferrets are highly endangered, and the plague puts them even more at risk. Not only can they catch the plague from prairie dogs they eat, but the high mortality rate of the plague can nearly exterminate the prairie dog population, the ferret’s largest food source.
Right now, the National Wildlife Health Center is working on vaccines for prairie dogs and ferrets, to try and save both species before it’s too late.

Plague sweeps al-Qaida camp in Africa

There are reports this week that an outbreak of bubonic plague has killed 40 members of AQLIM (al-Qaida in the Land of the Islamic Maghreb), the largest and most powerful al-Qaida group outside the Middle East, at a training camp in Algeria in North Africa. Although Bubonic plague is still endemic to this region there are rumors that the deceased were victims of al Qaeda biological warfare experiments at a camp in the forested hills of coastal Algeria. Although picked up by a number of international newspapers and media organizations, the original source appears to be the British Sun newspaper - not exactly well known for breaking stories of international terrorism. Curiously this week old story has not received much press in the US although the Washington Times does claim to have confirmation of the story from an anonymous 'senior US intelligence official':

The official, who spoke on the condition he not be named because of the sensitive nature of the issue, said he could not confirm press reports that the accident killed at least 40 al Qaeda operatives, but he said the mishap led the militant group to shut down a base in the mountains of Tizi Ouzou province in eastern Algeria.

He said authorities in the first week of January intercepted an urgent communication between the leadership of al Qaeda in the Land of the Maghreb (AQIM) and al Qaeda's leadership in the tribal region of Pakistan on the border with Afghanistan. The communication suggested that an area sealed to prevent leakage of a biological or chemical substance had been breached, according to the official.

Sexy mosquitoes? Superfly!

The other week I was browsing news sites after reading the chapter in The Coming Plague about cities and their effects on disease ecology. One of the most interesting parts of this chapter was the discussion of Dengue Fever, and how the spread of this disease and the mosquitoes that carry it was always facilitated by human attempts to curb the spread of this disease. Mosquito control has been a big part of the spread (or hopefully lack thereof) of many tropical diseases. Dr. Latto even mentioned the funny thing about DDT killing Bolivian cats last week, and how that may have contributed to an outbreak of a very nasty virus. We have come a long way from DDT now, and vector control methods are getting pretty sophisticated.
Scientists have been searching for ways to reduce the population of tiger mosquitoes in the world, as they are the primary carriers of malaria. What better way to do this than to simply stop them from creating offspring? Now it looks like that is a possibility. If sterile male mosquitoes were released into the wild, theoretically the population of mosquitoes would decline. Some scientists have even discovered ways to genetically engineer mosquitoes that can't carry malaria or dengue. The problem with this theory has been that female mosquitoes can tell that these guys have been altered, and they don't find the new males attractive at all.
In this BBC article scientists explain that they have discovered what mosquitoes find attractive in a mate, and apparently it is perfect pitch! When mosquitoes mate they beat their wings to create a humming harmony, and females can judge the fitness of male mosquitoes according to how well they "sing" with their wings. Previously, female mosquitoes rejected the genetically altered males. Maybe by releasing sexy sterile male mosquitoes into the wild we could see some very interesting effects on the ecology of the tropical illnesses that they traditionally carry.

Plague as an offensive manuever

During the second sino-japanese war, plague was used as a bacteriological weapon by the Imperial Japanese Army. These weapons were provided by Shirō Ishii's units and used in experiments on humans before being used on the field. For example, in 1940, the Imperial Japanese Army Air Service bombed Ningbo with fleas carrying the bubonic plague. During the Khabarovsk War Crime Trials the accused, such as Major General Kiyashi Kawashima, testified that, in 1941, some 40 members of Unit 731 air-dropped plague-contaminated fleas on Changde. These operations caused epidemic plague outbreaks.

The Triumph of Death

Hell on Earth, the nightmare depicted by Flemish painter Pieter Bruegel in his mid-16th-century "The Triumph of Death" reflects the social upheaval and terror that followed plague, which devastated medieval Europe.

National geographic has a plague photo gallery with some nice, and not so nice, pictures.

Everything You Want to Know about Copepods!

Professor Latto mentioned copepods being a reason for the re-emergence of Cholera. He said that the Cholera bacteria can remain dormant within copepods until conditions are suitable for the bacteria to re-emerge. I thought this was very interesting but I had no idea what a copepod was so I decided to show some videos on what it looks like as well as its behavioral actions.

Copepods are small crustaceans found in almost every freshwater habitat. They are extremely important to the global ecology of the ocean as they are prey for many sea animals. They are typically 1 to 2 millimeters with a tear-dropped shaped body and a large antennae. They have one single eye, and some may even be eyeless. Many of these copepods can be filtered out of water with a simply using a cloth filter.

If you want to see real videos of these interesting creatures, check out this link:
http://jaffeweb.ucsd.edu/pages/celeste/Animations/

Not just for doctors waiting rooms.....

Placid under sedation, a juvenile rhesus macaque yields biological samples that could show him to be infected with human diseases such as tuberculosis or measles. Similarly, primates can pass pathogens to humans—potentially touching off pandemics.

If you'd like to read a little more about zoonotic diseases National Geographic had a great article a little over a year ago: Deadly Contact: How Animals and Humans Exchange Disease

We will return to this topic, and the issue of bushmeat, when we talk about Ebola.

Global Warming as an Anthropogenic Factor

As a top environmental issue, global warming has been correlated to large amounts of illness and death in the United States and Canada. One factor that contributes to this is the spread of infectious disease, including Lyme disease. Ticks are being found much further north of their established habitat, since they are now able to survive in areas that were previously too cold for them. Scientists predict that tick-infested regions will stretch up to 200 kilometers north by the 2020s and 1000 kilometers by the 2080s. Other diseases are also making their way to previously uninhabitable areas via mosquitoes and pollen. There is also an increased risk of spreading disease due to rainfall after water contamination.

Details can be found here:
http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2007/04/17/MNGFCP9UL41.DTL

Zimbabwe Cholera update

Since we mentioned Cholera again this week I thought I'd pass on the latest news, and it isn't good.

The World Health Organization now puts the total number of deaths from cholera in Zimbabwe at 2,773 as of Thursday while the number of cases since August has exceeded 50,000. The disease has also spread to neighboring South Africa.

Even more concerning, the fatality rate continued to rise to 5.7% compared with the international norm of about 1%.

The situation is being exacerbated by the onset of the rainy season, by a movement of the disease to more rural areas and by Zimbabwe's economic turmoil. The Zimbabwe dollar is virtually worthless, because of hyperinflation. Last week, a new Z$100 trillion note was launched - worth about US$30.

Japan’s Secret Weapon

In scientist-writer Barclay Newman’s 1944 book, “Japan’s Secret Weapon,” there is evidence of a weaponized form of spirochetes, including borrelia microbes which cause Lyme disease. These spirochetes do not have a cell wall, which renders antibiotics ineffective. According to Newman, many of these spirochetes resistant to antibiotics are a result of weapon experimentation during World War II. Journalists of the 1980s finally uncovered the activities of Japanese Unit 731, including the experimentation of infectious disease on innocent civilians. Despite the atrocities, the United States allowed the bio-weapon engineers to continue their research, including Erich Traub, stationed on Plum Island, which is quite close to Lyme, Connecticut, where the first documented outbreak of Lyme disease occurred in the 1970s.

Details can be found here:
http://www.lyme-rage.info/spirowarfare.html

Rabies

Another zoonotic disease I briefly mentioned in passing was rabies. As you may know rabies is a very nasty viral disease that is invariably fatal once symptoms appear. Only six people are ever know to have survived rabies after symtpoms appeared, the last one a girl bitten by a rabid bat in Wisconsin in 2004.

Although it only causes a handful of cases a year in developed countries, and has been eliminated in some it still causes over 24,000 deaths a year in Africa, mostly children in poor rural communities.

A recent paper in the Journal of General Virology analyzed 182 samples of dog rabies virus from 27 African countries taken over a time period of 29 years. They showed that most of the rabies virus circulating in dogs in western and central Africa comes from a common ancestor introduced to the continent around 200 years ago, probably by European colonialists.

Dr Hervé Bourhy et al. Evolutionary history and dynamics of dog rabies virus in western and central Africa. Journal of General Virology, (in press)

For the picture to the right:
As Professor Latto was saying earlier today in class, Lyme Disease is much more prevalent on the East Coast. I came across this cartoon and thought it quite appropriate to today's lecture about coastal differences for the disease.

If the picture isn't large enough you can use this link: http://www.cartoonbank.com/item/41816

For the picture to the left:

The risk to humans for Lyme disease is determined by:

1. Density of nymphal ticks

2. Infection prevalence in nymphal ticks

3. Human behavior

The cartoon to the left is a humorous example of how human behavior could affect your encounters with Lyme disease.

Famous people and not-so-famous people...

When Professor Latto mentioned that he knew of some famous people with Lyme disease, I got curious. One Google search found the names of many recognizable people who have had Lyme disease. They included actors Richard Gere and Michael J. Fox, as well as authors Amy Tan (The Joy Luck Club) and Meg Cabot (The Princess Diaries).
While I was searching for these names, I came across two websites. The first, LymeBlog, contains news about Lyme disease, as well as the personal blogs of people who suffer from it. The second, TruthAboutLymeDisease, is similar, although it is geared more toward helping people discover if they themselves have Lyme disease, and what to do about it. The very existence of these websites does more to show the prevalence of Lyme disease today than any number of infected famous people ever could.

Bad tick, no nail varnish for you

When ticks bite they actually secrete a cement like substance that cements their mouthparts in place. That is why they are so hard to remove. Disturbing the tick can cause it to regurgitate material potentially infected with the Lyme disease bacteria into the wound so increasing the chances of infection. Most experts agree that the safest course of action is to avoid the fancy folk remedies involving nail varnish, open flames, or screwing the tick out counter clockwise and go with a straightforward tweezer removal - making sure you grasp the tick as close to the mouthparts as possible and pull smoothly away from the skin. The pictures here are form Cornell's 'Tick Biology for the homeowner' website.

Under Our Skin

There is a new documentary out called Under Our Skin that interviews people with Lyme disease and doctors who have been trying to help them. Many of the patients were told that "nothing is wrong with you" or that they just had a psychosomatic problem. It also addresses the political and economic issues tied with Lyme. I was touched by what some of the patients said in the trailer...

What's at stake is life or death.

Maybe my death can help other people so they don't have to suffer as I suffered for so long.

I was treated and then considered cured and went on to have two more children, I then gave it to them congenitally and they have been very ill.

The sad thing is that so many of these cases could have easily been treated if they had been caught in time, or if the doctors had even acknowledged that something was wrong with them.

The documentary also has a blog with information about the documentary and general Lyme disease news. For screenings near you or information on how to buy the dvd, check the website.

How does that make you feel …?

Lyme disease causes more than just physical ailments. Often times, when Lyme disease goes undiagnosed, the brain becomes infected, causing neuroborreliosis. Patients may appear to just be suffering from psychological problems, such as hallucinations, obsessive compulsive disorder, or manias. Referring the patients to psychologists or psychiatrists, physicians often do not diagnose patients who suffer from cognitive impairments with Lyme diseases. However, what they are suffering from is not created in their head, but instead by a bacteria which has created lesions in the brain. Much like syphilis, which can cause neuropsychiatric disease, once these sufferers are treated with antibiotics, they can return to a normal mindset (as long as brain damage is not too severe). A milder case of neuroborreliosis is encephalopathy, which results in a confused mind-state (i.e. inability to concentrate, lapses of memory, difficulty following asleep, and lethargy). Because these symptoms are not obviously associated with severe health problems, many Lyme disease sufferers live their lives unaware that they are suffering from this disease.

Check out this article, to read more about the psychological effects of Lyme disease.

Leprosy in Armadillos!!!

Armadillos have proven to be very important in the discovery of cures for leprosy because they are the only animal in North America that have shown to be susceptible to systematic infection of leprosy bacillus. This report shows the findings from wild armadillos in Texas. This article is unsure of how susceptible humans are to contracting leprosy from armadillos, but through excessive handling it is shown that the risk becomes greater.

The article includes many graphs to show where the infection of leprosy was the greatest and how these armadillos possibly contracted the disease.

http://www.jwildlifedis.org/cgi/reprint/23/2/220.pdf

Amy Tan

Amy Tan, the author of the Joy Luck club amongst others, is also a victim of Lyme disease. She has a section on her website where she describes some of the more bizarre psychological manifestations

Hallucinations began, what I now realize were likely simple partial seizures, the result of lesions on my brain. I saw people walking into my room, two girls jumping rope, numbers spinning on an odometer, a fat poodle hanging from the ceiling.

and her difficulty in getting an accurate diagnosis and treatment:

after I started antibiotic treatment I took part in a study in which my blood was sent out to five different labs for the ELISA and Western Blot. The results were all over the place -with Lyme-specific bands lighting up in one lab and not the other. There was almost not a single consistency.

The necessities of life

Another movie with a Tuberculosis tie-in made the news today as it made the short list to get on the Oscar nominations for best foreign language film. "The Necessities of Life," by Montreal director Benoit Pilon is about an Inuit hunter, his family, and community during an outbreak of tuberculosis in the 1950s when the government gathered up more than 1,500 Inuit in a bid to eradicate a tuberculosis outbreak.

Some earlier TB postings you might find interesting before we leave this topic:

• XDR-TB in South Africa
• Patients flee, drawing attention to quarantine dilemma
• Tuberculosis and AIDS
• XDR-Tb in California

Cholera in The Secret Garden

Although this revelation is a little overdue, I just realized that in the popular movie and book The Secret Garden an outbreak of cholera is what kills Mary Lennox's parents and ultimately forces her to move to England. I found a clip on Youtube from the 1987 version of the movie which shows Mary's parents becoming infected and the people of India trying to flee the disease.

http://www.youtube.com/watch?v=QgqwyFqx6oE

The clip cuts off before it is shown, but Mary's mother, father, and a majority of her servants die the morning after contracting the disease, illustrating cholera's high virulence; Mary goes to sleep with parents and wakes up the next morning an orphan.

Wordle

The picture above is from Wordle, a fun tool that generates “word clouds” from text. The clouds give greater prominence to words that appear more frequently in the source text. In honor of the 200th post on the blog I pasted in the entire blog and then just deleted a few words (‘posted’, ‘comments’,’label’) that automatically appear at the end of every post and aren't very informative. The remaining cloud is an interesting visual way of showing what this blog is about. Thanks to all the new posters this quarter - notice the prominence of ‘Cholera’ and Tuberculosis’, the two diseases we have covered to date.

Got TB? Have some heroin...

In the early 1800s, morphine and opium were the drugs of choice for treating tuberculosis (and many other diseases). Drugs that actually cured the disease, or even its symptoms didn’t exist yet, so all that physicians could do was dose their patients with something to dull their pain. Morphine, along with its derivatives, including opium, laudanum (used to induce sleep), and heroin (good for quieting a cough), were perfect for this. Unfortunately, many doctors neglected to mention its addictive qualities, and patients were addicted before they knew it.
With the antibiotic resistance that many strains of tuberculosis are now showing, how soon before we're back to morphine with no other alternative?
For more about morphine and its role in Victorian treatment, click here or here.

Another Reason to Love Green Tea

A study suggests that green tea helps antibiotics in their fight against resistant superbugs, making them up to three times more effective. In the study, scientists tested green tea in combination with antibiotics against 28 disease causing micro-organisms.

“In almost every case and for all types of antibiotics tested, drinking green tea at the same time as taking the medicines seemed to reduce the bacteria's drug resistance, even in superbug strains, and increase the action of the antibiotics.”

In some circumstances, the killing effect of one antibiotic was 99.99% better when taken with green tea than when taken alone. To read about the full study, and what this will mean for the future, check out the article from Science Daily.

[As promised, penicillin!]

TB Resistance in Impoverished Peru

Dr. Sanjay Gupta examines Tuberculosis in Peru's poorest living conditions. We see how easily this disease is spread from person to person where the quality of life is so low. People live in close quarters, potable water is a luxury, and there are less means available for treating the disease. In this in one village, steps were taken to improve living conditions and regulate care for the infected. Partners in Health teamed up with the Peruvian government to educate citizens and eventually cure 75% with drug-resistant TB.

(LINK IN 1ST COMMENT)

Hydramacin

Although new antibiotics are discovered quite regularly it is unusual that a whole new mode of action is discovered. A compound called Hydramacin was described in a paper yesterday. The compound was discovered in the freshwater hydra, hence the name.

In a series of laboratory experiments hydramacin was shown to kill a wide range of both Gram-positive and Gram-negative bacteria. Hydramacin works by sticking to the bacterial surface, promoting the clumping of nearby bacteria, then disrupting the bacterial membrane.

Corn Liquor as a Savior?

The discovery of penicillin as an antibiotic revolutionized drugs against disease, but one of the biggest problems was that there wasn’t enough of it to combat infectious diseases. In Peoria’s Northern Regional Research Laboratory (NRRL), five scientists, Robert Coghill, O.E. May, George Ward, Kenneth Raper, and Andrew Moyer worked on finding ways to mass produce penicillin. They used relatively cheap corn steep liquor and phenylacetic acid to increase the growth of the drug. The process involved four steps: 1) collection and analysis of molds, 2) feeding of molds with corn liquor, 3) fermentation, 4) recovery of penicillin from molds. After extracting penicillin by screening and pressing the molds, the National Research Council was able to ship the drug to doctors, hospitals, and the military.

Details can be found at:
http://www.lib.niu.edu/1996/ihy960452.html

Running Footmen

URTI = Upper Respiratory Tract Infection ie colds etc.

Although moderate exercise is good for your immune system there is an increasing understanding of the fact that a high training load can temporarily suppress the immune system. This is seen most prominently in marathon runners and ultra-distance runners.

This link has a simple discussion of some of the mechanisms involved and some of the studies that have demonstrated it. I was thinking of this because I was reading about the origin of distance running and came across a mention of Tuberculosis. Before motor cars the rich and wealthy would travel by coach and would employ 'footmen' who would run ahead to clear obstacles or summon help if the coach broke down or got stuck. As roads got better the demands on the footmen got greater and greater who as a result 'seldom survived three or four years, generally dying of consumption.' We can only assume this may have been a combination of crowded sleeping conditions on the road, mixing with a large variety of poor, and possibly infected people, and possibly a suppressed immune system from all that running.

As roads got better and footmen became unnecessary the rich found another use for them - race them and bet on the result! You can read an interesting article about the Basque running footmen.

Discovery of Penicillin

Dear Students of Ecology of Disease,

So this is now my second post and I decided I would focus my attention on short videos in order for all of you to gain knowledge through a different means then by reading. This video is about the discovery of Penicillin. We went over a lot of the details in lecture but in case any of you missed class or need a refresher this video is for you! Alexander Fleming is credited with the discovery of Penicillin after he left a petri dish out containing staphylococci. The bacteria seemed to be dying off because of a growth of what is now known as Penicillin. After his discovery Ernst Chain and Howard Florey further developed this antibiotic in order for it to be used in the human body. This video contains real footage of the laboratories and people involved in the discovery of this "miracle drug".

http://videos.howstuffworks.com/science-channel/29282-100-greatest-discoveries-penicillin-development-video.htm#

P.S. sometimes a preview for the history channel comes up first, but the video will appear right after.

Evolution of Antibacterial Resistance

http://www.pbs.org/wgbh/evolution/library/10/4/l_104_03.html

Around 50 years ago society thought that antibiotics were the final answer to healing the ill and stopping the spread of disease, but within the past few decades we find this answer to be fleeting.  Whenever someone uses antibiotics, a few germs survive and become resistant to the antibiotic.  This happens especially when the drugs are cut off prematurely.  Whenever antibiotics are used when are they are not needed or incorrectly, the resistant strains evolve and multiply creating stronger and more potent diseases.  This video shows an example of the evolution of antibacterial resistance in order to better illustrate the issue.

Tuberculosis in the News...and in Stuffed Animals

In 2007, tuberculosis made Time Magazine’s top 10 list under the category, “Top 10 Underreported Stories.” The article, “Coming to Grips with TB, ” stated that “41 countries have confirmed cases of extensively drug-resistant TB” and that the failure rate for treatments is very high. Cases of TB continue to climb the drug-resistant ladder, and unfortunately, some doctors still have to use detection and treatment methods that are “some 50 years old.”

However, when tuberculosis reappeared in Time’s top 10 lists in 2008, this time it was mentioned in the category “Top 10 Medical Breakthroughs.” Claudia Lorena Castillo Sanchez, a woman in Spain, had suffered from tuberculosis and lost function of one branch of her trachea. But doctors were able to line a donor trachea with Sanchez’s own adult stem cells (you can read more about it here) and now she is back to her pre-surgery life. While this transplant is still “experimental,” it does give hope for those who have suffered losses from tuberculosis or similar diseases, reinforcing the fact that science is always moving forward.

Staying on my “looking at the bright side” note, have you ever heard of GIANTmicrobes®? They are stuffed animals that look like different microbes—as the website says, “They're humorous, educational, and fun!” Each one comes with a picture and information about the real microbe it portrays, and if that didn’t sell you, they. are. adorable. Well, mostly. Anyway, I’m going to start posting pictures of them as they relate to the diseases we talk about in class. Hopefully it will add a little fun to your day. Here’s TB, and be on the lookout for penicillin sometime this weekend. Woop woop!


[GIANTmicrobes®'s stuffed animal interpretation of TB, pictured here with its microscopic picture and information card.]

Meet the Penicilliums

Penicillium is a genus of Fungi. I may have used the word 'mold' a few times - this is simply a term for a rapidly growing and asexually reproducing fungus. Because fungi were classified on the basis of the structures involved in sexual reproduction there used to be a group of Fungi, known as the Fungi imperfecti, that could not be classified because no-one had ever observed them to undergo sexual reproduction. This is less of a problem these days since we can look at their DNA and we understand more about how and why fungi switch from asexual to sexual reproduction.

Although the genus Penicillium is not particularly large it contains a surprisingly wide variety of both useful and nuisance species.

Good guys

• Penicillium chrysogenum (was notatum) produces Penicillin
  
• Penicillium camemberti, used, you guessed it, to produce Camembert (and Brie) cheese. Antibiotic substances produced by the fungus help keep bacteria from consuming the cheese.
  
• Penicillium glaucum used to produce a varity of cheeses including Gorgonzola and Stilton.
• Penicillium roqueforti used to produce Roquefort and other blue cheeses.

Bad guys

• Penicillium italicum and digitatum these are the ones you'll find on your citrus, and are both seen on the orange above (the smaller, bluer colony is italicum). Like many Penicillium species they grow well at cool temperatures and will easily grow in your fridge.
  
• Penicillium expansum causes a soft brown rot of apples. The rotted part of the apple contains a mycotoxin called patulin produced by the fungus. If such apples are squeezed for juice then the patulin persists in the juice. Although patulin has strong antibiotic properties there are studies showing it has toxic effects on all cells (both human and bacterial) and there are therefore usually restrictions on how much patulin apple juice can contain.
• Penicillium marneffei is the only known species of Penicillium that can infect humans. It has recently been seen in AIDS patients in SE Asia with a fairly alarming incidence. 10% of patients in Hong Kong get Penicillosis (the disease caused by Penicillium marneffei).

Allergic to Penicillin?

Penicillin appears to be the “miracle drug” for treating bacterial infections. For some people however, use of the antibiotic can cause strong and sometimes deadly allergic reactions.

Symptoms of an allergic reaction include:

• Hives
• Rash
• Itchy skin
• Wheezing
• Swollen lips, tongue or face

In rare cases however, penicillin may cause an allergic patient to fall into a potentially fatal anaphylactic shock. In fact, between 500 to 1,000 deaths related to penicillin are reported in the United States per year.

When patients do suffer a reaction, they usually receive an epinephrine shot. In milder reactions however, most people can use over the counter antihistamines such as Benadryl.

People with severe allergies often wear medical bracelets to warn medical workers not to administer penicillin if the patient is unconscious or cannot otherwise inform medics about their allergy. The bracelets are available at many places including Amazon.com (this one is made of Sterling Silver and sells for $175!). A common bracelet is pictured on the right.


Surprisingly, many people wrongly believe that they are allergic to the antibiotic. "Bad reactions" resulting in rashes and hives often occur.

These reactions do not necessarily mean a person is actually allergic to penicillin however. Of the people claiming to be allergic to the antibiotic, only 10% actually are. Testing for the allergy is done through either a skin or a blood test.

The New Sanatorium

In 1940, the New Delhi Tuberculosis Centre in India was developed to prevent, control, and treat cases of tuberculosis. The plan for the centre was to try domiciliary treatment, which has come to replace treatment provided by sanatoriums. Assisted by WHO, UNICEF and Government of India, the centre is made up of public health, clinical, laboratory, epidemiological, statistical, and administrative departments. All departments are focused on learning as much about tuberculosis as possible and circulating the findings to the public.

The New Delhi Tuberculosis Centre is affiliated with the Tuberculosis Association of India, which promotes Advocacy, Communication, and Social Mobilization (ACSM). Through these three strategies, the association hopes to increase detection and treatment of TB, as well as gain political involvement. TB rates in India have continued to increase, despite efforts by the government. Two people are dying approximately every three minutes due to drug resistant strains of the bacteria. The efforts by the centre and the government are being put heavily into research and social policies.

TB in the New World

A common idea exists that says that the crews of explorers like Columbus and Pizarro introduced tuberculosis to the New World. However, analysis of Peruvian mummies says differently.

Spinal tuberculosis, which is much less common than the lung-based form (about a 1:4 ratio), leaves distinctive marks on the lower vertebrae. By x-raying remains, archaeologists have found these marks on many mummies. This evidence, along with DNA analysis, proves the existence of pre-Columbian TB.

What other diseases did the New World have before Europeans got there?

Extra: It turns out that scientists have been hypothesizing about the presence of TB in the New World for a long time. Go here to read a 1947 article that will tell you more than you ever wanted to know about spinal tuberculosis and Peruvian artwork…

Cholera Exhibition

When looking for pieces of artwork that involved cholera I came across the New York Historical Society's website. Last April-August they had an exhibit on Cholera called "Plague in Gotham! Cholera in the Nineteenth-Century New York," which focuses on the epidemic that hit in 1832. The groups that were hit hardest were the Irish-Americans African-Americans. The exhibit includes maps of cholera-hit areas, reports from the Board of Health, sketches of cholera victims (alive and dead), and many other interesting pieces of history.

If you weren't lucky enough to be in New York at the time, you can check out the blog they made. It has some of the sketches, articles, and maps from the exhibit. One particularly interesting entry was about an article from the Brooklyn Daily Eagle 1849 about children who would "play cholera."

Nobel prize

As I mentioned the 1945 Nobel Prize in Physiology or Medicine was awarded to Fleming , Chain and Florey "for the discovery of penicillin and its curative effect in various infectious diseases". The Nobel foundation maintain a nice website with biographies of all the winners plus their Nobel lectures and banquet speeches. In this case the presentation speech is a nice summary of the work and provides a bit more information than that provided in class.

It is hard to imagine the impact of penicillin in a world without antibiotics. Not only were many wound infections now easily treated but many other diseases could now be treated quickly and easily.

World TB day

You can judge the success of World TB day in terms of raising awareness by whether you are aware of it or not. It's on March 24th every year to celebrate the day in 1882 when Dr Robert Koch astounded the scientific community by announcing that he had discovered the cause of tuberculosis. It is the brainchild of the Stop TB Partnership - established in the year 2000 with the goal of eliminating TB as a public health problem.

The World Health Organization is also working to dramatically reduce the burden of TB, and halve TB deaths and prevalence by 2015, through its Stop TB Strategy and supporting the Global Plan to Stop TB. What are they planning on doing differently this time, compared to the 1990-2000 attempt? Was the problem with funding (ie lack of), with their strategy or with the rise of AIDS and the interaction with Tuberculosis?

On a vaguely related theme, check out this earlier post on World Toilet Day.

The Flu Becomes More Drug Resistant

With flu season on the way, we should be concerned that the virus has become increasingly resistant to common vaccines, such as Tamiflu. What is interesting about this report is that epidemiologists at the CDC don't think that overuse of the vaccination led to the increase in resistance, but that the virus became more resistant by a spontaneous mutation. Luckily, the vaccination being administered at the moment is able to combat the Tamiflu-resistant strain.
Lots of controversy surrounds whether or not vaccines are overused in some cases, leading to strains of viruses that are resistant to those vaccines. With something as simple and relatively harmless as the flu, perhaps the vaccine should be reserved for infants and the elderly, whom the virus could do more damage to and the average citizen should have to deal with the sneezing and runny nose. It's a sacrifice I know I'm willing to make in order to slow the development of vaccine-resistant strains that could cause more damage in the future, but many people feel it is their right to protect themselves and their families, especially when a flu shot is so convenient and inexpensive. It's a debate that arises whenever a vaccination is made available to the general public and it seems impossible to determine which side of the issue is right, especially since it turns into a moral issue.

For more info on the Tamiflu-resistant flu strain, check out http://www.time.com/time/health/article/0,8599,1870601,00.html

Psychological Effects of Quarantine

The existence of lethal and crippling diseases creates an ethical problem, specifically the use of quarantine. Governments and leaders may find the question of whether quarantine is justifiable with the use of psychological studies on those affected by quarantine. The psychological effects of quarantine during the severe acute respiratory syndrome (SARS) outbreak were observed in a Toronto-based study. A web-based survey and validated scales such as the Impact of Event Scale-Revised (IES-R) and the Center for Epidemiologic Studies-Depression Scale (CES-D) were used to evaluate the impact of quarantine on the 129 participants. 28.9% reported symptoms of posttraumatic stress disorder (PTSD) and 31.2% reported symptoms of depression. Higher prevalence of PTSD was associated to those exposed to longer durations of quarantine and to people with direct exposure to victims of SARS.

Details can be found here: http://www.cdc.gov/ncidod/EID/vol10no7/03-0703.htm

Tuberculosis Folklore

Before the Industrial Revolution, tuberculosis may sometimes have been regarded as vampirism. When one member of a family died from it, the other members that were infected would lose their health slowly. People believed that this was caused by the original victim draining the life from the other family members. Furthermore, people who had TB exhibited symptoms similar to what people considered to be vampire traits. People with TB often have symptoms such as red, swollen eyes (which also creates a sensitivity to bright light), pale skin, extremely low body heat, a weak heart and coughing blood, suggesting the idea that the only way for the afflicted to replenish this loss of blood was by sucking blood.

Day-glo mice and hantavirus

We won't cover partner networks and superspreaders for another few weeks, and then it will be in the context of human diseases; however, the New York Times had an article today that links zoonoses (diseases that spread from animals to humans) and partner networks. The study, which involves dusting wild mice in Utah which are hosts for the Sin Nombre virus with vibrant powder, shows that a small number of individual mice are responsible for the majority of virus spread. These mice are called "superspreaders." When dusted mice contact other mice through mating or fighting, they leave behind powder on the other mice, allowing the researchers to monitor natural contacts between mice in the wild. These are the same types of contact that spread disease.

Daylight robbery

The connection to Tuberculosis may be a little tenuous but the Window Tax, which was not repealed until 1851, is still a nice example of the law of unintended consequences - the actions of people, and especially of government, always have effects that are unanticipated or unintended.

It is also possible, although far from certain, that this is the origin of the phrase 'daylight robbery' since the tax was widely seen as a tax on light and air.

Food poisoning in space

Astronaut Heide Stefanyshyn-Piper holds the sealed bacteria flasks.

Next week we will talk a couple of times about what it is that actually makes us sick when we are infected with a bacteria. One of the most common ways that bacteria make us sick is when they either produce a toxin that they excrete (an exotoxin) or contain a toxin that may be released when the bacteria die (an endotoxin). A lot of the exotoxins are VERY toxic, some of the most toxic substances we know such as Botulinum produced by the bacteria Clostridium botulinum (see earlier posting 'Meet the Clostridiums'). In fact much food poisoning is a consequence of exotoxins. As you may have heard there is currently a Salmonella outbreak in the US possibly caused by Peanut Butter contaminated with Salmonella typhimurium. (You may want to check the recall details if you have "King Nut" or "Parnell's Pride" peanut butter).

All things considered you would think that Salmonella typhimurium would be about the last organism you'd want to take on a space flight. But no, intrepid scientists took samples of Salmonella typhimurium into space on a 2006 Atlantis mission. Curiously the bacteria became three times more virulent under the zero gravity conditions of space. SpaceDaily has quite a thorough report.

Although they used triple enclosed containers, and, I suppose, the consequences of dropping a container are less severe in zero gravity, the consequences of severe food poisoning in zero gravity just don't bear thinking about. Doh! Now I've gone and thought about it....

The Ecology of Disease

I only discovered today that the Ecological Society of America has a series of monthly podcasts. In the October 10th 2008 issue Dr Raina Plowright explores the relationship between ecological change and disease emergence. This episode is based on a paper in the October issue of Frontiers in Ecology and the Environment entitled “Causal inference in disease ecology: investigating ecological drivers of disease emergence” and discusses some of the difficulties in definitively linking environmental changes with the emergence of diseases in cause-and-effect relationships.

We will be talking about these topics in week 3 but I thought this interview gave a nice sense of what scientists actually do, and some of the advantages, and difficulties, of taking an interdisciplinary approach.

Zimbabwe update

Sadly, the cholera outbreak in Zimbabwe continues. Yesterdays WHO update brings total number of cases to 35,931 with 1,778 deaths. The bad news is that the incidence does not seem to be declining.

If you look at the epidemic curve, although it doesn't show the increase from zero cases, you can see what is the broad, flat top of a continuous common source - an infected water supply. Imagine what this would look like if the disease was a) a point common source or b) a propagated source.

What is particularly tragic in this case is that until recently Zimbabwe had one of the best water and sewer systems in Africa. However after a decade of economic recession the infrastructure has collapsed, sewers are broken and there is no money to buy chemicals to kill bacteria in drinking water. NPR has run some reports on the situation and the outlook is not good.

The situation is likely to get worse now that Zimbabwe's rainy season has begun... because rain tends to carry untreated sewage into water supplies.

Stand Back!

Apparently, the idea to isolate the ill from the healthy has been around for thousands of years. As far back as the Old Testament, rules were put in place to separate lepers from the rest of society. From ancient times, people understood that diseases could spread, and that the best way to prevent an epidemic is to separate those who are ill. However, it wasn't until the 1300s, with the immense destruction and spread of the plague, that quarantines became official, begining in Ragusa (what is now Croatia). Ships were forced to wait 30 days before docking, and a place outside of the city was built to contain the sick. These regulations became commonplace across Europe for the next few hundred years. That is, until the cholera epidemics in the 1800s made the lack of quarantine uniformity on the international level apparent. Disease prevention was turned over to the federal governments of both Europe and America. Now, with the advent of bacteriology, the length and type of quarantine is based on the life cycle of the specific microbe. Unfortunately, there are still many diseases, such as HIV/AIDS, where quarantine is not effective. Quarantine has its limitations; it is not just a medical issue, but an ethical and legal one as well.

For information on the history of quarantine, visit http://www.pbs.org/wgbh/nova/typhoid/quarantine.html

When Hannibal’s army crossed the alps in 218 BCE, only half of his men survived. Could a disease like cholera have been responsible for these extreme losses?
Archaeologists and paleopathologists (those who study ancient diseases) already have the tools necessary to answer this question. By analyzing DNA from human remains, it is possible to discover what disease(s) a person had during their life, and what they died from. This technique has been used to identify leprosy victims from the first century, as well as the identity of the disease that killed half of Athens in 439 BCE (typhus).
The most likely candidates for killing off Hannibal’s army have been identified as cholera, salmonella, tuberculosis, diphtheria, and typhus, as these were all present at that time period. Hopefully, the Stanford Alpine Archaeology Project will get their funding, so we can know for sure!

Drug-resistant flu hits the US this year

Anyone else feeling under the weather these days? The New York Times reports today that 99% of flu cases in the US this year are resistant to the most commonly-used antiviral drug, Tamiflu. Only 11% of last year's flu strains were resistant to Tamiflu.

The strangest part of this story for me is that scientists believe that the Tamiflu resistance mutation occurred spontaneously, and NOT in response to overuse or misuse of the drug (as is the case in most antibiotic resistance cases). The mutation is apparently “just a passenger, totally unrelated to Tamiflu usage, but hitchhiking on another change.” They suggest that the mutation first occurred in Norway, which does not use much Tamiflu.

The good news is that it has been a mild flu season thus far. For the most recent flu data for the US this year, check out Google's really cool flu trends site. They use search terms to track the incidence of influenza. Not only do they get it right (their data matches the CDC's), but Google's data comes out about two weeks before the CDC's. Note that my home state of Georgia currently has lower flu incidence than California.

Preventives of Cholera

In the absence of knowledge of the true cause of Cholera, some of the suggested advice for avoiding it now seem a little odd. If you click the thumbnails for a larger image you'll notice again how the recommendations sometimes get close to the truth and sometimes miss by a mile.

Avoid raw vegetables.
Abstain from...ardent spirits and if habit have rendered them indispensible, take much less than usual.
Avoid getting wet!



The causes predisposing to CHOLERA are -
want of cleanliness of person,
intemperance in the use of spirits,
debauchery or excess of any kind,
sitting in wet clothes

Salmonella cases reported in the US

I though everyone knew not to eat raw eggs/meat... guess not. It is true that it might not be the individuals fault, meat that is not properly prepared or washed can transmit salmonella. This shocked me: food in the US isn't prepared safely? With the CDC, FDA, and other government agencies, one would have thought they would have figured out how to make sure our food is consumption safe (yes human error is possible, but 388 cases seems like a lot). If these agencies can't ensure our food is prepared safely, who's to say that our water is safe? With disasters like what happened in the Tennessee Valley, it might not be too far fetched to question the purity of our drinking water after such a contamination. From the lecture on 1/7 we learned that cholera is mostly present in impoverished countries where sanitation is neglected, but if our water isn't being properly cleaned, we might be at risk. It's time for government agencies to step up; as one of the most technologically advanced nations in the world, we should be able to eat and drink without fear of contracting salmonella or something far worse, like cholera.

For more information on the recent outbreak, follow this link:
http://news.yahoo.com/s/nm/20090107/ts_nm/us_salmonella_usa

Let's hope...

Speaking of Bird Flu....

And you thought making humans get their vaccines was hard

So it's been a while since I heard anything about bird flu, but I stumbled upon an article in the LA Times about a few recent human cases. For a while it seemed like a big media fear mongering, ratings-grubbing fad; then the excitement died off and so did public interest. Bird flu, or H5N1, started as an avian only disease. Influenzas often start off as animal viruses, and then make a trans-species jump to humans. People in close contact with farm animals are usually the first to experience the new flu. The flu virus is incredibly dynamic and constantly evolving, causing the need for newly developed flu vaccines each year.

Though bird flu is currently less pathologically dangerous than something like the Spanish Flu (which caused a horrific pandemic with a hefty mortality rate), no one knows what direction it will take. Without control, it could rapidly mutate into a very scary and contagious human flu.

So what are we doing to keep bird flu at bay? Oddly enough, we're vaccinating chickens! I wonder if chickens have to show their immunization records before they can work at McDonald's... as chicken McNuggets of course.

-Deirdre

Yes they really get volunteers

If you were wondering how infectious doses were established then the answer is that they really do challenge volunteers with different doses of live bacteria except with particularly dangerous diseases. Cholera, as we heard, under medical supervision is not very dangerous and so they do use human volunteers. This paper isn't actually trying to establish the infective dose but is available online so you can look at it.

I like the way that the volunteers 'were required to pass a written examination to document their knowledge of cholera and the study design.'

Also note in the methodology how they neutralized stomach acid with sodium bicarbonate before administering the cholera. Rehydration used CeraLyte, a rice based oral electrolyte.

WHO and UNICEF publish their own reccomendations for oral rehydration therapy which is
2.6g of sodium chloride, 2.9g of trisodium citrate, 1.5g of potassium chloride and 13.5g of glucose per liter of water.

Gatorade has more sugar (about 4 times as much if my math is right) but less salts (about a quarter as much) but would still be better than water. And water alone would be better than dying.

Some sports drinks do contain close to this amount of electrolytes, particularly those aimed at extreme endurance athletes, triathletes etc. Of course you can always make your own (whether for athletic use or an unexpected bout of cholera). Here's a recipe from WebMD that uses regular household ingredients. Not suitable for children under 12 though, the sugar level is too high. Drinks such as Pedialyte, aimed at children, have a much lower sugar content. So it's fine for adults to use childrens' oral rehydration therapies but not the other way around.

More on Zimbabwe Cholera outbreak

Another function of the blog is that it allows me to provide you with multimedia links easily. I was checking for updates on the Zimbabwe cholera epidemic when I came across this 'Media conference Call' at the Council for Foreign relations website. This is available as both streaming audio or you can download an mp3 file to listen to as you exercise, walk the dog etc etc.

"Listen to CFR experts Laurie Garrett and J. Anthony Holmes discuss the political and humanitarian crisis unfolding in Zimbabwe, including the recent outbreak of cholera."

Although the conference call is a few weeks old I thought you might find it interesting partly because you get to hear Laurie Garrett, the author of the Coming Plague, who is now a senior fellow at the Council on Foreign Relations.

Lecture 1

I added a link to the slides from today's lecture. As you can see you didn't miss too much, this was, after all, an introductory lecture. But I wouldn't want you to miss out.

WHO is maintaining a website that contains updates on the cholera outbreak in Zimbabwe.