Stories tagged infectious disease

Jun
17
2009

John Snow: Eats only vegetables, drinks only boiled water... dies of a stroke at age 41. Nuts.
John Snow: Eats only vegetables, drinks only boiled water... dies of a stroke at age 41. Nuts.Courtesy Wikimedia Commons
Here we are again, languishing in the long hours of June 17, enjoying a leisurely Snow day. A John Snow day.

Wait, you say, fractionally raising your heads from your overstuffed couches and baths full of tepid water. Didn’t John Snow actually die in June? And, like, didn’t he die on June 16, not on the 17th?

Well, yes, June 16, 1858, was in fact the day John Snow died. But I only just made up Snow day, and I wasn’t paying attention yesterday. Plus, do y’all even know who John Snow was?

Oh, John Snow was the most marvelous man! He drugged queen Victoria! He deprived thirsty communities of pump handles! He saved London from tiny invisible monsters! Oh, what a man!

John Snow was the sort of guy that posthumously gets the Cleverboots Award for Correct Thinking. Sort of like how I will surely be recognized with a Cleverboots Award years after I die, for how strikingly accurate my public ranting on the subjects of invisible lasers, lizard people, and “stay away from me, wizards!” will prove to be.

Snow was one of the first people to study the used of ether and chloroform as anesthetics. Which is to say, people had used those compounds as anesthesia before, but Snow calculated doses that would leave you somewhere between horrible pain and drugged to death. That was important. Everybody’s favorite queen of England (Victoria, duh) had Snow personally administer her anesthesia during the births of her eighth and ninth children. Once people saw Victoria doing it, everybody wanted in on anesthesia.

Snow’s greatest achievement, perhaps, came in an episode I like to call “Johnny Snow vs. Cholera.”

See, in the middle of 19th century in London, people were sort of split into three groups. There was the “Cholera is caused by poisonous gases” group. Most everybody thought that theory was the best, and it was called the “miasma theory.” There was also the “Cholera is caused by something tiny or invisible in water” group. This was pretty much what we call “germ theory,” and most everybody was all, “Germs? That’s stupid. Check your head!” And, finally, there was the “Hey, we’re actually dying of cholera over here” group, and most everybody thought they were gross.

But not John Snow! Instead of arguing and making up theories based on what seemed reasonable, he actually went out and looked at stuff. Gasp!

Without knowing for certain exactly how cholera was being transmitted (germs or miasma, or whatever), Snow began to record who in London was getting the disease, and he plotted cases on city street maps. He saw clusters of the disease in certain areas of the map, and so he looked for common elements. In the case of one outbreak, Snow realized that the majority of infected people were getting their water from one of two water companies, both of which were pulling water from a dirty (read: full of sewage) section of the Thames river. In another outbreak, Snow found that most of the victims of the disease were getting their water from a particular public pump. When John Snow had the handle of the pump removed, so that nobody could get water from anymore, the outbreak ended.

Snow’s discoveries from studying the cholera outbreaks added to the evidence for germ theory, and, perhaps more importantly, constituted a huge stride forward in the science of epidemiology. Snow wasn’t just figuring out how to cure diseases, he was tracking down where they start, and learning about how they move through populations. These are the same basic principles behind the actions health organizations still take today when dealing with outbreaks in the much larger population pools (or pool) of the 21st century.

It’s pretty interesting stuff. Check out this Snow-stravaganza: UCLA’s comprehensive page on John Snow and the cholera outbreaks.

Now enjoy what’s left of your Snow day.

First H1N1 Death in Minnesota.

by Anonymous on Jun. 16th, 2009

The first death in Minnesota of the H1N1 or also known as the Swine Flu. The five year old girl died on June 15, 2009. The very young girl did have multiple medical conditions before becoming ill.
To find more on this go to this link.
http://kstp.com/news/stories/S979151.shtml?cat=206

The WHO has raised the swine flu pandemic alert to the highest level. (A/H1N1 is the first flu pandemic in 41 years.) This doesn't mean the disease is more dangerous, just that it's in more places and continuing to spread. As of this morning, 28,774 confirmed A/H1N1 cases have been reported in 74 countries, with 144 deaths. (These counts are not precise anymore, however, because many people who catch this flu are recovering at home without being tested.)

Watch/listen to the press conference

Map of the outbreak

BBC coverage

According to the Global Humanitarian Forum, the number of deaths “that result from the spread of disease, malnutrition and natural disaster caused by climate change” is roughly 300,000 people per year.

Read more about it here.

May
31
2009

Vaccine production
Vaccine productionCourtesy AJC1

US pays billion dollars for developing new flu vaccine

The latest information from Pandemicflu.gov explains the next steps toward an H1N1 influenza vaccine.

BARDA

The Biomedical Advanced Research and Development Authority (BARDA), which is part of the Dept. on HHS, has an official "fact sheet" explaining 2009 H1N1 Vaccine Development Activities.

U.S. Department of Health & Human Services (HHS) Secretary Kathleen Sebelius is directing nearly $1.1 billion in existing preparedness funds to manufacture two important parts of a vaccine for the Strategic National Stockpile, to produce small amounts of potential vaccine for research, and to perform clinical research over the summer. HHS press release

How do vaccines work?

Vaccines work by tricking the immune system into thinking it has been infected with the H1N1 swine flu virus so that it creates antibodies against it. The vaccine is a hybrid of the virus which is similar enough that our immune system will develop antibodies against a specific virus.

How is swine flu vaccine made?

We are now starting step 4.

  1. obtain typical sample of novel H1N1 virus
  2. reproduce sample in eggs
  3. Mix H1N1 and PR8 viruses into eggs and allowing a hybrid strain to be created through a natural re-assortment of their genes
  4. Multiply seed virus into millions of doses
  5. test virus in people to determine the most effective and safest dose to generate a strong immune response to the 2009-H1N1 virus
  6. decide whether to use adjuvants
  7. mass produce vaccine

What is an adjuvant?

An adjuvant is an additive to a vaccine that helps to generate a stronger immune response to the vaccine. When using an adjuvant it is often possible to reduce the size of the vaccine dose and the number of doses needed. Special permission from the Food and Drug Administration will be needed for the adjuvants to be used, as neither one is currently approved for use in this country. Washington Post

Can vaccines be made without using eggs?

"The federal government has given the vaccine industry $1.3 billion to spur a shift from growing the viruses in eggs to growing them in stainless steel tanks containing mammalian cells.

Such cell culture could shave a few weeks off the process, experts estimate, and would eliminate the need for millions of eggs on short notice. Some vaccines made in cells have been approved in Europe but not in the United States." New York Times

Learn more about making swine flu vaccine

How to make a swine flu vaccine BBC
CDC May 28 Press Briefing transcript
Flu vaccine development questions and answers BARDA

May
24
2009

Antigenic shift in flu viruses: is when at least two different strains of a virus combine to form a new subtype having a mixture of the surface antigens of the two original strains.
Antigenic shift in flu viruses: is when at least two different strains of a virus combine to form a new subtype having a mixture of the surface antigens of the two original strains.Courtesy National Institute of Allergy and Infectious Diseases (NIAID)

Model of H1N1 flu virus takes shape

Genetic analysis of the new H1N1 virus shows that the hemagglutinin (the H in H1N1) and two other genes are from the 1918 Spanish flu virus and have been living in pigs ever since. Studies also show that the neuraminidase (the N in H1N1) segment is from the Eurasian swine flu virus that probably leaped from birds to pigs in about 1979.

The new virus differs in 21 of 387 amino acids from the H5N1 virus and the 1918 Spanish flu (also an H1N1 virus). - Singapore’s Agency for Science and Technology Research report in Biology Direct.

Shape shifting viral surface challenges vaccination success

"Viruses isolated from patients during the first two weeks of the current outbreak already have changes on the outer surface on the neuraminidase protein that could interfere with antibodies against the virus or alter the effectiveness of future vaccines. But none of the changes have altered the parts of the protein targeted by antiviral drugs, such as Tamiflu or Relenza." Science News

Learn more
If you click through to the source article in Science News, you will see a great three dimensional model of the influenza A/H1N1 virus with the origin of each of the virus's pieces explained.

May
17
2009

Cold noses are good for preventing bird flu

Don't let your children do this
Don't let your children do thisCourtesy KnOizKi

A recent study may explain why the bird flu has not become a pandemic. The human nose is too cold. Avian flu viruses prefer 104 degree F. The temperature in our noses is usually less than 90 degrees F. Critics of the study point out that it was only done in petri dishes so may not be an accurate reflection of what happens in humans.

Since the bird flu virus re-emerged in 2003, there have been only 423 reported cases. If the viruses manage to get into the lower lung, however, they replicate so quickly that 6 out of 10 victims (258) died.

The normal seasonal flu kills only 1 out of 1000 victims (250,000 to 500,000 people per year world wide).

Figuring the odds of a deadly mutation

Please comment what you think about this logic.

"When more people get the flu, the chances of a deadly mutation increases. Say the chance of a deadly mutation is one in a million. If 10,000 people get sick, the odds are 10,000/1,000,000 or 1/100. If a million people get sick the chance of a deadly mutation is almost a sure thing."

The new H1N1 virus appears to be more contagious

The percentage of contacts who catch the regular variety of flu from an infected person is between 5 and 15 percent, but current estimates for H1N1 being spread range from 22 to 33 per cent (according to WHO). Reuters via Yahoo News

As of May 15, 2009, 34 countries have officially reported 7520 cases of influenza A(H1N1) infection. World Health Organization

An intriguing mutation has been detected

The virus isolated from the second swine flu patient in the Netherlands has an intriguing mutation in a gene called PB2 that could mean that the virus has become better at spreading from person to person, a team of Dutch researchers reported on Friday on ProMED, a monitoring system for disease outbreaks. But they're the first to acknowledge that it could also be a red herring. Science Insider

You can make a difference

If you can behave in ways that prevent you from catching or spreading this new type of H1N1 flu, you will minimize the odds its changing into a more deadly form.

May
12
2009

Yes, this is on the list too
Yes, this is on the list tooCourtesy tsweden
Check it out: it turns out that women have more powerful immune systems than men. (I include myself in the “men/boys” group.)

So, let’s see… if we’re arranging the list in terms of the order in which I’ve realized each one, then this new development falls at the end, right after “better resistance to sunburn” and “less likely to get testicular cancer.”

If the list is alphabetical (how nice and neat!), it goes between “more powerful backstroke” and “more powerful interpersonal skills.”

Despite my rabbit-killing-strength grip and my powerful stammer (each unlikely to be beaten by women as a whole), the bite of each item on the list burns like jalapeño scorpion stings.

It’s nice, then, that this new fact isn’t quite so painful to accept. See, I like getting sick. I want to get sick. In particular, I want to get the swine flu. My great-grandfather was beaten (i.e. killed) by the swine flu back in 1920 or so, and I’ve been aching for a rematch. Swine Flu vs. JGordon Round II: The Final Showdown: This Time it’s Personal: A Century-Old Family Feud Comes to Blows: To the Death!

Sure, I don’t actually want to die at all, but this disease needs to at least get a foothold in my system if we’re finally going to see who’s the bigger man. (Me, duh.)

If I were what we often call a “lady,” my powerful immune system would make the flu showdown less likely. So thank goodness that that’s not the case. My female body would be producing estrogen left and right, and that estrogen would be blocking the production of an enzyme called Caspase-12. Caspase-12, precious Caspase-12, is needed in my body, because it blocks my inflammatory processes. Inflammation is one of the body’s primary defenses against infection. Blood flow increases at the site of an injury or infection during inflammation, beginning the healing process and delivering structures that kill and absorb pathogens. And I don’t want that. I mean, if every time Evander Holyfield approached Mike Tyson’s boxing ring a flood of blood and plasma crushed Holyfield and washed him away, how would The Dynamite Kid ever have gotten the chance to prove who’s tougher? I want to let the swine flu into my ring, and then I want to bite its ear off and threaten to eat its children.

I’m leaving it up to my frail male body to arrange this fight.

Take a look at the Disease Detectives web site! You will find more information and fun activities all about infectious diseases - including influenza.