Monday, July 25, 2011

Less spotty

On CNN today: Deaths from chickenpox down
Deaths from chickenpox (the varicella virus) have dropped 97 percent in adolescents and children since the use of the vaccine began in 1995, new analysis shows.

"Every kid did get chickenpox and, in the pre-vaccine era, there were 3-4 million cases a year," Seward said. "What people may not have realized, every year, about 105 people died of chickenpox. About half of those were children and about 11,000-12,000 were hospitalized with severe complications. We started preventing the disease to really prevent those very serious complications."

Saturday, July 23, 2011


The report of the 30 June - 1 July meeting of the Independent Monitoring Board (IMB) report has been released. Although affirming that polio eradication can be achieved in the near-term, the IMB states that 'this will not happen if things continue as they are'. 

You can read the latest about the global battle to eradicate polio at the Global Eradication Initiative website.

For a contrary view check out this New York Times article about Polio eradication that contains some interesting comments about Bill Gates funding for the initiative in particular:

The effort has now cost $9 billion, and each year consumes another $1 billion. By contrast, the 14-year drive to wipe out smallpox cost only $500 million in today’s dollars. 

“Bill Gates’s obsession with polio is distorting priorities in other ... areas. Global health does not depend on polio eradication.” 

Tuesday, July 19, 2011

Attractiveness of humans to mosquitoes

There were a couple of questions on this paper, Malaria Infection Increases Attractiveness of Humans to Mosquitoes, that I wanted to check up on, and like I said, the answer is usually more complicated and more interesting than expected.

First, children infected with malaria but NOT producing gametocytes were no more attractive to mosquitoes than uninfected children. Not even slightly. The data points are practically on top of one another.

BUT, what I hadn't realized was that when they treated the children the ones that had been infected with gametocytes were then LESS attractive to mosquitoes. Strange.

A striking aspect of our results is that former gametocyte carriers (i.e., after treatment) seem to repel mosquitoes, as only 22%, i.e., less than one third, of the responding mosquitoes prefer these children (t-test: t = −2.203, df = 11, p = 0.050; Wilcoxon signed-rank test: p = 0.040). An explanation for this result could be based on the slight anaemia in previously infected children. Mosquitoes might sense this anaemia and prefer those children with a higher concentration of red blood cells as it is these that the mosquitoes require. This would indicate a remarkable adaptation by the mosquitoes. The interpretation, however, would predict that the children previously infected with the asexual stage should also repel mosquitoes—but this was not observed.

Monday, July 18, 2011

Good news for tea and coffee drinkers

It's amazing how many times there is a story in the news at the same time we cover the topic in class.

In the news at the moment is the interesting story that coffee and tea drinkers could be at lower risk of a developing a deadly drug-resistant staph infection.

As part of the 2003-04 National Health and Nutrition Examination Survey (NHANES), more than 5,000 Americans from across the country were tested for methicillin-resistant Staphylococcus aureus — better known by its abbreviation, MRSA — in the nasal cavity. Although carrying MRSA in the nose is not at all dangerous by itself, some studies show that nasal colonization may put people at higher risk of systemic MRSA infection throughout the body, and that can be fatal.

The results of the NHANES testing, published in the July/August issue of the journal Annals of Family Medicine, showed that 1.4% of the nationally representative survey participants had nasal MRSA carriage. However, people who drank coffee or hot tea at least once a month were only about half as likely to be infected as those who did not — even after adjusting for age, race, sex, recent antibiotic use and hospitalization history, and a few other variables.

Coffee and tea drinkers saw advantages of about the same magnitude, no matter which drink they favored. The study authors say they cannot be sure why people drinking tea or coffee might be less likely to have nasal MRSA carriage, but that it could be the result of antimicrobial compounds known to exist in the beverages.

The actual research paper in the Annals of Family Medicine, Tea and Coffee Consumption and MRSA Nasal Carriage, is very readable. It's also interesting to see that statistic that 1.4% of people had nasal MRSA. Given that about 25% of people are carriers of S.aureus (actually 28% in this study) it means that about 1 in 17 of those carriers had the MRSA strain.

Sunday, July 17, 2011

Researchers believe they may be a step closer to HIV vaccine

Researchers are hoping they are one step closer to a HIV vaccine – using HIV. At the 6th International AIDS Society Conference on HIV Pathogens, Treatment, and Prevention in Rome, researchers with the Maryland-based VirxSys Corporation announced the findings of their VRX1273 vaccine.

The vaccine is a genetically altered version of SIV, the version of HIV found in non-human primates. Over the course of six months, five infected monkeys were injected with the vaccine three times, while five others were given a placebo vaccine. After 18 months, it was found that 40% of the vaccinated monkeys had very low to undetectable amounts of virus in their bodies.

Friday, July 15, 2011

Pills to prevent HIV

Pills found to be highly effective in preventing HIV transmission
Experts hail a pair of trials involving heterosexual couples in Africa as a breakthrough in AIDS prevention. The studies show that taking a pill containing one or two drugs each day can decrease transmission of HIV by as much as three-quarters.

The report above is from the LA Times. The report from the Guardian seems a little more realistic:
Daily pill can prevent HIV infection
Groundbreaking studies suggest tablets could help partners of people with HIV protect themselves – secretly, if necessary.

Wednesday, July 13, 2011

Did the CIA Fake a Vaccination Campaign?

Apparently the CIA faked a vaccination campaign in an attempt to collect DNA samples from Bin Laden's children. The scheme was concocted by the C.I.A. earlier this year when they were struggling to learn whether Bin Laden was hiding in the compound in Pakistan.

There's a fairly factual report in the New York Times, Vaccination Ruse Used in Pursuit of Bin Laden, but they miss the serious implications of this that are discussed in this post at Wired, File Under WTF: Did the CIA Fake a Vaccination Campaign?

This is awful. It plays, so precisely that it might have been scripted, into the most paranoid conspiracy theories about vaccines: that they are pointless, poisonous, covert shields for nefarious government agendas meant to do children harm.

The fallout from this scheme has already begun, Reported CIA vaccine ruse sparks fear in Pakistan.

One of the Pakistani Taliban's top commanders, Maulvi Faqir Mohammed, recently called on people in the northwest to avoid vaccines offered by the international community, claiming they were made with "extracts from bones and fat of an animal prohibited by God — the pig."
"Don't fall prey to these infidel NGOs and this U.S.-allied government and its army," said Mohammed over the illegal radio station he transmits from his sanctuary in eastern Afghanistan.
Pakistani officials and their international partners have pushed back against these claims, but the CIA's reported activities in the country may have made their job that much harder. 

Tuesday, July 12, 2011

The Emerging Race to Cure HIV Infections

 A recent article in Science, The Emerging Race to Cure HIV Infections, describes the effect that Timothy Ray Brown's cure has had on the research community. The abstract is below but the full article is fairly short and very interesting.

Four years after Timothy Ray Brown received bone-marrow transplants to fight leukemia, the most sophisticated labs in the world cannot find any trace in his body of the HIV that had infected him for 12 years. Brown is the only living human, a growing consensus contends, to be cured. Brown's treatment clearly does not offer a road map for many others. After all, the expensive, complex, and risky transplant only made sense because Brown was dying from leukemia. Nor is it clear exactly which components of the extensive transplant regimen cleared the virus from his body. But Brown's case has moved the much-ridiculed idea of curing HIV onto the most scientifically solid ground it has yet occupied, say leading AIDS researchers. Brown's case showed for the first time that it is possible to rid the body of the virus—even from the minuscule reservoirs where the virus can hide out for years, evading both the immune system and antiretroviral drugs (ARVs). His astonishing turnaround also raised hopes that other, more practical drugs and immune system modulators might find and destroy every last bit of virus—or at least reduce it to such low levels that people no longer need ARVs.

Monday, July 11, 2011

Bad news everyone..

 Hitting the news today is a report on a new strain of gonorrhea that is resistant to all available antibiotics.

Here's a link to the MSNBC article quoted below, but you can find hundreds of news reports on the story via google news.

For several years, public health officials have been concerned that gonorrhea, one of the most prevalent STDs in the world, might become resistant to the last widely available antibiotics used to treat it, a class of drugs called cephalosporins.  

Now, it has.

In the space of one week, infectious disease specialists have received a one-two punch of bad news that confirms those fears, including the discovery of a new, cephalosporin-resistant strain of the bacteria.

Saturday, July 9, 2011

Cholera returns

From the Washington Post today:
Cholera returns to rural Haiti amid fears that relief funds to contain it are running dry

The epidemic began in rural Haiti last fall, likely brought by U.N. peacekeepers from Nepal. It swept through the countryside of an impoverished nation already overwhelmed by a January 2010 earthquake that left hundreds of thousands homeless and by political instability following disputed elections.
The disease faded in winter and spring, when rain is less frequent, and many aid workers moved on. U.N. troops in Haiti turned their attention to the country’s many other pressing problems.
Now there is a fear among aid workers who remain that there won’t be enough resources if the latest surge gets much worse.

Wednesday, July 6, 2011

Insects, disease and history

If you are interested in history then there are a number of interesting articles at the 'Insects, disease and history' website: a site devoted to understanding the impact that insects have had on world history. This site focuses on the influence of insect-borne disease on history...

There are several articles on Typhus including, The Historical Impact of Epidemic Typhus , Typhus Fever on the Eastern Front in World War I and Insects, Disease, and Military History: The Napoleonic Campaigns and Historical Perception.

Tuesday, July 5, 2011

Bone Church

I was reading a novel this weekend and came across a reference to the Bone Church outside Prague in the Czech Republic. The Sedlec ossuary contains between 40,000 and 70,000 human skeletons which have been artistically arranged to form decorations and furnishings for the chapel. During the Black Death thousands of people were buried in the cemetery, many in mass graves, and when the cemetery was full and needed expanding a church was built in the center. Skeletons exhumed during the construction of the church were used to decorate it.

Saturday, July 2, 2011

The smart of the knife...

I mention the Crimean war (1853-1856) in this class a couple of times and I've posted on it here a couple of times previously (eg Crimean War Photographs and MiniƩ balls and infection before penicillin) but like most of you, I suspect, I don't really know much about it. So when I was in Goleta library last week and noticed Orlando Figes new history of the Crimean War I thought I'd pick up a little holiday weekend reading.

Interesting stuff, I had no idea the extent to which this was a religious war. But most shocking was the passage on the armies response to the new anaesthetic gases such as chloroform which were just becoming available. The use of such anaesthetic gases was embraced by the Russians, who used them to increase their surgical survival rates, but rejected by the British who favored a stiff upper lip. The Principal medical officer of the British Army, Dr John Hall, issued a memorandum cautioning:

'against the use of chloroform in the severe shock of serious gunshot wounds... for however barbarous it may appear, the smart of the knife is a powerful stimulant; and it is much better to hear a man bawl lustily than to see him sink silently into the grave.'

All this surgical amputation was, of course necessary because of the threat of infection - mainly by gram positive bacteria. For upper leg amputations, the most dangerous and the most common type of surgery, the Russian army used the new anaesthetics to improve their survival rate to 25%. In the British army it remained at 10%....

Thursday, June 30, 2011

How safe are vaccines?

Two very readable articles on the vaccine issue from the popular press.

First, How Safe are Vaccines? - a 2008 article from Time magazine.

CDC officials estimate that fully vaccinating all U.S. children born in a given year from birth to adolescence saves 33,000 lives, prevents 14 million infections and saves $10 billion in medical costs. Part of the reason is that the vaccinations protect not only the kids who receive the shots but also those who can't receive them—such as newborns and cancer patients with suppressed immune systems. These vulnerable folks depend on riding the so-called herd-immunity effect. 

and secondly, An Epidemic of Fear: How Panicked Parents Skipping Shots Endangers Us All - an article from Wired magazine at the end of 2009.

“I used to say that the tide would turn when children started to die. Well, children have started to die,” Offit says, frowning as he ticks off recent fatal cases of meningitis in unvaccinated children in Pennsylvania and Minnesota. “So now I’ve changed it to ‘when enough children start to die.’ Because obviously, we’re not there yet.”

Note that the Wired article attracted 690 comments! I think I remember reading in a following issue that this story attracted more letters and comments than any other story they had ever run.

Tuesday, June 28, 2011


It's traditional that at this point in the course I post this video.
For those who wish to know more about the flagellants of the middle-ages we mentioned today here's the Google article, the rather interesting Catholic Encyclopedia entry on the flagellants it links to and, above, a demonstration, albeit not from the middle ages, by German rock band Rammstein also courtesy of Google. That's the band beating themselves there and they seem to be really putting some effort into it.

Monday, June 27, 2011

The Rise of Superbugs

From an article in The Atlantic last week. Well worth a read:

The Rise of 'Superbugs': Time to End a Decades-Long Problem By Frances Beinecke
We've known since the mid-'70s that feeding animals antibiotics is dangerous—but we haven't changed our ways

All 27 EU nations have already successfully stopped using antibiotics for growth promotion. Denmark, the world's largest pork exporter, ended the practice over a decade ago, and industry data have shown a sustained decrease in overall antibiotic use and the amount of drug-resistant bacteria found in livestock and meat products. At the same time, livestock production has grown and prices have remained stable.

The American National Academy of Sciences estimated in 1999 that if we were to take similar steps in the U.S. to eliminate
all non-therapeutic use of antibiotics in livestock, it would cost grocery shoppers less than $10 annually. That's less than $13.50 per year in today's dollars. 

Sunday, June 26, 2011

BCG after all...

There's an unusual story making the rounds this weekend - I saw it in the LA times:
Is BCG a cure for diabetes?
The first trial in a handful of humans has suggested that injecting patients with Type 1 diabetes with an inexpensive vaccine normally used to prevent tuberculosis can block destruction of insulin-secreting pancreatic cells in humans and allow regeneration of the pancreas. Such a finding, if confirmed and expanded on, could lay the foundation for freeing the estimated 1 million U.S. Type 1 diabetics from their daily insulin shots. It brings up a word that is rarely or never used in considering the disease: "cure." 

So maybe the BCG vaccine will become more popular in the US - but as a cure for diabetes?!

Thursday, June 23, 2011

New TB Vaccine

The current Tb vaccine, the BCG vaccine, has been in use since 1921 and there are concerns that its protection may wear off over time - ie the protection given by the vaccine is not lifelong.

A new vaccine, with the catchy name MVA85A has recently passed clinical trials but, unfortunately it doesn't seem to work as well when given with other vaccines:

MVA85A was deemed to be safe, well tolerated and induced a strong immune response. And importantly, the responses to the standard childhood vaccines were not affected by giving MVA85A at the same time. But the immune response prompted by MVA85A was lower in infants who received it with standard childhood vaccines, compared with those who got it alone.
"It's reassuring to see that MVA85A does not affect immunity to the other vaccines," said Helen McShane of Oxford University, who helped develop the new shot. But she said scientists would now need to find the best way to integrate MVA85A into infant immunization plans in future without limiting its effect.

Report,  New TB Vaccine Passes Safety Tests, But proves less effective when given with other immunizations at Voice of America.

Wednesday, June 22, 2011

Rock 'n roll disease history moment

Link Wray was an aspiring musician when he contracted Tuberculosis during the Korean war and ultimately had a lung removed. Doctors apparently advised him that his singing career was over - I guess in those days a full complement of lungs was considered necessary for a vocalist. Wray devoted himself to his guitar, completely revolutionizing the way the instrument was used.

Quite simply, Link Wray invented the power chord, the major modus operandi of modern rock guitarists. Listen to any of the tracks he recorded between Rumble in 1958 through his Swan recordings in the early '60s and you'll hear the blueprints for heavy metal, thrash, you name it.
(All Music biography of Link Wray)

Wray's most distinctive record, Rumble, also has the distinction of being banned on several radio stations in the United States on the grounds that it glorified juvenile delinquency. An impressive feat for a song with no lyrics.

Tuesday, June 21, 2011

Cholera - next stop Chad and the Ivory Coast

Heavy rains in a number of African countries bring the threat of Cholera;

Rainy season to worsen Chad cholera outbreak - Oxfam
A cholera outbreak that has killed more than 100 people in Chad could worsen this June as the rainy season starts in the Central African country, Oxfam warned on Wednesday.

The Chadian government says only 0.6 percent of the country’s households use improved latrines, while 88 percent of people defecate in the open. There is no garbage collection system in villages, while in towns waste water disposal and storm drainage systems are nearly nonexistent.
UNICEF responds to cholera outbreak in Ivory Coast
 Following the confirmation of 10 cases of cholera in the Koumassi district of Abidjan, Ivory Coast, UNICEF has provided medical supplies to local health authorities to treat up to 1,000 patients infected with the disease and kits with soap, chlorine, and water treatment products for 400,000 people.

Thursday, June 16, 2011


Welcome to the blog for EEMB40 - the Ecology of Disease - for Summer 2011. It will also serve as a class website and you will find links to lectures etc. in a box at the top right imaginatively called 'links'. Lecture slides will be available shortly after each lecture. They are put there for your convenience (you don't need to scribble down details of a graph because you know it will be available later) but please note that they are not designed to be lecture notes. In fact in most cases my slides would make very poor notes. In order to help you take notes I have made a glossary for the class - also linked on the right. All the terminology you will be required to know is listed in the glossary.

You are all welcome, and encouraged to post here. To do that all you need to do is to send me an e-mail saying just that. I will then add your address and google will send you an invitation to be an author. Just follow the simple instructions and away you go.

Postings to the blog should be relevant to the class but the blog is specifically designed to be a place where you don't need to worry about how relevant your post is. (I give you 'Basket full of puppies' as an example). I will be posting lots of things that I read in the news or that I take out of lecture (for time purposes) but that some of you may find interesting. By putting it here you can look at it at your leisure and you know it won't be on the exam.

I try to post every day when the class is running and, where possible, the postings are relevant to the current topics we are covering in class. You can access older postings (there are over 750 (!) of them from the previous times I have taught this class) by using the 'Labels' (scroll down and they'll be on the right hand side) to pull up posts on particular topics.

Thursday, March 10, 2011

Culling Chickens as a Result of Avian Influenza Outbreak in India

After an outbreak of Avian Influenza in India veterinatires. In Tripura in a state-owned poultry farm in Ganhigram, veterinarians started to cull their chickens. This farm is one of the main breeding centers and it has a capacity of around 7,000 chickens.

Samples were sent to the High Security Animal Disease Laboratory in Bhopal after 380 birds died between March 1 and March 4. The samples tested for HIN5.

The culling is going to continue for the next few days in order. They people in charge of the poultry farm announced that they still have 1,400 Japanese peahens and 20,000 eggs that have to be dumped. Also the poultry in the surrounding 10 Km would be culled as well.

This is not the first time this outbreak has occurred in India. The last time there was an outbreak was in 2006.

Thermal scanning for flu

If there is an influenza pandemic then initial attempts at isolating the outbreak, or prevent its entry into particular countries, may involve the use of infrared thermal image scanners (ITIS) at airports to detect people with elevated body temperatures characteristic of influenza. We saw this in the 2009 H1N1 (Swine Flu) pandemic. Analysis suggests that countries that adopted the policy managed to delay disease entry for 7-12 days compared to countries that did not: Entry screening to delay local transmission of 2009 pandemic influenza A (H1N1). Of course there may be other differences between these two types of countries. Correlation is not causation...

A paper in PLoS ONE in January this year, Thermal Image Scanning for Influenza Border Screening: Results of an Airport Screening Study, looked at a sample of 1275 airline passengers who agreed to be screened, have their temperature actually measured and give a respiratory sample. Six of the travellers had a fever and thirty of the travellers tested positive for influenza. But none of the influenza-positive travellers had a temperature high enough to be considered in the fever group!

Our findings therefore suggest that ITIS is unlikely to be effective for entry screening of travellers to detect influenza infection with the intention of preventing entry of the virus into a country.

I'm sure we'll see more of these thermal scanners in airports in future pandemics even if they are fairly useless. Why? Because it makes it look like somebody is doing something (even if it is useless). Just like the rest of airport security

"Junk" Medicine

As the government releases 600,000 doses of the H1N1 vaccine today, predatory online “pharmacies” are dispensing junk medicine to a frightened public.

With the first 600,000 doses of swine flu vaccine scheduled to be released today and the media already swirling about how difficult it will be to get a dose, scam artists from Internet “pharmacies” are lining up to bridge the gap.

Specifically, the U.S. Food & Drug Administration, the World Health Organization and the pharmaceutical industry are bracing for an onslaught of fake and substandard drugs, with a special eye out for unauthorized versions of Tamiflu, the patented Roche vaccine that is the cornerstone of the public health-effort. “We don’t know what we could be seeing in the next few weeks,” says Gary Coody, who coordinates health-care enforcement for the FDA. “They (Internet drug operators) don’t necessarily have any regard for public-health safeguards.”

full blog post: "Swine Flu Swindle"

Wednesday, March 9, 2011

Blog wind up

A big hand for this quarter's bloggers: Ethan, Emily, Meghan, Blair, Nate, Kelsey, Marise and Eric. I hope you all enjoyed reading the blog, it really works well when we get several people involved and there are several new posts each day (as opposed to me scrambling to post something before midnight each day). I think we broke records this quarter for the overall number of posts and also the most posts in one day.

I'll keep posting until Friday and then I'll wrap up with some review questions etc.

New H1N1 Mutation

An article published in Science Daily today reveals that a mutation in the H1N1 strain of influenza virus (aka "swine flu") may allow it to become more easily transmitted from person to person. The strain of flu that the WHO declared a pandemic back in 2009 is actually a mixture of human, bird, and pig influenza genes. Despite the enormous amount of media attention it got, it proved to not be significantly deadlier or more debilitating than the seasonal flu humans encounter nearly every year. The swine flu proved to be relatively inefficient at moving from person to person... until now. Researchers at MIT have discovered a mutation that may allow this flu virus to transmit much more rapidly and effectively from person to person. A potentially deadly mutation to the virus' hemagglutin has been identified, but this should allow to WHO to quickly identify any outbreaks of the potential new strain and determine how deadly it can be. MIT scientists merely altered 1 amino acid chain that allowed the Hemagglutin to bind much more strongly to respiratory cells, increasing its ability to infect as well as kill humans. They identified this mutation as being a very possible one for the swine flu to evolve into. As the article is quick to point out (namely, the first few sentences), this potential two-wave pattern of flu outbreak is similar to the infamous 1918 Spanish Flu, which killed around 50 million people. Keep your fingers crossed everyone.

Tuesday, March 8, 2011

Swine Flu Survivors Built Super Flu Antibodies

A study of antibodies in people who were infected with H1N1 swine flu suggests that a universal flu shot that could neutralize many flu strains, including swine and avian flu. Scientists believe that people who were infected with H1N1 developed a unique immune response in which antibodies that could protect them from all the seasonal H1N1 flu strains that have appeared in the last decade were produced. A universal flu vaccine could have a major impact in controlling influenza which kills anywhere from 3,300 to 49,000 people every year in the U.S. Scientists are currently working on a vaccine from antibodies isolated from nine people who were infected with the first wave of the H1N1 swine flu pandemic. Of these, five of the antibodies were cross-productive so that they are able to interfere with many different flu strains. Studies in mice show that they were protected from what is considered a lethal dose of the flu. The vaccine is currently being tested in people.

Polio: To eradicate, or not to eradicate

Polio is one of the few human diseases that is on the brink of eradication. This article in the New York Times discusses the debate between Bill Gates, who has donated $1.3 billion for polio eradication, and public health experts who believe that polio eradication is not worth the cost. Gates points out that we have an effective and inexpensive vaccine, and that polio has been scaled back to just a few countries. Here's what some other experts say:

“Bill Gates’s obsession with polio is distorting priorities in other critical BMGF areas. Global health does not depend on polio eradication.” (The initials are for the Bill & Melinda Gates Foundation.) -- Richard Horton, editor of The Lancet

“We ought to admit that the best we can achieve is control.” -- Arthur L. Caplan, director of the University of Pennsylvania’s bioethics center, who himself spent nine months in a hospital with polio as a child.

Gates counters: “These cynics should do a real paper that says how many kids they’re really talking about. If you don’t keep up the pressure on polio, you’re accepting 100,000 to 200,000 crippled or dead children a year.”

Right now, there are fewer than 2,000. The skeptics acknowledge that they are arguing for accepting more paralysis and death as the price of shifting that $1 billion to vaccines and other measures that prevent millions of deaths from pneumonia, diarrhea, measles, meningitis, and malaria.

“And think of all the money that would be saved,” Mr. Gates went on, turning sarcastic. “It’d be like 5 percent of the dog food market in the United States.” (Americans spend about $18 billion a year on pet food, according to the American Pet Products Association.)

“If we fail, we’ll be consigned to continuing expensive control measures for the indefinite future,” said Dr. Thomas R. Frieden, director of the Centers for Disease Control and Prevention, which leads the country’s effort.

The article also points out some of the differences between polio and smallpox that have made polio so much harder to eradicate.

One injection stops smallpox, but in countries with open sewers, children need polio drops up to 10 times. Only one victim in every 200 shows symptoms, so when there are 500 paralysis cases, as in the recent Congo Republic outbreak, there are 100,000 more silent carriers. Other causes of paralysis, from food poisoning to Epstein-Barr virus, complicate surveillance. Also, in roughly one of every two million vaccinations, the live vaccine strain can mutate and paralyze the child getting it. And many poor families whose children are dying of other diseases are fed up with polio drives.

Not an easy debate to choose a side in, at least for me...

Flightless mosquitoes may curb dengue

Genetically altered mosquitoes that cannot fly may help slow the spread of dengue fever and could be a harmless alternative to chemical insecticides, U.S. and British scientists said on Monday. [Feb 22, 2010]

They genetically altered mosquitoes to produce flightless females, and said spreading these defective mosquitoes could suppress native, disease-spreading mosquitoes within six to nine months.

There is no vaccine or treatment for dengue fever, which is endemic in the tropics and is particularly prevalent in Asia and the western Pacific. The disease, which causes severe flu-like symptoms and can kill, is spread through the bite of infected female Aedes aegypti mosquitoes.

"This could be the first in a new wave of products that might supplant insecticides," researcher Anthony James of the University of California, Irvine, said in a telephone interview.

James's team, including a group from the British biotechnology firm Oxitec Ltd., altered mosquito genes to disrupt development of the insects' wing muscle.

The genetic modification grounded only the virus-carrying females and did not affect the males' ability to fly, they wrote in the Proceedings of the National Academy of Sciences here

The idea would be to distribute tens of thousands of eggs that would hatch out these genetically modified males, that would proceed to create a new generation of flightless, and thus doomed, daughters.

Because eggs are so small and easy to distribute, there would be far more genetically modified mosquitoes than natives, so they could in effect blot out the dengue-carrying population.

Flu trends

Google has been tracking flu trends for some time by analyzing people's choice of search terms. This method has been very successful and they can usually pick up trends a few weeks before the CDC data. In 2009 a variety of workers from Google and one from the CDC published a paper in Nature describing their technique: Detecting influenza epidemics using search engine query data.

For epidemiologists, this is an exciting development, because early detection of a disease outbreak can reduce the number of people affected. If a new strain of influenza virus emerges under certain conditions, a pandemic could ensue with the potential to cause millions of deaths (as happened, for example, in 1918). Our up-to-date influenza estimates may enable public health officials and health professionals to better respond to seasonal epidemics and pandemics. 
The graph above shows, for the United States as a whole, that the peak flu season is usually in February and that we are probably past the peak this year. You can also see how unusual last year was, pandemic years are always different. The big peak in October is from 2009-2010. The same pattern was seen in California except that our peak flu season seems a bit less predictable.

Monday, March 7, 2011


Two relevant but rather different papers in the latest Proceedings of the National Academy of Sciences (PNAS).

In the first: Bacillus anthracis comparative genome analysis in support of the Amerithrax investigation, they describe how genomic analysis was used in the investigation of the 2001 anthrax attacks.

The paper describes how the Institute for Genome Sciences faculty and collaborators from the FBI found that the anthrax samples used in all the attacks were genetically identical. Later, another group of scientists -- also including Institute for Genome Sciences faculty -- would trace the anthrax spore used in the letters back to a flask of Bacillus anthracis and several samples taken from that flask. The primary custodian of the flask was Bruce Ivins, Ph.D., a scientist at a U.S. Army biodefense laboratory in Maryland. With this key investigative lead from the scientific team, the FBI used additional police work to conclude that Dr. Ivins was the perpetrator of the mail attacks. Dr. Ivins killed himself before the case could go to court. The FBI has since closed the Amerithrax investigation. (From a report at ScienceDaily)

In the second paper, Hybrid influenza viruses may have pandemic potential, which is relevant to this weeks discussion,  the authors describe how the H1N1 strain that caused the 2009 pandemic, but relatively few deaths, may yet turn out to be problematic. 

The H1N1 influenza virus that spawned the 2009 pandemic is now predicted to circulate as a seasonal flu. However, researchers fear it could once again present a major public health threat by recombining with the H9N2 virus, which is endemic to several bird species in Asia, and has infected pigs and humans. Yipeng Sun et al. explored this possibility by dissecting the H1N1/2009 and H9N2 influenza viruses, and systematically mixing their genes to generate 127 hybrid viruses. The authors then tested the hybrid viruses in mice to assess the likelihood that genetic reassortment between H1N1/2009 and H9N2 could create a virus of pandemic proportions. More than half of the hybrid viruses instantly infected mice and replicated as efficiently as did the parent strains. Eight of the hybrids proved more virulent and dangerous than did either of the two parent strains. Curiously, each of these eight strains carried a gene encoding part of the RNA polymerase, known as the PA gene, from the pandemic H1N1/2009 virus. The authors suggest that the pandemic PA gene may play a key role in the virus’s pathogenicity, and that screening H9 viruses for the gene might help identify influenza viruses that pose a public health risk.

Building Immunity- Research for Artificial Antibodies

As you should know, antibodies are the bodies agents for seeking out pathogens, clumping them together, and signaling to the body so they can be destroyed by the immune system. Currently, the favored technique for getting new antibodies is to introduce the pathogen to an animal, and then to remove the antibody (or what created them) for further use.

Researchers at Arizona State University are pioneering a new method in which random chains of amino acids are combined to produce the artificial antibodies. The wondrous thing about this new method is that even when combined at random, the amino acids come together to produce something that can bind to a few proteins. After created, the "antibodies" are checked for matches with many, many proteins so scientists can find out what they might be the antibody to.

The advantages of this method are related mainly to saving time and money. This method is much easier (and humane) than waiting for a disease-infected monkey to create antibodies, and then stealing away the monkey's hard earned defenses through a needle, and it saves costs such as Mr. Banana's food and board. Obviously this method can't be used to easily create an antibody to anything that scientists want to fight, but with its low cost and easiness, this method should allow many new antibodies to be found.

Mosquito Nets Used for Fishing

When we covered Malaria in class, we discussed the helpfulness of Insecticide Treated Nets and learned about non-profit organizations focused on ending Malaria, which raise money to send these nets to infected countries. However, one student shared that he visited one of these countries and learned that the nets are actually stolen by fishermen and are not reaching the people who need them most. After doing some research, I found that the student was absolutely right: these nets are being used for fishing because they are stronger than normal nets and do not disintegrate. This is especially prevalent in Kenya and Zambia, but is a problem in many other countries as well. According to, "This phenomena has caused an increase in the malaria prevalence rate along the coastlines of various African countries."

Sunday, March 6, 2011

More iron lungs

When people are nostalgic for the 'simpler' times of the 1950's (after the war but before the turbulence of the sixties) they usually conveniently forget about horrors such as polio and iron lungs. These days many people probably only think of an iron lung as a Radiohead song, and even then many people miss the metaphor - something that keeps you alive but becomes very restrictive.

I am amazed by people who have lived their whole lives in them but have remained cheerful and happy. As well as the story below about John Prestwich there is also the story of Martha Mason who has lived in an ironlung for over 60 years.

(A)s one of the few surviving people left who live their lives encased in an iron tank, she said she intends to continue as she always has -- making the most out of what life has offered her.
"Get as much joy from life for yourself and others as you can squeeze out of it," she said.

Saturday, March 5, 2011

Polio: a virus' struggle

The story of Polio in comic book form. by James Weldon, a journalism student at the University of British Columbia. Learn the full story from the polio virus itself as it tells all in a group therapy session for 'diseases nearing extinction' with smallpox, guinea worm and leprosy. Lots of little jokes in here and a surprising amount of information. Enjoy.

Man lives in iron lung for 48 years

John Prestwich has needed the assistance of an iron lung for 48 years as a result of his teenage polio infection. However, John does not see his iron lung as a sort of prison, but rather embraces it as a life-saving friend. Prestwich would be unable to live without the lung, and if the machine stopped working he could die within three minutes.

However, he does not have to live in the iron lung all the time. With modern technology, people designed a smaller machine that he can use at home. The new machine is the size of his chest and performs almost the same exact functions as the large iron lung.

Prestwich also shares parts of his personal story:

Friday, March 4, 2011

Guinea Worm

The reason I wanted to briefly mention Guinea Worm at the end of today's lecture is that it looks like it will be a close race with Polio as to which disease is eliminated next. Both diseases are close to the verge of extinction, only found in 4 countries each and both had under 2,000 cases worldwide last year - down from a total that was once in the millions.

However what makes Guinea worm a very interesting case is that the main tool in eradication has not been vaccination (there is no vaccine) but has been breaking the life cycle of the parasites by both encouraging the use of clean drinking water and by preventing people from entering sources of drinking water with an active infection. Since there is no host other than man the disease can be eradicated if there are no infected people,

Guinea worm disease is set to become the second disease in human history, after smallpox, to be eradicated. It will be the first parasitic disease to be eradicated and the first disease to be eradicated without the use of a vaccine or medical treatment.

Much of the work in eradicating Guinea Worm has been funded by former President Jimmy Carter and the Carter Foundation. For over two decades the Carter Foundation have been slowly winning the war against Guinea worm.

Time magazine had a photo-essay on the effect of Guinea Worm on a Ghanaian village.

Thursday, March 3, 2011

Malaria Idol - 2010

In June of 2010, the nonprofit Malaria No More wanted to encourage people to use bed nets in order to prevent malaria. On June 9, 2010 in Dakar, Senegal nine finalists took to the stage to vie for a recording deal. All of the songs sung were written by the contestants and they were all on the topic of prevent malaria. The idea behind the campaign is simple and brilliant: if you’re working in public health and you want to change people’s behavior for the better, don’t try to convince them yourselves. Instead, find someone outside the medical community who already knows how.

The video above was recorded by one of Senegal's biggest pop stars. It is a cautionary tale about protecting yourself from malaria. It was released with a special concert the night before the Senegalese government kicked off a massive distribution of bed nets for all children younger than 5.

Are bednets the solution?

Not everyone agrees that bednets should be the main focus of our malaria eradication campaign. This video raises a number of very good points, particularly that the western world eliminated malaria via the use of DDT, a tool we now deny to other countries.

For further reading on the issue of using pesticides such as DDT check out Tina Rosenberg's controversial article in the New York Times: What the world needs now is DDT.

Also, it is interesting to note that even Rachel Carson, whose book Silent Spring sounded the alarm on the environmental dangers of DDT, did not call for a total ban on DDT:

Practical advice should be "Spray as little as you possibly can" rather than "Spray to the limit of your capacity."

Unfortunately because we did the latter we eventually saw environmental consequences and ultimately banned DDT, but only after we had eliminated malaria. Is it right to deny this tool to other countries, even its appropriate use, because we screwed up?

Comedians Fight Malaria

In this new campaign by Malaria No More, comedians including Elizabeth Banks and Aziz Ansari come together to end malaria deaths in Africa by 2015. Listen to the luminaries share their childhood dreams in this PSA.

View the 1 minute campaign clip for a light-hearted yet inspirational step in the cause of putting a stop to malaria.

Then take a look at the Malaria No More webpage--a site promoting the Malaria No More campaign. Malaria is a preventable and treatable disease and recent progress shows that malaria's days are numbered — but our help is needed. Together, we can make malaria no more. As seen in the video clip, Hollywood icons are using their powerful voices to make a difference. As part of the campaign, a large group of them are hosting "Hollywood Bites Back!," a live comedy show on April 16 at Nokia Theatre in L.A. to benefit Malaria No More.

Wednesday, March 2, 2011

Malaria & Malnutrition

Young children are more likely to fall victim to food shortages and thereby malnutrition, which increases their susceptibility to infectious disease, including an increase in mortality due to malaria. Severely malnourished children with a malarial infection may have no fever and show few or none of the classic signs of the disease, making it much more difficult to diagnosis & treat effectively. The World Health Organization suggests that all malnourished children in regions where malaria is endemic be screened proactively for malaria weekly even when they show no symptoms.

Depressing Polls

At the end of today's class I showed you some poll data on the public's opinion on cutting foreign aid. This result has been fairly consistent across a variety of polls.. For example Gallup repeat some of their polls on a yearly basis and this year's data, which has just been released, is no exception.

(A) majority of Americans said they favor cutting U.S. foreign aid, but more than 6 in 10 opposed cuts to education, Social Security, and Medicare. Smaller majorities objected to cutting programs for the poor, national defense, homeland security, aid to farmers, and funding for the arts and sciences.

One of the explanations for this rather ungenerous attitude is that the US public vastly over estimates how much money the government actually gives in foreign aid. This, again, has been shown by several research polls and seems to be a fairly consistent result. (Interestingly, and perhaps logically, people greatly underestimate how much of the US budget goes to other sources such as Medicare/Medicaid and defence.)

The only good news I can give you is that according to Kaiser Family Foundation 2010 Survey of Americans on the U.S. Role in Global Health when the specific purpose of the foreign aid is explained it is more likely to be supported.

When it comes to U.S. foreign aid in general, six in 10 Americans (61%) say the U.S. spends too much, and four in 10 incorrectly think that foreign aid is one of the two biggest areas of spending in the federal budget.  In comparison, when asked about “improving health in developing countries,” 28 percent say the U.S. spends too much, while nearly two thirds say such spending is too little (23%) or about right (42%).

“The old canard that most Americans do not support ‘foreign aid’ is a misunderstanding of how the public really feels,” said Kaiser President and CEO Drew Altman.  “When the specific purposes of spending abroad are put before the public, Americans are more supportive of health and development funding.”

Tuesday, March 1, 2011

Mechanics of Malaria: Elasticity of Red Blood Cells

The researcher from Brown and MIT are coming closer to finding valuable information that could lead to a cure for malaria, mainly cerebral malaria. The researchers are studying the effects of Plasmodium falciparum, the parasite causing cerebral malaria, on red blood cells. This form of malaria mainly affects children and is one of the deadliest forms of malaria.

The main goal of this research was to examine the features of this disease from a mechanical point of view. Through their research the team has discovered that the red blood cells that are affected by the parasite Plasmodium falicparum were far stiffer and more adhesive than healthy red blood cells. They stretched the cells in order to examine their elastic properties and saw that these infected cells were 10-20 times stiffer than normal cells.

Since red blood cells have to be fast messengers, traveling quickly through the capillaries, these stiffer cells cannot travel at the same speed. Also, since the cells become adhesive they tend to travel closer to the walls of the arteries while healthy red blood cells travel through the center. These two characteristics of the infected blood cells cause these red blood cells to stick to the capillaries in the brain, thus causing them to not reach the spleen. The spleen is responsible for filtering parasites from the blood. These infected red blood cells are unable to transport nutrients and oxygen to the rest of the body.

These discoveries could provide information extremely valuable to treating malaria.

Malaria Site: All About Malaria

While searching for something malaria-related to post on the blog this week I stumbled upon this site: Malaria Site. The website has numerous fascinating sections dedicated to the history of malaria including reports on the earliest written descriptions of malaria dating back thousands of years ago to Babylonian cuneiform tablets which attribute the disease to Nergal, the Babylonian god of destruction and pestilence (described as a double-winged, insect).

The site even has a section dedicated to "Famous Victims" which include notable figures such as Italian author Dante, Oliver Cromwell, Lord Byron, and a list of 8 American president's who suffered from the disease (though none of them died).

There is a lot of neat stuff on the website that I would advise you to check out if you're interested: Malaria Site.

Fighting Malaria with Candy

A spoonful of sugar may help the medicine go down, but why bother when you could just give patients chocolate? That's what Bill Gates wants to do.

Through the Bill & Melinda Gates Foundation, he's given $100,000 in grants each to scientists who want to use candy to diagnose and treat malaria. UCLA doctoral candidate Andrew Fung received a grant to use gum to detect malaria indicators in saliva, making the test painless. Steven Maranz, a researcher at Weill Cornell Medical College will use his money to study the effects of chocolate, which binds to and removes the cholesterol the malaria parasite needs to survive from the bloodstream. Maranz thinks chocolate may be able to kill most parasites while leaving enough in the blood to help children develop a lifetime resistance. The five-year grants for malaria are part of the foundation's Grand Challenges Exploration program, which also gave $100,000 to 74 other unconventional approaches to world problems.

from an article dated October 2009

Walter Reed: Physician, Researcher, Soldier

From the Military Health System website at the Department of Defense a short video about Major Walter Reed’s contributions to military medicine, which include discoveries that paved the way for health care modernization at the dawn of the 20th century.

Monday, February 28, 2011

Malaria Proof Mosquitoes

Time magazine recently named the development of that have been genetically modified to resist malaria as one of the 50 best inventions of 2010 and gave it the No. 1 spot in the health-and-medicine category.

Now the goal is to make the altered mosquitoes hardier than native varieties, which they could someday supplant in nature throughout the world.

"Our hope is to release them and drive the gene through the population," said professor Shirley Luckhart, a leader in the joint effort between scientists at UC Davis and the University of Arizona.

From an article last week, Researchers work to create malaria-proof mosquitoes, in The Republic Newspaper.

An alternative approach that I very briefly mentioned in class is to use knockout genes to drive certain mosquito species to extinction. This approach was described by Olivia Judson in a New York Times Op-Ed piece in 2003: A Bug's Death.

There's no shortage of ideas. So why are so many people still suffering from malaria and why do so many children die?

Does Malaria come from Great Apes?

I found a recently published article (September 2010), which presents information on research regarding the evolution of malaria. Scientists have concluded that the parasite most likely originated in the lowland gorillas, who may be infected with a "genetically identical microbe." Amazingly, researchers also believe that the parasite crossed the species border with just one mosquito bite--one bite is responsible for the outbreaks and epidemics of the disease!
Furthermore, scientists are hopeful as to the benefits of knowing the source of the parasite. They believe that with this new information they may be better able to understand and treat the disease. The article uses HIV as a parallel study, because knowing that HIV originated in primates has allowed for further research into the nature of the disease.
Finally, the researchers believe that the parasite does not have as negative an effect on the gorillas as it does on humans.

Pseudacteon Flies

This post is a little late, as it concerns a topic that we discussed last week, but it's another really interesting example of how a parasite can alter host behavior. Female Pseudacteon flies quickly inject an egg into the neck region of an ant through a rapid attack. The larva moves into the head cavity of the ant, where it eventually eats the brain of the ant (and therefore kills it). The head of the ant falls off, and the organism continues to develop inside the detached head. Once fully developed, the organism leaves the head as an adult fly.

Sunday, February 27, 2011

Transgenic fungi combat malaria

A day early for our malaria week, but too topical not to mention, is this report today on ScienceDaily about the use of transgenic fungi to combat malaria and other diseases. The ScienceDaily report is based on a paper out in the journal Science this week: Development of Transgenic Fungi That Kill Human Malaria Parasites in Mosquitoes.

New findings by a University of Maryland-led team of scientists indicate that a genetically engineered fungus carrying genes for a human anti-malarial antibody or a scorpion anti-malarial toxin could be a highly effective, specific and environmentally friendly tool for combating malaria, at a time when the effectiveness of current pesticides against malaria mosquitoes is declining.

The research team found that compared to the other treatments, spraying mosquitoes with the transgenic fungus significantly reduced parasite development. The malaria-causing parasite P. falciparum was found in the salivary glands of just 25 percent of the mosquitoes sprayed with the transgenic fungi, compared to 87 percent of those sprayed with the wild-type strain of the fungus and to 94 percent of those that were not sprayed. Even in the 25 percent of mosquitoes that still had parasites after being sprayed with the transgenic fungi, parasite numbers were reduced by over 95 percent compared to the mosquitoes sprayed with the wild-type fungus.

Saturday, February 26, 2011

Parasite Rex

If you'd like to read more about parasites that are capable of changing host behavior than Carl Zimmer's book, Parasite Rex, contains several chapters devoted to them. Zimmer is an excellent writer and this book is a very entertaining read. You can also check out his science blog, The Loom, where he frequently talks about parasites.

Imagine a world where parasites control the minds of their hosts, sending them to their destruction.
Imagine a world where parasites are masters of chemical warfare and camouflage, able to cloak themselves with their hosts' own molecules.

Imagine a world where parasites steer the course of evolution, where the majority of species are parasites.

Welcome to earth.

Friday, February 25, 2011

Friday videos

If you were unable to make class today here are two videos you missed. Plus a bonus video at the end if you already saw these two.

The last video shows a horsehair worm (Nematomorpha) exiting from its host.  The larvae live inside the insect and absorb nutrients directly through their skin. The adults are mostly free living in freshwater or marine environments

In Spinochordodes tellinii, which has grasshoppers and crickets as its larval host, the infection acts on the insect's brain and causes it to seek water and drown itself, thus returning the nematomorph to water. They are also able to survive the predation of their host, being able to wriggle out of the predator that has eaten the host! This manipulation of the host is documented here: Do hairworms (Nematomorpha) manipulate the water seeking behaviour of their terrestrial hosts?

office hours survey

I was contacted by some researchers at UCSB that want to do a survey of student attendance in office hours. If you want to participate, I'm copying the email and the link below. You are in no way required or expected to participate, and if you do it is anonymous.

My student group (Community Research Group @ UCSB) and I are working on research investigating how office hour attendance is related to undergraduates' grades. EEMB 40 was selected as part of the random sample for this project. It would be extremely helpful to us if you could take 3 minutes (it really is that quick) to fill out the survey and to forward the undergraduate-specific version (also extremely brief) to the students in this class. If you would like to see the content of the undergraduate survey, just open the link below. Of course, all responses are collected anonymously.

Please forward this address to the undergraduate students in this class via email:

We hope this project will demonstrate the importance of office hours to undergraduate success, and illuminate factors that prevent students from attending. If you have any questions about any part of the research (or about Community Research Group), please feel free to contact me.

Community Research Group is an undergraduate-run research team advised by Dr. Paolo Gardinalli (UCSB Social Science Survey Center).

Thank you for your participation!

Ilya Altshteyn
President | 858.349.9773

Thursday, February 24, 2011

No more litter boxes??

Someone in class talked about a cat toilet. here are a few options for a litter free home:

The Litter Kwitter-Cat Training System.

Richell Paw Trax Cat Potty

And my personal favorite...


So here we have another product that kills 99.9% of germs, but this one is a bit different from the rest. It has one ingredient, and thats good old H2O. This Activeion spray bottle ionizes water by sending it through an ion exchange membrane where the water is separated into a mixture of oxygenated positively and negatively charged nano-bubbles. The water stays in this state for about 45 seconds before returning to its normal state. The ions lift the dirt off the table and make it easier to clean so no residue is left, water or dirt. Also, it creates a small electrical field which can cause certain bacterium to become agitated and burst. Watch the video for more. It seems like it could be useful in hospitals or other places where alot of germs are present and I feel like its methods would be less likely to create resistant drugs since its merely ionized hydrogen and oxygen Heres the link to the website with a video that clearly demonstrates its method of action

Activeion Spray Video

A Positive of Protozoa

Protozoa, such as Toxoplasmosis gondii (the infectious agent of toxoplasmosis), may appear to be solely malignant organisms that infect a large portion of the worlds population, however, scientists working for Massachusetts-based company Petrel Biosensors have found an extremely beneficial use for the nasty single-celled organisms: testing water quality.

Sure we have modern methods to test water quality, however this newly developed technology, called Swimming Behavioral Spectrophotometer or “SBS”, is able to accomplish that task in a much cheaper and faster way than our current technologies.

The system, designed by Scott Gallager, detects toxins in the water supply through analysis of how the protozoa move throughout the sample. Most toxins are known to disrupt calcium transport and since the hair-like cilia responsible for protozoan motion are sensitive to aqueous calcium content, the presence of toxins can cause an erratic and irregular response in the microorganism (see original article on

This new method has a variety of applications including water monitoring for public drinking water supplies, for military units in the field, and for industrial waste discharge. Because the SBS acts as a “real-time” test, the quality of the water can be determined very quickly and appropriate action can be taken immediately. And at $1 to $2 per test, Gallager’s protozoan-dependent method presents a cheap and affordable system which rivals laboratory analyses ranging from $50 to $250 per evaluation.

However, in order to get his SBS technology moving forward, Gallager predicts that the company will need at least $2 million, on top of the $1 million Department of Defense grant already received, to get his new technology distributed to the world.

All cats are not created equal

Can I "catch" toxoplasmosis from my cat?
Because cats only shed the organism for a few days in their entire life, the chance of human exposure is small. Owning a cat does not mean you will be infected with the disease. It is unlikely that you would be exposed to the parasite by touching an infected cat, because cats usually do not carry the parasite on their fur. It is also unlikely that you can become infected through cat bites or scratches. In addition, cats kept indoors that do not hunt prey or are not fed raw meat are not likely to be infected with T. gondii.
In the United States, people are much more likely to become infected through eating raw meat and unwashed fruits and vegetables than from handling cat feces. 
From Cornell Feline Health Center's Toxoplasmosis brochure.

On the other hand because cats are the definitive host ONLY cats shed oocysts. This means that all infected meat, fruit and vegetables must ultimately have been contaminated from oocysts shed in cat faeces. Even though cats may only shed oocysts for a short while they can last a long time in the environment. Your domestic kitty may not be responsible for the environmental oocyst contamination but some kitty is....