The Mystery of Random Deaths in Previously Healthy People

[indigo girl]

http://www.bloomberg.com/apps/news?pid=20601202&sid=aMMBiJ78eqfo

One in seven affected people in New Zealand required critical care. It is disturbing to realize that we do not know why. Prior existing health problems can explain some cases but there is simply no logical explanation for a disturbingly large percentage of the deaths. Was it the strength of their own immune systems that helped to kill them?

Putting faith in innate good health, lifestlye choices, diet and remedial therapies is a reasonable coping strategy. People have to believe in something but, there simply are no guarantees that anything will protect people 24 hours a day. We have PPE at work. We practice good handwashing. We use the mitigation strategies such as social distancing to help slow down the spread of the disease. While all of this helps, we can still be unlucky.

I cannot help but remember that perfectly healthy marathon running RN in California that died from swine flu. She was the picture of health. Why, did this happen to her?

These fatal cases are occurring randomly, and we don't know why. This is reality.

Researchers are trying to determine why the H1N1 swine flu virus, much like the Spanish Flu of 1918, is lethal to a portion of young people in good health. The reason may involve a person’s genetics, or simply taking a deep breath just as a nearby infected person sneezes.

“That’s a question we have to find the answer to,” said Nikki Shindo, a Geneva-based doctor who has led the World Health Organization’s investigation of swine flu patients since the virus was discovered in Mexico in April.

Underlying conditions that can intensify the effects of flu include respiratory illnesses, especially asthma, cardiovascular disease, diabetes, a suppressed immune system, and even pregnancy. About 25 percent to 50 percent of severe cases worldwide involve healthy young and middle-aged people like Robb, according to WHO Director-General Margaret Chan.

It is a statistic that highlights how unpredictable the disease has turned out to be, said Ian Barr, deputy director of the WHO’s Collaborating Center for Influenza in Melbourne.

“People are happy to dismiss serious cases among people with underlying conditions,” Barr said in an interview. “It’s a wake-up call when healthy people are struck down.”

As many as 2 billion people, or 30 percent of the world’s population, may become infected by the new virus as it spreads globally, according to the WHO. Identifying those likely to recover without medical help, and those who may become severely ill will help prioritize vaccination and drug treatment.

In Australia, the median age of people dying from seasonal flu is 83. With the H1N1 swine flu, it is 54 years, according to the government’s Aug. 28 influenza surveillance summary report. In New South Wales, Australia’s most-populous state, the majority of H1N1 patients in intensive-care units are 30 to 59 years old, the state government’s Sept. 9 weekly report notes.

Global health experts are gathering this week in San Francisco at the Interscience Conference on Antimicrobial Agents and Chemotherapy, the world’s biggest meeting of infectious disease specialists. Scientists at the conference are set to report on a study that sifted through blood test results from dozens of patients with complications in search of a common genetic cause.

Bad luck may also play a role, Shindo said. Taking a deep breath or yawning immediately after an infected person nearby coughs or sneezes may enable large amounts of airborne viral particles to penetrate the lower lung, he said.

“There have got to be some host factors that are involved in terms of explaining why there are these rare, lethal pneumonias and why some folks don’t handle the virus at all well and the vast majority have an uncomplicated illness,” said Frederick Hayden, professor of clinical virology at the University of Virginia School of Medicine in Charlottesville.

Doctors have not been able to explain why Robb almost died while his partner, Susanna Gillies, and their 5-year-old son both escaped uninfected, Gillies said in an interview.

In New Zealand, about one in seven people hospitalized with H1N1 have needed intensive-care treatment, the Ministry of Health said in a Sept. 11 statement.

In most cases, flu remains in the nose, throat and bronchi, where it causes a runny nose, sore throat and cough until the body’s immune systems eliminates it, usually within a week.

The pandemic strain is more adept than seasonal flu at infiltrating the lower branches of the airway, where it can cause complications...including viral pneumonia, said Stephen Toovey, a senior research fellow at London’s Royal Free and University College Medical School.

While the pandemic virus tightly latches onto cells in the upper respiratory tract like seasonal virus, it also attacks cells in the lungs, researchers at London’s Imperial College wrote in a study reported Sept. 10 in the journal Nature Biotechnology.

In severe cases, influenza can damage the capillaries surrounding the tiny grape-like sacs, known as alveoli, where gas is exchanged through the blood. Damaged alveoli can bleed, causing pulmonary hemorrhage and blood clots.

“What makes it go from the bronchus to the alveoli is the $64,000 question,” said John Nicholls, associate professor of pathology at the University of Hong Kong, who has studied how cells interact with viruses like the H5N1 bird flu strain and SARS. Previous bouts of flu, particularly caused by strains similar to the H1N1 virus, may give some protection, he said.

Inflammatory chemicals are produced by the immune system to fight the infection and repair the damage. An over-exuberant response can worsen the effect by filling the lungs with fluid and cause permanent scarring that restricts the lungs.

“Pathologically, it’s identical to what happens with H5N1 infection,” known commonly as bird flu, said Shindo, the WHO doctor investigating case. “Pathologists say if they weren’t told it was H1N1 they would diagnose H5N1 as the cause.”

(hat tip Avian Flu Diary)

[JessicaR]

I believe I may be able to help out with this one because I recently was researching moving to New Zealand (although have decided against it for various reasons).

A vast majority of the housing in New Zealand is not insulated. As we know it is currently winter in NZ, and the country is prone to drastic weather changes and a great deal of rain. Many of the residences are very cold and very damp. Most people rely on space heaters, although they don't provide much help because of the lack of insulation. I read many stories of people saying they never experienced the cold like they did in NZ; it literally chills you to the bone. I also read many stories of people saying they had never gotten sick as much as they did while living in NZ.

All of this has led to NZ having one of the highest rates of asthma in the world. Approximately 15% of the adult population and 20% of children under 15 have asthma. For those who don't, there is still the exposure to the cold and damp environment. There is currently a push by the NZ government to get citizens to start updating and insulating housing, although the effort will likely take awhile.

I hope this helps a little. I have a strong feeling that environment plays a huge role in the problems in NZ.

[indigo girl]

Pandemic flu can infect cells deep in the lungs

http://www.bio-medicine.org/biology-news-1/Pandemic-flu-can-infect-cells-deep-in-the-lungs--says-new-research-9859-1/

Pandemic swine flu can infect cells deeper in the lungs than seasonal flu can, according to a new study published today in Nature Biotechnology. The researchers, funded by the Medical Research Council, Wellcome Trust and Engineering Physical Sciences Research Council, say this may explain why people infected with the pandemic strain of swine-origin H1N1 influenza are more likely to suffer more severe symptoms than those infected with the seasonal strain of H1N1. They also suggest that scientists should monitor the current pandemic H1N1 influenza virus for changes in the way it infects cells that could make infections more serious.

Influenza viruses infect cells by attaching to bead-like molecules on the outside of the cell, called receptors. Different viruses attach to different receptors, and if a virus cannot find its specific receptors, it cannot get into the cell. Once inside the cell, the virus uses the cell's machinery to make thousands more viruses, which then burst out of the cell and infect neighbouring ones, establishing an infection.

Seasonal influenza viruses attach to receptors found on cells in the nose, throat and upper airway, enabling them to infect a person's respiratory tract. The research shows that pandemic H1N1 swine flu can also attach to a receptor found on cells deep inside the lungs, which can result in a more severe lung infection.

The pandemic influenza virus's ability to stick to the additional receptors may explain why the virus replicates and spreads between cells more quickly: if a flu virus can bind to more than one type of receptor, it can attach itself to a larger area of the respiratory tract, infecting more cells and causing a more serious infection.

Professor Ten Feizi, a corresponding author on the paper from the Division of Medicine at Imperial College London, said:

"Most people infected with swine-origin flu in the current pandemic have experienced relatively mild symptoms. However, some people have had more severe lung infections, which can be worse than those caused by seasonal flu. Our new research shows how the virus does this - by attaching to receptors mostly found on cells deep in the lungs. This is something seasonal flu cannot do."

The researchers found that pandemic H1N1 influenza bound more weakly to the receptors in the lungs than to those in the upper respiratory tract. This is why most people infected with the virus have experienced mild symptoms. However, the researchers are concerned that the virus could mutate to bind more strongly to these receptors.

"If the flu virus mutates in the future, it may attach to the receptors deep inside the lungs more strongly, and this could mean that more people would experience serious symptoms. We think scientists should be on the lookout for these kinds of changes in the virus so we can try to find ways of minimising the impact of such changes," added Professor Feizi.

The researchers compared the way seasonal and pandemic H1N1 flu viruses infect cells by identifying which receptors each virus binds to. To do this, the researchers used a glass surface with 86 different receptors attached to it, called a carbohydrate microarray. When viruses were added to the glass surface, they stuck to their specific receptors and the corresponding areas on the plate 'lit up'. This meant the researchers could see which receptors the different viruses attached to.

Pandemic H1H1 influenza could bind strongly to receptors called α2-6, which are found in the nose, throat and upper airway, and it could also attach more weakly to α2-3 receptors, which are found on cells deeper inside the lungs. However, seasonal H1N1 influenza could only attach to α2-6.

Professor Feizi concluded:"Receptor binding determines how well a virus spreads between cells and causes an infection," said Professor Feizi. "Our new study adds to our understanding of how swine-origin influenza H1N1 virus is behaving in the current pandemic, and shows us changes we need to look out for."

[indigo girl]

Study involving 21 Spanish hospitals states 50% of swine flu, ICU patients had no health problems

http://www.barcelonareporter.com/index.php?/news/comments/study_involving_21_spanish_hospitals_states_50_of_swine_flu_icu_patients_ha/

Surprisingly 50% of the Spanish swine flu cases requiring ICU admission were without previous health issues. This is significant news, and remains unexplained. The study is a very interesting read, and contains much information also about critical cases in other countries.

Here is a link to the pdf file of the study. It's actually a very easy read and fascinating as well:

http://ccforum.com/content/pdf/cc8044.pdf

The study, presented on the website of the medical journal 'Critical Care' is the largest ever conducted in Europe on influenza cases requiring intensive care. Their findings contradict one of the messages on influenza A released by the Ministry of Health and the Department of Health, which have repeatedly reported that patients with influenza A cases had previous health problems.

The findings contain important messages for both the general population and for health authorities and medical intensivists. For the general population, an appeal to healthy people without risk factors to avoid falling prey to overconfidence in regard to influenza A. Although the vast majority of those affected will overcome the flu without complications, a small percentage will have pneumonia and should be hospitalized.

"The natural symptoms of the disease is usually three or four days of fever, generally over 38 degrees with a steady improvement in the following days. But a minority of patients, around the fourth or fifth day, get worse," reports Jordi Rello , head of the intensive care unit of Tarragona Joan XXIII Hospital and coordinator of the study. Therefore, if a sufferer experiences breathing difficulties after contracting the flu, they should seek medical attention urgently but the main point of the study is that no risk factors or diseases have made them particularly vulnerable.

Looking to health authorities, the study indicates that efforts to contain influenza A should not be limited to prevent disease and to address mild cases in primary care but also to meet serious cases in ICUs. It is estimated that only 0.2% of patients suffer serious complications, according to a calculation based on the experience of Britain. This means that for every million affected, two thousand suffer complications, a figure that may overwhelm the capacity of the ICU departments.

Although the virus primarily affects the lungs, 75% of patients arriving at the ICU in a few days develop multiorgan syndromes. "I had never seen this type of pneumonia in the 25 years I've been practising" says Rello.

The study results confirm that obesity and pregnancy are risk factors for serious complications. The average age of patients in ICU for influenza A is 40 years, of which about 25% die.

Much thanks to FlaMedic at Avian Flu Diary for pointing out this information, and to Crofsblog for tracking it down.