Tag Archives: human health

Antigen Shift in Influenza Viruses

Antigenic shift is the process by which at least two different strains of a virus, (or different viruses), especially influenza, combine to form a new subtype having a mixture of the surface antigens of the two original strains.

Pigs can be infected with human, avian and swine influenza viruses. Because pigs are susceptible to all three they can be a breeding ground for antigenic shift (as in the recent case of H1N1 Flu – Swine Flu) allowing viruses to mix and create a new virus.

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Influenza Pandemic Alert Raised to Level 5 (of 6)

WHO Director-General, Dr Margaret Chan, announced today that she has “decided to raise the current level of influenza pandemic alert from phase 4 to phase 5.” And she further comments:

Let me remind you. New diseases are, by definition, poorly understood. Influenza viruses are notorious for their rapid mutation and unpredictable behaviour. WHO and health authorities in affected countries will not have all the answers immediately, but we will get them.

WHO will be tracking the pandemic at the epidemiological, clinical, and virological levels. All countries should immediately activate their pandemic preparedness plans. Countries should remain on high alert for unusual outbreaks of influenza-like illness and severe pneumonia.

At this stage, effective and essential measures include heightened surveillance, early detection and treatment of cases, and infection control in all health facilities.

I have reached out to companies manufacturing antiviral drugs to assess capacity and all options for ramping up production. I have also reached out to influenza vaccine manufacturers that can contribute to the production of a pandemic vaccine.

The biggest question, right now, is this: how severe will the pandemic be, especially now at the start?

It is possible that the full clinical spectrum of this disease goes from mild illness to severe disease. We need to continue to monitor the evolution of the situation to get the specific information and data we need to answer this question.

From past experience, we also know that influenza may cause mild disease in affluent countries, but more severe disease, with higher mortality, in developing countries.

No matter what the situation is, the international community should treat this as a window of opportunity to ramp up preparedness and response.

Above all, this is an opportunity for global solidarity as we look for responses and solutions that benefit all countries, all of humanity. After all, it really is all of humanity that is under threat during a pandemic.

As I have said, we do not have all the answers right now, but we will get them.
—- end of her remarks —-
The latest WHO Epidemic and Pandemic Alert and Response release puts the total number of confirmed cases at 148, in 9 countries, with 8 deaths. Mexico has many more suspected cases but just 26 confirmed cases. The CDC Swine Influenza site, puts the total number of confirmed cases in the USA at 91, in 10 states, with 1 death.

Swine Flu: a Quick Overview

World Health Organization on Swine influenza

After reviewing available data on the current situation, Committee members identified a number of gaps in knowledge about the clinical features, epidemiology, and virology of reported cases and the appropriate responses. The Committee advised that answers to several specific questions were needed to facilitate its work.

The Committee nevertheless agreed that the current situation constitutes a public health emergency of international concern.

Based on this advice, the Director-General has determined that the current events constitute a public health emergency of international concern, under the Regulations.

Swine flu: a quick overview–and new New York and Kansas cases by Tara Smith

while the cases in the US have been mild and no deaths have occurred that we’re aware of, it seems in Mexico that young people are dying from this–a group that is typically not hard-hit by seasonal influenza viruses. Readers familiar with influenza and know the history of the 1918 influenza pandemic will recall that the “young and healthy” were disproportionally struck by that virus as well–so this knowledge is currently disconcerting and worrisome, but there are so many gaps in our information as far as what’s really going on in Mexico that it’s difficult to make heads or tails out of this data right now.

Third, is this really a new virus? So few influenza isolates are actually analyzed each year (in proportion to the number of people infected) that we aren’t sure yet whether this is something brand-new, or something that has been circulating at a low level for awhile, but just hadn’t been picked up. After all, H1N1 is a common serotype, so additional molecular testing is needed to determine that it’s “swine flu” versus “human” H1N1.
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this is a fast-developing story, and it will take much more investigation and field work to determine the true extent of the virus’s spread in the population; to figure out… how efficiently it’s transmitted…

This is very early in the scientific inquiry process looking into what exactly is going on. It is too early to tell how serious a threat this is. The reaction of WHO, CDC though shows they are taking the threat seriously. By far the biggest danger in such situations, is reacting too slowly to serious and contagious threats. If you wait to react until proof exists that the situation is very serious the situation can be almost impossible to control. So you need to react quickly to shut down the spread of the threat, hopefully before it has spread too far.

Honda’s Robolegs Help People Walk

The devices combine sensor-driven motors and weight-bearing chassis to guide strides and support body weight. Though derived from technologies pioneered during the ASIMO’s quarter-century of development, their use could be deeply human, boosting manual laborers or assisting people unable to walk without help.
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The devices are still in the research stage, and Honda has not yet formalized plans to go commercial. If they do, the market could be large, and not only in Japan. The number of Americans aged 65 and older is expected to double by 2030. More than 17 million report difficulty climbing stairs or walking a quarter-mile.

CDC: Reduce Salt in Your Diet

USA Center for Disease Control: Application of Lower Sodium Intake Recommendations for Adults, 1999-2006 study

In 2005-2006, an estimated 29% of U.S. adults had hypertension (i.e., high blood pressure), and another 28% had prehypertension. The estimated average intake of sodium for those in the United States over 2 years old was 3,436 mg/day while the U.S. Department of Health and Human Services and U.S. Department of Agriculture recommended adults should consume no more than 2,300 mg/day of sodium (equal to approximately 1 tsp of salt), but those in specific groups (i.e., all persons with hypertension, all middle-aged and older adults, and all blacks) should consume no more than 1,500 mg/day of sodium (69% of U.S. adults should consume no more than !,500 mg/day). There is substantial evidence linking greater sodium intake to higher blood pressure.

Sodium reduction is recommended for persons with hypertension and as a first line of intervention for persons with prehypertension. Public health actions to reduce sodium intake likely will include reducing the sodium content of processed foods; encouraging consumption of more low-sodium foods, such as fruits and vegetables; and providing more relevant information about sodium in food labeling.

The current daily percentage value for sodium in the nutrition facts panel of packaged foods is based on a previous federal guideline of 2,400 mg/day and is likely to mislead the majority of consumers, for whom the 1,500 mg/day limit is applicable.

Image of the Common Cold Virus

image created by Dr. Jean-Yves Sgro, Institute for Molecular Virology, University of Wisconsin-Madison, from published X-ray data. larger image

Sequences capture the code of the common cold

Conducted by teams at the University of Maryland School of Medicine, UW-Madison and the J. Craig Venter Institute, the work to sequence and analyze the cold virus genomes lays a foundation for understanding the virus, its evolution and three-dimensional structure and, most importantly, for exposing vulnerabilities that could lead to the first effective cold remedies.

“We’ve had bits and pieces of these things for a long time,” says Ann Palmenberg, of UW-Madison’s Institute for Molecular Virology and the lead author of the new study. “Now, we have the full genome sequences and we can put them into evolutionary perspective.”

As its name implies, the common cold is an inescapable, highly contagious pathogen. Humans are constantly exposed to cold viruses, and each year adults may endure two to four infections, while schoolchildren can catch as many as 10 colds.

“We know a lot about the common cold virus,” Palmenberg explains, “but we didn’t know how their genomes encoded all that information. Now we do, and all kinds of new things are falling out.”
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The newly sequenced viruses also show, says Palmenberg, why it is unlikely we will ever have an effective, all-purpose cold vaccine: The existing reservoir of viruses worldwide is huge and, according to the new study, they have a tendency to swap genetic sequences when cells are infected by more than one virus, a phenomenon that can lead to new virus strains and clinical manifestations.
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The ability of different cold virus strains to swap genes and make entirely new strains was thought to be impossible, notes Claire M. Fraser-Liggett, a co-author of the new study and director of the Institute for Genome Sciences and professor of medicine and microbiology at the University of Maryland School of Medicine. “There is the possibility that this could lead to the emergence of a new rhinovirus strain with fairly dramatic properties,” says Fraser-Liggett.

Value of Prostate Cancer Screening Questioned by Two Studies

Ben Goldacre, in his bad science blog, again takes on journalist’s articles of health research in: Venal, misleading, pathetic, dangerous, stupid, and busted

1410 men would need to be screened to prevent one death. For each death prevented, 48 people would need to be treated: and prostate cancer treatment has a high risk of very serious side effects like impotence and incontinence. These figures are not hard to find: they are in the summary of the research paper.

For complex risk decisions like screening, it has been shown in three separate studies that patients, doctors, and NHS purchasing panels make more rational decisions about treatments and screening programmes when they are given the figures as real numbers, as I did above, instead of percentages. I’m not saying that PSA screening is either good or bad: I am saying that people deserve the figures in the clearest form possible so they can make their own mind up.
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So newspapers ignore one half of the evidence, and they fail to explain the other half properly.
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They can also link directly and transparently to scientific papers, which mainstream media still refuses to do. Journalists insist that we need professionals to mediate and explain science. From today’s story, their self belief seems truly laughable.

He also says some journalists got it right including the Washington Post in, Prostate Cancer Screening May Not Reduce Deaths:

The PSA blood test, which millions of men undergo each year, did not lower the death toll from the disease in the first decade of a U.S. government-funded study involving more than 76,000 men, researchers reported yesterday. The second study, released simultaneously, was a European trial involving more than 162,000 men that did find fewer deaths among those tested. But the reduction was relatively modest and the study showed that the tests resulted in a large number of men undergoing needless, often harmful treatment.

I think it is true that most people need help having science mediated to some extent. But he is also right that those doing so need to do better. And also everyone needs to learn about science to understand the choices they personally and politically (for policy issues) need to make decisions on. Being scientifically illiterate is dangerous.

Why People Often Get Sicker When They’re Stressed

Researchers at UT Southwestern Medical Center identified a receptor, known as QseE, which resides in a diarrhea-causing strain of E coli. The receptor senses stress cues from the bacterium’s host and helps the pathogen make the host ill. A receptor is a molecule on the surface of a cell that docks with other molecules, often signaling the cell to carry out a specific function.

Dr. Vanessa Sperandio, associate professor of microbiology at UT Southwestern and the study’’ senior author, said QseE is an important player in disease development because the stress cues it senses from a host, chiefly epinephrine and phosphate, are generally associated with blood poisoning, or sepsis.

“Patients with high levels of phosphate in the intestine have a much higher probability of developing sepsis due to systemic infection by intestinal bacteria,” Dr. Sperandio said. “If we can find out how bacteria sense these cues, then we can try to interfere in the process and prevent infection.”

Millions of potentially harmful bacteria exist in the human body, awaiting a signal from their host that it’s time to release their toxins. Without those signals, the bacteria pass through the digestive tract without infecting cells. What hasn’t been identified is how to prevent the release of those toxins.

“There’s obviously a lot of chemical signaling between host and bacteria going on, and we have very little information about which bacteria receptors recognize the host and vice versa,” Dr. Sperandio said. “We’re scratching at the tip of the iceberg on our knowledge of this.”

“When people are stressed they have more epinephrine and norepinephrine being released. Both of these human hormones activate the receptors QseC and QseE, which in turn trigger virulence. Hence, if you are stressed, you activate bacterial virulence.” Dr. Sperandio said the findings also suggest that there may be more going on at the genetic level in stress-induced illness than previously thought.

“The problem may not only be that the stress signals are weakening your immune system, but that you’re also priming some pathogens at the same time,” she said. “Then it’s a double-edged sword. You have a weakened immune system and pathogens exploiting it.”

Previous research by Dr. Sperandio found that phentolamine, an alpha blocker drug used to treat hypertension, and a new drug called LED209 prevent QseC from expressing its virulence genes in cells. Next she will test whether phentolamine has the same effect on QseE.

Full press release: Researchers probe mechanisms of infection

Ozone Pollution Taking Toll on American Lives

Ozone Pollution Taking Toll on American Lives by Amanda Gardner

Thousands of Americans are dying each year from lung disease caused by atmospheric ozone, a new study finds.

The greatest risk may for those living be in hot, dry cities such as Los Angeles, which has one of the highest concentrations of ozone. Residents of Los Angeles may face a 25 percent to 30 percent higher annual risk of dying from a respiratory ailment versus people in low-ozone areas such as the Great Plains, the researchers said.
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An estimated 240,000 people in the United States and 7.7 million people worldwide die of respiratory disease each year, according to data from the World Health Organization. Efforts to reduce ground-level ozone have stalled in recent years, Jarrett said, and now one in three Americans lives in an area that exceeds the national standard for ozone levels.
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Ozone is also a powerful greenhouse gas, Jerrett said, so measures to improve health might have the added benefit of slowing climate change.

Study Shows Weight Loss From Calorie Reduction Not Low Fat or Low Carb

A Randomized Trial Comparing Low-Fat and Low-Carbohydrate Diets Matched for Energy and Protein

The preliminary results presented in this paper are for the first four of six postmenopausal overweight or obese participants who followed, in random order, both a VLC [very-low-carbohydrate] and an LF [low-fat] diet for 6 weeks. Other outcome measures were serum lipids, glucose, and insulin, as well as dietary compliance and side effects. Our results showed no significant weight loss, lipid, serum insulin, or glucose differences between the two diets. Lipids were dramatically reduced on both diets, with a trend for greater triglyceride reduction on the VLC diet. Glucose levels were also reduced on both diets, with a trend for insulin reduction on the VLC diet. Compliance was excellent with both diets, and side effects were mild

Essentially the study showed that the calories had an impact on weight loss but the makeup of those calories did not. Don’t forget this is just one study. Listen to interview with the Author, Frank Sacks, on Science Friday on NPR.