Preparing for the Flu Season

This illustration provides a 3D graphical representation of a generic influenza virions structure. (Photo credit: CDC/ Douglas Jordan)

This illustration provides a 3D graphical representation of a generic influenza virion’s structure. (Photo credit: CDC/ Douglas Jordan)

Tis the season for coughs, sneezes, sore throats, body aches, and high fevers. Are you ready for the flu season? [Read more…]

Researchers Find H1N1 Flu Virus Able To Infect Lung Cells

The H1N1 flu virus. (Photo credit: C. S. Goldsmith and A. Balish / CDC)

The H1N1 flu virus. (Photo credit: C. S. Goldsmith and A. Balish / CDC)

Researchers at Imperial College London have determined that, unlike the seasonal flu, the H1N1 flu virus is able to infect cells deep within the lungs, which potentially can lead to serious lung infections. The scientists believe this is one reason why H1N1 fly infections commonly have more severe symptoms than seasonal flu infections.

In their research, the scientists used a method called a carbohydrate microarray to determine to which receptors the two different viruses are able to connect. In this method, a glass surface was covered with 86 different receptors. The researchers then added the viruses to the glass surface. A “lit up” surface indicated that a virus was able to bind with a receptor.

Like most viruses, the flu virus infects cells by attaching to receptors on the outside of the cell. After connecting to a cell, the virus enters the cell and takes over the cell’s functions and manufactures more copies of the virus. The cell then lyses (bursts), and the new virus copies infect nearby cells, continuing the process. The seasonal flu virus is able to infect (that is, attach onto receptors on) cells in the nose, throat, and upper airway of the respiratory system. The H1Ni flu virus is also able to attach to cells in these same areas. However, in contrast, to the seasonal flu virus, the H1N1 virus can also attach onto cell receptors located deep in the lungs.

The researchers discovered that the H1N1 virus’s attachment to cells in the lungs is a weak bond. They think this is one reason why not everyone who is infected by the virus experience severe lung problems. However, the scientists worry that a mutation could make the virus better able to attach to receptors in the lungs, leading to more cases of severe lung infections.

Results of the scientists’ research was published in the September 2009 issue of the journal Nature Biotechnology. The research was funded in part by the Wellcome Trust, the Medical Research Council, and the Engineering and Physical Sciences Research Council.

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WHO Declares H1N1 Flu Virus Outbreak a Pandemic

On June 11, 2009, the World Health Organization raised the alert level to phase 6meaning that the occurrence of swine flu can be categorized as a pandemic. Since the virus was first identified, over 30,000 cases of swine flu have been diagnosed in North America, Europe, Australia, South America, and other locations across the globe. The WHO opted to change the alert level due to the global spread of the flu virus, and not because of the severity of the virus. Thus far, most cases of the H1N1 flu virus in the United States have been mild, and most people infected by the virus have recovered without requiring professional medical treatment. However, because the H1N1 flu virus is a new virus, most people have little to no immunity against it. Health officials worry that the severity of the H1N1 flu virus could increase over time, especially during the fall and winter when the flu season hits. This is especially worrisome given the current lack of a vaccine against the virus.

Cases of the H1N1 flu virus were first detected in Mexico, and have since spread into the United States and worldwide. The first confirmed case of the H1N1 flu virus in the United States was identified on April 15, 2009. Since the outbreak began, cases have been identified in all 50 states. Early outbreaks around the globe centered on travelers who had recently returned from trips to Mexico. Currently, countries in the Southern Hemisphere, including Australia and New Zealand, are experiencing an rise in the number of H1N1 flu virus infections; that part of the world is just entering the influenza season.

Of the 30,000 reported cases of H1N1 flu virus infection, there have only been 144 deaths. To put this in perspective, according to data presented by the Centers for Disease Control (CDC), every year in the United States, about five to 20 percent of the population comes down with a case of the seasonal flu, and about 36,000 Americans die every year from flu-related complications.

Following are a few answers to some questions you may have about the H1N1 flu virus.

What is the H1N1 virus?

The influenza A(H1N1) virus is a new type of flu that was first detected in the United States in April 2009.

The H1N1 flu virus. (Photo credit: CDC Influenza Laboratory)

Why was it called the swine flu?

The H1N1 virus was originally referred to as the “swine flu” because initial testing showed that the virus carried a number of genes similar to flu viruses that typically occur in North American pigs. Further testing showed that the virus is actually a quadruple reassortment virus that contains two genes that normally infect European and Asian pigs along with a gene from humans and a gene from birds.

What are the symptoms of the H1N1 virus?

Symptoms of the H1N1 flu virus are similar to the symptoms of the seasonal flu. These symptoms include fever, body aches, headache, chills, cough, sore throat, and fatigue. In some cases, occurrences of diarrhea and vomiting have also been reported. Although cases in the United States have generally been mild, some populations of people may be more susceptible to the virus, including the very young the very old, pregnant women, and those with chronic conditions or compromised immune systems.

How is the virus spread?

The virus is spread by human-to-human contact through coughing, sneezing, or touching something infected by the virus and then touching one’s eyes, nose, or mouth. You cannot contract the H1N1 virus by eating cooked pork or pork products.

What are ways to prevent illness?

Wash your hands frequently with soap and water. Alcohol-based hand sanitizers can also be used to protect yourself from flu germs. Use a tissue to cover your mouth when you cough or sneeze and throw the tissue away after it’s used. If you have symptoms of the flu, stay at home. If at all possible, limit your contact with those you know to be infected with the H1N1 flu.

Is there a vaccine for the H1N1 virus?

There is not currently a vaccine for the H1N1 virus, though scientists are at work developing one. There are several antiviral medications that are recommend for use for those who have the H1N1 virus such as oseltamivir and zanamavir. These medications help prevent the flu virus from reproducing in your body and make flu symptoms milder. However, in many cases getting plenty of rest and drinking plenty of fluids is all that is necessary to get over a case of the H1N1 flu.

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Substance Found in Fruits and Vegetables May Reduce Chance of Flu

In a recent study published by The American Physiological Society, researchers found that mice given quercetin had a smaller chance of catching the flu. The researchers also found that stressful exercise increased the likelihood of contracting flu in the mice. When the mice that had exercised were given quercetin, however, the researchers found that the mice were less susceptible to the flu–quercetin effectively canceled out the negative effects of stressful exercise.

What is Quercetin?

Quercetin is a substance that is naturally found in fruits and vegetables. It is an example of a flavonol, a type of flavonoid. Flavonoids are substances found within plants that produce pigments in some flowers and protect the plant from attack by insects or microbes.

Foods rich in quercetin include red grapes, red onions, tea, and berries such as blueberries. Previous studies have indicated that quercetin is an effective anti-inflammatory agent and helps to prevent the processes that cause inflammation. Studies have also shown that quercetin, when combined with ultrasound therapy, works to inhibit the growth of cancerous tumors.

Blueberries are an example of a fruit rich in quercetin. (Photo Credit: USDA)

Blueberries are an example of a fruit rich in quercetin. (Photo Credit: USDA)

Quercetin and the Flu

In this most recent study, researchers based at the University of South Carolina and Clemson University studied the relationship between stressful exercise and susceptibility to flu in mice. In the experiment, the researchers studied four groups of mice. Two groups exercised to fatigue on a treadmill for three days in a row to imitate a short episode of stressful exercise. One group of exercising mice was given quercetin; the other was not. The two remaining groups of mice did not exercise. One of the non-exercising groups of mice was given quercetin; the other was not. Next, all four groups of mice were exposed to the common flu virus.

The results of the experiment were five-fold. First, mice that experienced stressful exercise were more likely to catch the flu. Second, the mice that exercised caught the flu sooner than the mice that had not exercised. Third, mice that exercised and were given quercetin had nearly the same rate of illness as the mice that did not exercise. Fourth, those mice that did not exercise, or that did exercise but took quercetin, experienced the same severity of flu symptoms. And fifth, the mice that did not exercise but were given quercetin experienced protective effects from the supplement.

How these results in mice relate to humans is less understood. In one study involving humans, it was shown that, following three consecutive days of stressful exercise, those who had taken quercetin were less likely to suffer from illnesses than those who did not take the supplement. However, further research is needed to fully understand how quercetin affects humans and whether or not its affects are the same for humans as they are for mice.

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Will There Be Another Flu Pandemic Soon?

The last flu pandemic ended in 1968; it was the third flu pandemic of the 20th century. Experts at the World Health Organization (WHO) believe that we are closer to another flu pandemic than any time since then. However, there is no way to predict when a pandemic will hit because each past pandemic was very different. National and multinational organizations must use other tools to anticipate and prepare for a grave public health threat.

The WHO uses a pandemic alert system to track whether a new virus strain is at risk to start a pandemic. The alert system runs from phase 1, which stands for no new virus strain infecting humans, to phase 6, describing a pandemic. Moving from one phase of alert to another is the decision of the Director-General of WHO and is influenced by the characteristics of the virus and how easily it is spread, among other things. The world is now in phase 3, characterized by the new influenza virus subtype H5N1 avian flu. Bird flu, as it is known, causes disease in humans but does not spread from human to human efficiently or sustainably.

There are different goals, actions, and policy decisions for each stage of the WHO phases. These range from preparedness, use of isolation or quarantine and vaccinations and antiviral medications to the maintenance of civil order in a pandemic period.

Another tool used by organizations is computer modeling. Currently there are computer models that simulate pandemics in the United States and other countries. The models are based on previous pandemic information and help officials when drafting preparedness plans. Researchers continue to refine their models and test scenarios as new information becomes available.

With better information and better responses, hopefully the next pandemic won’t take as many lives when it finally strikes.

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