Flu Syndrome: Seasonal Influenza or Stomach Flu?

by James Thompson, M.D. Health Professional, Medical Reviewer

Many areas of the U.S. are reporting a decrease in the number of severe flu syndromes over the past week but another threat appears to be sticking around. There are continued concerns that stomach flu may accentuate the end of flu season by accounting for several more hospitalizations and death. But what is the difference between seasonal flu syndrome and stomach flu?** Take This Quiz:** True or False?

The stomach flu only comes from contact with infected people.

The flu vaccine you had last fall should protect you against the stomach flu.

Like the seasonal flu, the stomach flu should not be contagious after a person has been without fever or flu symptoms for seven days.

One of the available antibiotic medications for treating flu syndrome should help me get over the stomach flu faster.

Since I had stomach flu last year I shouldn't get it again.

Okay, let's answer and explain the above questions.

The most common virus associated with current stomach flu outbreaks is called Sydney2012. It originated in Australia last spring and then made its way to several other continents including the United States. It belongs to a genus of viruses called Norovirus and is passed on to others by direct contact with people that have been infected, by contaminated food, or by contact with objects (tables, door knobs, keyboards, utensils or tools).

Norovirus is completely different from the seasonal flu virus. It is currently the most common cause of the stomach flu in the United States. Flu vaccines do not protect you from Norovirus and antiviral flu drugs (antibiotics) are not effective against it. Norovirus is highly contagious and typically causes nausea, severe vomiting, diarrhea and stomach pain. People may also have low grade fever, chills, headaches and muscle aches. Symptoms are usually severe for a couple of days and may be fatal, especially for young children, the elderly and those who have immune deficiencies. Fatalities most often occur as a result of severe dehydration.

People who have been infected by Norovirus may shed the virus for two or more weeks after recovering from the illness. Some people with milder symptoms may not realize they have Norovirus and unknowingly spread it to others, who may have a more severe infection. It only takes about 18 virus particles to cause infection. Billions are found in vomit and diarrheal collections. Some reports estimate that virus particles can survive for more than 2 weeks on countertops and other surfaces.

Early last year the dominant strain of stomach flu in America was GII.4 New Orleans. This strain was not very lethal but over the course of the year became less prevalent as the current Australian strain emerged. GII.ydney had its start in Australia in March of 2012 but quickly spread to the United States. The newcomer is more lethal and has resulted in more than 140 deaths and numerous hospitalizations.

Like the seasonal flu virus, Noroviruses frequently mutate. This means you can get the stomach flu again from year to year. Natural immunity is uncommon. In fact, because of the simultaneous prevalence of multiple strains of stomach flu it is possible to get re-infected within a short period of time.

_(All the Above True/False Quiz Questions are False)hat Steps Can You Take To Avoid Stomach Flu?

There are three important recommendations emphasized by the CDC (Centers for Disease Control):

Frequent hand washing with soap and water is essential. The next best alternative is to use hand sanitizer.

Wiping surfaces with antiseptic solution (dilute bleach is effective but exercise caution by avoiding direct contact and inhalation of bleach fumes) may reduce spread from viruses contaminating surfaces touched by others.

People with symptoms of stomach flu should be isolated from others and follow the above two guidelines. They should immediately contact their doctor.

Although there is no cure for Norovirus infection, supportive care (fluids and rest) may be enough for the majority of people. Your physician should advise you regarding the need for aggressive treatment (intravenous fluids, hospital admission etc.).

Flu season 2012-13 appears to be past the peak but the need to maintain precautions to prevent new cases remains high. The stomach flu usually peaks in January but this new strain is highly lethal (Sydney) and raises some concerns among health officials. Let's continue to follow their advice and stay tuned for new information.

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James Thompson, M.D.
Meet Our Writer
James Thompson, M.D.

Dr. Thompson completed medical school and specialty training in allergy and immunology at Washington University in Saint Louis. He is board certified in Internal Medicine, Allergy and Immunology. He sees adults and children in Chicago and greater Chicago area. He is also certified in Integrative Nutrition Coaching. Dr. Thompson is dedicated to incorporating holistic nutrition concepts into the treatment of asthma and other allergic diseases in order to achieve better health and reduce the need for medications.