tag:theconversation.com,2011:/us/topics/stomach-flu-6700/articlesStomach Flu – The Conversation2020-01-10T13:44:25Ztag:theconversation.com,2011:article/1291252020-01-10T13:44:25Z2020-01-10T13:44:25ZYour blood type may influence your vulnerability to norovirus, the winter vomiting virus<figure><img src="https://images.theconversation.com/files/308691/original/file-20200106-123411-1f6nutm.jpg?ixlib=rb-1.1.0&rect=43%2C96%2C5769%2C3796&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Projectile vomiting is common with norovirus.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/man-suffering-sick-stomach-vomiting-674213719">Elnur/Shutterstock.com</a></span></figcaption></figure><p>In the last few months, schools all over the country have closed because of outbreaks of norovirus. Also known as <a href="https://www.cdc.gov/norovirus/about/index.html">stomach flu</a>, norovirus infections cause watery diarrhea, low-grade fever and, most alarming of all, projectile vomiting, which is an extremely effective way of <a href="https://doi.org/10.1371/journal.pone.0143759">spreading the virus</a>.</p>
<p>Norovirus is very infectious and spreads rapidly through a confined population, such as at a school or on a cruise ship. Although most sufferers recover in 24 to 48 hours, norovirus is a leading cause of childhood illness and, in developing countries, results in about <a href="https://www.cdc.gov/norovirus/trends-outbreaks/worldwide.html">50,000 child deaths each year</a>. </p>
<p>Interestingly, not everyone is equally vulnerable to the virus, and whether you get sick or not <a href="https://doi.org/10.3390/v11030226">may depend on your blood type</a>. </p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/308462/original/file-20200103-11909-1c1i1uc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/308462/original/file-20200103-11909-1c1i1uc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=237&fit=clip" srcset="https://images.theconversation.com/files/308462/original/file-20200103-11909-1c1i1uc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=397&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308462/original/file-20200103-11909-1c1i1uc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=397&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308462/original/file-20200103-11909-1c1i1uc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=397&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308462/original/file-20200103-11909-1c1i1uc.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=499&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308462/original/file-20200103-11909-1c1i1uc.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=499&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308462/original/file-20200103-11909-1c1i1uc.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=499&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">3D print of Norwalk virus, a type of norovirus. Noroviruses are the most common cause of acute gastroenteritis (infection of the stomach and intestines) in the United States.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/niaid/14550066332/in/photolist-oaJTNC-9kN9fS-zT8zR-zRqum-7JT92b-2fHvpyV-nPdK6g-4nS4tN-bkSbTa-9iHCcg-zRqqG-4dHSzJ-dT7574-ehXMFj-mvhVYa-4BWSQk-fjrZgr-zRqrj-5suMaZ-GdQtN9-FPgYQG-dUtuUb-dMVx4Y-R2HhVV-kc9sdG-e4ZuwX-BhXmt-bBSVNr-2g7RMr6-R2agqV-Qg6WSu-2g7S1zi-7n7421-ehRTcF-dPNyUq-dPGX22-yF16XT-dKeb3j-pBZyB5-dPGXwn-fox1yW-dPGA68-4QTPtv-8i7Pxd-6N6awr-d6BGam-jCdHzU-byxjM8-dQS3gV-dQqL4r">NIH</a></span>
</figcaption>
</figure>
<h2>Norovirus is hard to get rid of</h2>
<p><a href="https://biology.indiana.edu/about/faculty/foster-patricia.html">I am a microbiologist</a>, and I got interested in norovirus because, while norovirus symptoms are distressing under any circumstances, my encounter with the virus was particularly inconvenient. During a seven-day rafting trip down the Grand Canyon, the illness passed through the rafters and crew, one by one. Obviously, the wilderness sanitary facilities were not the best to cope with this outbreak. Luckily, everyone, including me, recovered quickly. It turns out that <a href="https://azdailysun.com/news/local/norovirus-back-in-canyon/article_cd739e60-ea66-5d94-9b1c-7648df60b9fa.html">norovirus outbreaks on Colorado River rafting trips</a> are common. </p>
<p>As debilitating as the illness it causes can be, the norovirus particle is visually beautiful. It is a type of virus known as “non-enveloped” or “naked,” which means that it never acquires the membrane coating typical of other viruses, such as the flu virus. The norovirus surface is a protein coat, called the “capsid.” The capsid protects the norovirus’ genetic material. </p>
<p>The naked capsid coat is one factor that makes norovirus so difficult to control. Viruses with membrane coatings are susceptible to alcohol and detergents, but not so norovirus. <a href="https://www.cdc.gov/vitalsigns/norovirus/index.html">Norovirus can survive</a> temperatures from freezing to 145 degrees Fahrenheit (about the maximum water temperature in a home dishwasher), soap and mild solutions of bleach. Norovirus can persist on human hands for hours and on <a href="https://doi.org/10.4315/0362-028X.JFP-15-570">solid surfaces and food for days</a> and is also resistant to alcohol-based hand sanitizers. </p>
<p>To make things worse, only a tiny dose of the virus – <a href="https://doi.org/10.1002/jmv.21237">as few as 10 viral particles</a> – is needed to cause disease. Given that an infected person can excrete many billions of viral particles, it’s very difficult to prevent the virus from spreading.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/308693/original/file-20200106-123364-11tc4wa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/308693/original/file-20200106-123364-11tc4wa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308693/original/file-20200106-123364-11tc4wa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=375&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308693/original/file-20200106-123364-11tc4wa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=375&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308693/original/file-20200106-123364-11tc4wa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=375&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308693/original/file-20200106-123364-11tc4wa.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=471&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308693/original/file-20200106-123364-11tc4wa.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=471&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308693/original/file-20200106-123364-11tc4wa.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=471&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Norovirus, also called winter vomiting bug, infects cells in the human intestine causing diarrhea, vomiting and stomach pain.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/norovirus-human-intestine-called-winter-vomiting-1098015311">Kateryna Kon/Shutterstock.com</a></span>
</figcaption>
</figure>
<h2>Susceptibility to norovirus depends on blood type</h2>
<p>When norovirus is ingested, it initially infects the cells that line the small intestine. Researchers don’t know exactly how this infection then causes the symptoms of the disease. But a fascinating aspect of norovirus is that, after exposure, <a href="https://doi.org/10.3390/v11030226">blood type determines, in a large part, whether a person gets sick</a>. </p>
<p>Your blood type – A, B, AB or O – is dictated by genes that determine which kinds of molecules, called oligosaccharides, are found on the surface of your red blood cells. Oligosaccharides are made from different types of sugars linked together in complex ways.</p>
<p>The same oligosaccharides on red blood cells also appear on the surface of cells that line the small intestine. Norovirus and a few other viruses use these oligosaccharides to grab onto and infect the intestinal cells. It’s the specific structure of these oligosaccharides that determines whether a given strain of virus can attach and invade.</p>
<p>The presence of one oligosaccharide, called the H1-antigen, is required for attachment by many norovirus strains. </p>
<p>People who do not make H1-antigen in their intestinal cells make up 20% of the European-derived population and are <a href="https://doi.org/10.1007/s00439-019-02090-w">resistant to many strains of norovirus</a>. </p>
<p>More sugars can be attached to the H1-antigen to give the A, B or AB blood types. People who can’t make the A and B modifications have the O blood type. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/308689/original/file-20200106-123381-ly8t7m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/308689/original/file-20200106-123381-ly8t7m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/308689/original/file-20200106-123381-ly8t7m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=144&fit=crop&dpr=1 600w, https://images.theconversation.com/files/308689/original/file-20200106-123381-ly8t7m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=144&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/308689/original/file-20200106-123381-ly8t7m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=144&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/308689/original/file-20200106-123381-ly8t7m.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=181&fit=crop&dpr=1 754w, https://images.theconversation.com/files/308689/original/file-20200106-123381-ly8t7m.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=181&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/308689/original/file-20200106-123381-ly8t7m.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=181&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Each blood type is distinguished by a different sugar marker on the red blood cell. Cells lining the intestine also have these sugar markers.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/blood-cells-1777906">Fernando Jose V. Soares/Shutterstock.com</a></span>
</figcaption>
</figure>
<h2>Different strains of norovirus infect different people</h2>
<p>Norovirus evolves rapidly. There are <a href="https://doi.org/10.1097/qco.0000000000000476">29 different strains</a> currently known to infect humans, and each strain has different variants. Each one has different abilities to bind to the variously shaped sugar molecules on the intestinal cell surface. These sugars are determined by blood type. </p>
<p>If a group of people is exposed to a strain of norovirus, who gets sick will depend on each person’s blood type. But, if the same group of people is exposed to a different strain of norovirus, different people may be resistant or susceptible. In general, those who do not make the H1-antigen and people with B blood type will tend to be resistant, whereas people with A, AB, or O blood types will <a href="https://doi.org/10.1002/wsbm.1355">tend to get sick</a>, but the pattern will depend on the specific strain of norovirus.</p>
<p>This difference in susceptibility has an interesting consequence. When an outbreak occurs, for example, on a cruise ship, roughly a third of the people may escape infection. Because they do not know the underlying reason for their resistance, I think spared people engage in <a href="https://www.britannica.com/science/magical-thinking">magical thinking</a> – for example, “I didn’t get sick because I drank a lot of grape juice.” Of course, these mythical evasive techniques will not work if the next outbreak is a strain to which the individual is susceptible. </p>
<h2>Immunity to norovirus is short-lived</h2>
<p>A norovirus infection provokes a robust immune response that eliminates the virus in a few days. However, the response appears to be short-lived. Most studies have found that immunity guarding against reinfection with the same norovirus strain lasts <a href="https://doi.org/10.1002/eji.201545512">less than six months</a>. Also, infection with one strain of norovirus offers little protection against infection from another. Thus, you can have repeated bouts with norovirus.</p>
<p>The diversity of norovirus strains and the impermanence of the immune response complicates development of an effective vaccine. Currently, clinical trials are testing the effects of <a href="https://investors.vaxart.com/news-releases/news-release-details/vaxarts-tableted-oral-bivalent-norovirus-vaccine-meets-primary">vaccines made from the capsid proteins</a> of the two most prevalent norovirus strains. </p>
<p>In general, these experimental vaccines produce <a href="https://doi.org/10.1093/infdis/jiw259">good immune responses</a>; the <a href="https://clinicaltrials.gov/ct2/show/NCT03897309">longevity</a> of the immune response is now <a href="https://clinicaltrials.gov/ct2/show/NCT03039790">under study</a>. The next phase of clinical trials will test if the vaccines actually prevent or <a href="https://clinicaltrials.gov/ct2/show/NCT03039790">reduce the symptoms of norovirus infection</a>.</p>
<p>[ <em>Like what you’ve read? Want more?</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&utm_medium=inline-link&utm_campaign=newsletter-text&utm_content=likethis">Sign up for The Conversation’s daily newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/129125/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Patricia L. Foster receives funding from the US Army Research Office. She is a member of the Union of Concerned Scientists and Concerned Scientists at Indiana University.</span></em></p>Norovirus, the winter vomiting bug, is highly infectious among people in confined places – like cruise ships. But not everyone is equally vulnerable. Your blood type may determine if you get sick.Patricia L. Foster, Professor Emerita of Biology, Indiana UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/564242016-04-24T20:51:36Z2016-04-24T20:51:36ZHealth Check: what to eat and drink when you have gastro<figure><img src="https://images.theconversation.com/files/119564/original/image-20160421-8007-xti90t.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">Inflammation in your stomach and intestinal tract causes diarrhoea, nausea, vomiting, abdominal cramping and pain.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-340548818/stock-photo-reflection-in-mirror-of-teenage-girl-feeling-sick.html?src=NcOTgmqCVe9Id2PVPZTKQw-3-35">Photographee.eu/Shutterstock</a></span></figcaption></figure><p>When you catch a bug that causes <a href="https://theconversation.com/explainer-what-is-gastroenteritis-and-why-cant-i-get-rid-of-it-34351">acute infectious gastroenteritis</a> (gastro), your stomach and intestinal tract become inflamed, causing diarrhoea, nausea, vomiting, abdominal cramping and pain. The last thing you probably feel like doing is eating. </p>
<p>As you recover and the inflammation dies down, your appetite will gradually return. But what should you eat? Information abounds online but it’s difficult to sort fact from fiction. </p>
<h2>Electrolytes</h2>
<p>Oral rehydration therapy is a type of fluid replacement containing sodium and potassium. It is the cornerstone of treatment for gastro, especially if you’re suffering from mild to moderate dehydration. </p>
<p>You can buy oral rehydration solution from a pharmacy, or make it by combining water, salts and sugar. Diluted juice or lemonade (mixed as one part juice or lemonade with four parts water) <a href="http://www0.health.nsw.gov.au/policies/gl/2014/pdf/GL2014_024.pdf">can also be used</a>, as can sports drinks, but not in young children. </p>
<p>Oral rehydration therapy should be favoured over plain water, as water simply doesn’t have the essential electrolytes required to maintain electrolyte balance. </p>
<h2>Food</h2>
<p>Eat small, light meals and build up from there. </p>
<p>Bland foods such as crackers are typically recommended to avoid irritating the stomach, although there is no scientific evidence to support this. </p>
<p>Chicken soup is often touted to aid recovery from gastroenteritis, among other illnesses, but again there is no data to support this claim. </p>
<p>Keep in mind that chicken broth has <a href="http://www.ncbi.nlm.nih.gov/pubmed/4047121">high levels of sodium</a> and can very occasionally result in high blood sodium levels and <a href="http://connection.ebscohost.com/c/articles/16741527/fluid-overload-following-chicken-soup-rehydration-gastroenteritis-demything-therapeutic-legacy">fluid overload</a>.</p>
<p>One <a href="https://www.researchgate.net/publication/242524660_The_BRAT_diet_for_acute_diarrhea_in_children_Should_it_be_used">popular diet</a> recommended for people recovering from gastroenteritis is the BRAT diet, which stands for “bananas, rice, apple sauce and toast”. </p>
<p>The bananas and rice portions of this diet are higher in fibre, leading to more solid stools and a decrease in the frequency of diarrhoea. </p>
<p>But a major disadvantage is that it does not supply a source of protein that the body needs during an acute illness. In <a href="http://www.ncbi.nlm.nih.gov/pubmed/9669718">two rare cases</a>, a very restrictive BRAT diet for acute diarrhoea led to severe protein malnutrition. </p>
<p>When recovering from gastro, it’s good to avoid caffeine and alcohol for several days, as these <a href="http://www.mckinley.illinois.edu/handouts/gastroenteritis.html">can worsen dehydration</a>. But you don’t need to restrict your diet. </p>
<h2>Probiotics</h2>
<p>Probiotics are live microorganisms that are thought to be effective in the treatment and prevention of diarrhoea. They <a href="http://www.ncbi.nlm.nih.gov/pubmed/25459995">alter the composition</a> of gut microbes and can act against noxious gut pathogens.</p>
<p>Probiotics have been <a href="http://www.ncbi.nlm.nih.gov/pubmed/21069673">found to have a moderate benefit</a> in the treatment of infectious gastroenteritis in adults and children. But more research is needed and is <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4728803/">under way</a>. </p>
<h2>Babies and young children</h2>
<p>Dramatic changes have occurred over the last century in the treatment of acute gastroenteritis in children, who are more likely than adults to get gastro and can become dehydrated very quickly. </p>
<p>In the late 1920s, the <a href="http://archpedi.jamanetwork.com/article.aspx?articleid=1174359">standard practice was to</a> administer fluids and withhold foods for a period of time, usually at least 24 hours. After a period of starvation, young children would be reintroduced to food in gradually increasing amounts. </p>
<p>This <a href="http://www.ncbi.nlm.nih.gov/pubmed/9427881">approach was justified</a> in part by the belief that intolerance to foods was a main cause of diarrhoea in children. </p>
<p>Later on, with the realisation that infection was a major cause of gastroenteritis, along with the availability of oral rehydration therapy, this treatment approach was challenged. </p>
<p>Subsequent research has found the gradual re-feeding approach provides <a href="http://www.ncbi.nlm.nih.gov/pubmed/86003">no benefit</a> over regular, continued breastfeeding, which was <a href="http://www.ncbi.nlm.nih.gov/pubmed/3918683">shown to be safe</a> when babies have diarrhoea. </p>
<p>In children older than six months, studies <a href="http://www.ncbi.nlm.nih.gov/pubmed/7039519">found</a> that after oral rehydration therapy, full feeding <a href="http://www.ncbi.nlm.nih.gov/pubmed/3286579">was best</a>. Restarting a child’s normal feeding after four hours of rehydration with a glucose oral rehydration solution <a href="http://www.ncbi.nlm.nih.gov/pubmed/9161945">led to greater weight gain</a> than late feeders. And it didn’t prolong diarrhoea or make it worse. </p>
<p>Importantly, if you’re caring for a child (or adult) who has gastro and becomes dehydrated, consult a medical professional immediately. Signs and symptoms of deydration can include thirst, dry or sticky mouth, <a href="https://www.nlm.nih.gov/medlineplus/ency/article/000982.htm">reduced urine volume, headache</a> and dry skin that doesn’t bounce back when you pinch it. </p>
<p>Severe dehydration is serious and can lead to a rapid heartbeat, rapid breathing, sunken eyes and a reduced level of consciousness.</p><img src="https://counter.theconversation.com/content/56424/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Vincent Ho does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Oral rehydration is the cornerstone of treatment for gastro, especially if you’re suffering from mild to moderate dehydration.Vincent Ho, Lecturer and clinical academic gastroenterologist, Western Sydney UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/154122013-08-21T04:32:00Z2013-08-21T04:32:00ZExplainer: what is stomach flu?<figure><img src="https://images.theconversation.com/files/29218/original/vbgqw863-1376448050.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=496&fit=clip" /><figcaption><span class="caption">The dreaded stomach flu strikes again? Not likely.</span> <span class="attribution"><span class="source">RLHyde</span></span></figcaption></figure><p>Nausea, vomiting, tummy pain and cramps, watery diarrhoea … We’ve all had acute <a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Gastroenteritis">gastroenteritis</a> at some stage.</p>
<p>As a general practitioner, my patients usually refer to their condition in more colloquial terms – “gastro”, “the runs”, “the trots”, “stomach flu”, as well as other colourful names that are too indecent to publish.</p>
<p>Gastroenteritis is usually an infection of the gastrointestinal tract and can be caused by many different organisms:</p>
<ul>
<li>viruses (such as <a href="http://en.wikipedia.org/wiki/Norovirus">norovirus</a>, <a href="http://en.wikipedia.org/wiki/Enterovirus">enterovirus</a>, and <a href="http://en.wikipedia.org/wiki/Rotavirus">rotavirus</a>),</li>
<li>bacteria (such as <em><a href="http://en.wikipedia.org/wiki/Enterotoxigenic_Escherichia_coli">E. coli</a></em> and <em><a href="http://en.wikipedia.org/wiki/Campylobacter_jejuni">Campylobacter</a></em>), and</li>
<li>parasites (such as <a href="http://en.wikipedia.org/wiki/Giardiasis">giardia</a>).<br></li>
</ul>
<p>In Australia, acute gastroenteritis is most commonly due to viruses, and is typically mild. Although it is not usually dangerous, it can be severe and even life-threatening in rare cases.</p>
<p>Australian readers may be aware of norovirus, which has had some recent notoriety in the news. <a href="http://www.smh.com.au/travel/travel-incidents/qantas-passengers-struck-down-with-gastro-on-flight-from-chile-20130802-2r2wh.html">Earlier this month</a>, it was responsible for 26 passengers vomiting and having diarrhoea on a flight from Chile to Sydney. </p>
<p>The “<a href="http://theconversation.com/new-norovirus-strain-could-cause-gastroentiritis-epidimic-11614">Sydney 2012 mutant</a>” strain of norovirus has been responsible for major outbreaks of gastroenteritis <a href="http://www.smh.com.au/world/australias-mutant-vomiting-bug-spreads-misery-around-the-world-20130116-2cs6r.html">worldwide</a> over the past year.</p>
<p>It is also worth mentioning rotavirus, which is a contemporary public health triumph. Rotavirus is one of the leading causes of severe gastroenteritis in children aged under five and responsible for half a million deaths a year – mainly in low-income countries.</p>
<p>In Australia, it was previously responsible for more than 10,000 hospitalisations each year. But since the introduction of the <a href="http://www.immunise.health.gov.au/internet/immunise/publishing.nsf/Content/nips-ctn">oral rotavirus vaccine</a> into the national immunisation program in 2007, there’s been a sustained reduction in hospitalisation due to this organism by <a href="http://www.mja.com.au/journal/2012/197/8/changes-hospitalisations-acute-gastroenteritis-australia-after-national-rotavirus">over 70%</a>.</p>
<p>Bacterial and parasitic causes of gastroenteritis are uncommon in Australia, except in the case of returned travellers. <a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/Traveller's_diarrhoea">Traveller’s diarrhoea</a> is frequently the result of an infection with one of the strains of <em>E. coli</em> that release toxins that affect the bowel.</p>
<p>Like gastroenteritis, traveller’s diarrhoea is also known by a range of popular names, generally in keeping with the exotic locale where disaster struck. We have “Montezuma’s revenge”, “Bali belly”, the “Rangoon runs”, and the “Hong Kong dog” among others.</p>
<h2>Where did it come from?</h2>
<p>On the theme of the use of vernacular slang for diarrhoeal diseases, one of interesting changes that I have noticed as an Australian GP is use of the term “stomach flu” for gastroenteritis. Reflecting back, I don’t think any of my patients used this label even a few years ago.</p>
<p>The fantastic <a href="http://www.google.com.au/trends/">Google Trends</a> tool seems to bear out my (unscientific) observation. As far as Google is concerned, the first occurrence of “search interest” for the term “stomach flu” in <a href="http://www.google.com.au/trends/explore?q=stomach+flu#q=%22stomach%20flu%22&geo=AU&cmpt=q">Australia</a> was in August 2008 (Figure 1).</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/28969/original/7dqdhbhh-1376029163.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/28969/original/7dqdhbhh-1376029163.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/28969/original/7dqdhbhh-1376029163.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=227&fit=crop&dpr=1 600w, https://images.theconversation.com/files/28969/original/7dqdhbhh-1376029163.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=227&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/28969/original/7dqdhbhh-1376029163.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=227&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/28969/original/7dqdhbhh-1376029163.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=286&fit=crop&dpr=1 754w, https://images.theconversation.com/files/28969/original/7dqdhbhh-1376029163.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=286&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/28969/original/7dqdhbhh-1376029163.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=286&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Figure 1 - Google Trends Web Search Interest “stomach flu”; Australia 2004-2013.</span>
<span class="attribution"><span class="source">Google Trends</span></span>
</figcaption>
</figure>
<p>There have been subsequent spikes of interest in the winters of 2009 to 2013, which is consistent with the fact that outbreaks of viral gastroenteritis tend to occur in the colder months. </p>
<p>In fact, the British call norovirus by the descriptive (and rather unimaginative) moniker “<a href="http://www.nhs.uk/Conditions/Norovirus/Pages/Introduction.aspx">winter vomiting disease</a>”.</p>
<p>We see different search statistics for the <a href="http://www.google.com.au/trends/explore?q=stomach+flu#q=%22stomach%20flu%22&geo=US&cmpt=q">United States</a> (Figure 2) where the term “stomach flu” is used much more frequently. There are consistent search interest spikes for “stomach flu” in winter months of the northern hemisphere all the way back to 2004, the earliest available data.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/28971/original/4b58skc5-1376029759.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=1000&fit=clip"><img alt="" src="https://images.theconversation.com/files/28971/original/4b58skc5-1376029759.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&fit=clip" srcset="https://images.theconversation.com/files/28971/original/4b58skc5-1376029759.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=600&h=227&fit=crop&dpr=1 600w, https://images.theconversation.com/files/28971/original/4b58skc5-1376029759.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=600&h=227&fit=crop&dpr=2 1200w, https://images.theconversation.com/files/28971/original/4b58skc5-1376029759.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=600&h=227&fit=crop&dpr=3 1800w, https://images.theconversation.com/files/28971/original/4b58skc5-1376029759.jpg?ixlib=rb-1.1.0&q=45&auto=format&w=754&h=286&fit=crop&dpr=1 754w, https://images.theconversation.com/files/28971/original/4b58skc5-1376029759.jpg?ixlib=rb-1.1.0&q=30&auto=format&w=754&h=286&fit=crop&dpr=2 1508w, https://images.theconversation.com/files/28971/original/4b58skc5-1376029759.jpg?ixlib=rb-1.1.0&q=15&auto=format&w=754&h=286&fit=crop&dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Figure 2 - Google Trends Web Search Interest “stomach flu”; United States 2004-2013.</span>
<span class="attribution"><span class="source">Google Trends</span></span>
</figcaption>
</figure>
<p>The community shift in calling gastroenteritis “stomach flu” in Australia has come with some confusion; some of my patients recently asked whether the “flu vaccine” would protect them against “stomach flu”!</p>
<h2>What influenza is (and isn’t)</h2>
<p>Although many viruses can cause acute gastroenteritis, <a href="http://www.betterhealth.vic.gov.au/bhcv2/bhcarticles.nsf/pages/flu_influenza?open">influenza</a>, the virus that is responsible for “flu” is not one of them. </p>
<p>Influenza is a respiratory disease, not a gastrointestinal one. Although people suffering from influenza may experience nausea, vomiting and diarrhoea, they are rarely the main symptoms. </p>
<p>Common symptoms of the flu include fever, sweats, body aches, lethargy and coughs. Influenza immunisation is not effective against contracting gastroenteritis – even in the slightest.</p>
<p>For the most part, acute gastroenteritis is a self-limiting disease. It usually resolves completely without medical treatment. </p>
<p>Most people simply require some rest and plenty of fluids. <a href="http://en.wikipedia.org/wiki/Oral_rehydration_therapy">Oral rehydration solutions</a>, which contain a specific mix of sugar and salts, can be useful in recovering from dehydration and are available from community pharmacies.</p>
<p>But gastroenteritis is contagious, so scrupulous hand hygiene is important to <a href="http://www.health.gov.au/internet/main/publishing.nsf/content/F2A4C351C705B6C6CA257783000C24CA/$File/norovirus-guidelines.pdf">prevent transmission</a>. Other simple preventive strategies include not preparing food for others, and avoiding child care, school or work for at least 48 hours after diarrhoea or vomiting stops. </p>
<p>As always, if you are unsure or have questions about your health, you should seek the assistance of your regular general practitioner.</p><img src="https://counter.theconversation.com/content/15412/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Michael Tam is a community general practitioner and sees patients suffering from gastroenteritis.</span></em></p>Nausea, vomiting, tummy pain and cramps, watery diarrhoea … We’ve all had acute gastroenteritis at some stage. As a general practitioner, my patients usually refer to their condition in more colloquial…Michael Tam, Lecturer in Primary Care and General Practitioner, UNSW SydneyLicensed as Creative Commons – attribution, no derivatives.