Once You Have the Stomach Flu Can You Get It Again
In the terminal few [winter] months, schools all over the state have airtight because of outbreaks of norovirus. Too known as breadbasket flu, norovirus infections cause watery diarrhea, low-grade fever and, most alarming of all, projectile airsickness, which is an extremely effective way of spreading the virus.
Norovirus is very infectious and spreads rapidly through a confined population, such as at a school or on a cruise transport. Although most sufferers recover in 24 to 48 hours, norovirus is a leading crusade of childhood affliction and, in developing countries, results in about fifty,000 kid deaths each twelvemonth.
Interestingly, not everyone is every bit vulnerable to the virus, and whether you get sick or not may depend on your blood type.
Norovirus is difficult to get rid of
I am a microbiologist, and I got interested in norovirus because, while norovirus symptoms are distressing under any circumstances, my encounter with the virus was specially inconvenient. During a seven-day rafting trip down the One thousand Canyon, the illness passed through the rafters and coiffure, one past one. Obviously, the wilderness germ-free facilities were not the best to cope with this outbreak. Luckily, everyone, including me, recovered speedily. It turns out that norovirus outbreaks on Colorado River rafting trips are common.
Every bit debilitating as the affliction information technology causes can exist, 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 poly peptide coat, called the "capsid." The capsid protects the norovirus' genetic material.
The naked capsid coat is ane factor that makes norovirus so difficult to control. Viruses with membrane coatings are susceptible to alcohol and detergents, but non so norovirus. Norovirus tin can survive temperatures from freezing to 145 degrees Fahrenheit (about the maximum water temperature in a abode dishwasher), soap and mild solutions of bleach. Norovirus can persist on human hands for hours and on solid surfaces and food for days and is as well resistant to booze-based hand sanitizers.
To make things worse, only a tiny dose of the virus—as few as 10 viral particles—is needed to cause disease. Given that an infected person tin excrete many billions of viral particles, it'southward very hard to forbid the virus from spreading.
Susceptibility to norovirus depends on blood type
Your blood blazon—A, B, AB, or O—is dictated by genes that make up one's mind 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.
The same oligosaccharides on red blood cells also announced on the surface of cells that line the small intestine. Norovirus and a few other viruses use these oligosaccharides to catch onto and infect the intestinal cells. Information technology'south the specific construction of these oligosaccharides that determines whether a given strain of virus can attach and invade.
The presence of ane oligosaccharide, called the H1-antigen, is required for attachment past many norovirus strains.
People who practise non make H1-antigen in their intestinal cells make up 20% of the European-derived population and are resistant to many strains of norovirus.
More sugars tin be attached to the H1-antigen to requite the A, B or AB claret types. People who can't brand the A and B modifications have the O blood type.
Unlike strains of norovirus infect unlike people
Norovirus evolves rapidly. There are 29 different strains currently known to infect humans, and each strain has different variants. Each i has different abilities to demark to the variously shaped saccharide molecules on the abdominal cell surface. These sugars are determined past blood type.
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 grouping of people is exposed to a dissimilar strain of norovirus, different people may be resistant or susceptible. In general, those who practise not make the H1-antigen and people with B blood blazon will tend to be resistant, whereas people with A, AB, or O claret types will tend get sick, but the pattern will depend on the specific strain of norovirus.
This divergence in susceptibility has an interesting upshot. When an outbreak occurs, for case, on a cruise ship, roughly a third of the people may escape infection. Because they practice not know the underlying reason for their resistance, I think spared people appoint in magical thinking—for case, "I didn't go ill 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.
Immunity to norovirus is short-lived
A norovirus infection provokes a robust immune response that eliminates the virus in a few days. Withal, the response appears to be brusk-lived. Well-nigh studies have plant that immunity guarding against reinfection with the same norovirus strain lasts less than six months. Also, infection with one strain of norovirus offers little protection against infection from another. Thus, you tin can have repeated bouts with norovirus.
The diverseness of norovirus strains and the impermanence of the immune response complicates evolution of an effective vaccine. Currently, clinical trials are testing the effects of vaccines fabricated from the capsid proteins of the ii most prevalent norovirus strains.
In general, these experimental vaccines produce good allowed responses; the longevity of the immune response is now under report. The next phase of clinical trials volition exam if the vaccines really prevent or reduce the symptoms of norovirus infection.
Source: https://biology.indiana.edu/news-events/newsletters/2020-spr-newsletter/norovirus.html
0 Response to "Once You Have the Stomach Flu Can You Get It Again"
Post a Comment