Norovirus and Clinical Research

I've written a lot about bacteria and plants over the last few weeks, so in celebration of the fact that my project is finally on it's way out (with a whimper rather than a bang, unfortunately, but that's how it goes sometimes) I've decided to descend into the world of viruses. I've also decided to have a go at deconstructing some clinical papers, to make a change from academia. The difference between clinical and academic research can probably be described as follows (and I'm pretty sure I've stolen this quote from somewhere else, but can't remember where):

Clinical Researcher: "That's interesting, but it is useful?"

Academic Researcher: "That's useful, but is it interesting?"

[Industrial worker: "That's useful and interesting....can we sell it?"]

Clinical papers therefore have a different slant from academic ones. They tend to be a lot more precise, a lot clearer. Most will include data from actual people rather than just biochemical data, and the real-world applications come across as the main focus of the study, rather than just tacked onto the end for funding purposes. It comes across in presentations as well, I went to the Society for General Microbiology conference last year and you could usually tell within about ten minutes whether you were listening to an academic, industrial or clinical researcher.

But anyway...on to the papers, which deal with Norovirus, a viral infection usually thought of as a mild (if unpleasant) winter vomiting disease. Norovirus is an RNA virus, which means that it consists of a coil of RNA wrapped up inside a spherical protein coat, as shown to the right

(image taken from the Naked Scientists):

The virus enters the body through the mouth, and invades the small intestine, resulting in lesions in the small intestine tissue and an increase in mucus production. This affects the absorption of nutrients, and leads to build-up of food in the stomach (which can't move down into the intestine) which in turn leads to vomiting and diarrhoea and generally feeling unwell.

Norovirus usually peaks during the winter months, probably because during the winter people tend to spend a lot of time stuck in the enclosed areas with other people. However in 2002, this decline during the summer months halted, and incidents of the disease began to increase, particularly in the over-65 age range. This is due to the emergence of a new variant of the virus which has a higher human-to-human transmission and is therefore more likely to spread in areas where people are living in very close proximity, such as nursing homes and hospitals.

As these places tend to be full of people who are not at their most healthy, this can lead to serious complications in the disease. The damage to the intestines can lead to dehydration which in some cases has been severe enough to lead to kidney failure. Diarrhoea and vomiting cause potassium loss, which can lead to problems in the heart. Deaths are thankfully uncommon, but have been reported.

What this means is that norovirus shouldn't really just be thought of a mild disease any more particularly (which one of the main issues with for clinical researchers) when it happens in hospitals. There's no vaccine against it, as multiple strains exists and having norovirus doesn't really give you much of a defence against getting it again. There has been some work done with the capsid proteins (which surround with RNA of the virus) but as yet this is still happening in mice, and I'm not sure whether it's even entered clinical trials. The best current defence against norovirus is still just to keep things as clean as possible, especially in places where many people are in close proximity, to keep very ill patients away from as many other patients as possible, and to tell doctors to stay at home if they wake up vomiting.

One of the great things about Medical science of course, is that it's an ongoing process and we are the data-sets. This summer rolling around (soon, hopefully!) will bring more information about the state of norovirus, whether the trend in increasing virulence is still around, or whether it's starting to die down. Either way it's a good reminder that sometimes all it takes is a particularly busy hospital and a blip in a piece of floating DNA to turn a relatively harmless disease into a much more problematic one.

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Hane Htut Maung (2008). Norovirus Infection: An Underestimated Danger Cambridge Medicine, 22, 22-24

Lopman BA, Reacher M, Gallimore C, Adak GK, Gray JJ, & Brown DW (2003). A summertime peak of "winter vomiting disease": surveillance of noroviruses in England and Wales, 1995 to 2002. BMC public health, 3 PMID: 12659651

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