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Noroviruses, cause of diarrhoea & vomiting

New estimates have suggested that noroviruses cause around a fifth of all cases of acute gastroenteritis (diarrhoea and vomiting) across all age groups. 

Noroviruses are responsible for almost a fifth (18 per cent) of all cases worldwide. According to the authors, new estimates highlight the importance of developing norovirus vaccines.

Lead author Dr Benjamin Lopman from the Centers for Disease Control and Prevention in the USA, said including data from 48 countries and involving more than 187 000 gastroenteritis cases worldwide, these new estimates are the largest analysis of norovirus infection and disease to date. There has been a proliferation of research on norovirus globally in the last five years, and we harnessed that data for this study.

Lopman and colleagues analysed 175 published reports to compile data on the prevalence of norovirus in individuals with acute gastroenteritis between 1990 and 2014. 

They found that norovirus tended to be more common in cases of acute gastroenteritis in the community (24 per cent) and outpatient (20 per cent) settings than in emergency department visits and hospitalisations (17 per cent), supporting the notion that norovirus is a more common cause of mild disease. However, because of its sheer frequency, norovirus causes a substantial amount of severe disease.

Norovirus was also found in a considerable proportion of cases of acute gastroenteritis cases in both developing countries (14–19 per cent) and developed countries (20 per cent). “This highlights that norovirus, unlike bacterial and parasitic pathogens, cannot be controlled just by improved water and sanitation,” explains Lopman.

Study links nearsightedness to higher education

A new study has revealed that that attaining a higher level of education and spending more years in school are two factors associated with a greater prevalence and severity of nearsightedness, or myopia.

According to German researchers, environmental factors may outweigh genetics in myopia development and suggested that students should spend time outdoors. Researchers at the University Medical Center in Mainz, Germany examined nearsightedness in 4,658 Germans ages 35 to 74, excluding anyone with cataracts or who had undergone refractive surgery and found that myopia appeared to become more prevalent as education level increased.

The study found that 24 per cent with no high school education or other training were nearsighted, 35 per cent of high school graduates and vocational school graduates were nearsighted, while 53 per cent of university graduates were nearsighted. The researchers also found that people who spent more years in school proved to be more myopic, with nearsightedness worsening for each year of school. Furthermore, the researchers looked at the effect of 45 genetic markers, but found it a much weaker factor in the degree of nearsightedness compared to education level.
How do we recognise foodstuffs by smell alone?

A new study has revealed how people recognise foodstuffs like strawberries, coffee or barbecued meat by just with its aroma.

Foodstuffs contain more than 10,000 different volatile substances. But only around 230 of these determine the odor of the food we eat and between just 3 and 40 of these key odors are responsible for encoding the typical smell of an individual foodstuff, which are then decoded by around 400 olfactory receptors in the nose.

The researchers found that the almost unlimited variety of food smells is based on 230 key odorants and each foodstuff has its own odor code comprised of a core group of between just 3 and 40 of the 230 key odorants, in specific concentrations, so these small groups of odorous substances are what give all kinds of foodstuffs from pineapple to wine to roast meat their unmistakable aromas.

The chemical odor codes are translated into olfactory stimulus patterns when food is consumed. For this, the key odorous substances have to interact with one or more of the 400 olfactory receptors in the nose.

The mapping of odor codes opens up new possibilities for biotechnology applications and it will also lay the scientific groundwork for the next generation of aroma products, which use the potential of optimized biosynthetic pathways in plants for industrial-scale production of high-quality food odorants.

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