Eating well could spread infections faster, water-flea study shows

It may be an old wives' tale to say that starving a fever is an effective remedy – but now scientists have shown that plentiful food can accelerate the spread of infections.

Scientists studying bacterial infections in tiny water-fleas have discovered that increasing their supply of food can speed up the spread of infection. They carried out the study to better understand factors that affect how diseases are transmitted.


Researchers found that when a population of parasite-infected water-fleas was well-fed, some of them became highly contagious, compared with when food was limited.

Scientists say the discovery highlights that, under certain conditions, some individuals may be more prone to spreading disease than others. Their findings could help inform ways to monitor and control the spread of infections, such as epidemics, in large populations.

Some well-fed water-fleas were more infectious than others because they were able to survive for longer with the parasite, giving it more time to multiply.

Researchers say it is unclear whether food supply is a vital factor in infections in people and animals, but suggest their study highlights the need to consider the impact of environmental conditions, such as nutrition, on individuals in large populations at risk of disease.

Scientists at the University of Edinburgh studied the impact of food quantity on the spread of a bacteria parasite that grows in the water-flea gut, releasing infectious spores when the water-flea dies. Among those water-fleas that were well-fed, some were found to be carrying many more parasites than others, and so were more prone to spreading the disease.

The study, published in Biology Letters, was supported by the Wellcome Trust and the Centre National de la Recherche Scientifique in France.

Dr Pedro Vale, of the University of Edinburgh’s School of Biological Sciences, who led the study, said: “If we have an idea of which individuals transmit a lot of disease, we will be better able to stop its spread. We know that contact between individuals is important; but now we know that, for some animals at least, nutrition may also play an important role in the spread of disease.”


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