Good nutrition linked to spread of viral infections

New research[1] suggests that healthy and well-fed fleas become more infectious than malnourished ones. Increasing the supply of food can accelerate the rate in which bacterial and viral infections are passed.

Scientists surmise that these fleas (Daphnia magna) were more infectious than others because they were able to survive for longer with the parasite, giving it more time to multiply. Among those that were well fed, some were found to be carrying more parasites than others, and so were more prone to spreading the disease.

[Foto: FAO]

This could also mean that migratory birds that are well-fed, healthier and thus more likely to survive their journey have a higher viral load in their excrement. Thus, in a favourable summer season, these birds fatten up and then dump more viruses on the terrain below, which in turn may result in higher infectious rates among local birds, pigs and humans. A chain of events like this can easily lead to an epidemic because if more people are infected they are likely to infect others.

This may also mean that a good summer in the north may act as a predictor for (the speed of) the spread of viruses like influenza later in the year.

[1] Vale et al: Host nutrition alters the variance in parasite transmission potential in Biology Letters - 2013