Here's an interesting article that explains why we are more likely to become infected by some viruses but not others. The spread of viral infections depends on a number of factors, including how infectious the virus is and how aware/ill a person becomes with the virus. Interestingly the flu is not that infectious, but those coming down with influenza are contagious for a day or two before they show any symptoms, so it is very hard to bring a flu epidemic under control! That's also a concern for us, because we won't be aware that someone we've met is contagious either...
With a mix of five authors, all Associate Professors or Fellows from the University of Melbourne, University of Adelaide and Australian National University in the disciplines of Population Health, Mathematical Biology, Applied Mathematics and Epidemiology and Biostatistics, these academics have managed to deliver a short, to the point article. In addition to the flu, Severe Acute Respiratory Syndrome (SARS) , Middle East Respiratory Syndrome (MERS), Ebola, measles chicken pox and HIV also get specific mention.
Photo: Gossamer spiders catching a ride on the breeze to spread themselves to new pastures.
Apologies for the low resolution and small depth of field, but these spiders are only a couple of millimetres long and I found it challenging to get close enough to photograph them without scaring them away. The field was covered with undulating webs of gossamer silk and I'd collected more than a few strands of silk by the time I'd taken this shot.