# insect borne diseases

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How can tiny insects like fleas, ticks, mosquitos, etc. physically carry enough of a virus to impact a full grown adult human.

In: 2

Viruses and bacteria replicate fast and furiously. So that tiny amount that is injected quickly grows to be enough to make a human sick if their immune system isn’t able to kill it quickly enough.

Viruses are tiny. For example, Sars-CoV-2 which causes COVID-19 is around 80-120 nanometers in diameter. A nanometer is a billion of meter, you need around 1000 of them side by side for the width of a human hair.

If you do the calculation of the total volume of all Sars-CoV-2 om the world at one moment in time during the pandemic the total volume is less then you expect. A human would have around 10 billion viruses in them at the peek of an infection and if you assume 3 million get infected each day the total volume of all viruses is less than a soft bottle

https://www.bbc.com/future/article/20210210-why-the-entire-coronavirus-would-fit-in-a-can-of-coca-cola

A cube with a side the with of a human hair can fit 1 billion viruses if you assume they are cubes with the diameter as sides, you could fit even more spheres. So you could fit all Sars-CoV-2 viruses a human has in their body during the peek of a infection in a mosquitoes Theoretical 1 virus is enough for an infection, in practice you likely need to stop the immune system, from beating them initially

Sars-CoV-2 is not transported by insects but the link to the calculation gives you an idea of how tiny viruses really are.