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Hello! My name is Rolf Ypma.
I study avian influenza, 

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a disease carried by many wild birds.
Although it usually doesn't cause severe 

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illness in wild birds, 

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the virus can be transferred to poultry,
to whom it's highly infectious and lethal. 

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The virus can kill humans as well,
luckily the probability of getting 

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infected is extremely low. 

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Still, it's obviously important that any
outbreak of the virus is detected and 

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stopped as quickly as possible, 

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to halt further spread. The only viable
way we currently have of stopping an 

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outbreak is preemptive culling
of healthy animals. 

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For example, in a large epidemic in the Netherlands in 2003, 

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30 million birds had to be culled.
If we want to stop the virus more efficiently

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we'll need a better understanding of
how it spreads. One possibility is that 

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virus particles are blown to new
farms by wind.  

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This hypothesis can be tested from the
2003 outbreak by reconstructing the 

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transmissions between farms of the virus. 

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Such a reconstruction is possible using
the viral DNA we obtained from all 

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infected farms.

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My part of the study was to use this DNA
to calculate viral movements. 

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I did this by formulating mathematical
equations that describe both how the 

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virus transmits, 

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and how it mutates. We then compared the
transmissions between farms with the

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wind direction at time
of transmissions. 

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We found that the two were suspiciously
often in the same direction, 

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which led to our conclusion that wind
plays a role in spreading the disease. 

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This information can be used to
halt the virus, 

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for example by installing special
filters that stop virus particles from 

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getting through.