De or het wormbesmetting?

The correct Dutch article is:

de wormbesmetting

Rule Words ending in -ing: almost always de. See the rule

How to use wormbesmetting

the wormbesmettingde wormbesmetting
this wormbesmettingdeze wormbesmetting
that wormbesmettingdie wormbesmetting
our wormbesmettingonze wormbesmetting
your wormbesmettingjouw wormbesmetting
every wormbesmettingelke wormbesmetting
which wormbesmetting?welke wormbesmetting?
a big wormbesmetting / the big wormbesmettingeen grote wormbesmetting, de grote wormbesmetting