virus in English:

viral infection

You can reach more potential customers by using viral marketing technique.

viral video posted online which becomes popular very quickly

The definition of viral is something that has become very popular very quickly on the Internet. An example of viral is a video that is released and watched by a million people within a few days.

Campaigns can quickly go viral on social media, gathering thousands of supportive signatures in a few hours.

The old man came down with viral pneumonia, and died soon after

The news on their affair went viral.

Male circumcision decreases the risk of viral infections that cause herpes and cancer.

Linguistic resources are far more valuable if they are unencumbered by share-alike or viral licences.