I think the use of the word 'eat' is a bit non-specific. Macrophages cannot survive on a diet of virus. They can absolutely 'eat' it in the sense of taking it f

I think the use of the word 'eat' is a bit non-specific. Macrophages cannot survive on a diet of virus. They can absolutely 'eat' it in the sense of taking it from outside the cell, breaking it down into constituent components inside the cell, and then putting it back outside the cell as waste, but they can't use viruses as a food source.