Explanation:

The most alarming fact is that infection is spreading across the state and reaching villages and small towns.
Spread Across is a Phrase: o move over the entirety or majority of some area; to be distributed or dispersed The plague spread across the region incredibly quickly, killing millions of people in its wake. ... Of information, to disseminate over the entirety or majority of some area or place.
Hence, option 2 is the correct answer.