Answer:
poverty and disease
Step-by-step explanation:
due to the gold rush, many people travelled west to dig for gold. they made pop up towns which had no laws or healthcare. this created a lot of disease as when they were travelling west, most medications and resources would have been thrown away to make their carriages lighter so the horses could carry their weight after a long time.
poverty was also a major factor as not many people would actually find gold so they'd end up working for bigger companies to find gold and would get paid barely anything.
I hope that was helpful, friend :)