I can't tell if this is accidental or deliberate, but there are a whole bunch of spam entries in Google for the 43.gs domain as you can see from this search.
It looks like some sort of redirect or copy, but the odd thing is that the 43.gs subdomain actually points to the legitimate server.
For example, ethviumvthvie.43.gs resolves as 18.104.22.168 which belongs to the US Centers for Disease Control (CDC). For some reason, the CDC server accepts requests for ethviumvthvie.43.gs as a request to display the genuine website.
As a result, Google has about 3.2 million results for 43.gs subdomains, all of which are duplicates of existing sites.
It looks like 43.gs offers some sort of legitimate URL shortening service based on subdomain names rather than the more common tinurl/bit.ly. Have the bad guys found a way to use this to their advantage? Are they suddenly going to switch traffic to somewhere bad?
43.gs is showing a small bump in traffic recently, perhaps as a result of this?
Presumably there is a way of telling your web server to reject this kind of request.