D.S.H.S. planes took off from Alpine on Monday to drop rabies vaccines across the Big Bend region.
The vaccine doses are closed into packets that are dipped in fish oil and covered with fish meal crumbles.
The packets pose no risk to humans.
However, people should still avoid touching them -- so that wild animals can get eat them and get vaccinated.
D.S.H.S. officials have been dropping rabies vaccine packets across the area for 18 years now.
The vaccine program has been incredibly effective, as well.
D.S.H.S. officials say that cases of the fox strain of the deadly virus in West Texas have dropped from 244 in 1995 to 0 in 2010.