When I was in South America I saw something that made my heart break.
Stray dogs would get infested with ticks. Whole carpets of them that would breed on them until they formed bulbous grey patches of them all over their bodies. I was told that eventually the dog would lay down and die.
The problem is that they creatures take and take from their host, and unless something is done to remove them, the poor dog will grow ever weaker.
The only solution is a whole body tick-removal bath.
You will not even believe how out of control some of this stuff is.