Keep that in mind if you decide to rescue a stray dog yourself. It may be better to keep your eye on them and call the local Humane Society so they can send someone out and catch the dog. After all, you may be doing a good deed by rounding up a stray and taking it into your local animal shelter, but if you get bitten by an infected dog in the process, or bring back some type of parasite that affects your other animals or family, it's not going to be worth it.
A good saying is that all strays have been abandoned but not all abandoned dogs are strays. In many large cities or in rural settings, there are actually packs of wild dogs that have become feral. These dogs, while still technically strays, have had little or no human contact, and they will resist, many times aggressively, any attempt at being captured. So when it comes to catching a stray, here are some things to consider.