Rattlesnakes are everywhere though may be found less frequently in more populated areas. New developments on the edge of the undeveloped deserts tend to have more snake-dog encounters.
Most dogs get too close out of curiosity and ignore the warnings the snake is putting out. Some dogs may inadvertently walk over or into a snake while running in the desert or bushes.
Other than seeing the bite take place the only sign initially is the sudden onset of swelling in the bite area. The most common first sign other than a painful reaction is swelling of the bite wound area. The most common areas are the face and front limbs. Sometimes an acute allergic reaction or bee sting can look like a snake bite and vice a versa.
Snake bites tend to be one sided ..swell quickly and the pet is painful and very unhappy.
Snake bite damage varies with amount of venom ..number of bites and area of bites.
The intensity of treatment varies on the severity of the case and the financial resources of the owner as severely affected pets may need prolonged expensive treatment.
A rattlesnake vaccine is on the market and its usefulness has not been established definitively. One problem is the variation of the amount of venom and its potency. Rattlesnakes do not always want to waste venom on an animal they have no intention of eating and dry bites or low volume bites can happen so many dogs will do fairly well independent of the vaccine.
Some dogs who live in areas of high snake populations or whose work will bring them in contact with snakes can go to classes that teach them to avoid snakes.