Rapid muscle twitching, as if a person had snakes crawling under the skin, is the telltale sign to Roy Johnson that the Southern Pacific rattlesnake has struck. On occasion, this symptom can progress to difficult breathing, coma and death. This snake's bite is one of the few to induce neurological symptoms, in contrast to most other rattlesnake bites, which initially produce swelling and bruising around the wound, notes Johnson, a physician in Palomar, Calif.,
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