Look for:
• several animals that become ill at once;
• a marked drop in milk, egg, or other production;
• multiple sudden deaths or changed behaviors in animals;
• tenderfootedness or loss of coordination;
• head swelling, discharges, breathing difficulties, or multiple sudden abortions;
• blisters (vesicles) around the mouth, nose, teats, or hooves (cattle, pigs, sheep, goats, or horses).