The pathogen typically shows a high affinity for epithelial tissue:

• Epitheliotropism: skin and cutaneous mucous membranes
• Myotropism: skeletal and cardiac muscles
• Neurotropism (very rare): Nervous tissue

General symptoms in all affected animal species are aphthae formation (blisters, vesicles) on the udder (teat, resistance to milking harness), on the claws (inter-claw gap, coronal margin, in pigs aphthae up to the tarsal joint, reluctance to move, tripping, slow standing up) and in the mouth area (inside of lips, tongue, gums, animals salivate and show reduced appetite); fever (40-42 °C), pain, apathy.

Other symptoms in cattle: decrease in milk yield, high mortality rate in calves.

Other symptoms in pigs: changes in the claw/extremity area often very severe, shoing possible, deaths in piglets without clinical symptoms frequent.

Other symptoms in sheep: mainly fever. Lameness and lesions in the mouth area are often mild. Peracute deaths in young animals.