AALAS Laboratory Animal Technician (LAT) Practice Test

Clinical disease is when the animal shows observable signs of illness, indicating active disease. The visible signs—such as lethargy, coughing, lesions, or behavioral changes—signal that the animal is clinically affected, not just carrying the pathogen invisibly. So the statement that an animal develops visible signs of the disease is true and captures this idea.

Lab tests can support a diagnosis but are not the only way to identify clinical disease, since signs alone can point to illness. Infectiousness varies and isn’t determined by the mere presence of clinical signs—some animals with subclinical or carrier states can shed organisms without obvious illness. Latent disease refers to a state where the pathogen persists without signs and can reactivate later; that’s different from the active, visible illness described by clinical disease.