Asymptomatic

Asymptomatic: Exhibiting no symptoms of a disease.
Auto-immune disease: The body's own defense mechanisms attacks normal tissues.

asymptomatic
Term used to refer to a condition of having a disease or affliction but not displaying symptoms of it.
urinalysis ...

Asymptomatic: Neither causing nor exhibiting symptoms of disease.
Australian Mist Cat: A breed of cat developed by crossing Burmese cats, Abyssinian cats and domestic shorthair cats, creating a shorthaired cat with a spotted coat.

Asymptomatic - Without noticeable symptoms.
Ataxia - Shaky movements, unsteadiness or staggering; Lack of voluntary muscle coordination.
Atelectasis - The collapse of a lung.

Even asymptomatic UTIs, if left untreated, can lead to a number of much more serious conditions.

Most infections with Giardia are asymptomatic. In the rare cases in which disease occurs, younger animals are usually affected, and the usual sign is diarrhea. The diarrhea may be acute, intermittent, or chronic.

bronchiseptica from a cat with respiratory tract disease is supportive of the diagnosis, but carriage of the organism in asymptomatic cats precludes establishing a direct cause-and-effect relationship.

See also: Veterinarian, Parasite, Behavior, Species, Bacteria