Which term refers to when an animal is infected with parasites but clinical signs are not observable?

The term that refers to an animal being infected with parasites without observable clinical signs is "parasitiasis." In this state, while the parasites are present and may be causing some physiological effect on the host, the animal does not display any outward symptoms that would indicate the presence of the parasites. This can make it challenging for veterinarians to diagnose the issue based solely on clinical symptoms, as the animal appears healthy despite the underlying infection.

The other terms relate to varying aspects of parasitic infections. For example, "parasitosis" specifically denotes an infection with parasites that does produce clinical signs, indicating that the host is experiencing adverse effects from the infestation. "Subclinical infection" can describe an infection where the host is infected but does not exhibit obvious symptoms, however, it is typically more general and may not specify that it involves parasites. "Asymptomatic infestation" could also imply no symptoms; however, it is less commonly used in veterinary contexts compared to parasitiasis, which is specifically defined in relation to parasites.

Understanding these distinctions helps clarify how parasitic infections can manifest differently in host animals, leading to various diagnostic and treatment approaches.