Assistant Laboratory Animal Technician (ALAT) Practice Exam

What term is used to describe animals that harbor no detectable bacteria, viruses, or other microorganisms?

1. Gnotobiotic

2. Convention

3. Specific Pathogen-Free

4. Germfree

The correct answer is: Germfree

The term that accurately describes animals harboring no detectable bacteria, viruses, or other microorganisms is germfree. Germfree animals, also known as axenic animals, are raised in sterile environments to ensure that they do not come into contact with any microbes. This state is crucial for various types of scientific research, as it allows researchers to study the effects of the absence of microorganisms on the animals' physiology and immune responses. The germfree status is essential for experiments that require a controlled environment free from the influence of microbial flora, which can impact biological processes. In contrast, the other terms, while related to the topic of animal microbiota, do not specifically refer to a complete absence of all microorganisms. For instance, gnotobiotic refers to animals that have a known set of microorganisms, often used to study specific interactions between the animal and its microbiota. Specific Pathogen-Free (SPF) describes animals that are free from certain specified pathogens but may still harbor other non-pathogenic microorganisms. Convention refers to standard practices in animal husbandry that do not imply any particular status regarding microbial presence. Therefore, germfree is the most precise term for animals without any detectable microorganisms.