Assistant Laboratory Animal Technician (ALAT) Practice Exam

Which organism is not classified as a parasite?

1. Fungi

2. Bacteria

3. Virus

4. Protozoa

The correct answer is: Virus

Viruses are considered obligate intracellular pathogens rather than parasites in the strict sense. They require a host's living cells to replicate and propagate, but they do not exhibit the characteristics typically associated with parasitism. Unlike parasites, viruses do not live on or in their hosts; they enter host cells and hijack the cellular machinery to reproduce themselves. In contrast, fungi, bacteria, and protozoa can be classified as parasites, as they can live on or within a host organism, often deriving nutrients at the host's expense and potentially causing harm. Understanding the distinctions between these microorganisms is crucial for laboratory animal technicians, as it informs appropriate handling, care, and treatment of laboratory animals that may be affected by parasitic infections.