Final answer:
The time to trace bacteria and viruses varies due to differences in their replication needs and the diverse methods needed for their identification in laboratories.
Step-by-step explanation:
The time to trace bacteria in the extracellular fluid and a virus that has infected cells varies from case to case. Unlike bacteria, which can often be grown on an artificial nutrient medium, viruses require living host cells for replication, as they rely on the cellular machinery of their host to multiply. When a virus infects a host cell, it can be cultured and the growth medium harvested to obtain the virus. Techniques like centrifugation or filtration are used to separate virions from the host cells.
Diagnosing infectious diseases might involve identifying the pathogen causing the disease. This can be accomplished by growing a sample on a culture medium or examining it under a microscope. While bacteria typically reveal unique growth patterns on these media, viruses are identified by their effects on cultured cells, biochemical tests, or by serological tests that identify pathogens by their antigens.
Therefore, given the complexities involved in the growth and identification of pathogens, especially viruses, the tracing time is not constant and depends on various factors, including the type of pathogen, available detection methods, and specific laboratory conditions.