Problem: A research team is investigating a newly identified virus associated with severe respiratory illness. The team attempts to evaluate the organism using Koch's postulates and documents the following findings: Research Finding Result Virus detected in clients with the illness Confirmed Virus detected in healthy individuals Not detected Virus grown in artificial laboratory media Not successful Disease reproduced in animal model Not attempted Based on the data in the chart, which step in this investigation is most difficult to fulfill? Need Assignment Help?
Re-isolating the microorganism from the newly infected host Isolating the microorganism and growing it in pure culture Reproducing the same disease in a healthy host organism Demonstrating the microorganism is present in diseased hosts