Question

Disease Transmission and Prevention Directions: Read the passage below. Answer the questions that follow. The German physician Robert Koch (1843-1910) established a procedure for diagnosing causes of infection. In his research with anthrax, Koch developed the following four-step procedure, known as Koch’s postulates, as a guide for identifying specific pathogens. Biologists have used Koch’s postulates to identify many pathogens

1. The pathogen must be found in an animal with the disease and not in a healthy animal.

2. The pathogen must be isolated from the sick animal and grown in a laboratory culture.

3. When the isolated pathogen is injected into a healthy animal, the animal must develop the disease.

4. The pathogen should be taken from the second animal and grown in laboratory culture. The pathogen should be the same as the original pathogen.

1. What is indicated when, in spite of being injected with a pathogen isolated from a sick animal, another animal remains healthy?

Answer 1