Robert Koch • Causation Studio

Koch's Postulates: Interactive demonstration of linking microbes to disease

Step through Koch’s classic framework: from finding a microbe in sick hosts, to isolating it in pure culture, reproducing the disease in a test subject, and re-isolating the same organism. Designed for undergraduate microbiology.

Teal-themed, low-friction learning

Click each step or use the guided flow to see icons animate and the explanation update.

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Step 1: Association in diseased hosts

The suspected pathogen is found in all cases of the disease, but not in healthy individuals.

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Step 2: Isolate & grow pure culture

The microbe is isolated from the host and grown as a pure culture on lab media.

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Step 3: Reproduce disease in test subject

The pure culture causes the same disease when introduced into a healthy, susceptible host.

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Step 4: Re-isolate the same organism

The same microbe is re-isolated from the newly diseased host, confirming the link.

Follow the microbe through Koch's postulates

Current step: 1 / 4

Step 1 focuses on consistent association: the same suspect bacterium appears in all diseased hosts, but is absent or rare in healthy controls. This is the starting clue for causation.

Learning goals

Visualize how Koch’s postulates link a specific microbe to a specific disease.
See each step as a separate, testable requirement, not just a memorized list.
Connect icons and motion with real lab ideas: microscopy, pure culture, infection, and re-isolation.
Recognize that modern microbiology adapts these ideas (e.g., viruses, unculturable microbes).

Step-by-step interpretation

In Step 1, diseased hosts on the left show clusters of teal-highlighted bacteria, while healthy hosts show none. This visual emphasizes "found in diseased, not in healthy".

Quick classroom uses

Have students narrate each step while the animation runs.
Ask which types of pathogens do NOT fully fit Koch’s postulates (e.g., viruses, polymicrobial diseases).
Use the visuals to distinguish correlation vs. causation in infectious disease.

The simulation is intentionally simple and teal-themed so learners can focus on the causal logic, not interface complexity.