Case study

MICROBIOLOGY 233 Chapter 13: Viruses, Viroids, and Prions

Priority Guide for Healthcare Majors (Viroids Excluded)

WHY THIS CHAPTER MATTERS (Healthcare Focus)

In healthcare, viruses are:

– Among the most common causes of disease (flu, COVID, HIV, hepatitis)

– Not treatable with antibiotics

– Highly dependent on host cells

Understanding this chapter helps you:

– Interpret infections correctly

– Understand transmission and prevention

– Recognize persistent infections and cancer risk

HIGH PRIORITY Used Frequently in Healthcare

Topic What It Means Why It Matters in Real Life

Viral Structure Capsid, envelope, genome Determines infection and

treatment

Animal Virus Replication Attachment entry

replication release

Explains infection

progression

Acute vs Persistent Short vs long-term Explains HIV, herpes

Cancer-Causing Viruses Alter host DNA HPV, Hepatitis cancer

Transmission How viruses spread Infection control

MODERATE PRIORITYTopic Viral Taxonomy Bacteriophages Lytic vs Lysogenic Release Diagnostics LOW PRIORITY

Topic Detailed phage models Plant viruses Advanced methods REAL-WORLD CONNECTION

Concept Envelope Replication Persistent infection Cancer viruses Transmission KEY CONCEPTS

Concept Viruses not cells Envelope Lytic Lysogenic Acute What It Means Why It Matters

Classification Helps identify viruses

Infect bacteria Emerging therapies

Active vs dormant Latency

Lysis vs budding Tissue damage differences

PCR, cultures Clinical testing

What It Means Why It Matters

Examples Concept support

Non-human Low relevance

Lab research Limited clinical use

Example

Soap destroys flu

Hijacks host cells

HIV, HPV

HPV

Airborne, blood

Explanation Importance

Need host No antibiotics

Lipid layer Survival differences

Fast destruction Acute disease

DNA integration Latency

Short infection FluPersistent Long infection HIV

STUDY STRATEGY

Focus on:

– Virus vs bacteria

– Replication steps

– Infection types

– Cancer link

CLINICAL THINKING

If you see this Think this

Antibiotics fail Viral infection

Chronic disease Persistent virus

Cancer link Viral cause

Rapid spread High transmission

BOTTOM LINE

Viruses infect, replicate, and persist using host cells.

Understanding this explains treatment limits and prevention.

Lets decide a clinical case just to explore for Wednesday

A clinical case: Why didnt antibiotics work? (viral vs bacterial)

A case on HPV cancer progressionCASE STUDY

MICROBIOLOGY 233 STUDENT CASE STUDY

HPV Cancer Progression (Healthcare Focus)

CASE TITLE: It Started as a Routine Checkup

PATIENT SCENARIO

A 32-year-old woman comes in for her annual checkup. She feels fine and has no symptoms.

Her provider performs a Pap smear and HPV test.

TEST RESULTS (VISIT #1)

Pap Smear: Abnormal (early cell changes)

HPV Test: Positive for HPV Type 16 (high-risk)

WHAT IS HAPPENING IN THE BODY

HPV infects epithelial cells through micro-abrasions and targets basal cells.

The virus uses host cell machinery to replicate and may persist long-term.

CRITICAL CONCEPT

E6 protein turns off p53 damaged cells do not die

E7 protein turns off Rb cells divide uncontrollably

FOLLOW-UP (2 YEARS LATER)

Pap Smear: High-grade abnormal cells

Biopsy: Precancerous changes (CIN III)PREVENTION AND CLINICAL CONNECTION

HPV vaccine prevents infection before exposure

Pap smear detects early changes

Persistent infections increase cancer risk.Answer the following questions belowYou can any other

resource but be sure to reference your book

when your looking for answers.

QUESTIONS

1. What type of virus is HPV (DNA or RNA)?

2. Why is HPV Type 16 considered high-risk?

3. Is this infection acute or persistent? Explain.

4. What normally happens to damaged cells when p53 is active?

5. What happens when cells divide without control?

6. Why didnt the immune system eliminate the virus?

7. What type of infection is this after 2 years?

8. What happens if this condition is untreated?

9. Why is the HPV vaccine most effective before exposure?10. Why dont antibiotics work for HPV?

11. Why can HPV go unnoticed for years?

12. How does viral DNA integration increase cancer risk?

13. Why is early screening important?

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