Exam 3 - Chapter 31

What disease transmission is the hardest to contain?

Airborne pathogens

Types of airborne pathogens

Aerosols and droplets

Bacterial diseases caused by airborne pathogens

• Strep throat

• Scarlet fever

• Streptococcal toxic shock syndrome

• Necrotizing fasciitis

• Pneumonia

• Diphtheria

• Pertussis

• Tuberculosis

• Hansen’s disease (leprosy)

• Bacterial meningitis

Diseases caused by Streptococcus pyogenes

• Strep throat

• Scarlet fever

• Streptococcal toxic shock syndrome

• Necrotizing fasciitis

Characteristics of Streptococcus pyogenes

Beta-hemolytic

Is there a vaccine for Streptococcus pyogenes?

No

Diseases caused by Streptococcus pneumoniae

Pneumonia

Characteristics of Streptococcus pneumoniae

Encapsulated and alpha-hemolytic

Is there a vaccine available for Streptococcus pneumoniae?

Yes

Diphtheria

Severe respiratory disease that typically infects children

Pathogen that causes Diphtheria

Corynebacterium diphtheriae

Lysogenized bacteriophage

Powerful exotoxin that causes pseudomembrane

Diphtheria is encoded by…

Lysogenized bacteriophage

Is there a vaccine available for diphtheria?

Yes - in Tdap vaccine

Pertussis is also known as…

whooping cough

What pathogen causes pertussis?

Bordetella pertussis

Is there a vaccine available for pertussis

Yes - in Tdap vaccine

What pathogen causes tuberculosis?

Mycobacterium tuberculosis

Is there a vaccine available for tuberculosis?

No

What pathogen causes Hansen’s disease/leprosy?

Mycobacterium leprae

Is there a vaccine available for leprosy?

No

What pathogen causes bacterial meningitis?

Neisseria meningitidis

Is there a vaccine available for bacterial meningitis?

Yes

Airborne viral diseases

• Measles

• Mumps

• Rubella

• Varicella-Zoster

• Common cold

• Influenza

• SARS-Covid2

What diseases does the MMR vaccine cover?

Measles, mumps and rubella

Is there a vaccine available for Varicella-Zoster infections?

Yes

What pathogens can cause common colds?

Rhinoviruses, coronaviruses, etc.

Is there a vaccine available for common colds?

No

Is there a vaccine available for influenza?

Yes

Is there a vaccine available for SARS-Covid2?

Yes

Influenza structure

Single-stranded, negative-sense, RNA genome - 8 segments

Due to influenza’s structure, what can occur?

Antigenic shift (and drift)

Direct contact bacterial and viral diseases

• Staphylococcus aureus infections

• Helicobacter pylori and gastric diseases

• Hepatitis viruses

Infections caused by Staphylococcus aureus

• Acne

• Boils

• Pimples

• Impetigo

• Pneumonia

• Osteomyelitis

• Carditis

• Meningitis

• Arthritis

Is there a vaccine available for Staphylococcus aureus?

No

Is there a vaccine available for Helicobacter pylori?

No

Strains of hepatitis

• HPA

• HPB

• HPC

• HPD

• HPE

For which hepatitis strains is there a vaccine?

HPA & HPB

Sexually transmitted diseases/infections can be caused by…

Variety of bacteria, viruses, protists, and even fungi

Pathogens for STDs are generally only found in…

bodily fluids from the genitourinary tract that are exchanged during sexual activity

Major STDs

• Gonorrhea

• Syphilis

• Chlamydia trachomatis infections

• Genital herpes

• Genital warts

• AIDS

What is the pathogen that causes gonorrhea?

Neisseria gonorrhoeae

What is the pathogen that causes syphilis?

Treponema pallidum

What is the pathogen that causes genital herpes?

Herpes simplex 2

What is the pathogen that causes genital warts?

Human papillomavirus (HPV)

What is the pathogen that causes AIDS?

Human immunodeficiency virus (HIV)

For what STD is there a vaccine?

Some strains of HPV/genital warts

Recommended treatment for gonorrhea

Cefixime or ceftriaxone and azithromycin or doxycycline

Recommended treatment for syphilis

Benzathine penicillin G

Recommended treatment for Chlamydia trachomatis

Doxycycline or azithromycin

Recommended treatment for genital herpes

No known cure; symptoms can be controlled by several antiviral drugs

Recommended treatment for genital warts

No known cure but preventable by vaccine; symptomatic warts can be removed surgically, chemically, or by cryotherapy

Recommended treatment for AIDS

No known cure; several drugs can stop viral replication and slow disease progression; prophylactic drug available

Shape of Treponema pallidum

spirochete

How has the number of syphilis cases in the US changed over time?

Decreased after World War II and stayed very low since mid-1900s

How has the number of gonorrhea cases in the US changed over time?

Increased drastically after the invention of birth control pills, then decreased over time since the 1970s

HIV pathogenesis

Infects cells that contain the CD4 cell surface protein (macrophages and T helper cells)

Process for HIV infection

1. HIV gp120/gp41 protein binds CD4 receptor and CCR5 receptor

2. Interaction of the virus with a receptor-coreceptor pair on the host cell

3. The viral envelope and host membrane fuse

4. The nucleocapsid is inserted into the host cell, beginning the viral infection

What is the greatest risk factor for men to contract AIDS?

Having sex with other men

What is the greatest risk factor for women to contract AIDS?

Heterosexual contact

_____ are associated with HIV/AIDS

Opportunistic pathogens and Kaposi’s sarcoma

Progression of HIV infection

1. Symptom free

2. Swollen lymph glands

3. Subclinical immune dysfunction

4. Opportunistic infections

5. Systemic immune deficiency

6. Death

As HIV infection progresses, what happens?

CD4 T lymphocytes decrease in numbers

What factors could affect the progression of HIV?

• Opportunistic pathogens

• Anti-retroviral therapy

• Provirus integrated into host genome