Intro to Infectious Diseases

Question 1

**List organisms/infectious diseases that are “old” but have a continued threat today.

quiz question

Answer 1

 Tuberculosis – emergence of multi-drug resistant strains
 Syphilis
 Black Plague
 Influenza
 Bird/Swine flu
 Anthrax
 Smallpox

Question 2

**List relatively “new” infectious diseases.

quiz question

Answer 2

 AIDS
 Legionnaires Disease
 Lyme Disease
 Toxic Shock
 Ebola
 Respiratory viruses (i.e. Covid-19, etc.)
 Resistant and Multi-resistant (MRSA, VRE, CRE, etc.)
 Immunocompromised patient infections

Question 3

Recognize the infectious agents associated with the following chronic diseases: peptic ulcers, cervical cancer, liver carcinoma, and poliomyelitis like paralysis.

Answer 3

 Peptic ulcers – Helicobacter pylori (H. pylori)
 Cervical cancer – Human Papillomavirus (HPV)
 Liver carcinoma – Hepatitis B & C
 Poliomyelitis like paralysis – West Nile Virus

Question 4

Diagram the three elements involved in the “Triad of Infectious Diseases.”

Answer 4

A diagram that describes causation and factors that allow for infectious disease to occur

 Infectious agent – causes disease
 Host – the agent that can obtain the disease
 Environment – permits transmission to occur

Question 5

Recognize the role of each bacterial virulence factor discussed in class.

Answer 5

 Adherence – attachment to host cells
 Certain antigens
 Toxins
 Invasiveness – penetration of tissues
 Capsules (protects against phagocytosis)
 Slime layers (inhibits phagocytosis/aid in adherence; i.e. biofilm)
 Enzymes
 Hyaluronidase: hydrolyzes hyaluronic acid that binds connective tissue allowing for infection to spread
 Streptokinase: breaks down fibrin, which is formed to wall off infections allow for infection to spread
 Hemolysins: destroy RBCs

Question 6

Discuss the specific environmental factors presented in class that impact the incidence of infectious diseases.

Answer 6

 Poor socioeconomic conditions
 Deforestation
 Natural disasters
 Travel (population migration)
 Antibiotics/immunosuppressant therapies (alters normal flora)

Question 7

**Compare and contrast the characteristics of exotoxins, endotoxins and enterotoxins.

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Answer 7

Exotoxins Endotoxins Enterotoxins
Organism Type Gram negative & positive Gram negative *Subgroup of exotoxins
Composition Protein Lipopolysaccharide (part of cell wall) – ANTIBIOTIC ALERT! *cause damage to intestinal mucosa cells
Type of Release Extracellular Lysed cells
Stability to heating Labile Stable
Antitoxin produced Yes No

Question 8

Recognize the type of toxin responsible for “Gram negative shock.”

Answer 8

Endotoxins

Question 9

Identify various host resistance factors, including the body’s “first line of defense.”

Answer 9

 Physical Barriers
 Skin – “first line of defense”
 Acidic environment of stomach, bladder, vagina
 Bile of intestines
 Normal flora (space and nutrient competition)
 Cleansing mechanisms – desquamation (sluffing of skin), tear production, mucous membranes (i.e. respiratory, GI,
etc.)
 Traditional immune defenses (i.e. phagocytosis, complement, antibodies, etc.)

Question 10

Discuss the impact of immunodeficiency on infectious disease incidence and recognize common causes of immunodeficiency.

Answer 10

A breakdown in immune defenses that lead to susceptibility to infections with opportunistic pathogens – this is the CONCERN! – pathogens that typically do not cause disease, but will under these conditions

 Genetics
 Diet
 Drugs
 Cancer
 Disease
 Newborn, elderly, or pregnant state

Question 11

List the various routes of transmission.

Answer 11

 Air (inhalation)
 Food and water (ingestion)
 Close contact
 Cuts and bites
 Arthropods (tick, flea, mite, mosquito)
 Zoonoses – contact with animals (75% of emerging pathogens)

Question 12

Recognize the route of transmission responsible for most emerging infections and bioterrorism threats.

Answer 12

Zoonoses – contact with animals

Question 13

**Differentiate which body sites should be sterile and which normally retain usual flora. It is NOT necessary, at this time, to know the names of usual flora organisms.

quiz question

Answer 13

Normal flora Sterile body sites
Skin Blood
Mouth CSF
Upper respiratory tract Joint fluids
Intestines (increased further away from stomach) Organs
Vagina Tissues (not exposed to outside)
Upper urinary/genital tract
Lower respiratory tract

Question 14

Differentiate between “colonization” and “usual flora,” relative to organism pathogenicity, recognizing that all organisms can be pathogenic in certain areas of the body and in some patients.

Answer 14

Colonization refers to virulent organisms that colonize a certain site(s) of the body, patients are initially asymptomatic, but this can later serve as a source of infection – “they are living as normal flora, but ARE NOT true normal flora organisms”

Usual flora set up habitat in certain select areas of the body, in which we maintain a symbiotic relationship, but ALL organisms are considered pathogenic when introduced into sterile sites/non-familiar areas

Question 15

Identify proven methods for prevention of infectious diseases.

Answer 15

 Handwashing
 Vaccines
 Public Health Measures
 Sanitation
 Animal/vector control
 Education

Question 16

List the most effective method for infection prevention.

Answer 16

Handwashing!!!!!