BIOS 2210 Chapter 15/16

What is an infection?

Invasion and multiplication of a microbe in the body, which may or may not cause symptoms.

What occurs when an infection disrupts normal body function?

Disease.

What are symptoms?

Subjective effects felt by the patient (e.g., pain, fatigue, nausea).

What is a transmissible disease?

A disease that can spread from person to person (also called communicable).

What does epidemiology study?

How diseases spread, their patterns, causes, and control in populations.

What is a pathogen?

A microbe that can cause disease.

What is an opportunistic pathogen?

Normally harmless, but can cause disease in weakened immune systems or disrupted microbiota.

What is pathogenicity?

The ability of a microbe to cause disease.

What is virulence?

The degree of harm a pathogen causes; how severe the disease is.

What is a virulence factor?

Specific traits (toxins, enzymes, etc.) that help a pathogen invade, evade, or damage the host.

What is direct contact transmission?

Transmission via physical touch, droplets, or sexual contact.

What is indirect contact transmission?

Transmission through touching contaminated surfaces (fomites).

What describes airborne transmission?

Inhaling aerosols or fine droplets.

What is vector-borne transmission?

Transmission via insects like mosquitoes or ticks.

What is vehicle transmission?

Transmission through food, water, or air.

What is vertical transmission?

Transmission from mother to child during pregnancy or birth.

What occurs during the prodromal stage of disease?

Early stage with mild, non-specific symptoms (fatigue, headache) before the full illness.

What is the relationship between pathogen load and symptoms?

As the number of pathogens increases, symptoms usually become more severe.

What is bacteremia?

The presence of bacteria in the bloodstream.

What is septicemia?

A serious, life-threatening condition caused by the multiplication of pathogens in the blood, triggering an overwhelming immune response.

What are adhesins?

Surface proteins or molecules that allow bacteria to stick to host cells.

What do exoenzymes do?

Secreted by bacteria to break down host tissues and spread the infection.

What are exotoxins?

Proteins secreted by bacteria that are toxic to host cells.

What are endotoxins?

Part of the outer membrane of Gram-negative bacteria, specifically the lipid A portion of lipopolysaccharide.

What characterizes an intracellular pathogen?

A pathogen that lives and replicates inside host cells.

What factors increase viral virulence?

Evading immune responses, high replication rate, mutability, tissue tropism, and immune suppression.

What does the WHO stand for?

World Health Organization.

What is the role of the WHO?

Coordinates global health efforts, monitors disease outbreaks, and sets international health standards.

What is the function of virulence factors in bacteria?

Help bacteria invade the host, cause disease, and evade immune defenses.

What is the purpose of a vaccine?

To prepare the immune system to recognize and combat pathogens.

What is the primary method of HIV transmission?

Through sexual contact, blood transfusions, or from mother to child.

What can be considered a asymptomatic infection?

An infection that does not cause noticeable symptoms.

What is the significance of tissue tropism in viruses?

The ability to infect specific cell types critical for the virus's lifecycle.

What is the impact of high replication rates of viruses?

Increases damage to host tissues, facilitating disease progression.

Define mutability in the context of viral infections.

The ability of viruses to mutate and escape immunity.

What is the function of enterotoxins?

They cause food poisoning by affecting the gastrointestinal tract.

Provide an example of an obligate intracellular pathogen.

Chlamydia trachomatis.

Provide an example of a facultative intracellular pathogen.

Listeria monocytogenes.

What role do cytokines play in the immune response?

They act as signaling molecules that mediate and regulate immunity, inflammation, and hematopoiesis.

What is the importance of sanitation in disease prevention?

Reduces the spread of pathogens through food, water, and surfaces.

What can be a result of septic shock if untreated?

Organ failure and death.

How can inflammation contribute to disease symptoms?

It can cause pain, redness, swelling, and heat in the affected area.

What type of pathogens can cause opportunistic infections?

Pathogens that take advantage of weakened immune systems.

What is the role of the innate immune system?

The first line of defense against pathogens, providing immediate but general protection.

Explain the difference between active and passive immunity.

Active immunity develops after exposure to an antigen; passive immunity is acquired through antibodies from another source.

What is the role of macrophages in the immune response?

Engulf and digest pathogens and dead cells, and activate other immune cells.

How does vaccination confer immunity?

By exposing the immune system to a harmless form of the pathogen, stimulating an immune response.

What is herd immunity?

When a substantial proportion of the population is immune to a disease, providing indirect protection to those not immune.

What can happen if a pathogen develops resistance to antibiotics?

Infections may become harder to treat and can lead to increased morbidity and mortality.