CH.3 Host-Microorganism Interactions

Flashcards about Host-Microorganism Interactions

What are microbial reservoirs?

Environments or places of origin of infecting agents, such as humans, animals, water, air, and soil

What is mode of transmission?

Means by which microbes are brought in contact with a human host (direct or indirect)

What is direct transmission?

When a host directly contacts a microbial reservoir

What is indirect transmission?

When a host contacts a microorganism through an intervening agent of transmission

What is a vector?

Living intermediate agent of indirect transmission (e.g., insect)

What is a vehicle?

Nonliving intermediate agent of indirect transmission (e.g., air)

What is a fomite?

Inanimate object that serves as an intermediate agent of indirect transmission (e.g., surfaces, bedding)

What are healthcare-associated infections?

Infections acquired from any healthcare setting

What are nosocomial infections?

Infections acquired in a hospital or long-term care facility

What are zoonotic infections?

Accidental human infection of an animal microbe

What is colonization?

Persistent survival of microorganisms on body surfaces

What protects internal tissues and organs against microbial invasion?

First defenses, always present and nonspecific defense mechanisms (e.g., skin, mucous membranes)

What are transient colonizers?

Do not multiply, shed with host cells

What are resident microbiota?

Survive, thrive, and multiply, making them persistent

What are virulence factors?

Characteristics that make microbes able/good at causing disease

What are opportunistic pathogens?

Organisms that cause disease when they gain access to a different site or if the host is immunocompromised

What are biofilms?

Accumulation of microorganisms embedded in a complex matrix, providing a protective environment and antibiotic resistance

What is an acute infection?

Develops quickly

What is a chronic infection?

Develops slowly

What is a latent infection?

Silent phase with no symptoms

What are signs of infection?

Measurable indications or physical observations (e.g., fever, rash)

What are symptoms of infection?

Indicators described by a patient (e.g., headache, fatigue, nausea)

What is active immunization or vaccination?

Modified antigens are introduced into the body and is long lasting

What is passive immunization or vaccination?

Antibodies are transferred to the host for temporary protection

What is epidemiology?

Science that characterizes the circumstances associated with the acquisition and dissemination of infectious diseases

What are endotoxins?

Lipopolysaccharide portion of the cell envelope released when a gram-negative bacterial cell is destroyed

What are exotoxins?

Specific toxins produced and released by living bacteria which targets specific host cells

What is a vector?

A living organism, typically an arthropod such as an insect or tick, that transmits a disease-causing microbe from one host to another. Vectors play an essential role in the life cycle of certain pathogens, facilitating their spread and survival. Common examples include mosquitoes transmitting malaria and ticks transmitting Lyme disease.

Active immunization, also known as vaccination, involves introducing modified antigens (weakened or inactive pathogens or their components) into the body. This process stimulates the immune system to produce antibodies and memory cells, providing long-lasting protection against future infections by the same pathogen.

What is a chronic infection?

A chronic infection is an infection that develops slowly and persists over a long period, often months or years. Symptoms may be mild or absent for extended periods, making diagnosis challenging. Examples include HIV, hepatitis B, and tuberculosis.

What is an acute infection?

An acute infection develops rapidly, typically within days or weeks, and is characterized by a relatively short duration. Symptoms are often severe and appear quickly. Examples include influenza (the flu), the common cold, and strep throat. These infections usually resolve completely once the pathogen is eliminated by the host's immune system or through medical treatment.