bios242 unit 4 host-microbe interactions (3/4)

A collection of 50 flashcards covering host-microbe interactions, including microbiota acquisition, infectious disease terminology, stages of infection, and modes of transmission.

What are the microbial cells that live on or in our bodies called?

Resident microbiota

What process involves resident microbiota inhibiting or destroying potentially infectious microorganisms through competition?

Microbial antagonism

When does the acquisition of the normal biota begin?

While the fetus is developing in utero

By what methods does a baby's microbiota develop during the first $6\,\text{months}$?

Bottle feeding, breastfeeding, and contact with people

According to recent findings, what is the role of the uterus's microbiota?

It colonizes the fetus with its initial microbiota and aids in a healthy pregnancy

How do babies born via C-section acquire their microbiota?

Through milk and contact with caregivers and the environment

What is the definition of a pathogen?

A microbe that has a parasitic relationship with its host

How is virulence described?

The pathogenicity of a microbe based on its ability to establish itself in a host and cause damage

What is defined as a condition where pathogenic microorganisms penetrate host defenses, enter tissues, and multiply?

Infection

What term describes the pathologic state occurring when an infection damages tissues and organs?

Disease

Under what condition does an 'abnormal site' situation occur for opportunistic pathogens?

When normal biota are introduced to a previously sterile site

List three examples of factors that can cause an individual to be immunocompromised.

Age (very young or old), genetic mutations, and HIV infection

How do broad-spectrum antibiotics contribute to the rise of opportunistic pathogens?

They kill normal bacteria and allow pathogenic bacteria to colonize without competition

What is the difference between exogenous and endogenous pathogens?

Exogenous pathogens originate from outside the body, while endogenous pathogens already exist in the body

Through which systems do microbes characteristically enter the body?

The integumentary system and mucous membranes of the gastrointestinal, respiratory, and urogenital systems

What does the acronym TORCH describe?

Infections that can transfer from mother to fetus and cause spontaneous abortion, congenital defects, or premature birth

Which structures do bacteria, fungi, and protozoa use to attach to host cells?

Fimbriae, surface proteins, slime, and capsules

What structures do viruses use to enter host cells?

Spikes

What are virulence factors?

Traits that allow pathogenic bacteria to evade the immune system

Which types of bacteria secrete leukocidins to kill phagocytes?

Streptococcus and Staphylococcus

How do some pathogens reduce the response of immune system cells regarding DNA?

By making epigenetic or chemical changes to the host DNA

What is the difference between exotoxins and endotoxins?

Exotoxins are secreted by living microbes and cause specific damage, while endotoxins are lipopolysaccharides shed from dying Gram-negative bacteria causing generalized damage

What is a localized infection?

An infection where the microbe enters the body and remains confined to a specific tissue

What is a systemic infection?

When an infection spreads to several sites and tissue fluids, usually in the bloodstream, nerves, or cerebrospinal fluid

What is a focal infection?

When an infectious agent breaks loose from a local infection and is carried to other tissues

What is the difference between a primary and a secondary infection?

A primary infection is the initial infection; a secondary infection occurs when a primary infection is complicated by a different microbe

How do acute and chronic infections differ in progression?

Acute infections come on rapidly and are short-lived, while chronic infections progress and persist over a long period of time

What is a 'sign' in the context of infectious disease?

Any objective evidence of disease as noted by an observer (e.g., fever)

What is a 'symptom' in the context of infectious disease?

Subjective evidence of disease as sensed by the patient (e.g., chills)

What is a syndrome?

A disease identified or defined by characteristic signs and symptoms

What is the incubation period of an infection?

The time from initial contact with an infectious agent to the appearance of first symptoms

What happens during the prodromal stage of an infection?

Pathogen numbers start to increase and notable symptoms start

What occurs during the height of infection (acute) stage?

The agent multiplies at high levels, exhibits greatest virulence, and signs/symptoms are most severe

What occurs during the convalescence stage?

Symptoms and pathogen numbers decline, and recovery occurs

Name two infections that may involve a continuation stage.

Lyme disease and typhoid

What is latency?

A state where a pathogen becomes dormant and the host does not experience symptoms

Which causative agent is associated with latency involving chickenpox and shingles?

Human herpes virus 3

What are sequelae?

Long-term or permanent damage to the host produced by some infectious diseases

What is an example of a sequela of Lyme disease?

Arthritis

What is a reservoir?

The place where pathogens originate, which may be inanimate objects or living hosts

How can pathogens be transmitted from animals (other than humans/arthropods) to humans?

Directly by bite or scratch, or indirectly through contaminated fluids or vectors like fleas

What is a carrier?

A person who is infected with a pathogen and can unknowingly spread it to others directly or indirectly

What characterizes an asymptomatic carrier?

They are infected but show no symptoms of disease (e.g., Gonorrhea)

What is an incubating carrier?

A person who is infected but shows no symptoms while the microbes are multiplying (e.g., infectious mononucleosis)

What is a convalescent carrier?

A recuperating patient without symptoms who continues to shed viable microbes (e.g., Hepatitis A)

What is a chronic carrier?

An individual who shelters the infectious agent for a long period after recovery due to latency (e.g., Tuberculosis)

What is a passive carrier?

Medical/dental personnel who accidentally transfer pathogens from contaminated patient materials to other patients

How do pathogens of the respiratory and salivary portals typically exit the host?

Via moist secretions such as mucus, sputum, and nasal drainage

What are biological vectors in the context of reservoirs?

Infected arthropods, such as mosquitoes, that transmit pathogens to a new host

What defines a communicable disease?

A disease where the pathogen spreads from an infected host to a new host