Infection & Disease: Interactions Between Microbes and Humans

A set of flashcards covering key terms and concepts related to infection and disease interactions, focusing on microbes and humans.

Reservoir

Primary habitat of the pathogen, can be human or animal carriers, soil, water, and plants.

Transmitter

Individual or object from which an infection is acquired.

Pathogen

An agent capable of causing disease.

Zoonosis

An infection indigenous to animals but naturally transmissible to humans.

Commensalism

A type of symbiotic relationship where the microbe benefits and the host is unaffected.

Mutualism

A symbiotic relationship where both the host and the microbe benefit.

Parasitism

A relationship where the pathogen causes damage to the host.

Endoparasites

Parasites that live inside the host.

Ectoparasites

Parasites that live on the outside of the host.

Virulence

The ability of a microorganism to establish itself in a host and cause damage.

Infection

The multiplication of a microbe in a host that produces inflammation.

Disease

The effects of infection that cause damage or disrupt the host’s tissues or organs.

Symbiosis

Interaction between different biological species, which can be mutualistic, commensalistic, or parasitic.

Human Microbiome Project (HMP)

A worldwide research effort to characterize microbes living on healthy human bodies.

Infectious dose (ID)

The minimum number of microbes necessary to cause an infection.

Asymptomatic

An infection that does not present noticeable symptoms.

Sign

Objective evidence of disease as noted by an observer.

Symptom

Subjective evidence of disease sensed by the patient.

Incubation period

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

Prodromal stage

The initial phase of infection when earliest symptoms begin to appear.

Acute phase

The stage of infection when the infectious agent multiplies rapidly, causing notable symptoms.

Convalescent period

Period during which the patient begins to recover and symptoms decline.

Sequelae

Long-term or permanent damage to tissues or organs caused by an infectious disease.

Exoenzymes

Enzymes secreted by microbes that break down and damage host tissues.

Toxin

A specific chemical product of microbes that is poisonous to other organisms.

Endotoxin

A chemical called Lipopolysaccharide (LPS) that causes systemic effects and is part of the gram-negative cell wall.

Exotoxin

Small proteins produced by bacteria that have specific effects on target cells.

Pathogenicity

The potential of a microbe to cause disease.

Obligate parasite

A parasite that must use a host to survive.

Fomite

An inanimate object that can harbor and transmit pathogens.

Vertical transmission

Transmission of a disease from parent to offspring.

Horizontal transmission

Transmission of a disease from one infected individual to another within the same population.

Healthcare-associated infection (HAI)

An infection acquired during a hospital or healthcare facility stay.

Microbial antagonism

Normal biota that prevent incoming microbes from displacing them.

Carriers

Individuals who harbor pathogens without showing symptoms.

Polymicrobial infections

Infections that involve multiple pathogens simultaneously.

Adhesion

The process where microbes gain a stable foothold on host tissues.

Antiphagocytic factors

Strategies used by pathogens to avoid being engulfed by phagocytes.

Chronic carrier

An individual who continues to harbor an infectious agent for an extended period after recovery.

Serotype

A distinctive variation within a species of bacteria or viruses.

Biofilm

A community of microorganisms adhering to a surface.

Immunocompromised

A state in which an individual's immune system is weakened.

Morbidity rate

The rate of incidence of a disease in a population.

Mortality rate

The rate of death in a population due to a specific disease.

Index case

The first case of a disease that brings attention to the outbreak.

Endemic

A disease that exhibits a stable frequency over a long period within a geographic area.

Sporadic

Occasional instances of disease reported at irregular intervals.

Epidemic

A sudden increase in the number of cases of a disease above expected levels.

Pandemic

An epidemic that has spread across continents.

Bacteremia

Presence of bacteria in the blood.

Viremia

Presence of viruses in the blood.

Leukocytosis

Increase in white blood cell levels indicative of infection.

Leukopenia

Decrease in white blood cell levels.

Septicemia

A systemic condition where microorganisms multiply in the blood.

Causative agent

The specific pathogen responsible for causing a disease.

Noncommunicable disease

A disease that cannot be transmitted from host to host.

Infestation

Colonization of a host by parasites, especially ectoparasites.

Control measures

Strategies implemented to prevent and reduce infections.

Virulence factors

Characteristics or structures that enhance a microbe's ability to cause disease.

Natural immunity

Immunity one has from birth.

Artificial immunity

Immunity gained through vaccines or infections.

Active immunity

Immunity that develops after exposure to an infection.

Passive immunity

Short-term immunity provided through antibodies.

Clostridioides difficile

A bacterium that causes gastrointestinal infections and is a common cause of HAIs.

Staphylococcus aureus

A common bacterium associated with various infections and HAIs.

Klebsiella species

Bacteria known for causing UTIs and resistant to many antibiotics.

Escherichia coli

Bacteria that are common in the intestines and can cause opportunistic infections.

Enterococcus species

Bacteria associated with HAIs, especially in surgical sites.

Influenza

A contagious viral infection that affects the respiratory tract.

Measles

Highly contagious viral disease characterized by rash.

Rabies

A viral disease transmitted from animals to humans via bites.

West Nile virus

A viral infection spread by mosquitoes that can cause severe illness.

Mass vaccination

A strategy to protect populations from infectious diseases.

Epidemiologist

A professional who studies the distribution and determinants of health-related states.

Public health

The science of protecting and improving the health of communities.

Infection control

Practices to minimize incidence of infection, especially in healthcare settings.

Pathogen transmission

The process by which infections are spread from one host to another.

Contagion

The communication of disease from one person to another.

Epidemiological surveillance

Ongoing systematic collection and analysis of health data.

Outbreak investigation

The process of identifying and containing an increase in disease cases.

Clinical features

Signs and symptoms associated with a disease.

Cohort study

A study that follows a group of people over time to see how many get a disease.