Microbe-Human Interactions (copy)

Microbiota

The community of microorganisms living in or on the human body.

Resident microbiota

Established microorganisms that regularly inhabit specific regions of the body and do not normally cause disease.

Transient microbiota

Temporary microorganisms that influence or change due to environmental factors, diet, and lifestyle.

Pathogenic microbes

Microorganisms capable of penetrating host defenses and causing disease.

Infection

The invasion and disruption of host tissues by pathogens.

Etiology

The specific cause or origin of a disease.

Pathogen

Any microbe capable of causing disease.

Normal microbiota

Microbes that colonize the human body beginning at birth and influenced by interactions with the environment.

Human Microbiome Project

A research initiative aimed at sequencing the complete biota present in humans.

Primary pathogens

Microbes that cause disease in healthy individuals with normal immune function.

Opportunistic pathogens

Microbes that cause disease only when host defenses are compromised.

Virulence

The degree of pathogenicity of a microbe.

Virulence factors

Characteristics that enhance a microbe’s ability to cause disease.

Infectious dose (ID50)

The number of microorganisms required to infect 50% of a test population.

Lethal dose (LD50)

The number of organisms necessary to cause death in 50% of an inoculated group.

Microbial antagonism

The prevention of harmful microorganism overgrowth by normal microbiota.

Incubation period

The time interval from initial infection to appearance of the first symptoms.

Prodromal period

The phase marked by initial vague symptoms signaling the onset of illness.

Convalescent stage

The recovery phase where symptoms lessen, and the individual begins to regain health.

Reservoir

The natural habitat from which a pathogen originates, which can be living or non-living.

Carrier

An individual or object that transmits infection without showing symptoms.

Horizontal transmission

Spread of infection between individuals through direct or indirect contact.

Vertical transmission

Transmission of pathogens from parent to offspring during pregnancy, childbirth, or breastfeeding.

Zoonotic diseases

Infections transmitted from animals to humans.

Emerging infectious diseases (EIDs)

Newly identified infectious diseases that pose global health challenges.

Epidemiology

The study of the distribution and determinants of health-related states and events in specified populations.

Prevalence

The total number of existing cases of a disease in a population at a given time.

Incidence

The number of new disease cases that occur during a specified time period.

Mortality rate

The frequency of deaths within a specified population due to a disease.

Localized infection

Infection confined to a specific area of the body.

Systemic infection

Infection that spreads throughout the body, affecting multiple organ systems.

Focal infection

An initially localized infection that spreads to other tissues.

Primary infection

The first infection in a course of disease.

Secondary infection

An infection that occurs following a primary infection.

Signs

Observable and measurable changes in the body.

Symptoms

Subjective feelings experienced by the patient, not directly measurable.

Asymptomatic infection

Infection without noticeable symptoms in the host.

Latent infection

A dormant infection that can reactivate under certain conditions.

Attachment of pathogens

The use of specialized structures by pathogens to adhere effectively to host tissues.

Exiting pathogens

Methods through which pathogens leave the host, including respiratory secretions, blood, and feces.

Microbial communities

Diverse populations of microorganisms that play critical roles in health and disease.