Transmission of Infection, the Compromised Host, Epidemiology, and Diagnosing Infections

Vocabulary flashcards covering transmission of infection, pathogen reservoirs, vector mechanisms, host compromise, epidemiology concepts, and diagnostic techniques from Chapter 6.

Pathogen Reservoirs

Places where infectious organisms can grow and accumulate.

Mechanisms of Transmission

The various ways in which pathogens move from place to place.

Carriers of Infections

Individuals who do not show symptoms of infection but remain infectious.

Zoonotic Diseases

Diseases transferred from animals to humans, usually transmitted through direct contact, indirect contact with waste, fur, or infected meats, or via vectors.

Direct Contact Transmission

Pathogen transfer where there is no intermediary between infected and uninfected individuals, including touching, kissing, and sexual interactions.

Fomites

Nonliving intermediates, such as handkerchiefs, towels, bedding, or contaminated needles, that act as agents of indirect contact transmission.

Droplet Transmission

Transfer of respiratory disease pathogens over short distances via sneezing, coughing, or laughing in airborne fluid droplets.

Vehicle Transmission

Pathogen transmission involving nonliving mediums such as air, food, water, blood, bodily fluids, or intravenous fluids.

Mechanical Vector Transmission

Mode of vector transmission where pathogens reside on the vector's body parts and are passively brushed off onto a host.

Biological Transmission

Mode of vector transmission where pathogens reside within the vector and are transmitted to the host through a bite.

Portals of Exit

Specific sites through which pathogens exit a host, usually via bodily secretions such as saliva, sputum, respiratory droplets, blood, urine, feces, or genital secretions.

Immunocompetence

The ability of a host's immune system to mount a functional defense against infection.

Neutropenia

A condition characterized by lower-than-normal numbers of neutrophils in the blood, reducing primary phagocytic defense.

Opportunistic Pathogens

Microorganisms that are normal flora but cause disease when moved to non-native body sites or when normal flora balance is disrupted.

Nosocomial Infections

Any infection acquired by a patient or health care worker within a hospital or medical facility.

Epidemiology

The study of the factors and mechanisms involved in the frequency and spread of disease and health-related problems.

Incidence

The number of new cases of a disease in a set population over a specific period.

Prevalence

The total number of individuals infected with a specific disease within a population at any given time.

Morbidity Rate

The number of individuals affected by a disease during a set period divided by the total population number.

Mortality Rate

The number of deaths due to a specific disease divided by the total population number.

Sporadic Disease

A disease that occurs in a random manner and poses a low threat to public health.

Endemic Disease

A disease that is constantly present in a specific population in low numbers.

Epidemic

A disease occurrence where the incidence suddenly becomes higher than expected within a population.

Pandemic

A global epidemic affecting widespread human populations across multiple countries or continents.

Common Source Outbreak

An epidemic arising from contact with contaminated substances, affecting a large number of people quickly and subsiding once the source is resolved.

Propagated Epidemic

An epidemic amplified by person-to-person contact that remains in the population for a long time and is difficult to control.

Herd Immunity

Protection conferred to a population when the majority is immune to an infection through vaccination or exposure, preventing disease spread due to lack of susceptible hosts.

Descriptive Epidemiological Study

A study concerned with physical aspects of patients and disease spread, recording case counts, affected population segments, location, age, race, and occupation to identify the first case.

Analytical Epidemiological Study

An epidemiological study focusing on establishing cause-and-effect relationships using a control group.

Diagnostic Specificity

The ability of a diagnostic assay to identify a specific pathogen reliably and correctly.

Diagnostic Sensitivity

The ability of a diagnostic test to detect very small amounts of a pathogen or host antibodies.

Selective Media

Growth media designed to suppress the growth of unwanted organisms in mixed clinical samples.

Elective Media

Growth media formulated specifically to support the growth of an organism of interest.

Differential Media

Growth media that demonstrate visible differences between different organisms growing in mixed samples.

Gruber Reaction

A direct serological assay that uses a known antibody to detect or identify an unknown antigen in a patient sample.

Widal Reaction

An indirect serological assay that uses a known antigen to detect an unknown antibody in a patient sample.

Clone Cell

The single cell from which an identical population of monoclonal antibodies is generated.

Monoclonal Antibodies

Antibodies derived from a single clone cell that possess identical binding specificity and affinity.

ELISA (Enzyme-Linked Immunosorbent Assay)

A serological immunoassay performed in microtiter plate wells where antigen-antibody binding is detected using enzyme-conjugated antibodies.

Lateral Flow Assay (LFA)

A point-of-care dipstick immunoassay where capillary action pulls liquid samples through a matrix containing labeled antibodies to capture target antigens at test lines.

Proteomics

The large-scale analysis of all proteins expressed and modified in a cell and their functional interactions within the host organism.